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The Capture and Culture of Post-Larval Fish and Invertebrates for the Marine Ornamental Trade
Abstract
Governments, non-government organizations, and other stakeholders are striving to develop practices, policies, and vehicles to make the tropical marine ornamental trade sustainable. Small-scale fisheries based on post-larval capture and culture (PCC) promise to contribute to this goal by (1) removing the risk of damaging corals (inherent in harvesting adults of target species established on reefs) by collecting post-larvae with light traps, nets, and purpose-built temporary shelters as they settle from the plankton to the substrate; and (2) translating the high mortality of post-larvae at settlement into high rates of survival in culture. Possible concerns about overfishing of post-larvae, harvesting the juveniles after they have run the gauntlet of predation at settlement, and the large proportion of bycatch can be eliminated or greatly alleviated by restricting the size and quantity of fishing gear, designing it to retain bycatch alive, and releasing bycatch at times and places that minimize predation. However, special caution is needed when PCC is used at small, isolated islands with self-replenishing populations. Although PCC is environmentally friendly, its contribution to the ornamental trade is expected to be limited. Large variation in the abundance and species composition of settling post-larvae among years, the logistics and costs of operating labor-intensive operations in remote locations, and competition with responsible enterprises harvesting wild adults or producing ornamentals in hatcheries are expected to constrain the viability and market share of dedicated PCC enterprises. PCC is expected to have the greatest uptake by part-time artisanal fishers in developing countries with infrastructure for exporting marine ornamentals. Such fishers are more immune to temporal variation in the supply of post-larvae—they can engage in PCC when valuable post-larvae are abundant and switch to other sources of income when they are scarce. Livelihood opportunities for smallholders could be enhanced through promotion of the environmental benefits of PCC among hobbyists maintaining marine ornamentals.
... The installation of artificial habitats with ecologically-engineered elements has been widely advocated and implemented for replacement of lost or degraded natural habitat, ecological conservation, biodiversity enhancement, and improvement of ecosystem services [11][12][13][14]. Specific goals of artificial habitats may include supporting local biodiversity and communities of fish or invertebrates of commercial or ecological interest [12,[15][16][17][18][19], building ecosystem resilience, and enhancing ecological connectivity [4,[20][21][22]. ...
... The examination of post-installation monitoring data found that artificial habitats (Dock Biohut) hosted taxonomically diverse assemblages of invertebrate species, including molluscs, crustaceans, and echinoids of ecological, commercial, and social interest. Our analysis aims to complement the already-existing studies focused on the fish species associated with artificial habitats [17][18][19]22]. Communities develop and are structured over time, whereby pioneering species initially colonise areas, with the abundance and composition of colonising assemblages depending on interacting factors including habitat ...
... The examination of post-installation monitoring data found that artificial habitats (Dock Biohut) hosted taxonomically diverse assemblages of invertebrate species, including molluscs, crustaceans, and echinoids of ecological, commercial, and social interest. Our analysis aims to complement the already-existing studies focused on the fish species associated with artificial habitats [17][18][19]22]. Communities develop and are structured over time, whereby pioneering species initially colonise areas, with the abundance and composition of colonising assemblages depending on interacting factors including habitat size and connectivity, the proximity of source populations, local hydrodynamics, inter-annual temporal variation in larval supply, and competitive interactions with other species [20,27,[35][36][37]. ...
In highly modified coastal environments, such as commercial harbours, the installation of artificial habitats has garnered support as a means of enhancing local biological recruitment and connectivity. The success of these measures depends largely on the patterns of species colonisation. Using post-installation monitoring data, we compared the composition of assemblages of invertebrates colonising artificial habitats that were immersed for different periods (~6 vs. ~18 months) in three commercial harbours along the French Mediterranean coast. The artificial habitats were colonised by taxonomically diverse invertebrate assemblages of ecological and economic importance, including molluscs, crustaceans, and echinoids. Composition differed significantly with the immersion time of the artificial habitats, with total abundance, species richness, and evenness being significantly higher after ~18 than after ~6 months of immersion, indicating that long periods are necessary to enrich these new habitats with economically and ecologically important species. These results can inform restoration protocols and emphasise the value of post-installation monitoring programs.
... For example, while captured and cultured local wild post-larvae will have comparable gene frequencies to the wild stock (Munro and Bell, 1997;Hair et al., 2002), some risks remain due to minimized selective processes otherwise experienced during development in the wild, potentially allowing over-representation of certain genotypes compared to natural populations, overdomestication effects which may lead to reduced fitness in the wild, or conversely through selection of certain traits resilient to the trapping, transport and rearing processes associated with PCCR (Lorenzen et al., 2012). Wider ecological impacts include trophic impacts of removal of post-larvae as a valuable component of the food web, and issues of bycatch during post-larvae capture (Hair et al., 2002;Bell et al., 2009). Nonetheless, the capture and culture of wild-caught postlarvae to enhance fisheries has proven successful in several cases, and where done responsibly represents an exciting opportunity to enhance fishery production where local recruitment limitation may be driven by factors such as high mortality and advection of larvae, creating a disconnect between spawning grounds and suitable nursery habitat . ...
... Nonetheless, the capture and culture of wild-caught postlarvae to enhance fisheries has proven successful in several cases, and where done responsibly represents an exciting opportunity to enhance fishery production where local recruitment limitation may be driven by factors such as high mortality and advection of larvae, creating a disconnect between spawning grounds and suitable nursery habitat . Whilst most successful examples of PCCR are for marine invertebrate species (Sadovy de Mitcheson and Liu, 2008;Bell et al., 2009), including scallops in Japan (Uki, 2006), rock lobsters in Australia and spiny lobsters in Vietnam (Tuan et al., 2000), there is increasing interest in the expansion of PCCR techniques to finfish species, with recent examples for mullet in Egypt (Saleh, 2008), trials with reef-fishes in the Philippines (Lecaillon and Lourie, 2007), and for white seabream in the northwest Mediterranean (examined in detail in Tables 1-3). However, few studies have quantified the influence of PCCR on fishery yield, measured its economic benefits over other management approaches, or studied impacts on naturally recruited individuals in the enhanced stock (Lorenzen et al., 2010). ...
... milkfish, catfish, mullet, seabass, snapper) (Sadovy de Mitcheson and Liu, 2008). Identifying where, when, and how to catch abundant, healthy post-larvae is essential for viable PCCR operations, and relies on an understanding of species-specific behavior and ecology, and the local gene frequency of the wild fishery stock to ensure genetic complementarity on release (Bell et al., 2006;Sadovy de Mitcheson and Liu, 2008;Bell et al., 2009). The arrival of settlement-stage coral reef fishes to shallow coastal waters typically occurs at night (Dufour and Galzin, 1993;Holbrook and Schmitt, 1997), but the temporal and spatial abundance of post-larvae can be highly variable (Bell et al., 2009). ...
Demand for marine fisheries is rising despite global impacts on the productive capacity of wild fish stocks due to overfishing, habitat loss, and global warming. Fisheries enhancement programs—aimed at augmenting stocks by releasing juveniles into the wild—are expected to play an increasingly important auxiliary role in addressing capture-based fishery limitations into the future. However, concerns exist over the impacts and efficacy of aquaculture-based enhancement (ABE), releasing captive-bred fish into wild populations. An alternative but understudied approach for fisheries enhancement is wild post-larvae capture, culture, and release (PCCR). Here, we provide an overview of the PCCR process, from initial planning to measuring success, providing an overview of its implementation in a viable finfish fishery, the white seabream Diplodus sargus in the Mediterranean. We discuss management application of PCCR-based enhancement and its limitations, highlighting existing knowledge gaps and future research required to realize the full potential of this alternative approach. Notwithstanding some limitations–including limited uptake for full evaluation, some species restrictions, density-dependent mortality, and the remaining open challenge for stock enhancement generally of tracking released fish through to reproduction–PCCR offers potential as a credible auxiliary management tool for fisheries restoration.
... The culture of marine ornamental species is commonly regarded as part of the solution of the marine aquarium trade sustainability issue but can accidentally also be the part of the problem. An example of this scenario is the harvest of wild postlarvae of fish and marine invertebrates for grow-out in captivity (Hair et al. 2004;Lecchini et al. 2006;Bell et al. 2009). The number and size of collected postlarvae, the by-catch of postlarvae from species with no value for the aquarium trade, and the effects of removing postlarvae from the ecosystem are some of the concerns expressed about the collection of marine ornamental species postlarvae (Bell et al. 2009). ...
... An example of this scenario is the harvest of wild postlarvae of fish and marine invertebrates for grow-out in captivity (Hair et al. 2004;Lecchini et al. 2006;Bell et al. 2009). The number and size of collected postlarvae, the by-catch of postlarvae from species with no value for the aquarium trade, and the effects of removing postlarvae from the ecosystem are some of the concerns expressed about the collection of marine ornamental species postlarvae (Bell et al. 2009). With the exception of small, isolated islands with limited postlarval recruitment, the responsible collection of postlarvae appears to be adequate for most locations and has insignificant negative impacts (Bell et al. 2009). ...
... The number and size of collected postlarvae, the by-catch of postlarvae from species with no value for the aquarium trade, and the effects of removing postlarvae from the ecosystem are some of the concerns expressed about the collection of marine ornamental species postlarvae (Bell et al. 2009). With the exception of small, isolated islands with limited postlarval recruitment, the responsible collection of postlarvae appears to be adequate for most locations and has insignificant negative impacts (Bell et al. 2009). The implementation of fishing strategies similar to those used for the collection of spiny lobster puerulus may be enough to reach "biological neutrality" (either by operating through a quota lease system and/or returning a number of juveniles to area of collection after grow-out in captivity to compensate for potential negative effects; Gardner et al. 2006). ...
The global trade of aquatic organisms for home and public aquariums, along with associated equipment and accessories, has become a multi-billion dollar industry. Aquaculture of marine ornamental species, still in its infancy, is recognized as a viable alternative to wild collection as it can supplement or replace the supply of wild caught specimens and potentially help recover natural populations through restocking.
This book collects into a single work the most up-to-date information currently available on the aquaculture of marine ornamental species. It includes the contributions of more than 50 leading scientists and experts on different topics relevant for the aquaculture of the most emblematic groups of organisms traded for reef aquariums. From clownfish, to angelfish, tangs and seahorses, as well as corals, anemones, shrimps, giant clams and several other reef organisms, all issues related with the husbandry, breeding, and trade are addressed, with explanatory schemes and illustrations being used to help in understanding the most complex topics addressed.
Marine Ornamental Species Aquaculture is a key reference for scientists and academics in research institutes and universities, public and private aquaria, as well as for hobbyists. Entrepreneurs will also find this book an important resource, as the culture of marine ornamental species is analyzed from a business oriented perspective, highlighting the risks and opportunities of commercial scale aquaculture of marine ornamentals.
... The culture of marine ornamental species is commonly regarded as part of the solution of the marine aquarium trade sustainability issue but can accidentally also be the part of the problem. An example of this scenario is the harvest of wild postlarvae of fish and marine invertebrates for grow-out in captivity (Hair et al. 2004;Lecchini et al. 2006;Bell et al. 2009). The number and size of collected postlarvae, the by-catch of postlarvae from species with no value for the aquarium trade, and the effects of removing postlarvae from the ecosystem are some of the concerns expressed about the collection of marine ornamental species postlarvae (Bell et al. 2009). ...
... An example of this scenario is the harvest of wild postlarvae of fish and marine invertebrates for grow-out in captivity (Hair et al. 2004;Lecchini et al. 2006;Bell et al. 2009). The number and size of collected postlarvae, the by-catch of postlarvae from species with no value for the aquarium trade, and the effects of removing postlarvae from the ecosystem are some of the concerns expressed about the collection of marine ornamental species postlarvae (Bell et al. 2009). With the exception of small, isolated islands with limited postlarval recruitment, the responsible collection of postlarvae appears to be adequate for most locations and has insignificant negative impacts (Bell et al. 2009). ...
... The number and size of collected postlarvae, the by-catch of postlarvae from species with no value for the aquarium trade, and the effects of removing postlarvae from the ecosystem are some of the concerns expressed about the collection of marine ornamental species postlarvae (Bell et al. 2009). With the exception of small, isolated islands with limited postlarval recruitment, the responsible collection of postlarvae appears to be adequate for most locations and has insignificant negative impacts (Bell et al. 2009). The implementation of fishing strategies similar to those used for the collection of spiny lobster puerulus may be enough to reach "biological neutrality" (either by operating through a quota lease system and/or returning a number of juveniles to area of collection after grow-out in captivity to compensate for potential negative effects; Gardner et al. 2006). ...
Syngnathids, particularly seahorses, have long fascinated humans. Surprisingly, their biology and ecology is still poorly known. That is probably one of the reasons why reared fishes of these species have only recently been introduced into the aquarium trade. Currently, rearing techniques are available for a dozen seahorse species and for a few ornamental pipefishes. Even though the morphology of all these species is rather similar, their biology and rearing requirements largely differ among species. As a result, the methodological procedures for cultivation must be studied and assessed explicitly for each species. Noteworthy survivals have been achieved for some species but there is a need for optimization of rearing techniques, and increased knowledge in many aspects including breeding, nutritional requirements and diseases. This chapter is focused on general aspects of the biology of seahorses and pipefishes and on current knowledge of their rearing techniques. Data sheets on the rearing requirements for selected seahorse and pipefish species are also provided, as well as for seadragons.
... Additional or supplementary management tools offer alternate solutions to restricting human access to resources, often by creating methods to enhance or diversify the livelihoods of people reliant on the reef. One such method is the implementation of early life history phase fisheries, or post-larval capture for culture (PCC) (Bell et al. 2009, Dufour 2002, Lecchini et al. 2006, Lourie & Lecaillon 2005, Ziemann 2001). This involves catching fishes when they are in the late-larval stage. ...
... The target species can, therefore, still be collected but with a reduced impact on the adult population. This can reduce the fishing pressure from individuals that have successfully recruited to the reef, leaving them to reproduce for future generations (Bell et al. 2009). For the marine aquarium trade, collection of the larval stage provides an alternative method to the more damaging techniques that are used to capture fish, such as cyanide fishing (Bell et al. 2009, Lourie & Lecaillon 2005, Dufour 2002). ...
... This can reduce the fishing pressure from individuals that have successfully recruited to the reef, leaving them to reproduce for future generations (Bell et al. 2009). For the marine aquarium trade, collection of the larval stage provides an alternative method to the more damaging techniques that are used to capture fish, such as cyanide fishing (Bell et al. 2009, Lourie & Lecaillon 2005, Dufour 2002). The main cause of mortality in fish that are collected for the marine aquarium trade, however, is not from capture itself but rather due to the failure of captured fish to feed on artificial aquarium food. ...
Coral reef fish larvae take an active role in selecting their settlement site and
sensory cues may help them to orientate during this process. As settlement is
a period of transition through which the majority of individuals do not survive,
it is often a focal point for the management of coral reef populations, which
are of high conservation concern. In this thesis, I used choice tests and in
situ techniques to assess the response of settlement-stage larvae to a range of
odour, light and acoustic cues and I found that larvae are more selective in
their response to sensory stimuli than previously thought. Micro-habitat odours
are not likely to be used during settlement orientation, and odour cues may be
used to avoid inappropriate settlement sites. The photopositive behaviour of
larval fish is likely to match their spectral sensitivity but this proved difficult to
assess in situ because of the high amount of spatial and temporal variation in
larval distribution. The positive response of settlement-stage fish to played back
reef noise is location specific as well as being highly specific to the reef sound
recording. To understand whether it might be the composition of reef sound that
drives the selective response of larvae to acoustic cues, I took sound recordings
while collecting visual data on fish diversity and the behavioural activity of
a sound producing, or soniferous, fish species. I found that the variation in
intensity of reef noise matches the activity patterns of a soniferous species, and
when reef noise is most intense is when visual estimates on the diversity of
the reef fish assemblage are decreased. This information provides the basis for
understanding how changes in the reef soundscape may effect larval recruitment
and has exciting implications for using sound recordings as a method to monitor
coral reefs. Finally, I tested the viability of releasing reared larvae to boost
depleted populations and found that collecting and holding settlement-stage fish
for a week can increase survival, relative to natural settlement. These data
demonstrate that applying our knowledge of the settlement behaviour of coral
reef fish will make a significant contribution to developing tools for management.
... The culture of marine ornamental species is commonly regarded as part of the solution of the marine aquarium trade sustainability issue but can accidentally also be the part of the problem. An example of this scenario is the harvest of wild postlarvae of fish and marine invertebrates for grow-out in captivity (Hair et al. 2004;Lecchini et al. 2006;Bell et al. 2009). The number and size of collected postlarvae, the by-catch of postlarvae from species with no value for the aquarium trade, and the effects of removing postlarvae from the ecosystem are some of the concerns expressed about the collection of marine ornamental species postlarvae (Bell et al. 2009). ...
... An example of this scenario is the harvest of wild postlarvae of fish and marine invertebrates for grow-out in captivity (Hair et al. 2004;Lecchini et al. 2006;Bell et al. 2009). The number and size of collected postlarvae, the by-catch of postlarvae from species with no value for the aquarium trade, and the effects of removing postlarvae from the ecosystem are some of the concerns expressed about the collection of marine ornamental species postlarvae (Bell et al. 2009). With the exception of small, isolated islands with limited postlarval recruitment, the responsible collection of postlarvae appears to be adequate for most locations and has insignificant negative impacts (Bell et al. 2009). ...
... The number and size of collected postlarvae, the by-catch of postlarvae from species with no value for the aquarium trade, and the effects of removing postlarvae from the ecosystem are some of the concerns expressed about the collection of marine ornamental species postlarvae (Bell et al. 2009). With the exception of small, isolated islands with limited postlarval recruitment, the responsible collection of postlarvae appears to be adequate for most locations and has insignificant negative impacts (Bell et al. 2009). The implementation of fishing strategies similar to those used for the collection of spiny lobster puerulus may be enough to reach "biological neutrality" (either by operating through a quota lease system and/or returning a number of juveniles to area of collection after grow-out in captivity to compensate for potential negative effects; Gardner et al. 2006). ...
With the increase in popularity of aquariums, marine ornamental fish play an extremely important role today in the international fish trade. The total value of the wholesale ornamental trade is estimated at close to US 3 billion. Many fish collectors in tropical and subtropical countries employ destructive fishing methods such as cyanide and dynamite to stun fish, making it easier to collect them, but can also harm the delicate coral reefs and alter marine ecosystems. In addition, these practices threaten the food sources of local populations. The present chapter consists of an overview of data on breeding and rearing protocols for some high value marine ornamental species. Details on spawning, embryo development, hatching, feeding, plankton culture, and tank design are presented with particular emphasis on their application for the included species. For most of these species the reproductive cycle has been closed but, for others, further research is necessary. In addition, much effort is still needed to increase early survival rates in order to produce these species in commercial numbers. The main goal of this chapter is to provide a valid source of updated scientific data on marine ornamental fish production as well as a starting point for the development of marine ornamental aquaculture, which could play a role in coral reef preservation.
... Several governments, non-government organizations and other stakeholders in the South Pacific are striving to develop practices and policies to make the tropical marine ornamental trade sustainable. Small-scale fisheries based on larval capture and culture (PCC) promise to contribute to this goal by collecting larvae with light traps or crest nets (Lecchini et al. 2006, Bell et al. 2009). Indeed, as fish larvae stock is numerically more impor-s fish larvae stock is numerically more important than adult stock, and as catches of aquarium fish are based upon a number of individuals (and less on biomass or size), it is preferable to encourage fishing pressure on larvae stock and rear them with aquaculture methods to increase their survival (Bell et al. 2009 (1) of fish larvae disappear before adult age (e.g. ...
... Small-scale fisheries based on larval capture and culture (PCC) promise to contribute to this goal by collecting larvae with light traps or crest nets (Lecchini et al. 2006, Bell et al. 2009). Indeed, as fish larvae stock is numerically more impor-s fish larvae stock is numerically more important than adult stock, and as catches of aquarium fish are based upon a number of individuals (and less on biomass or size), it is preferable to encourage fishing pressure on larvae stock and rear them with aquaculture methods to increase their survival (Bell et al. 2009 (1) of fish larvae disappear before adult age (e.g. Doherty et al. 2004, Lecchini et al. 2007). ...
... Doherty et al. 2004, Lecchini et al. 2007). The adult breeding stock would be thus preserved and the recruitment rate would be the exploitable theoretical limit not to be exceeded for overfishing (Bell et al. 2009). Thus, the high potential capture of some endemic fish species at larval stage in the Marquesan Islands could constitute a new product in terms of species, sizes and quality of ornamental fish on the international aquarium market. ...
This preliminary study explored the capture potential of the Marquesan Islands for fish larvae, especially endemic species, with the set up of light traps on either offshore site or coastal site between January and March 2012. Among the 323 fish larvae belonging to 29 captured species, 151 fish larvae belonging to five species were endemic. Light traps captured more endemic larvae in coastal site than in offshore sites. Overall, this study allows to better understand larval supply of endemic fish species in an isolated region such as the Marquesan Islands.
... Eggs, larvae, and even postlarvae of marine animals are usually considered nonexploitable marine resources, as opposed to juveniles and/or adults, which are actively harvested. However, it is now fully accepted that, given the very large number of postlarvae arriving from the ocean, collecting a small percentage of them has a negligible impact which is also limited in time (Bell et al., 2009). ...
... An alternative but understudied approach to the release of farmed juveniles is the harvesting and rearing of wild pelagic postlarvae for release as juveniles (Postlarval Capture, Culture, and Release; PCCR), sometimes termed capture-based enhancement (Bell et al., 2009;Hair et al., 2002). By catching and keeping wild postlarvae until they have reached a size refuge from predation, PCCR-based enhancement aims to mitigate concerns over the negative genetic impacts of releasing cultured hatchery-seed and offers a potentially lower cost, and more genetically diverse source of juveniles better adapted to natural conditions (Bartley and Bell, 2008;Hair et al., 2002). ...
Fish habitat restoration has long been carried out with the aim of enhancing fish populations to support fisheries. Seagrass beds have been protected and restored in many countries because they are known to provide essential ecosystem services, including relevant support for fisheries. Other physical habitats, such as natural shellfish reefs, have been damaged by human activities and need to be restored. An overview is given of the different techniques used to restore marine fish habitats and populations. Beyond the regulatory aspects, which can be seen as the first step in protecting essential habitats and populations, this chapter provides concrete examples of restoration actions that can help maintain communities, preserve biodiversity and ensure the continued exploitation of target species. While it is not possible to compensate for all the environmental damage that has led to the decline of certain species, it is possible to limit the impact and contribute to the restoration of ecological functions by acting in favor of the species concerned.
Although the success of restoration interventions depends on many factors, experience show that once a habitat is restored, fish fauna and ecological status recover rapidly. The implementation of restoration plans is expected to lead to the recovery of the fish directly and indirectly associated with the habitat, thus promoting the conservation of fish biodiversity and the management of fishery resources.
... Eggs, larvae, and even postlarvae of marine animals are usually considered nonexploitable marine resources, as opposed to juveniles and/or adults, which are actively harvested. However, it is now fully accepted that, given the very large number of postlarvae arriving from the ocean, collecting a small percentage of them has a negligible impact which is also limited in time (Bell et al., 2009). ...
... An alternative but understudied approach to the release of farmed juveniles is the harvesting and rearing of wild pelagic postlarvae for release as juveniles (Postlarval Capture, Culture, and Release; PCCR), sometimes termed capture-based enhancement (Bell et al., 2009;Hair et al., 2002). By catching and keeping wild postlarvae until they have reached a size refuge from predation, PCCR-based enhancement aims to mitigate concerns over the negative genetic impacts of releasing cultured hatchery-seed and offers a potentially lower cost, and more genetically diverse source of juveniles better adapted to natural conditions (Bartley and Bell, 2008;Hair et al., 2002). ...
... Additionally, post-larval rearing enhances future acclimatisation because fishes will then be accustomed to artificial food (Lecchini et al. 2006). However, Bell et al. (2009) note that while post-larval capture and culture can benefit smaller scale or artisanal enterprises near export hubs, its commercial viability is reduced by the huge and often unpredictable fluctuations in available species and quantities within a given locale, leading to mismatches of supply and demand. There is also a risk to isolated island fish communities dependant on local replenishment rather than pelagic dispersal. ...
... Despite detailed analyses of some small subsections of the domain such as Indonesia (Reksodihardjo-Lilley and Lilley 2007) and post-capture culture (Bell et al. 2009), recent analyses of the whole domain have either focused on single strategies such as consumer advocacy (Livengood and Chapman 2010), or have been restricted to a minimalist expert consensus position (Tissot et al. 2010). This review is intended as a comprehensive, yet succinct, review of the domain, in the expectation that a comprehensive ontology and DPSIR framework will allow for better recommendations to emerge. ...
About 27 million tropical marine ornamental fishes are traded each year. Of these, 80% come from Indonesia, the Philippines, the United States, and Sri Lanka. Over 80% go to North America, the European Economic Area, Switzerland and Japan. The trade depends on wild capture, but is becoming increasingly supplemented by aquaculture-produced ornamental species. The trade has impacts on three core areas:
1) habitat integrity and biodiversity of tropical marine ecosystems (sustainability), including the genetic diversity within individual species; 2) development of coastal communities related to practice safety, economic sustainability, food security, and trade fairness (equity); and 3) mortality, morbidity and husbandry of the fishes being cultivated and traded (welfare). There are numerous solutions to identified problems, but efforts to date have focused predominantly on voluntary certification or legislation. However, problems have not been adequately defined, and solutions have not been sufficiently explored to be confident about all policy recommendations or decisions. New analytical tools yet to be used include topic mapping and the DPSIR (driving forces, pressures, states, impacts and responses) framework. This review is an attempt to provide a comprehensive update on the trade and to suggest new ways forward, with an emphasis on the Pacific Ocean region for production, and the United Kingdom for consumption.
... This postlarval phase continues to be studied to understand the settlement processes (Dufour, 1994;Hendriks et al., 2001;McCormick et al., 2002;Lecaillon, 2017). Several studies have used settlement stage reef fishes to realize small-scale fisheries based on postlarval capture and culture (Bell et al., 2009). This method has also been integrated into experimental protocols as a potential tool for restoration of fish assemblages as a proof-of-concept (Heenan et al., 2009;Abelson et al., 2016). ...
... The results obtained are very promising in terms of species richness, diversity, abundance, and CPUE as well as an innovative way to drive restoration of coral reef services and functions. This sampling method provides the benefit of increasing the productivity of target species, for example, commercial and herbivorous fishes (Bell et al., 2009). These efforts can contribute to identifying settlement areas for reef fish, biodiversity monitoring (McLeod and Costello, 2017), managing of MPAs , and supporting fisheries control through research and social engagement (Hein et al., 2020;Cortés-Useche et al., 2021). ...
The changing world presents negative impacts on marine ecosystems and has led to the development of diversified tools to support reef restoration. Harnessing restoration to achieve success needs innovative techniques that also address the restoration of reef fish assemblages, contributing to the conservation of biodiversity and ecosystem functions and also tackle the cost-effectiveness through impact-driven solutions. Here, we propose a proof-of-concept for enhancing fish populations on reefs using: (1) postlarvae capture, (2) aquarium culture, and (3) release to reef sites. We conducted field studies in the Mexican Caribbean to analyze for the first time, the possibility of using the capture and aquarium culture of postlarvae fish species and release of juveniles as a tool for the potential recovery of reef biodiversity resilience. We tested the potential of postlarvae capture using two distinct night light traps (BOX and collect by artificial reef ecofriendly traps, C.A.R.E.) in three sampling sites with different distances from shoreline and depth. We collected 748 postlarvae reef fishes from eight orders, 20 families, and 40 species. Acanthuridae, Pomacentridae, Monacanthidae, and Tetraodontidae comprised the highest species number of postlarvae families. We also set up a pilot release experiment with Stegastes partitus using two trials (32 and 1 day after capture) and propose analysis to determine appropriate reef sites to release the cultured juveniles and to aid ecological planning. We present the results of the pilot release experiment with S. partitus, showing that there is a positive effect in survivorship during the capture (80%) and release (76–100%) procedures into suitable habitat and good chance that more studies will bring novelty to the field. Although trials carried out with more species relevant to restoration will be needed. The use of these techniques can be a great opportunity to improve the research of restoration efforts in the Caribbean region with fish-depleted coral reefs with vulnerable food webs, especially at local scales and supporting other management strategies.
... French Polynesia is in a fairly good position regarding its future food security through its access to marine resources (Bell et al., 2013;Bell, Clua, Hair, Galzin, & Doherty, 2009;Bell, Johnson, & Hobday, 2011). Resource exploitation and tourism is dependent on transport infrastructure. ...
... In the last 15 years, they have focused on reef fisheries in Moorea (Yonger, 2002), and in the frame of the PROCFISH program Mataiea (in Tahiti), Maatea (in Moorea), Fakarava, Tikehau, and Raivavae (Kronen et al., 2008). They concluded that French Polynesia on average has one of the highest consumption of fish per capita in the Pacific with 70.3 kg yr −1 , with 72% of this volume obtained by subsistence fishing, and 28% by purchase (Bell, Clua, et al., 2009). Moorea is the most studied eco-socio-system, with the most recent studies applying a spatial approach which is also applied in the context of giant clam fishery management in Tuamotu atolls (Thiault, Collin, Chlous, Gelcich, & Claudet, 2017;Van Wynsberge, Andréfouët, Gaertner-Mazouni, & Remoissenet, 2015). ...
... French Polynesia is in a fairly good position regarding its future food security through its access to marine resources (Bell et al., 2013;Bell, Clua, Hair, Galzin, & Doherty, 2009;Bell, Johnson, & Hobday, 2011). Resource exploitation and tourism is dependent on transport infrastructure. ...
... In the last 15 years, they have focused on reef fisheries in Moorea (Yonger, 2002), and in the frame of the PROCFISH program Mataiea (in Tahiti), Maatea (in Moorea), Fakarava, Tikehau, and Raivavae (Kronen et al., 2008). They concluded that French Polynesia on average has one of the highest consumption of fish per capita in the Pacific with 70.3 kg yr −1 , with 72% of this volume obtained by subsistence fishing, and 28% by purchase (Bell, Clua, et al., 2009). Moorea is the most studied eco-socio-system, with the most recent studies applying a spatial approach which is also applied in the context of giant clam fishery management in Tuamotu atolls (Thiault, Collin, Chlous, Gelcich, & Claudet, 2017;Van Wynsberge, Andréfouët, Gaertner-Mazouni, & Remoissenet, 2015). ...
... Today it is fully accepted that, given the very large number of post-larvae arriving from the ocean, collecting a small percentage of them has a negligible impact, which is also limited in time (Bell et al., 1999(Bell et al., , 2009). Thus PCC can effectively exploit a resource that would otherwise be largely and naturally wiped out (Lecaillon, 2004;Lecaillon & Lourié 2007). ...
... The various inexpensive PCC tools and the different steps required to reach saleable size (sorting, rearing, etc.) are described in various papers (Bell et al., 1999(Bell et al., , 2009 Lecaillon, 2004;Hair & Doherty, 2003;Lecaillon & Lourié, 2007) and are not detailed here. However, PCC technology involves the following major steps: (1) overnight catching of live, healthy and uninjured post-larval fish or crustaceans; (2) identifying and segregating/sorting species which could harm or consume one another; and (3) weaning and growing the fish to a saleable size (average of 3 months). ...
Post-larval capture and culture (PCC) is a sustainable technique whereby post-larval (PL) fish are collected from plankton in the open ocean without physically impacting the marine environment. Wild reef fish undergo extremely high natural mortality (>95%) during reef colonization and settlement as they transition from the planktonic to the juvenile phase of their life cycle. Post-larval capture collects a tiny proportion of post-larvae prior to this high natural mortality event, impacting minimally on overall plankton biomass. Post-larval culture rears and conditions captured post-larvae into healthy, superbly conditioned fish with a high survival rate. Thus PCC not only reduces environmental and human impacts of devastating wild fish collection methods, it also produces first-class specimens for aquarium hobbyists, a win-win situation for all concerned. Nevertheless, even after a decade of development, PCC is not yet widely implemented. The reasons are many but often unrelated to the technique itself.
... explosivos, cianuro, pesca de arrastre), generando grandes impactos en el ecosistema y daños a la salud de los organismos objetivo de la captura (Bell et al., 2009;Reynoso-Lango et al., 2012). ...
Seahorses (genus Hippocampus) are highly endangered, vulnerable species. Aquaculture has been propose as part of the mitigation strategies to address the overexploitation of these species. One of the main difficulties in farming ornamental marine species is the lack of information in the early stages of life, which leads to poor performance and consequently high mortality rates. That is why the general objective of this work is to describe the attachment behavior of early juvenile Hippocampus ingens at different times of the day, different times related to feeding and with different stocking densities. A series of observations were made to quantify attachment behavior by recording the number of animals suspended in the water column and attached to the substrate or to each other. Three factors were evaluated: time of day, density and times associated with feeding. The observations of the moment of the day were taken in 4 moments (morning, noon, afternoon and night), and those associated with feeding in 3 (before, during and after). Two culture densities (8 and 16 ind l−1) in two stages of ontogenic development (Phase I or critical, and Phase II or intermediate) were taken into account. The results showed that H. ingens juveniles have the ability to attach a few days after birth, however, most of the time they are suspended in the water column. They are diurnal animals, presenting their peak of activity around noon, and in the twilight hours their activity decreases until it is practically null, it is in these hours where the largest proportion of seahorses attached to the substrate are found. The presence of food did not modify their attachment behavior, but their swimming was more active when searching for food. Culture density did not affect their attachment behavior either, however it negatively affected survival. There were no significant differences between both stages of ontogenetic development evaluated.
... • determining the size, distribution and genetic variability of existing stocks (see Montalvo et al., 1997); • determination of the type and form of aquaculture adapted to the needs of the local context (e.g. production/collection of postlarvae, juveniles, adults; hatchery, ponds, cages; low or high technology/intensification (Bell et al., 2009;Gilles et al., 2013;Tidwell, 2012) and inadequacy with the retention of genetic variability (if released into the wild), respect of biosafety and biosecurity policies (Hughes et al., 2008;Scarfe et al., 2006); • a deep understanding of the biology/ecophysiology of red-tailed goby for reproduction; • determination of potential bottleneck in production (e.g. larval feeding, mortalities); • cost and production time optimization (e.g. ...
Sicydiinae species are amphidromous gobies, adults spawn in freshwater, whereas free embryos undergo a pelagic open sea phase. Post‐larvae or juveniles are caught for human consumption when entering in freshwater after their pelagic larvae life in seawater. Such goby‐fry fisheries are existing since centuries and widespread in tropical areas over the world. There are uncertainties related to caught volumes and trends but, overall, go‐fry fisheries are declining and their sustainability is questionable. Aquaculture is a potential tool in conservation and management of wild goby stocks. Among Sicydiinae species, the red‐tailed goby Sicyopterus lagocephalus is the most spread and used as a model species in numerous works involving amphidromous fish. The aim of the study was to evaluate the potential in aquaculture of the red‐tailed goby through the analysis of the literature available on this species. We found that this species has some assets to be a potential candidate for aquaculture such as a short production cycle and a high fecundity as well as potential high market values. Nevertheless, given the small size at hatching and the long pelagic larval life, larval rearing is likely to be a challenging rearing phase but appears to be feasible based on past experiences with other goby species. Throughout the paper, we provided recommendations for future research in red‐tailed goby aquaculture.
... This systematic review aimed to locate and analyse available quantitative data on the trade in marine ornamental fishes. Given historical reports, there was an expectation that data will be lacking-a state of affairs that has been lamented by scientists and conservationists for decades [5,8,10,11,[20][21][22][23][24]. This study further aims to document where possible the global scale of the industry by region and country, while identifying any major knowledge deficits. ...
The multi-billion dollar trade in ornamental fishes has rarely been reliably monitored. Almost all coral reef fishes are wild-caught, and few scientific analyses have attempted to elicit exact quantities and identify species involved. The consequences of the removal of millions of these fishes are poorly understood. This article collates and examines available information, including scientific studies and formal publications, in order to create a more accurate picture of this commerce. We demonstrate that it is almost impossible to analyse the trade in marine ornamental fishes due to a lack of data, and that available data for marine species is frequently combined with that for freshwater species. Figures range from 15 to 30 million coral reef fishes being traded annually, but could be as high as 150 million specimens. The global value of this trade was only estimated for 1976 and 1999 between USD 28–40 million. This review highlights the urgent need to introduce a specific harmonised system tariff code and for a global monitoring system, such as the Trade Control and Expert System already in use in Europe, in order to gather accurate and timely information on the number and species of marine ornamental fishes in commerce, where specimens originated, and whether they were wild-caught or captive-bred.
... For this reason, researchers focussing on the exploitation of marine resources have proposed some suggestions on how to improve the sustainability of many harvested species, especially those not listed in the Convention on the International Trade in Endangered Species (CITES, www.cites.org), for example on the collecting of coral fish larvae in the wild for subsequent culture and stocking in aquaria as ornamentals (Bell et al. 2009;Lucas and Southgate 2019). The improvement of breeding in captivity is also highlighted but it is still only feasible for a few species due to a lack of proper methods and technologies (Tlusty 2002;Olivotto et al. 2011). ...
The pet trade in aquatic organisms is a significant source of non-indigenous species introductions. In comparison with ornamental animals, unintentionally transported invertebrate assemblages are easily overlooked by traders and keepers. Moreover, hitchhiking species detection and identification is difficult even for experts. The densities of "hitchhikers" in aquaria may be relatively higher than those in the wild. These phenomena are known in freshwater aquaria but poorly studied in marine ones. We found 17 species of non-ornamental marine invertebrates in one of the leading importers of aquarium species in the Czech Republic in November 2017. The set comprised six gastropods, two bivalves, three cnidarians, two echinoderms, two crustaceans, and two polychaete worms. In one case, a symbiont was also detected, associated with the host "hitchhiker". No "live rocks" are traded by the surveyed wholesaler. Thus, the found animals were not imported together with this item as larvae or eggs. Contrary to the transport of targeted ornamental species, it is clear that transport of "hitchhikers" is occurring despite standard legislative regulations and should be brought to the attention of conservationists, wildlife managers, policymakers and other stakeholders.
... Les stocks de civelles et de poutine ont drastiquement chuté au cours du XXe siècle (Feunteun 2002), de même que les stocks de gobies amphidromes ont manifestement chuté en régions tropicales (Bell et al., 2009). Manacop écrivait déjà en 1953, « qu'un déclin continu est observé » faisant référence à la pêche des « ipon » aux Philippines. ...
Les enjeux liés à la conservation des gobies amphidromes à La Réunion, sont de nature écologique mais également socio-économique. Les deux espèces concernées, Sicyopterus lagocephalus et Cotylopus acutipinnis contribuent fortement à la diversité faunistique des rivières, en plus d’être la cible d’une pêche traditionnelle à forte valeur économique et patrimoniale. La pêche des « bichiques » fait localement référence aux deux espèces que l’on capture à l’état de post-larve lorsqu’elles entament leur recrutement dans les rivières. Dans un contexte où l’affaiblissement du recrutement larvaire est manifeste, cette thèse s’attache à décrire les enjeux qui gravitent autour de cette ressource, à travers l’étude de la variabilité du recrutement et de ses répercussions sur le socio-écosystème. Les résultats s’appuient sur la collecte de données écologiques et la réalisation d’une enquête auprès des acteurs de la pêche, entre octobre 2014 et février 2016. L’étude de la variabilité spatio-temporelle des traits d’histoire de vie des post-larves au recrutement révèle que les rivières de l’est, pourraient être des « secteurs sources » essentiels au maintien des populations de Gobbidae. L’analyse des entretiens révèle que la pêche depuis qu’elle s’est organisée en filière informelle, a fortement contribué à l’affaiblissement du recrutement et s’enlise désormais dans des conflits pour le partage de l’eau et de la ressource, au détriment de l’environnement et des pratiques traditionnelles. Les services de l’Etat qui ont entamé une démarche de régularisation de l’activité depuis 2012, sont dans un processus de coopération avec les pêcheurs qui se voit menacé par le braconnage. L’analyse croisée des connaissances acquises dans les deux volets de cette thèse, nous a permis de schématiser le socio-écosystème dans lequel s’insère le bichique et de communiquer sur le besoin de gérer les diverses pressions anthropiques à l’échelle des bassins versants, afin de préserver la fourniture durable de services écosystémiques dont dépend l’Homme.
... A vast array of literature exists on the aquarium hobby, eliciting over 8,000 Google Scholar hits; however, it is primarily focused on understanding the aquarium industry's effects on the environment at both ends of its supply chain. For example, there are numerous studies on the impacts of removing aquatic organisms from the wild (Parks et al., 2003;Jones et al., 2008), the impacts of aquaculture (Tlusty, 2002;Parks et al., 2003;Rhyne and Tlusty, 2012;Bush and Marschke, 2017;Duggan and Pullan, 2017;Lorenzen et al., 2017), and the capture and care of organisms (Wood, 2001;Jones et al., 2008;Bell et al., 2009;Militz et al., 2016). ...
In technology-driven societies, scientists, and educators alike flounder in making science interesting and applicable. Communicating science, defined as communicating scientific facts as well as teaching and using the scientific process, can also be done informally though leisure activities. In this qualitative study, I examined the leisure activity of aquarium keeping and its ability to communicate relative aquatic facts and processes. This study examined aquarium keepers across the United States via interviews, participant observation, and an ongoing analysis of aquarium hobby literature. Thus, this study indicates (1) caring for a home aquarium communicates science latently, (2) over time, latent science communication becomes activated, and (3) long-term aquarium keeping leads to a personal response in science, as well as conservation. In addition, artistic expression and innovation intersect with scientific knowledge and application to create beautiful, biodiverse, ecosystems. Through the process of successfully maintaining an aquarium, continued participation leads to a proficiency in applicable scientific facts, a better understanding of scientific processes, and an improved conservation ethic for aquatic resources. Further, this intersectionality motivates participation by providing new challenges and various forms of satisfaction. The human dimensions of the aquarium hobby and the values of aquarists are important to understand for many purposes, most notably because it encompasses an enormous sample of the American population and is extremely lucrative to those along most of the supply chain. Aquarium keeping is not only a hobby, but because of the relationship between science and art, it can communicate, as well as spark conservation efforts in serious aquarists.
... Wild-captured eggs and larvae of various fish species have been cultured for food production, the aquarium trade and freshwater restocking (Bell et al., 2009;Crossman et al., 2011;Pillay and Kutty, 2005). The feasibility and genetic implications of using wildcaught fertilised eggs to culture a marine fish for restocking or stock enhancement purposes has received comparatively little attention. ...
Restocking or stock enhancement programs have traditionally relied on captive broodstock to produce individuals for release into the wild. However, this is costly and may limit genetic diversity of the resulting progeny. If fertilised eggs could be collected from the wild and individuals reared for release, the genetic diversity of the released progeny may be improved and associated restocking/enhancement programs may become more cost-effective. Snapper (Chrysophrys auratus: Sparidae), is an iconic recreational and commercial fish species across Australia and New Zealand and has been subjected to overfishing in many locations. Enhancement programs may be useful for increasing biomass in some circumstances, but would require careful evaluation of advantages and disadvantages before commencement. This study developed and optimised egg collection methods for snapper from its wild spawning aggregations in Cockburn Sound, Western Australia, and developed effective otolith marking techniques that would enable future monitoring of released individuals. The study identified the optimum sea conditions for collecting large numbers (>100,000) of eggs using plankton nets, in addition to the need for side-scan sonar to locate spawning aggregations, the distance from aggregations at which to sample and the water depth for plankton net tows. Large numbers of eggs collected in 2014 and 2015 were subsampled and visually screened for presence of snapper eggs using known egg diameters. Real-time PCR techniques validated visual identifications of snapper eggs and larvae, limiting accidental rearing of non-target species and reducing associated costs. Trials on larvae reared from these eggs, successfully determined appropriate alizarin complexone concentrations and immersion times for producing enduring marks on post-larvae otoliths. These marks remained visible in otoliths after 12 months, potentially allowing future monitoring of fish released into the wild. Delayed disinfection of eggs to the second day after capture resulted in improved egg viability. Following optimisation of collection and culture techniques, 208,000 larvae were stocked from a single sampling occasion in 2015, of which 19% survived to 55 days post hatch (dph). This survival rate is typical for snapper produced from captive broodstock. This study demonstrated that wild spawned snapper eggs can be captured and cultured in high numbers and future identification of recaptured released fish potentially conducted. An associated genetic study also demonstrated no loss of genetic diversity in cultured fish versus that of adults in the spawning aggregations. This technique has the potential to reduce both the cost of restocking/stock enhancement programs for snapper (and could be evaluated for other suitable aggregating species) and the risks of altering the genetic makeup of wild stocks.
... These PL are reared and constitute a new resource to be exploited sustainably for the local populations and their economic development via the production of aquacultural resources for the local markets (food fish and ecotourism) and international markets (the aquarium trade). PCC experiments are recent, and for the most part have been carried out in the Pacific (Dufour et al., 1996;Hair, 2002;Malpot et al., 2008;Bell et al., 2009;. The only known experiment in the Indian Ocean was led in Reunion Island (unpublished data); the one described here is thus the first to have been carried out in Madagascar. ...
La dégradation des habitats coralliens et de ses populations associées par la pêcherie récifale se généralise dans le Sud Ouest de Madagascar. Ainsi, la mise en place de mesures de gestion à travers la fermeture des zones de pêche en réserves marines est utilisée sur l’ensemble de ses littoraux malgaches dans un but d’une gestion durable des écosystèmes coralliens. Une étude de l’impact de la fermeture des zones pêche et de la faisabilité d’une méthode alternative à la pêche (Post-larve Capture et Culture, PCC) a été initiée à des fins de conservation, de valorisation de la biodiversité et de gestion participative. Une expérimentation de capture de post-larves a été réalisée avec des pêcheurs autour de la période de nouvelle lune dans la baie de Toliara. Des enquêtes ont été effectuées dans deux villages de pêcheurs se trouvant dans la baie de Toliara et dans la baie de Ranobe. Elles avaient pour objectif d’analyser la perception des pêcheurs sur l’impact des réserves marines ainsi que l’acceptabilité sociale de la PCC. Parallèlement, un suivi de l’activité de pêche, de ses captures, les ventes et consommations de ses produits de pêche (poissons, poulpes, calmars) a été conduit avec des femmes de pêcheurs pour appréhender les pratiques, les comportements adaptatifs par rapport aux mesures de gestion et les confronter aux perceptions révélées par les enquêtes. Les résultats montrent des arrivées importantes de postlarves malgré la dégradation des récifs et une forte acceptation de la PCC, activité pouvant être proposée comme alternative à la pêche pour améliorer la perception, les pratiques, les comportements de pêche raisonnées dans une optique de mise en place de réserves marines. De plus, les résultats illustrent une variabilité des perceptions et des comportements face à la fermeture des zones de pêche, laquelle est surtout relative aux captures par unité d’effort (poissons, céphalopodes), et à la fréquentation des zones de pêche. Ce travail nous a montré l’importance de la prise en compte de la perception des usagers des ressources dans l’efficacité et la durabilité des mesures de gestion telles que la mise en place d'aires marines protégées.
... ¾ Expand the marine aquarium trade: The collection of fish, corals and other invertebrates for export to aquarium enthusiasts overseas has become a multimillion dollar business in PICTs over the last 20 years 25,26 . The trade is attractive because it provides an income from species which are not used for food, and can be managed sustainably through controls on a small number of exporters (especially important in the case of corals, which could otherwise be overexploited). ...
... As a result, millions of adult coral reef fish are caught from the wild (Moorhead & Zeng 2010) simply to meet the demands from these aquarium displays. The destructive fishing methods commonly used in collecting fish, such as the illegal use of sodium cyanide (Rubec, Cruz, Pratt, Oellers, McMullough & Lallo 2001), usually results in more individuals being killed during collection or removed for the requirements for display (Bell, Clua, Hair, Galzin & Doherty 2009). The relatively nondestructive fish collection methods, such as hand-net fishing, also pose negative effects on wild populations of reef fish (Kolm & Berglund 2003). ...
Coral reef fish are collected from the wild and exhibited in aquaria worldwide. Some of the fish spawn in captivity; however, the eggs are usually neglected. In this study, we collected the eggs spawned naturally in the exhibit tanks, hatched and cultured them indoor in 2000-L fibreglass tanks (initial density = 18 000 egg tank−1). We applied an inorganic fertilization method commonly used in freshwater fish culture in raising these coral reef fish larvae. We maintained inorganic phosphorus concentration at 100 μg P L−1 and inorganic nitrogen at 700 μg N L−1 daily in the fertilized group (n = 4), while the control tanks (n = 4) were fed with rotifers (10 ind mL−1). Chlorophyll a at particle sizes of both 0.45–20 μm and >20 μm, as well as NH3-N, NO3-N, and PO4-P concentrations were significantly higher in the fertilized group than the control. Zooplankton in the size groups of 10–50 μm (mainly flagellates) and 50–100 μm (mainly ciliates) were abundant (about 10~60 ind mL−1) during 3–7 days in fertilized tanks. The average larval fish survival rate at 21 day after hatch in fertilized group was consistently higher than the control in two trials. The experiments demonstrated that the inorganic fertilization approach can be successfully adapted for coral reef fish culture in an aquarium to achieve sustainable exhibits.
The present study evaluates the Condition Index (CI) and Feed Conversion Ratio (FCR) of Carassius auratus, commonly coined as Gold Fish under controlled conditions in two aquariums A and B. Growth parameters such as length (L), weight (W) and CI were recorded over eight months (March 2024-October 2024) to assess the health and growth performance of the species using the Python script for data analysis, designed for a Streamlit app. Along with these, change in feed consumption and change in weight were also provided as inputs to know the FCR values. The study of goldfish (Carrassius auratus) in aquarium A and aquarium B reveals interesting insights into their growth parameters, particularly Condition Index (CI). The CI, which is an indicator of the fish's overall health and well-being, varies between the two aquariums. In Aquarium A, the CI starts at a relatively higher value of 42.08 and gradually decreases over time, suggesting a decline in condition as the fish grow. Similarly, Aquarium B shows a decline in CI, but the initial value is slightly higher, indicating better early-stage growth conditions. A lower FCR in Aquarium B suggests better feed efficiency, meaning the fish in this aquarium utilized their feed more effectively for growth (increase in biomass) compared to those in Aquarium A.
The local diversity and global richness of coral reef fishes, along with the diversity manifested in their morphology, behaviour and ecology, provides fascinating and diverse opportunities for study. Reflecting the very latest research in a broad and ever-growing field, this comprehensive guide is a must-read for anyone interested in the ecology of fishes on coral reefs. Featuring contributions from leaders in the field, the 36 chapters cover the full spectrum of current research. They are presented in five parts, considering coral reef fishes in the context of ecology; patterns and processes; human intervention and impacts; conservation; and past and current debates. Beautifully illustrated in full-colour, this book is designed to summarise and help build upon current knowledge and to facilitate further research. It is an ideal resource for those new to the field as well as for experienced researchers.
The local diversity and global richness of coral reef fishes, along with the diversity manifested in their morphology, behaviour and ecology, provides fascinating and diverse opportunities for study. Reflecting the very latest research in a broad and ever-growing field, this comprehensive guide is a must-read for anyone interested in the ecology of fishes on coral reefs. Featuring contributions from leaders in the field, the 36 chapters cover the full spectrum of current research. They are presented in five parts, considering coral reef fishes in the context of ecology; patterns and processes; human intervention and impacts; conservation; and past and current debates. Beautifully illustrated in full-colour, this book is designed to summarise and help build upon current knowledge and to facilitate further research. It is an ideal resource for those new to the field as well as for experienced researchers.
The local diversity and global richness of coral reef fishes, along with the diversity manifested in their morphology, behaviour and ecology, provides fascinating and diverse opportunities for study. Reflecting the very latest research in a broad and ever-growing field, this comprehensive guide is a must-read for anyone interested in the ecology of fishes on coral reefs. Featuring contributions from leaders in the field, the 36 chapters cover the full spectrum of current research. They are presented in five parts, considering coral reef fishes in the context of ecology; patterns and processes; human intervention and impacts; conservation; and past and current debates. Beautifully illustrated in full-colour, this book is designed to summarise and help build upon current knowledge and to facilitate further research. It is an ideal resource for those new to the field as well as for experienced researchers.
Ce travail de thèse s’inscrit dans le cadre de deux programmes de recherche à financements européens: le Life+ SUBLIMO(Life10 NAT/FR/000200) vise à analyser, suivre et restaurer la biodiversité marine en Méditerranée et Ressources Halieutiques/Post-larves(75/SAEU/FEDER/RD-34 448)quia pour objectif d'évaluer les impacts de certains facteurs environnementaux sur cette biodiversité. Dans le cadre de ces travaux, nous avonsdéveloppéune nouvelle méthode d’identification (APLIM: Alive Post Larvae Identification Method)permettant d’aller jusqu'à la détermination desespèces pour les post-larvesde poissons, ce qui est novateurpour les taxons méditerranéens. Cette méthode regroupe différents outils: collecte de post-larvesvivantes, mise en bassin d’élevage, suivis photographiques, définition descaractèresméristiques, morphologiques et pigmentaires. Laméthode fournitles fiches de 80 espèces identifiées au stade post-larvaire, valorisées par la publication d'un Atlas regroupant ces fiches.Cet Atlaspermet ainsi d’apporter de nouvelles connaissances,essentiellement au niveau des techniques de pêche, d’identification mais également d’élevage en bassinsaquacoles, qui seront utiles aux professionnels de la mer (pêcheurs, aquaculteurs, gestionnaires) pour la gestion durable des ressources halieutiques et le maintien de la biodiversité marine. Ce guide vise à être un outil pour une meilleure gestion des futurs stocks halieutiques. Les assemblages spécifiques de biodiversité post-larvairesnous indiquentles espèces les plus contributives pourchaque site. Par ailleurs,nous avons remarquéla présence ubiquiste de Mullus surmuletus.Des variations spatio-temporelles ont mis en exerguedesdifférences entre la zone continentaleet la zone corse, mais également une saisonnalité marquée,surtout en été, grâce notamment à l’élaboration des calendriers d’arrivées des individussur les littoraux. Cependant, la déterminationdes habitats d’installation préférentiels en zone côtière demeure complexe et les mécanismes qui la régissentrestent encore à définir.Nous avons pu observer une succession trophique des troiscompartiments décrits (phytoplancton, zooplanctonetpost-larves).Par la suite, nous avonstestéles interactions entre ces différents compartiments et déterminéles relations proies/prédateurs possibles entre les groupes caractérisés. Les analyses par ADN barcodingdes contenus stomacaux desfamilles principalement rencontréesont permis de déterminer les différents régimes alimentairesdes post-larves de poissons côtiers.Les paramètres environnementaux qui semblent le plus influencer les arrivées sur les côtes corses sont la température, les vents et les courants côtiers.
Seahorses (Hippocampus spp.) are threatened as a result of habitat degradation and overfishing. They have commercial value as traditional medicine, curio objects, and pets in the aquarium industry. There are 48 valid species, 27 of which are represented in the international aquarium trade. Most species in the aquarium industry are relatively large and were described early in the history of seahorse taxonomy. In 2002, seahorses became the first marine fishes for which the international trade became regulated by CITES (Convention for the International Trade in Endangered Species of Wild Fauna and Flora), with implementation in 2004. Since then, aquaculture has been developed to improve the sustainability of the seahorse trade. This review provides analyses of the roles of wild-caught and cultured individuals in the international aquarium trade of various Hippocampus species for the period 1997–2018. For all species, trade numbers declined after 2011. The proportion of cultured seahorses in the aquarium trade increased rapidly after their listing in CITES, although the industry is still struggling to produce large numbers of young in a cost-effective way, and its economic viability is technically challenging in terms of diet and disease. Whether seahorse aquaculture can benefit wild populations will largely depend on its capacity to provide an alternative livelihood for subsistence fishers in the source countries. For most species, CITES trade records of live animals in the aquarium industry started a few years earlier than those of dead bodies in the traditional medicine trade, despite the latter being 15 times higher in number. The use of DNA analysis in the species identification of seahorses has predominantly been applied to animals in the traditional medicine market, but not to the aquarium trade. Genetic tools have already been used in the description of new species and will also help to discover new species and in various other kinds of applications.
The conservation and active restoration of European flat oyster (Ostrea edulis) populations are a major focus of ecological restoration efforts to take advantage of the wide-ranging ecosystem functions and services this species provides. Accordingly, additional and new demands for seed oysters have arisen. In commercial aquaculture (mariculture), the production of O. edulis is still largely based on natural seed collection. Considering the specific requirements, related to ecological restoration, such as the absence of pathogens and the preservation of high genetic diversity, the current supply is insufficient. Despite the development of breeding and controlled reproduction techniques for this species since the late 1930s, seed production today is mainly based on empirical concepts. Several of the issues that producers still face are already subjects of research; many others are still unanswered or even unaddressed. This review provides a summary of all available knowledge and technologies of O. edulis seed production. Furthermore, it provides a detailed reflection on implications for restoration, future challenges, open questions and it identifies relevant research topics for sustainable seed supply. The study covers the following aspects on (i) biology of the species, (ii) stres-sors-including pathogens and pollutants, (iii) genetics, (iv) history of production technologies, (v) seed production in polls, (vi) seed production in ponds and (vii) seed production in hatcheries. Future research needs on sex deter-minism, gametogenesis, cryopreservation, nutrition, selective breeding, pathogens and disease, and the development of reliable protocols for production are highlighted.
The local diversity and global richness of coral reef fishes, along with the diversity manifested in their morphology, behaviour and ecology, provides fascinating and diverse opportunities for study. Reflecting the very latest research in a broad and ever-growing field, this comprehensive guide is a must-read for anyone interested in the ecology of fishes on coral reefs. Featuring contributions from leaders in the field, the 36 chapters cover the full spectrum of current research. They are presented in five parts, considering coral reef fishes in the context of ecology; patterns and processes; human intervention and impacts; conservation; and past and current debates. Beautifully illustrated in full-colour, this book is designed to summarise and help build upon current knowledge and to facilitate further research. It is an ideal resource for those new to the field as well as for experienced researchers.
The local diversity and global richness of coral reef fishes, along with the diversity manifested in their morphology, behaviour and ecology, provides fascinating and diverse opportunities for study. Reflecting the very latest research in a broad and ever-growing field, this comprehensive guide is a must-read for anyone interested in the ecology of fishes on coral reefs. Featuring contributions from leaders in the field, the 36 chapters cover the full spectrum of current research. They are presented in five parts, considering coral reef fishes in the context of ecology; patterns and processes; human intervention and impacts; conservation; and past and current debates. Beautifully illustrated in full-colour, this book is designed to summarise and help build upon current knowledge and to facilitate further research. It is an ideal resource for those new to the field as well as for experienced researchers.
The local diversity and global richness of coral reef fishes, along with the diversity manifested in their morphology, behaviour and ecology, provides fascinating and diverse opportunities for study. Reflecting the very latest research in a broad and ever-growing field, this comprehensive guide is a must-read for anyone interested in the ecology of fishes on coral reefs. Featuring contributions from leaders in the field, the 36 chapters cover the full spectrum of current research. They are presented in five parts, considering coral reef fishes in the context of ecology; patterns and processes; human intervention and impacts; conservation; and past and current debates. Beautifully illustrated in full-colour, this book is designed to summarise and help build upon current knowledge and to facilitate further research. It is an ideal resource for those new to the field as well as for experienced researchers.
The local diversity and global richness of coral reef fishes, along with the diversity manifested in their morphology, behaviour and ecology, provides fascinating and diverse opportunities for study. Reflecting the very latest research in a broad and ever-growing field, this comprehensive guide is a must-read for anyone interested in the ecology of fishes on coral reefs. Featuring contributions from leaders in the field, the 36 chapters cover the full spectrum of current research. They are presented in five parts, considering coral reef fishes in the context of ecology; patterns and processes; human intervention and impacts; conservation; and past and current debates. Beautifully illustrated in full-colour, this book is designed to summarise and help build upon current knowledge and to facilitate further research. It is an ideal resource for those new to the field as well as for experienced researchers.
The local diversity and global richness of coral reef fishes, along with the diversity manifested in their morphology, behaviour and ecology, provides fascinating and diverse opportunities for study. Reflecting the very latest research in a broad and ever-growing field, this comprehensive guide is a must-read for anyone interested in the ecology of fishes on coral reefs. Featuring contributions from leaders in the field, the 36 chapters cover the full spectrum of current research. They are presented in five parts, considering coral reef fishes in the context of ecology; patterns and processes; human intervention and impacts; conservation; and past and current debates. Beautifully illustrated in full-colour, this book is designed to summarise and help build upon current knowledge and to facilitate further research. It is an ideal resource for those new to the field as well as for experienced researchers.
The local diversity and global richness of coral reef fishes, along with the diversity manifested in their morphology, behaviour and ecology, provides fascinating and diverse opportunities for study. Reflecting the very latest research in a broad and ever-growing field, this comprehensive guide is a must-read for anyone interested in the ecology of fishes on coral reefs. Featuring contributions from leaders in the field, the 36 chapters cover the full spectrum of current research. They are presented in five parts, considering coral reef fishes in the context of ecology; patterns and processes; human intervention and impacts; conservation; and past and current debates. Beautifully illustrated in full-colour, this book is designed to summarise and help build upon current knowledge and to facilitate further research. It is an ideal resource for those new to the field as well as for experienced researchers.
The local diversity and global richness of coral reef fishes, along with the diversity manifested in their morphology, behaviour and ecology, provides fascinating and diverse opportunities for study. Reflecting the very latest research in a broad and ever-growing field, this comprehensive guide is a must-read for anyone interested in the ecology of fishes on coral reefs. Featuring contributions from leaders in the field, the 36 chapters cover the full spectrum of current research. They are presented in five parts, considering coral reef fishes in the context of ecology; patterns and processes; human intervention and impacts; conservation; and past and current debates. Beautifully illustrated in full-colour, this book is designed to summarise and help build upon current knowledge and to facilitate further research. It is an ideal resource for those new to the field as well as for experienced researchers.
The local diversity and global richness of coral reef fishes, along with the diversity manifested in their morphology, behaviour and ecology, provides fascinating and diverse opportunities for study. Reflecting the very latest research in a broad and ever-growing field, this comprehensive guide is a must-read for anyone interested in the ecology of fishes on coral reefs. Featuring contributions from leaders in the field, the 36 chapters cover the full spectrum of current research. They are presented in five parts, considering coral reef fishes in the context of ecology; patterns and processes; human intervention and impacts; conservation; and past and current debates. Beautifully illustrated in full-colour, this book is designed to summarise and help build upon current knowledge and to facilitate further research. It is an ideal resource for those new to the field as well as for experienced researchers.
The local diversity and global richness of coral reef fishes, along with the diversity manifested in their morphology, behaviour and ecology, provides fascinating and diverse opportunities for study. Reflecting the very latest research in a broad and ever-growing field, this comprehensive guide is a must-read for anyone interested in the ecology of fishes on coral reefs. Featuring contributions from leaders in the field, the 36 chapters cover the full spectrum of current research. They are presented in five parts, considering coral reef fishes in the context of ecology; patterns and processes; human intervention and impacts; conservation; and past and current debates. Beautifully illustrated in full-colour, this book is designed to summarise and help build upon current knowledge and to facilitate further research. It is an ideal resource for those new to the field as well as for experienced researchers.
The local diversity and global richness of coral reef fishes, along with the diversity manifested in their morphology, behaviour and ecology, provides fascinating and diverse opportunities for study. Reflecting the very latest research in a broad and ever-growing field, this comprehensive guide is a must-read for anyone interested in the ecology of fishes on coral reefs. Featuring contributions from leaders in the field, the 36 chapters cover the full spectrum of current research. They are presented in five parts, considering coral reef fishes in the context of ecology; patterns and processes; human intervention and impacts; conservation; and past and current debates. Beautifully illustrated in full-colour, this book is designed to summarise and help build upon current knowledge and to facilitate further research. It is an ideal resource for those new to the field as well as for experienced researchers.
The local diversity and global richness of coral reef fishes, along with the diversity manifested in their morphology, behaviour and ecology, provides fascinating and diverse opportunities for study. Reflecting the very latest research in a broad and ever-growing field, this comprehensive guide is a must-read for anyone interested in the ecology of fishes on coral reefs. Featuring contributions from leaders in the field, the 36 chapters cover the full spectrum of current research. They are presented in five parts, considering coral reef fishes in the context of ecology; patterns and processes; human intervention and impacts; conservation; and past and current debates. Beautifully illustrated in full-colour, this book is designed to summarise and help build upon current knowledge and to facilitate further research. It is an ideal resource for those new to the field as well as for experienced researchers.
The local diversity and global richness of coral reef fishes, along with the diversity manifested in their morphology, behaviour and ecology, provides fascinating and diverse opportunities for study. Reflecting the very latest research in a broad and ever-growing field, this comprehensive guide is a must-read for anyone interested in the ecology of fishes on coral reefs. Featuring contributions from leaders in the field, the 36 chapters cover the full spectrum of current research. They are presented in five parts, considering coral reef fishes in the context of ecology; patterns and processes; human intervention and impacts; conservation; and past and current debates. Beautifully illustrated in full-colour, this book is designed to summarise and help build upon current knowledge and to facilitate further research. It is an ideal resource for those new to the field as well as for experienced researchers.
This chapter explores whether reefs can be a model with regard to ecosystem services, their users, their reactions when facing disturbances and their methods of protection. It focuses on a particular characteristic of coral reefs, the role of diversity on this production of biomass. The management of ecosystems is largely based on the principle that species diversity must be protected. Many threats to reefs are specific, but others, such as global changes and even the destruction of habitats or over-exploitation, are common to current complex systems. Coral reefs have many unique characteristics, particularly in terms of habitats, traits associated with recruitment and colonization of environments as well as a rather peculiar evolutionary history. Coral reefs are one of the most threatened ecosystems on the planet. They are particularly vulnerable due to their dependence on corals as habitat builders.
Global audiences are increasingly being exposed to digital media with fictitious storylines that draw on animal characters involuntarily entering wildlife trades. An understudied problem in wildlife trade is the potential for motion pictures to influence their audience's desire to become more acquainted, often via acquisition, with animals portrayed in the films. The 2003 Disney motion picture Finding Nemo connected audiences with a wildlife trade already commonplace: the marine aquarium trade. In this trade, fisheries supply live coral reef organisms to millions of public and private aquaria worldwide. Here, we examine the perception and reality of Finding Nemo's impact (coined the “Nemo Effect”) on the fisheries of the species complex representing the film's primary protagonist “Nemo” (Amphiprion ocellaris/percula). Import and export figures show little evidence for fan-based purchases of wild-caught fish immediately (within 1.5 years of release) following the film. We argue that the perceived impact on these species, driven by popular media with an emotive but scientifically uninformed approach to conserving coral reef ecosystems, can be more damaging to the cause of conservation than helpful. This perspective is intended to encourage marine aquarium trade stakeholders to consider the ecological and social repercussions of both media driven consumption and opposition to the trade. Using lessons learned from Finding Nemo, we discuss the likely impacts the sequel, Finding Dory, will have on wild populations of its protagonist “Dory” (Paracanthurus hepatus).
The local diversity and global richness of coral reef fishes, along with the diversity manifested in their morphology, behaviour and ecology, provides fascinating and diverse opportunities for study. Reflecting the very latest research in a broad and ever-growing field, this comprehensive guide is a must-read for anyone interested in the ecology of fishes on coral reefs. Featuring contributions from leaders in the field, the 36 chapters cover the full spectrum of current research. They are presented in five parts, considering coral reef fishes in the context of ecology; patterns and processes; human intervention and impacts; conservation; and past and current debates. Beautifully illustrated in full-colour, this book is designed to summarise and help build upon current knowledge and to facilitate further research. It is an ideal resource for those new to the field as well as for experienced researchers.
The authors of this book have explored the major oceans of the world to document the diversity of habitats, structures and marine food webs. From coastal zones to deep-sea habitats, several environments are investigated: the phytplankton system, the first level of ecological and climatic dynamics via the carbon cycle; the coral ecosystems and their associated seagrass, among the most diverse on the planet; and the deep ecosystems, oases organized around hydrothermal vents on mid-ocean ridges. In order to reveal the spatial and temporal dynamics of these systems and the complexity of trophic interactions, observation strategies and long-term monitoring were needed. In addition, the topics covered allow the reader to address the problem of preservation of resources, living or non-living, and the services rendered to our societies endangered by environmental change. Thus, concepts and strategies emerge as ecological resilience. Like the previous volumes, this seventh book of the "Seas and Oceans" Set adopts a transversal approach that leads to the governance and sustainable management of marine environment.
Introduction The aquatic ornamental industry Trade in ornamental fish Comparing the freshwater and marine ornamental fish trades Tropical marine ornamentals Aquaculture of coral reef fish Aquaculture of marine invertebrates Aquaculture of live rock Culture versus field collection of marine ornamentals Tropical freshwater ornamentals Commonly traded freshwater species Aquaculture of freshwater ornamental species Production and marketing goals The future of the ornamental industry References
Each year, over 45 countries export 30 million fish from coral reefs as part of the global marine ornamental aquarium trade. This catch volume is partly influenced by collection methods that cause mortality. Barotrauma in fish resulting from forced ascent from depth can contribute to post-collection mortality. However, implementing decompression stops during ascent can prevent barotrauma. Conversely, venting (puncturing the swim bladder to release expanded internal gas) following ascent can mitigate some signs of barotrauma like positive buoyancy. Here, we evaluate how decompression and venting affect stress and mortality in the Yellow Tang (Zebrasoma flavescens). We examined the effects of three ascent treatments, each with decompression stops of varying frequency and duration, coupled with or without venting, on sublethal effects and mortality using histology and serum cortisol measurements. In fish subjected to ascent without decompression stops or venting, a mean post-collection mortality of 6.2% occurred within 24 h of capture. Common collection methods in the fishery, ascent without decompression stops coupled with venting, or one long decompression stop coupled with venting, resulted in no mortality. Histopathologic examination of heart, liver, head kidney, and swim bladder tissues in fish 0d and 21d post-collection revealed no significant barotrauma- or venting-related lesions in any treatment group. Ascent without decompression stops resulted in significantly higher serum cortisol than ascent with many stops, while venting alone did not affect cortisol. Future work should examine links in the supply chain following collection to determine if further handling and transport stressors affect survivorship and sublethal effects.
This book is needed as it helps in translating theories related to entrepreneurship into an understanding of the action on the ground in a developing country influenced by Buddhism. By doing so, the book builds entrepreneurial capacity regarding context and business activities in countries similar to Sri Lankan. The book does this by evidencing a case of co-creation of knowledge involving two universities, University of Nordland, Norway and University of Ruhuna, Sri Lanka. The chapters all relates to how entrepreneurship is conducted, and how the institutional framework in Sri Lanka limits and opens for entrepreneurial opportunities. Together, the chapters evidence the interdisciplinary nature of entrepreneurship.
The book project came into being when The Norwegian Centre for Cooperation in Higher Education (SIU) funded a NUFU cooperation project, “The entrepreneurial university”, as a co-operation between University of Nordland, Norway (UoN) and University of Ruhuna, Sri Lanka (UoR). NUFU is an abbreviation for “The Norwegian Programme for Development, Research and Education”, and its aim is to build research and educational capacity in the south on issues important for the south. SIU is Norway’s official agency for international programmes and measures related to higher education. It is commissioned by several national and international public organisations to administer programmes within all levels of education.
The aim of the book project is to generate new knowledge related to how UoR could facilitate entrepreneurial growth in its region. The NUFU project suggests that exploitations of marine resources could be the content of such an entrepreneurial effort. The studies reported in this book then represent different approaches to an understanding of how the institutional structures hinders or facilitate entrepreneurship in Sri Lanka. The universities involved in the book project hope that the outcome could strengthen our efforts to serve our public responsibilities as knowledge developers and knowledge providers. Universities also have a responsibility to activate knowledge and to help creating viable societies. This we seek to accomplish by doing the research reported in the book. We also hope that the reader of the book will gain new insights useful in their work.
The teacher in entrepreneurship that would like to offer his students knowledge on the conditions for entrepreneurship in Sri Lanka would find a set of helpful insights. These insights are to some extent also relevant for other developing countries and countries similar to Sri Lanka. The practitioner is also provided support in his strives to understand the limitations and the opportunities that are available in such an environment. The included chapter also offers implication for policy makers seeking to improve the conditions and the institutional framework for entrepreneurship. Aid organizations need to cooperate with the forces shaping the business environment and the findings reported in the book could be helpful in this task. The ones interested in developing joint research between universities in the north (west) and the south (east) are also offered hints for improved practises.
We are grateful for the opportunity offered to us by SIU for to gain more knowledge on conditions for, processes of and results from entrepreneurship activities in Sri Lanka. We would not be able to achieve our accomplishments without the support and guiding from SIU. The contribution from the reviewers is invaluable. Their supporting and constructive critique has enhanced the learning process and improved the papers. I also would like to thank the Vice Chancellor at UoR, the Rector at UoN, the deans at The Faculty of Management and Finance and The Faculty of Fisheries and Marine Sciences & Technology at UoR, and the Deans at Bodø Graduate School of Business and Faculty of Biosciences and Aquaculture at UoN for their assistance. The authors have all worked hard in order to build new competence and share this new knowledge with the readers.
I thank you all for your enthusiasm and effort!
Bjørn Willy Åmo
Associate Professor
Bodø Graduate School of Business
University of Nordland
Despite the fact that recruitment can significantly influence the population dynamics of benthic marine populations, relatively little is known about the biological and physical processes controlling recruitment. We selected eight closely related coral reef fishes (wrasses in the family Labridae) to examine the temporal and spatial patterns of juvenile recruitment to the Caribbean island of Barbados. We used a comparative approach to study the relationships among patterns of recruitment, early life history traits, and aspects of the physical environment. For 10 wk during each of three peak recruitment (spring) seasons (1990-1992), we used a biweekly census of recently settled juveniles (8-25 mm standard length, SL) to measure the abundance of six congeners, Halichoeres bivittatus, H. radiatus, H. poeyi, H. garnoti, H. pictus, and H. maculipinna, and two confamilial labrids, Thalassoma bifasciatum and Bodianus rufus. Analysis of the otoliths of a sample of collected specimens provided estimates of larval durations, postsettlement ages, sizes at settlement, and juvenile growth rates, enabling back-calculation of settlement day for all collected juveniles. We compared temporal patterns of recruitment among species, and spatial patterns of recruitment for the most common species. Temporal patterns of recruitment were consistent among seasons for most of the labrids examined, although the magnitude of recruitment was less predictable (particularly for H. poeyi, H. maculipinna, and B. rufus). The eight labrids could be divided into two groups based on their early life history traits and within-season temporal patterns of recruitment. Halichoeres bivittatus, H. radiatus, H. poeyi, H. garnoti, and H. pictus had larval durations that were relatively short and invariant (means of 23-27 d), and all settled at fairly large sizes (9-12 mm SL) during the new moon and first maximum amplitude tide. In contrast, T. bifasciatum, B. rufus, and H. maculipinna had larval durations that were longer or more variable, and all three were able to delay metamorphosis. These three species settled at relatively smaller sizes (8-10 mm SL) during the third-quarter moon and second minimum amplitude tide. We compared temporal patterns of T. bifasciatum recruitment between Barbados and Caribbean Panama in an attempt to identify further the proximate environmental cues operating during settlement. Contrasting patterns of T. bifasciatum recruitment between the two geographical locations probably result from differences in the relative timing of the lunar and tidal amplitude cycles. Recruitment of labrids to Barbados occurred along the entire west coast of the island. Although some labrids had rather specific habitat requirements (e.g., B. rufus associated exclusively with large seaward-facing coral heads such as Montastrea spp.), most species were ubiquitous along the west coast. Species-specific juvenile densities did not often vary significantly among sites following major recruitment events, although overall densities were generally lower at a central site. Lower recruitment to that site likely results from reduced rates of larval supply due to prevailing offshore tidal flows. Thus, temporal and spatial patterns of labrid recruitment to Barbados appear to be more predictable than previously thought for reef fishes. In particular, variation in the tidal amplitude cycle may influence both the timing of settlement and, to a lesser degree, the spatial scale of larval supply. Finally, the interaction of larval biology with such physical processes is evident in the correlation between temporal patterns of recruitment and early life history traits. The functional nature of this relationship clearly warrants further study.
Replenishment of benthic marine populations typically involves ''settle-ment'' from pelagic larval to benthic juvenile habitats. Mortality during this transition has been unknown because of the difficulty of measuring propagule supply in open water. For three weeks, we compared the nocturnal passage of presettlement fishes across the barrier reef encircling Moorea Island (French Polynesia) with the abundance of benthic recruits in the back-reef lagoon on the following morning. During this time, 40,000 presettlement unicornfish, Naso unicornis entered our study area of 1 km 2 with half arriving on just two nights. Using coupled Beverton-Holt functions to describe the decay of each cohort, we were able to predict the daily abundance of recruits and their final age structure from the presettlement inputs. The best model estimated that 61% of the potential settlers were lost between their nocturnal arrival and the following morning, independent of cohort size. Postsettlement mortality was density dependent, varying between 9% and 20% per day. We attribute all mortality to predation and suggest that high risk associated with settlement has shaped colonization strategies. Because fishing targets the survivors of this population bottleneck, aquarium fisheries may be more sustainable when sourced from pelagic juveniles .
Instantaneous daily growth and mortality rates each increased c0.01 per °C increase in temperature, but there was no significant regression of gross growth efficiency on temperature (mean K1=0.29), indicating no latitudinal relationship. The large increases in growth rate at high temperatures must be supported by increased food consumption, not increased growth efficiency. Oxygen uptakes also increased significantly in relation to temperature, but relatively slowly compared to growth rates. Larval stage duration was inversely related to growth rate. Potential variability in growth rate increased with temperature; the opposite trend was observed for stage duration, which tended to be both long and potentially variable in high latitudes. Early life, density-dependent regulation is thus more probable in high than in low latitudes. The required ingestion to support average growth rate increased 3-fold in the 10-30°C range, indicating that fish larvae in warm seas may be more likely to starve than larvae in cold seas. Spawning in low latitudes often is protracted with frequent batches in contrast to spawning in high latitudes, where seasons are brief with one or a few batches. -from Author
Six sampling devices were deployed simultaneously over three nights near a coral reef at Lizard Island, Great Barrier Reef, Australia. The resulting 83 samples captured 57 701 larval and pelagic juvenile fishes of 70 families (excluding clupeoids). The bongo net took the most families, the light-trap the fewest. In all methods, a few families dominated the catch. Fishes collected by aggregation devices were generally larger than those taken by net, and light-traps caught very few fish <5mm. -from Authors
This book contains 17 chapters. Topics covered are: management of marine aquaculture: the sustainability challenge; marine mammals and aquaculture: conflicts and potential resolutions; recreational fishing and aquaculture: throwing a line into the pond; aquaculture: opportunity of threat to traditional capture fishermen; advances in marine stock enhancement: shifting emphasis to theory and accountability; aquatic polyculture and balanced ecosystem management: new paradigms for seafood production; the role of marine aquaculture facilities as habitats and ecosystems; mangroves and coastal aquaculture; environmental effects associated with marine netpen waste with emphasis on salmon farming in the Pacific Northwest; issues associated with non-indigenous species in marine aquaculture; genetic changes in marine aquaculture species and the potential for impacts on natural populations; what role does genetics play in responsible aquaculture; understanding the interaction of extractive and fed aquaculture using ecosystem modelling; shrimp farm effluents; fish meal: historical uses, production trends and future outlook for sustainable supplies; the use of wild-caught juveniles in coastal aquaculture and its application to coral reef fishes; contending with criticism: sensible responses in an age of advocacy.
There is a significant trade in live coral reef fishes for aquarium and niche food markets. Resistance to these operations in many places is based upon the threat of overfishing and the use of destructive fishing techniques. The Australian Centre for International Agricultural Research (ACIAR) is funding a development project in Solomon Islands by ICLARM. The World Fish Center to demonstrate the feasibility of supplying these markets through a new artisanal fishery based upon harvesting presettlement fishes. In the pilot phase, we used crest nets and light traps to examine the spatio-temporal characteristics of the supply of suitable presettlement fish. In six months of sampling (November 1999 to April 2000), we collected 84,568 individuals from 66 families with obvious differences in catch composition taken by the two techniques. Analysis of variance indicated significant monthly variation in catch rates but with no pattern common to both techniques nor all components of the catches. Compared with Australia, seasonal variation is not evident at this latitude. Both light traps and crest nets have produced juveniles fit for culture, albeit predominantly for ornamental species rather than for potential food fishes. Fish maintained alive after capture have shown rapid growth rates and the product has been accepted by aquarium fish exporters.
Between 1.5 and 2 million people worldwide are believed to keep marine aquaria. The trade which supplies this hobby with live marine animals is a global multi-million dollar industry, worth an estimated US$200-330 million annually, and operating throughout the tropics. Ornamental marine species (corals, other invertebrates and fish) are collected and transported mainly from Southeast Asia, but also increasingly from several island nations in the Indian and Pacific Oceans, to consumers in the main destination markets: the United States, the European Union (EU) and, to a lesser extent, Japan.
Very few of the species in trade are exploited directly for other purposes, and there is little doubt that aquarium animals are the highest value-added product that can be harvested from a coral reef. If managed sustainably, the trade could support jobs in predominantly rural, low-income coastal communities and so provide strong economic incentives for coral reef conservation in regions where other options for generating revenue are limited. However, damaging techniques occasionally used to collect the animals, possible over harvesting of some species and the high levels of mortality associated with inadequate handling and transport of sensitive living organisms undermine this potential, and continue to pose significant challenges to achieving sustainability. As a result the trade has seldom been free of controversy as traders try to generate a profit, conservationists try to avoid further decline in coral reefs also suffering from other pressures, and policy makers try to assemble a legislative framework that protects coral reefs without threatening a legitimate business activity or the incomes of communities engaged in aquarium fishing.
In the main, this debate has taken place without access to impartial and quantitative data on the trade and, with so many different viewpoints, achieving consensus on its impacts, and hence the identification of suitable responses, has been difficult. In 2000, the United Nations Environment Programme World Conservation Monitoring Centre (UNEP-WCMC), the Marine Aquarium Council
(MAC) and members of various aquarium trade associations
collaboration, to address this need for better information and created the Global Marine Aquarium Database (GMAD). Trade data have been obtained from wholesale exporters and importers of marine aquarium organisms, most often through copies of trade invoices, integrated and standardized into quantitative, species-specific information which has been placed in the public domain: www.unep-wcmc.org/marine/GMAD. Fifty eight companies, approximately one-fifth of the wholesalers in business, and four government management authorities have provided data to GMAD. In August 2003 the dataset contained 102,928 trade records (7.7 million imported and 9.4 million exported animals) covering a total of 2,393 species of fish, corals and invertebrates and spanning the years 1988 to 2003. These data have permitted the most accurate quantitative estimates to date of the size of the global trade in marine ornamental fish and corals, and the first ever estimates for invertebrates other than corals, a previously overlooked section of the industry.
FISH
A total of 1,471 species of fish are traded worldwide with the best estimate of annual global trade ranging between 20 and 24 million individuals. Damselfish (Pomacentridae) make up almost half of the trade, with species of angelfish (Pomacanthidae), surgeonfish (Acanthuridae), wrasses (Labridae), gobies (Gobiidae) and butterflyfish (Chaetodontidae) accounting for approximately another 25-30 per cent. The most traded species are the blue-green damselfish (Chromis viridis), the clown anemonefish (Amphiprion ocellaris), the whitetail dascyllus (Dascyllus aruanus), the sapphire devil (Chrysiptera cyanea) and the threespot dascyllus (Dascyllus trimaculatus). The ten most
traded species account for about 36 per cent of all fish traded for the years 1997 to 2002. Trade data, correlated with aquarium suitability information, indicate that two species known not to acclimatize well to aquarium conditions are nonetheless very commonly traded. They are the bluestreak cleaner wrasse (Labroides dimidiatus: GMAD records 87,000 worldwide imports of this species from 1997 to 2002) and the mandarin fish (Synchiropus splendidus: GMAD records 11,000 live individuals exported to the EU in the same period). Data further indicate that species characterized as ‘truly unsuitable’, mainly due to their restricted dietary requirements, such as the foureye butterflyfish (Chaetodon capistratus), the harlequin filefish (Oxymonacanthus longisrostris) and the Hawaiian cleaner wrasse (Labroides phtirophagus), are also commonly traded, albeit in lower numbers.
CORALS
A total of 140 species of stony coral, nearly all scleractinians, are traded worldwide, with the best estimate of annual global trade ranging between 11 and 12 million pieces. Although difficulties associated with accurate coral identification probably make species data less reliable for corals than for fish, it is clear that species in seven genera (Trachyphyllia, Euphyllia, Goniopora, Acropora, Plerogyra, Catalaphyllia) are the most popular, accounting for approximately 56 per cent of the live coral trade between 1988 and 2002. Sixty-one species of soft coral are also traded, amounting to close to 390,000 pieces per year. Sarcophyton spp. (leather/mushroom/ toadstool coral) and Dendronephthya spp. (carnation coral) are two of the most commonly traded species. However, whilst the biology of the former makes it a hardy, fast-growing and easily propagated species under
aquarium conditions, Dendronephthya spp. usually die within a few weeks, mainly due to the fact that they lack photosynthetic symbionts and rely on filtering particles and nutrients in the water column for food.
INVERTEBRATES
More than 500 species of invertebrates (other than corals) are traded as marine ornamentals, though the lack of a standard taxonomy makes it difficult to arrive at a precise figure. The best estimate of global annual trade ranges between 9 and 10 million animals, mostly molluscs, shrimps and anemones. Two groups of cleaner shrimp, Lysmata spp. and Stenopus spp., and a group of anemones, Heteractis spp., account for approximately 15 per cent of all invertebrates traded.
We have (i) tested modified western rock lobster sandwich collectors at different depths and distances offshore (ii) tested different collector designs (iii) examined the effect of collector size, and (iv) tested the effect of frequency of servicing the collectors. The only catches recorded in the onshore-offshore trials were on gear set at the inshore site (depths <5 m). Published data from the 1970s on the effect on catches of collector arrays and locations were reexamined with a general linear model. The analysis revealed marginally significant corner and layer effects, carry-over effects, and square-of-time effects. Five collector designs were therefore set in the shallows, two of which had replicates of three different sizes, and were checked over four lunar months during peak settlement. Sandwich collectors had significantly better catch rates than others (P <0.001), and settlement rates were highly correlated with collector dimensions (r = 0.72). Daily servicing for seven days around the time of new moon yielded catches 170% higher than those from a single monthly servicing (P <0.001). Results indicate that tests for collectors must take into account corner, carry-over, neighbour, and layer effects and that to do so they must be set out in an array and repositioned after each sampling.
Global trade in marine ornamental species includes numerous countries; however, 80% of the trade involves exports from the Philippines and Indonesia to the USA. The worldwide import value of marine ornamentals is estimated at US$ 200–330 million annually. Recent concern regarding sustainability and environmental impacts on coral reefs where collection occurs has spurred debate as to how best to monitor, manage and regulate the industry. A certification programme proposed by the Marine Aquarium Council (MAC) has the potential to manage the trade efficiently by minimizing environmental impacts, thus continuing this important source of income for impoverished coastal villagers. The MAC Ecosystem and Fishery Management (EFM) Standard was established to protect fish stocks from overexploitation and will be the most difficult component of the certification programme to implement. Prerequisites for successful EFM in developing nations are local control over fisheries and accurate records to monitor catch. Collector logs were found to be a useful tool to monitor both catch per unit effort (CPUE) and catch composition from collection areas in the Philippines. Comparison of catch composition in two distinct regions of the Philippines indicated that one site was severely overfished while the other was moderately overfished. The Collection Area Management Plan required by the MAC certification programme, combined with the current legal framework in the Philippines allowing for local jurisdiction of reef resources, has the potential to prevent further overfishing in the latter region. Until sufficient ecological data can be obtained, CPUE can provide an effective means to monitor and manage the fishery within the framework of the MAC certification programme. Despite effective management plans in source nations, legislation in receiving nations may be required to help stimulate a strong market demand for certified ornamentals if the MAC certification programme is to be successful.
Marine Ornamental Species: Collection, Culture and Conservation is a comprehensive resource containing information on the growing and economically important marine ornamental industry. Experts address current issues from a global perspective, covering the full-range of topics from world economics and product demand to aquatic animal health to ethnic and social/cultural concerns. This up-to-date overview will contribute to the creation of an economically and environmentally viable future for this dynamic industry worldwide and for its diverse clientele by: outlining improvements in the methods for the collection and distribution of wild marine ornamental species; providing information to accelerate an increase in the variety, quantity, and availability of cultured marine ornamental species; and encouraging outreach activities in the conservation and husbandry of marine ornamental species The value of and the interest in marine ornamentals from many governments as well as conservation organizations underline the critical need for this book. It is also essential reading for scientists involved in marine biology and conservation issues, aquarists at public and private aquaria, tropical fish farmers, advanced hobbyists, fishery biologists, importers and exporters of marine ornamentals, commercial collectors, veterinarians who specialize in fish disease, and businesses that manufacture or sell aquarium media, equipment, and feed.
For close to a century, recruitment of larvae to a local population has been widely accepted as a primary determinant of marine population dynamics. However, progress in elucidating the causes of recruitment variability has been greatly impeded by our ignorance of the sources of recruits. Although it is often assumed that recruitment is independent of local reproduction, there is increasing circumstantial evidence that physical and behavioural mechanisms could facilitate larval retention near source populations. To develop a direct method for reconstructing the dispersal history of recruiting larvae, we put forward the hypothesis that differences in nutrient and trace-element concentrations between coastal and open oceans could result in quantifiable differences in growth rate and elemental composition between larvae developing in coastal waters (locally retained) and larvae developing in open ocean waters (produced in distant locations). Using this method, we show that recruitment to an island population of a widely distributed coral-reef fish may often result from local retention on leeward reefs. This result has implications for fisheries management and marine reserve design, because rates of dispersal between marine populations-and thus recruitment to exploited populations-could be much lower than currently assumed.
The spatial and temporal patterns of distribution of new settlers of 23 species of damselfish (Pomacentridae) within One Tree Island lagoon, southern Great Barrier Reef (GBR) were measured for 3 summers to assess the persistence of spatial patterns of recruitment. Overall recruitment was 3 times higher in 1993/1994 than 1994/1995, and 1.5 times higher than 1999. In general, recruitment decreased towards the lagoon centre, even though habitat availability was not lower there on average, suggesting that most fish settled at outer sites as they were advected from adjacent waters. There was also great variation in numbers of recruits among outer sites. Patterns of recruitment to continuous reef and patch reef habitats also differed among species, suggesting habitat selection at this broad level. For example, Pomacentrus nagasakiensis was primarily found on patch reefs, while P. moluccensis was largely found on continuous reef. One site (Shark Alley) received the highest number of recruits of most species during the study, and this pattern has been observed in studies since 1975. Despite interannual variability in abundance of potential settlers and differences in the habitat preferences of some species, therefore, some sites on the reef can receive relatively high numbers of settlers over decadal time scales. This consistency of spatial pattern may be due to local topography and oceanography at Shark Alley, which appear to favour the input of potential settlers. The availability of live coral may also be important, but species which showed no preferences for live cover also recruited at high levels at this site. The attributes of Shark Alley were compared with those at other sites. Overall, sites that clustered on the basis of oceanographic and habitat features also had similar recruitment, suggesting that these features may be useful in predicting recruitment hotspots on reefs elsewhere.
Swimming speeds of the late-stage, pelagic larvae of coral-reef fishes were measured in situ near Lizard Island on Australia's Great Barrier Reef, and Rangiroa Atoll, Tuamotu Islands, French Polynesia during 1995-96. Larvae were captured with light traps End crest nets, and released individually in open water. They were then followed by SCUBA divers, normally for 10 min, and their speed was measured with a modified plankton-net flow meter and a stop watch. Swimming speeds of 260 larvae of 50 species in 15 families of mostly perciform reef fishes are presented. Most measurements were for pomacentrids (8 genera, 16 species, 127 individuals), apogonids (1 genus, similar to 5 species, 18 individuals), chaetodontids (3 genera, 8 species, 49 individuals), lethrinids (1 genus, similar to 4 species, 11 individuals), nemipterids (1 genus, 2 species, 10 individuals), serranids (2 genera, 2 species, 14 individuals) and acanthurids (2 genera, similar to 4 species, 13 individuals). Numbers of individuals per species ranged from 1 to 25. Speeds were remarkably high for such small fishes (0.7 to 5.5 cm). Average speed was 20.6 cm s(-1) (range 2 to 65), or 13.7 body lengths s(-1) (range 2 to 34). SE for species with n > 4 ranged from 0.8 to 5.3 cm s(-1) (4.1 to 25.0% of mean speed), but speed of the fastest individual of each species averaged 144% of mean speed. A taxonomic component was evident, with apogonids the slowest (2 to 13 cm s(-1)), followed by nemipterids (10 cm s(-1)). Speed of pomacentrids and chaetodontids varied widely among species (7 to 35 cm s(-1)), whereas acanthurids, lethrinids and serranids were fast (19 to 55 cm s(-1)). Except for apogonids and nemipterids, nearly all species had mean swimming speeds greater than average ambient current speeds in the Lizard island area. Mean speed was positively correlated with size (slope 8.2, r(2) = 0.43) when all taxa were included, but was not correlated with size for the Pomacentridae and Chaetodontidae when each were considered alone. The speeds reported here combined with data on swimming endurance recently reported by Stobutzki & Bellwood (1997; Mar Ecol Prog Ser 149:35-41) reveal remarkable swimming abilities for late-stage pelagic larvae of coral-reef fishes which could either greatly enhance dispersal or eliminate it.
Despite the fact that recruitment can significantly influence the population dynamics of benthic marine populations, relatively little is known about the biological and physical processes controlling recruitment. We selected eight closely related coral reef fishes (wrasses in the family Labridae) to examine the temporal and spatial patterns of juvenile recruitment to the Caribbean island of Barbados. We used a comparative approach to study the relationships among patterns of recruitment, early life history traits, and aspects of the physical environment. For 10 wk during each of three peak recruitment (spring) seasons (1990-1992), we used a biweekly census of recently settled juveniles (8-25 mm standard length, SL) to measure the abundance of six congeners, Halichoeres bivittatus, H. radiatus, H. poeyi, H. garnoti, H. pictus, and H. maculipinna, and two confamilial labrids, Thalassoma bifasciatum and Bodianus rufus. Analysis of the otoliths of a sample of collected Specimens provided estimates of larval durations, postsettlement ages, sizes at settlement, and juvenile growth rates, enabling back-calculation of settlement day for all collected juveniles. We compared temporal patterns of recruitment among species, and spatial patterns of recruitment for the most common species. Temporal patterns of recruitment were consistent among seasons for most of the labrids examined, although the magnitude of recruitment was less predictable (particularly for H. poeyi, H. maculipinna, and B. rufus). The eight labrids could be divided into two groups based on their early life history traits and within-season temporal patterns of recruitment. Halichoeres bivittatus, H. radiatus, H. poeyi, H. garnoti, and H. pictus had larval durations that were relatively short and invariant (means of 23-27 d), and all settled at fairly large sizes (9-12 mm SL) during the new moon and first maximum amplitude tide. In contrast, T. bifasciatum, B. rufus, and H. maculipinna had larval durations that were longer or more variable, and all three were able to delay metamorphosis. These three species settled at relatively smaller sizes (8-10 mm SL) during the third-quarter moon and second minimum amplitude tide. We compared temporal patterns of T. bifasciatum recruitment between Barbados and Caribbean Panama in an attempt to identify further the proximate environmental cues operating during settlement. Contrasting patterns of T. bifasciatum recruitment between the two geographical locations probably result from differences in the relative timing of the lunar and tidal amplitude Cycles. Recruitment of labrids to Barbados occurred along the entire west coast of the island. Although some labrids had rather specific habitat requirements (e.g., B. rufus associated exclusively with large seaward-facing coral heads such as Montastrea spp.), most species were ubiquitous along the west coast. Species-specific juvenile densities did not often vary significantly among sites following major recruitment events, although overall densities were generally lower at a central site. Lower recruitment to that site likely results from reduced rates of larval supply due to prevailing offshore tidal flows. Thus, temporal and spatial patterns of labrid recruitment to Barbados appear to be more predictable than previously thought for reef fishes. In particular, variation in the tidal amplitude cycle may influence both the timing of settlement and, to a lesser degree, the spatial scale of larval supply. Finally, the interaction of larval biology with such physical processes is evident in the correlation between temporal patterns of recruitment and early life history traits. The functional nature of this relationship clearly warrants further study.
Predator swamping was an adequate explanation for the occurrence of within-season reproductive synchrony when the predator exhibits a Holling type-II functional response (specialist predator), but, in the case of a generalist predator switching from alternative prey (Holling type-III functional response), which is expected to be a common functional-response type when particular prey are unavailable at certain times of the year, highly asynchronous reproduction may be the best reproductive strategy. In particular, when prey switching occurs at high offspring densities and/or the satiation density of the predator is high relative to the total reproduction of the prey population, the peak predation rate is expected to occur when reproduction is completely synchronous. Spatially clumped prey populations are expected to experience a dramatically increased predation rate if reproduction is synchronized within clumps but not between them. Hence, it is predicted that mechanisms promoting within-group reproductive synchrony are even less likely to have evolved as a predator-swamping strategy in patchily distributed populations, in which reproduction cannot be synchronized between groups. -from Author
This chapter focuses on the various sensory mechanisms of coral reef fishes. The clear waters around coral reefs provide a well-lit environment and illumination at dawn, dusk, and moonlit nights. Various interactions of coral reef fishes with their predators, prey, competitors, mates, and physical environment rely on light and, especially on vision. The eyes of most teleosts are oriented and designed so that light can enter from almost any direction. In front, a fish can view an object with both eyes to create binocular vision and improved depth perception. Many species use ocular movements to adjust the size of the binocular field. Most fishes can see objects in the lateral fields with only one eye, where depth perception is presumably compromised. However, L. fasciatus, a predator that lies in wait buried in the sand, appears to be able to judge the distance of its prey monocularly. Visual acuity—the degree to which a fish can resolve detail within its visual field—is largely dependent on eye size, the density of retinal photoreceptors, and ganglion cells. The distribution of photoreceptors and ganglion cells across the retinal hemisphere is often uneven, and retinal topography in coral reef fishes can be related to ecological niche. Hearing in teleost and chondrichthyan fishes involves the inner ear, along with accessory organs such as the swim bladder or analogous structures, and neural components of the inner ear. The inner ear consists of dorsally positioned semicircular canals, which use fluid inertia to detect angular head motions, and three sac-like organs—the sacculus, the lagena, and the utriculus—which respond to sound and head position.
The ecology of coral reef fishes seems to invite a metapopulation perspective. A metapopulation structure is determined by the spatial arrangement of local populations, coupled with life-history traits that allow metapopulation dynamics to be enacted. There certainly is evidence to suggest that coral reef fishes may form metapopulations, at least when metapopulations are defined with reference to spatial structure and connectivity rather than extinction recolonization dynamics. Extinction recolonization may be evident at the edge of species ranges, such as within the Capricorn Bunker group of the Great Barrier Reef. Metapopulation dynamics are viewed as something more than extinction recolonization dynamics, and greater potential is seen for the presence of metapopulations among coral reef fishes. Demographic traits and behavior can vary even among very proximal populations, or among adjacent reef zones, reflecting a part of the independence of these populations. The population dynamics that result from dispersal patterns and local demography typically show asynchrony among populations, at least as indicated by recruitment data. To provide better answers, reef fish ecologists need, first and foremost, to continue the burgeoning trend of large-scale, interdisciplinary research on larval dispersal and demographic connectivity. At the same time, one should not accept too blindly the assumption that postsettlement reef fishes are sedentary; one should be looking to test this assumption in situations where it is likely to be violated.
The larval stage of most coral reef fishes is spent in the pelagic environment, away from the reef proper. Survival at this stage is tenuous, being mediated by factors such as food availability, predator abundance, and physical conditions. The complex biological and physical interactions of these factors can result in a seemingly stochastic larval supply that drives temporal and spatial variation in recruitment intensity. Although fish larvae are often considered strict constituents of the zooplankton community, evidence suggests that many species exhibit some form of active behavior during their pelagic stage. Variability in larval transport is determined by the interaction of water masses and the effects of external forces such as winds and tides. Active behavior by larvae may modulate some of this variability, yet a strong change in the direction or intensity of flow of a particular water mass may result in a substantial change in larval supply to a given reef or island, or may carry larvae away from a suitable food environment. The scale over which larval transport or retention occurs varies substantially among species and even among locations within a single species. For some species, larval dispersal is minimal and possibly nonexistent, whereas at the other extreme dispersal can occur over thousands of kilometers. For most coral reef fish species, with larval durations of weeks to months, transport will usually be on the scale of tens to hundreds of kilometers.
This chapter focuses on the various ecological issues that are related to the trade of live reef fishes. Well-managed live reef fish fisheries offer an excellent chance for high-value and relatively low-volume trades that could employ many fishers without damaging wild populations, with the income providing strong local incentives to care for marine resources. Similarly, well-considered and cautious mariculture has the potential to help support local people, but then all mariculture operations and proposals should be very carefully scrutinized for ecological integrity, economic viability, and social implications. Currently, mariculture proposals are often viewed as intrinsically positive without considering their potential impacts. Mariculture, like the import of exotic fishes, could threaten local fish fauna because of the potential for releases and escapes, as well as the spread of disease. Infact, the World Conservation Union (IUCN) actively discourages releases unless they are a part of a well-conceived and long-term international program. Moreover, the polluting and resource-expensive (for feed) demands of the larger carnivorous species being cultured pose a range of problems that are have yet not been addressed. Successful management of live fish fisheries for sustainability requires a creative and interdisciplinary mix of management measures, well supported by government, local fishing communities, traders, and consumers. Ecosystem-level approaches, such as MPAs, offer considerable hope as they help conserve habitat and biodiversity simultaneously. Pre-emptively established no-take zones can become increasingly critical as the live fish trades and associated abusive fishing practices spread into new regions. The direct loss of populations through capture and associated disruption, the damage to other species, and the degradation of reefs from illegal capture methods are all very costly in terms of future fishing income and alternative income-earning opportunities, such as tourism.
Publisher Summary
This chapter focuses on the relationship between variable replenishment and the dynamics of reef fish populations. The populations of coral reef fishes can experience variable replenishment and these variations may have lasting impacts on patterns of demography and abundance. Populations of siganids in Guam, acanthurids in Minicoy Atoll and Johnston Atoll, balistids in Panama, and serranids in Moorea and La Reunion have all shown conspicuous mass mortalities following exceptional replenishment. Modern theoretical models of reef fish populations tend to be based upon bounded stochastic dynamics, with variable replenishment of populations that provide a strong source of change when populations are not near their upper limits. Under this density-vague scenario, population dynamics feature both density-dependent and density-independent fluctuations, and the relative importance of each varies with context. When replenishment is drawn from strongly skewed probability distributions, density dependence is most important at the extremes of density, where its primary effect is to dampen exceptional cohorts. For sedentary prey that fall between these extremes, the foraging behavior of predators interacting with the spatial dispersion of settlers has the potential to produce density-dependent outcomes that are linked only indirectly to absolute abundance. Fish populations are very tolerant of crowding, with numerical responses detected only at very high and very low levels of abundance. Between these extremes, social behavior can have a big effect on individual access to essential resources, including food, with impacts on growth and maturation. Some populations may be able to store fecundity in the form of stunted subadults that could be recruited into the breeding pool as required to buffer egg production from the impacts of variable settlement. Thus, it is likely that numerical fluctuations in fish populations are a poor proxy for changes in egg production.
We examined the pattern of development of assemblages of coral reef fishes on artificial reefs at One Tree Reef, Great Barrier Reef. Two sets of 8 reefs were built. To investigate the effects of habitat structure on species diversity, each set consisted of replicate pairs of 4 different reef types: plain (no holes), small-holed, medium-holed, and large-holed reefs. To examine seasonal differences in colonization, 1 set was established in summer (October 1971) and the other set in winter (July 1972). Visual censuses of the reefs' fish assemblages were made at monthly intervals over 32 mo (summer set) and 23 mo (winter set). We recorded a total of 105 resident species from the artificial reefs. Although less diverse, the fish assemblages differed little in terms of species composition from those of small natural patch reefs. Artificial reefs showed a high between-reef variability in species composition that was largely unrelated to habitat structure. Competitive interactions between species appeared unimportant in explaining the distribution of species between reefs. Likewise, possible positive associations between species were indicated for only a few species. Almost all settlement of the artificial reefs was by juvenile fishes. Recruitment was markedly seasonal and occurred mainly over summer (September-May). Juvenile recruitment patterns showed little year-to-year constancy. Most species tested showed nonrandom, clumped patterns of settlement on replicate reefs. More than half of species tested showed no significant differences on numbers of individuals which settled on different reefs, but the remainder showed significantly greater settlement on some reefs, suggesting habitat selection. For a few species, there was also greater recruitment to reefs already occupied by conspecifics, suggesting possible social facilitation of settlement. For most species, there were no significant interspecific interactions between adults and newly settling juveniles. Between-census variability in species composition was high and species turnover ranged from @?17% of species/mo in winter to @?39% in summer. Maximum times of persistence for most species were
The demand for fish is expected to rise substantially by 2020. Although aquaculture must provide much of the additional fish, it remains to be seen whether restored or enhanced capture fisheries can also help fill the projected gap in supply. The key challenges for capture fisheries involve reducing fishing effort, removing excess fishing capacity and building the institutional arrangements needed to restore spawning biomass to more productive levels, and to reverse degradation of the supporting habitats. Two interventions, based largely on hatchery technology, have the potential to reduce the time needed to rebuild some severely over-exploited fisheries, or improve the productivity of other ‘healthy’ fisheries. These interventions are ‘restocking’, which involves releasing cultured juveniles to restore spawning biomass to levels where the fishery can once again support regular harvests, and ‘stock enhancement’, which involves release of cultured juveniles to overcome recruitment limitation. However, despite the potential of these interventions, few restocking and stock enhancement programmes have met expectations. The main problems have been a pre-occupation with bio-technical research at the expense of objective analysis of the need for the intervention, and failure to integrate the technology within an appropriate management scheme that has the participation and understanding of the users. The papers presented at the Special Symposium on this subject at the Seventh Asian Fisheries Forum provide a series of valuable lessons to guide objective assessment of the potential for restocking and stock enhancement. They also show how to implement these interventions responsibly and effectively where they are deemed to add value to other forms of management. Above all, these studies demonstrate that restocking and stock enhancement programmes are applied in complex human–environment systems, involving dynamic interactions between the resource, the technical intervention and the people who use it.
We compared catches of settlement-stage reef fishes in light traps attached to underwater speakers playing reef sounds with those of silent traps during a summer recruitment season at Lizard Island, Great Barrier Reef, Australia. Of the total 40191 reef fishes we collected, significantly more (67%; Wilcoxon and Binomial tests: p<0.001) appeared in the traps with broadcast reef noise. Traps deployed with speakers consistently caught a greater diversity of species (Wilcoxon test: p<0.001, total 81 vs 68) than did silent traps. This study provides a clear demonstration that the settlement-stages of a broad range of families of coral reef fishes are attracted to reef sounds.
The sustained swimming abilities of the late pelagic stages of 9 families of reef fishes were measured at 13.5 cm s(-1). There was a 25-fold difference in abilities among the families. Acanthurid juveniles swam on average for 194.3 h, covering the equivalent of 94.4 km. In comparison nemipterids swam for only 7.4 h, the equivalent of 3.6 km. The distances covered by other taxa ranged from 8.3 to 62.2 km. Among the families swimming ability was related to size and age but this relationship explained little of the variation present (R-2 = 0.403). Our results demonstrate that the pelagic stages of reef fishes are competent swimmers and capable of actively modifying their dispersal. This has direct implications on the replenishment of reef fish populations, especially with respect to mechanisms for self-seeding and maintenance of regional biogeographical patterns.
Larval supply is crucial for the persistence of coral reef fish populations, yet little direct information exists about any aspect of this life history phase. Using light traps, this study directly measured larval supply of 27 coral reef fish taxa to Lizard Island (northern Great Barrier Reef) over 2 successive recruitment seasons. Descriptions of the magnitude and synchrony of replenishment to 3 different habitats (front-reef, back-reef and lagoon) within a single reef are the first of their kind and reveal several important facets of the larval supply process. Larval supply during the first season was much stronger into the front-reef side than into the back-reef habitat. Synchrony of daily replenishment between these 2 habitats was characteristically weak during this year. This result was not related in any simple way to low levels of absolute abundance in the back-reef habitat. In the following year, this dominance of the front-reef habitat was diminished. In many cases, this decline could be explained by a rise in the strength of the replenishment signal in the back-reef habitat. Correlated with this, there was a general increase in the strength of synchrony in larval supply between the 2 habitats. Again this trend could not be simply explained by any increase in absolute abundance in the back-reef habitat. It appears that there was a change in the nature of the larval supply process between these habitats over the 2 years. Although temporally variable, replenishment into either habitat showed consistent patterns across many taxa indicating that larval supply to a single reef is systematic rather than 'stochastic'. We suggest that investigation of the relationship between larvae and the local physical conditions surrounding each reef may reveal the reasons for much of this complexity in replenishment. Larval supply into the lagoon was highly variable among taxa. The greater association of the lagoon with the front-reef habitat was revealed by the cross-correlation coefficients of many taxa. In some cases this could be explained by a progressive depletion of larvae as they crossed the front-reef crest and entered the lagoon. However, larval abundance of 4 taxa in the lagoon was so low (seasonal sum < 10 for Pomacentrus coelestus, Lethrinidae, P. lepidogenys and Neopomacentrus spp.) that active behavioural choice of settling larvae seems to be involved.
Colonization of the lagoon at Moorea Island, French Polynesia, by fish larvae was studied with a net fixed on the outer reef crest in order to observe diel and lunar cycles. Fish larvae entered the lagoon at dusk and at night, mainly during moonless periods. Colonization was closely related to decreasing light intensity; it was 4 times greater during new moon than during full moon. Other environmental factors such as hydrodynamic features of the water mass above and in front of the reef crest may have also influenced this colonization. More than 97 % of the larvae that colonized the lagoon were postflexion or later stage larvae and were probably competent to settle in the lagoon. Gobiidae were the most numerous with 60.5 % of the catches. Scaridae and Labridae were the second and the third most important families with 10.3 and 6.2 % of the catches respectively.
Replenishment of benthic marine populations typically involves “settlement” from pelagic larval to benthic juvenile habitats. Mortality during this transition has been unknown because of the difficulty of measuring propagule supply in open water. For three weeks, we compared the nocturnal passage of presettlement fishes across the barrier reef encircling Moorea Island (French Polynesia) with the abundance of benthic recruits in the back-reef lagoon on the following morning. During this time, >40,000 presettlement unicornfish, Naso unicornis entered our study area of ∼1 km2 with half arriving on just two nights. Using coupled Beverton-Holt functions to describe the decay of each cohort, we were able to predict the daily abundance of recruits and their final age structure from the presettlement inputs. The best model estimated that ∼61% of the potential settlers were lost between their nocturnal arrival and the following morning, independent of cohort size. Postsettlement mortality was density dependent, varying between 9% and 20% per day. We attribute all mortality to predation and suggest that high risk associated with settlement has shaped colonization strategies. Because fishing targets the survivors of this population bottleneck, aquarium fisheries may be more sustainable when sourced from pelagic juveniles.
We used plankton nets, floating postlarval collectors, and arrays of benthic settling devices, along with diver surveys of juvenile lobster abundance and nursery habitat structure, to estimate the spatial pattern of settlement, abundance of settlers, and characteristics of postsettlement juvenile Panulirus argus populations in Florida Bay, the primary nursery for spiny lobsters in Florida. Within a 200 km2 region of Florida Bay, settlement was patchy and locally unpredictable, although settlement occurred at most sites each lunar phase. However, the number of postlarvae entering inlets to the bay was significantly correlated with regional settlement, and areas with abundant red macroalgae (settlement substrate) and numerous sponges (benthic juvenile shelter) were the most productive sites, even though settlement within them varied widely during lunar influxes. Floating collector catches accurately estimated the number of postlarvae in the water column at inlets, but results from collectors deployed in the bay did not correlate with the number of postlarvae settling on benthic collectors nearby. Estimates of postsettlement mortality in the field yield a natural mortality of about 97% in the year following settlement.
We conducted a field experiment in the Florida Keys in which we manipulated Caribbean spiny lobster (Panulirus argus) settlement and shelter for juveniles to (i) investigate how these factors influence local recruitment and (ii) evaluate the efficacy of such practices proposed to enhance spiny lobster populations. The number of small juvenile lobsters significantly increased at six 0.05-ha sites where 12 artificial shelters were added, but was unchanged on three unmanipulated sites. Adding over 150 new settlers to three of the shelter-supplemented sites did not measurably increase juvenile lobster abundance above that attributable to shelter enhancement alone. Mark recapture results confirmed that the observed increase in small juveniles on shelter-supplemented sites was not due to immigration. The addition of artificial structures to nursery sites appears to have reduced predation on the vulnerable small juveniles and led to their local retention. In contrast, larger more mobile juveniles were no more abundant where shelter was added than on the unmanipulated sites. These results support the proposition that local recruitment of P argus may be increased by augmenting natural shelter with appropriately designed artificial structures, but the broader implications of enhancing lobster populations on the surrounding natural communities are unknown.