No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Near extinction of a highly fecund fish: The one that nearly got away
Abstract
Abstract It is widely assumed that commercial fisheries of highly fecund species are particularly resilient to exploitation, and that, should populations become seriously diminished, economic constraints will force fishing to cease before biological extinction can occur. Indeed, among commercially exploited marine fishes there is not one confirmed global extinction. Here we document, using nonconventional means, a story that not only questions such assumptions but that should also alert us to how little we know about significant fisheries in some parts of the world. Our case study is that of the highly threatened Chinese bahaba, Bahaba taipingensis, a member of the Sciaenidae (the drums or croakers), and an example of a fecund and commercially important group of fishes that appears to be especially vulnerable to fishing. We also demonstrate that the careful use of informal, or traditional, information can provide a powerful, sometimes unique, means of identifying and assessing the status and history of species that might be quietly slipping away before we learn anything about them.
... Understanding the effects that diet has on farmed totoaba swim bladder characteristics and composition may provide insight into their potential marketability and inform what nutritional benefits may be derived from totoaba swim bladders. In addition to the effects of diet on buche quality, a better understanding of how diet affects swim bladder size relative to fish size (Sadovy and Cheung, 2003) may also inform efforts to estimate the pressure on portions of wild populations subject to poaching. Here we address these challenges by evaluating several components of swim bladder size and quality, as well as the growth response of T. macdonaldi juveniles, fed diets in which fishmeal was differentially replaced by soy protein concentrate. ...
... Dried swim bladders of some fish, also known as fish maw, are luxury food commodities in the Chinese seafood market (Sadovy and Cheung, 2003). Fishes belonging to the family Sciaenidae (croakers) have been Table 5 Selected fatty acid composition (mg g − 1 wet tissue) of swim bladder and whole body of Tototaba macdonaldi fed diets with three inclusion levels of soy protein concentrate (SPC) in place of fishmeal. ...
... This index, never before reported for cultivated totoaba, may be useful for developing a swim bladder-body weight relationship. Such a tool, in conjunction with data on moisture content of this organ, may help infer body size of poached fish from weights of confiscated swim bladders (Sadovy and Cheung, 2003), providing insight into population structure of fish caught illegally. With respect to the dietary effects of SPC at levels of 0, 30%, and 60% on fish performance, observations from this study were consistent with Trejo-Escamilla et al. (2017), who found that growth performance of totoaba was not altered when up to 45% SPC by weight was included in the diet. ...
Totoaba (Totoaba macdonaldi) is a large species of croaker, endemic to the upper Gulf of California in Mexico, which has been under extreme poaching pressure due to its highly valuable swim bladder, or buche. For more than 20 years, totoaba aquaculture has been developing as one, among many, conservation strategies in the ongoing management of the species. Competing with illegally poached buche requires farming high quality product. This study provides the first report of the influence of alternative aquaculture feeds-fishmeal versus soy protein concentrate (SPC)-on key cultured totoaba traits that affect the market value of its swim bladder. Since the price of farmed buche is key to the successful displacement of illegally poached product, options for replacing expensive fishmeal are key to conservation success. A variety of characteristics related to buche size and quality were affected by diet composition, but partial inclusion of soy protein as a substitute for fishmeal can produce buche of comparable quality to product grown from more expensive fishmeal diets. These findings highlight a path for diet changes to produce high value totoaba swim bladders from aquaculture at substantially lower costs.
... Fish swim bladdercommonly known as mawis among the most expensive dried seafood in China ( Fig. 1; [5,8]). Similar to other expensive seafood delicacies in the country, fish maw is linked to wealth, prestige and honor [5]. ...
... The fish is now rarely caught, but occasionally one is hooked and often makes headlines. In 2012, a single ~80 kg fish was sold for £300,000 [8,17]. The abundance of Chinese bahaba appears to be so low that it may be the first commercial marine species to become extinct in the wild [8]. ...
... In 2012, a single ~80 kg fish was sold for £300,000 [8,17]. The abundance of Chinese bahaba appears to be so low that it may be the first commercial marine species to become extinct in the wild [8]. ...
The demand for fish maw (i.e., dried swim bladder) has apparently intensified during the past decades in Hong Kong and mainland China; currently, maw has similar annual import volumes but far higher mean unit values than other important seafood delicacies like shark fins and sea cucumber. Escalated demand for seafood delicacies can significantly contribute to the depletion of marine resources; yet a comprehensive understanding of maw value and the fisheries that supply it is lacking. We review available information on eight important maw-supplying species in major and largely undocumented source countries to examine the susceptibility and exposure of fisheries to the maw trade, which primarily serves Chinese demand. Comparing ex-vessel price ratios of maw to flesh (USD/kg), the overall mean price of maw can be as much as 72 times higher (range between 12:1 and 8389:1). Catch, price and export trends demonstrate that demand for maw is likely intensifying in countries already supplying it, shifting or expanding to new species, and emerging in new regions. We find that most maw-supplying species are under high fishing pressure, poorly or not protected. Those that yield the highest maw prices exhibit spawning aggregations, making them exceptionally vulnerable to overexploitation. While management interventions are needed to sustain fishery resources and capture economic benefits, their effectiveness will be challenged by the high value of maw.
... Overfishing and ocean pollution in the past decade have led to a dramatic decrease in fish in the wild fisheries of China (Liu & Sadovy 2008;Sadovy & Cheung 2003). The endemic species of giant yellow croaker (Bahaba taopongensos), which is highly valued as a traditional medicine of its swim bladder and was an important fish stock before the 1960s, collapsed in the wild and was determined to be commercially extinct in 1997 (Sadovy & Cheung 2003). ...
... Overfishing and ocean pollution in the past decade have led to a dramatic decrease in fish in the wild fisheries of China (Liu & Sadovy 2008;Sadovy & Cheung 2003). The endemic species of giant yellow croaker (Bahaba taopongensos), which is highly valued as a traditional medicine of its swim bladder and was an important fish stock before the 1960s, collapsed in the wild and was determined to be commercially extinct in 1997 (Sadovy & Cheung 2003). The spotted drum (Protonobea doacanthus) and large yellow croaker (Laromochthys crocea, which is endemic to East Asia and was once one of the three top commercial marine fishes in China), have been severely depleted throughout their geographic range since the 1980s and have now almost entirely disappeared from landings (Liu & Sadovy 2008;Sadovy & Cheung 2003). ...
... The endemic species of giant yellow croaker (Bahaba taopongensos), which is highly valued as a traditional medicine of its swim bladder and was an important fish stock before the 1960s, collapsed in the wild and was determined to be commercially extinct in 1997 (Sadovy & Cheung 2003). The spotted drum (Protonobea doacanthus) and large yellow croaker (Laromochthys crocea, which is endemic to East Asia and was once one of the three top commercial marine fishes in China), have been severely depleted throughout their geographic range since the 1980s and have now almost entirely disappeared from landings (Liu & Sadovy 2008;Sadovy & Cheung 2003). The most recent study of Indo-Pacific humpback dolphins (Sousa chonensos, locally called the Chinese white dolphin) biosonar activity in the Pearl River Estuary indicated that its diel, seasonal and tidal patterns might be ascribed to the spatial-temporal variability of its prey (Wang et al. 2015b); however, little attention has been paid to local fishes, with only sporadic fishery distribution data with poor temporal and spatial resolution obtained from 1986-1987 by bottom trawl and in 1998 by beam trawl and hang trawl (Li et al. 2000b;Wang & Lin 2006).The fine-scale distribution pattern of humpback dolphin prey has yet to be investigated. ...
Background. Repetitive species-specific sound enables the identification of the presence and behavior of soniferous species by acoustic means. Passive acoustic monitoring has been widely applied to monitor the spatial and temporal occurrence and behavior of calling species. Methods. Underwater biological sounds in the Pearl River Estuary, China, were collected using passive acoustic monitoring, with special attention paid to fish sounds. A total of 1408 suspected fish calls comprising 18,942 pulses were qualitatively analyzed using a customized acoustic analysis routine. Results. We identified a diversity of 66 types of fish sounds. In addition to single pulse, the sounds tended to have a pulse train structure. The pulses were characterized by an approximate 8 ms duration, with a peak frequency from 500 to 2600 Hz and a majority of the energy below 4000 Hz. The median inter-pulsepeak interval (IPPI) of most call types was 9 or 10 ms. Most call types with median IPPIs of 9 ms and 10 ms were observed at times that were exclusive from each other, suggesting that they might be produced by different species. According to the literature, the two section signal types of 1+1 and 1+N 10 might belong to big-snout croaker ( Johnius macrorhynus ), and 1+N 19 might be produced by Belanger's croaker ( J. belangerii ). Discussion. Categorization of the baseline ambient biological sound is an important first step in mapping the spatial and temporal patterns of soniferous fishes. The next step is the identification of the species producing each sound. The distribution pattern of soniferous fishes will be helpful for the protection and management of local fishery resources and in marine environmental impact assessment. Since the local vulnerable Indo-Pacific humpback dolphin ( Sousa chinensis ) mainly preys on soniferous fishes, the fine-scale distribution pattern of soniferous fishes can aid in the conservation of this species. Additionally, prey and predator relationships can be observed when a database of species-identified sounds is completed.
... Overfishing and ocean pollution in the past decade have led to a dramatic decrease in fish in the wild fisheries of China (Liu & Sadovy 2008;Sadovy & Cheung 2003). The endemic species of giant yellow croaker (Bahaba taopongensos), which is highly valued as a traditional medicine of its swim bladder and was an important fish stock before the 1960s, collapsed in the wild and was determined to be commercially extinct in 1997 (Sadovy & Cheung 2003). ...
... Overfishing and ocean pollution in the past decade have led to a dramatic decrease in fish in the wild fisheries of China (Liu & Sadovy 2008;Sadovy & Cheung 2003). The endemic species of giant yellow croaker (Bahaba taopongensos), which is highly valued as a traditional medicine of its swim bladder and was an important fish stock before the 1960s, collapsed in the wild and was determined to be commercially extinct in 1997 (Sadovy & Cheung 2003). The spotted drum (Protonobea doacanthus) and large yellow croaker (Laromochthys crocea, which is endemic to East Asia and was once one of the three top commercial marine fishes in China), have been severely depleted throughout their geographic range since the 1980s and have now almost entirely disappeared from landings (Liu & Sadovy 2008;Sadovy & Cheung 2003). ...
... The endemic species of giant yellow croaker (Bahaba taopongensos), which is highly valued as a traditional medicine of its swim bladder and was an important fish stock before the 1960s, collapsed in the wild and was determined to be commercially extinct in 1997 (Sadovy & Cheung 2003). The spotted drum (Protonobea doacanthus) and large yellow croaker (Laromochthys crocea, which is endemic to East Asia and was once one of the three top commercial marine fishes in China), have been severely depleted throughout their geographic range since the 1980s and have now almost entirely disappeared from landings (Liu & Sadovy 2008;Sadovy & Cheung 2003). The most recent study of Indo-Pacific humpback dolphins (Sousa chonensos, locally called the Chinese white dolphin) biosonar activity in the Pearl River Estuary indicated that its diel, seasonal and tidal patterns might be ascribed to the spatial-temporal variability of its prey (Wang et al. 2015b); however, little attention has been paid to local fishes, with only sporadic fishery distribution data with poor temporal and spatial resolution obtained from 1986-1987 by bottom trawl and in 1998 by beam trawl and hang trawl (Li et al. 2000b;Wang & Lin 2006).The fine-scale distribution pattern of humpback dolphin prey has yet to be investigated. ...
Background. Repetitive species-specific sound enables the identification of the presence and behavior of soniferous species by acoustic means. Passive acoustic monitoring has been widely applied to monitor the spatial and temporal occurrence and behavior of calling species. Methods. Underwater biological sounds in the Pearl River Estuary, China, were collected using passive acoustic monitoring, with special attention paid to fish sounds. A total of 1408 suspected fish calls comprising 18,942 pulses were qualitatively analyzed using a customized acoustic analysis routine. Results. We identified a diversity of 66 types of fish sounds. In addition to single pulse, the sounds tended to have a pulse train structure. The pulses were characterized by an approximate 8 ms duration, with a peak frequency from 500 to 2600 Hz and a majority of the energy below 4000 Hz. The median inter-pulsepeak interval (IPPI) of most call types was 9 or 10 ms. Most call types with median IPPIs of 9 ms and 10 ms were observed at times that were exclusive from each other, suggesting that they might be produced by different species. According to the literature, the two section signal types of 1+1 and 1+N 10 might belong to big-snout croaker ( Johnius macrorhynus ), and 1+N 19 might be produced by Belanger's croaker ( J. belangerii ). Discussion. Categorization of the baseline ambient biological sound is an important first step in mapping the spatial and temporal patterns of soniferous fishes. The next step is the identification of the species producing each sound. The distribution pattern of soniferous fishes will be helpful for the protection and management of local fishery resources and in marine environmental impact assessment. Since the local vulnerable Indo-Pacific humpback dolphin ( Sousa chinensis ) mainly preys on soniferous fishes, the fine-scale distribution pattern of soniferous fishes can aid in the conservation of this species. Additionally, prey and predator relationships can be observed when a database of species-identified sounds is completed.
... However, its numbers have reduced sharply in recent years owing to the deterioration of the water environment and illegal overfishing, and the Chinese bahaba is currently on the verge of extinction. Until now, it was only occasionally found in "Dragon's Nest Island-Shajiao-Dahu Island" in the waters of Dongguan in the estuary of the Pearl River [1][2][3]. The Chinese bahaba was enlisted as a critically endangered species in the Red List of endangered species by the International Union for Conservation of Nature (IUCN) in 2006 and was listed as a national first-class key protected aquatic wildlife in 2021 [1,3]. These reports indicate that it is urgently necessary to improve the resource protection of Chinese bahaba and preserve this endangered species. ...
... Until now, it was only occasionally found in "Dragon's Nest Island-Shajiao-Dahu Island" in the waters of Dongguan in the estuary of the Pearl River [1][2][3]. The Chinese bahaba was enlisted as a critically endangered species in the Red List of endangered species by the International Union for Conservation of Nature (IUCN) in 2006 and was listed as a national first-class key protected aquatic wildlife in 2021 [1,3]. These reports indicate that it is urgently necessary to improve the resource protection of Chinese bahaba and preserve this endangered species. ...
The Chinese bahaba (Bahaba taipingensis), belonging to the Sciaenidae family, is one of the largest croakers with a limited geographical distribution. It is a critically endangered fish species according to the IUCN and a protected animal in China. In this study, the morphological characteristics of Chinese bahaba were observed and analyzed across different developmental stages, namely, the embryonic, larval, juvenile, and young fish stages. The results demonstrated that the mature eggs had a terminal yolk and a single oil globule. The eggs remained floating, and the mean diameters of the fertilized egg and oil globules were 1.14 ± 0.09 mm and 0.35 ± 0.07 mm, respectively. The findings revealed that the embryonic development of Chinese bahaba occurs broadly in seven stages, including the blastogenesis, cleavage, blastocyst, gastrula, neuro embryonic, organ differentiation, and membrane emergence stages, which lasted approximately 27 h and 10 min until hatching under 22.5 ± 0.5 °C. After 70 d, the larvae developed into young fish with a mean total length and body length of 97.75 ± 12.61 and 75.27 ± 13.27 mm, respectively. The digestive organs and the swim bladder began to differentiate, and the swim bladder, bladder duct, intestine, stomach, and mouth gradually formed at 2 d after hatching. Juvenile development occurred via six stages and there were certain differences in the morphological characteristics of Chinese bahaba across the different stages of growth and development. This study provides a theoretical reference for studying the growth, development, and artificial breeding of Chinese bahaba.
... As a result, many species are targeted in commercial fsheries. Te high fshing pressure has led to concern around the sustainability of Sciaenid fsheries worldwide [5,6]. ...
... Te species has experienced population declines throughout its range, with localised depletion of some populations being associated with large increases in targeted fshing practices [7]. In most cases, intensifcation of fshing pressure on P. diacanthus populations has been driven by increasing prices and demand for their swim bladder [5]. As a result, the global status of the species was recently listed as "near threatened" by the IUCN Red List [8]. ...
The black jewfish (Protonibea diacanthus) occurs in tropical coastal waters throughout the central Indo-Pacific. It has long been valued as an important recreational and artisanal fishery species but has become increasingly targeted by commercial fisheries due to demand for its large swim bladder. To better understand how changes in fishing pressure may impact the sustainable exploitation of P. diacanthus populations throughout Eastern Australia, we evaluated the reproductive biology of the species across two management regions in Central Queensland. Reproductive characteristics studied included the size at maturity, fecundity, spawning mode, and season. Spawning periodicity was evaluated throughout the two major management regions and revealed an increase in the gonadosomatic index during the early austral spring, followed by evidence of spawning occurring from September through March with a peak from September to November. Females were found to produce ∼4.5 million ± 1.4 million oocytes (mean ± SE) per batch. Spawning periodicity did not vary latitudinally but was found to differ from other regions in northern Australia. The present study provides reliable maturity and fecundity information to improve future assessment and sustainable management of P. diacanthus.
... All sampling sites had similar nuclear genetic diversity levels, suggesting that either none of the examined populations are experiencing severe declines or that they are all under similar levels of pressure (e.g., fishing effort). Given that meagre are heavily targeted at all sampling sites particularly during spawning aggregations, and that large reductions in population size have been documented 29,30 , we hypothesise that fishing pressure is equivalent (and high) at all locations. ...
... Although considered as Least Concern by the International Union for Conservation of Nature 67 , meagre has faced local extinctions and decreases in abundance 29,30 . These highlight the need to put in place effective management and conservation measures to prevent further collapses. ...
Information on population structure and connectivity of targeted species is key for proper implementation of spatial conservation measures. We used a combination of genomics, biophysical modelling, and biotelemetry to infer the population structure and connectivity of Atlantic meagre, an important fisheries resource throughout its distribution. Genetic samples from previously identified Atlantic spawning locations (Gironde, Tejo, Guadalquivir, Banc d'Arguin) and two additional regions (Algarve and Senegal) were analysed using genome-wide SNP-genotyping and mitochondrial DNA analyses. Biophysical models were conducted to investigate larval dispersal and connectivity from the known Atlantic spawning locations. Additionally, thirteen fish were double-tagged with biotelemetry transmitters off the Algarve (Portugal) to assess movement patterns and connectivity of adult individuals. This multidisciplinary approach provided a robust overview of meagre population structure and connectivity in the Atlantic. Nuclear SNP-genotyping showed a clear differentiation between the European and African populations, with significant isolation of the few known Atlantic spawning sites. The limited level of connectivity between these subpopulations is potentially driven by adults, capable of wide-ranging movements and connecting sites 500 km apart, as evidenced by tagging studies, whilst larval dispersal inferred by modelling is much more limited (average of 52 km; 95% of connectivity events up to 174 km). Our results show sufficient evidence of population structure, particularly between Africa and Europe but also within Europe, for the meagre to be managed as separate stocks. Additionally, considering the low degree of larvae connectivity, the implementation of marine protected areas in key spawning sites could be crucial towards species sustainability.
... Historical data, informal interviews and anecdotal evidence have been useful to predict local extinctions, such as of three species of skates and angel sharks , and the Chinese bahaba (Sadovy & Cheung, 2003). Ferretti et al. (2013), using a similar analysis, also detected a structurally depleted elasmobranch community in the Adriatic Sea. ...
... Fishers in Malvan perceive a drastic increase in the number of fishers in the recent past with many coming in from neighbouring states, and acknowledge the increase in hours and expenses spent on fishing resources but yielding a decrease in fish catch (TERI, 2013). A decline in the diversity of species caught and the catch of sexually immature individuals suggests a case of overexploitation (Lam & Sadovy de Mitcheson, 2011;Sadovy & Cheung, 2003;To & De Mitcheson, 2009). The reduction in the sizes of large-bodied elasmobranchs caught could affect fishery sustainability and species recovery (To & De Mitcheson, 2009). ...
Although elasmobranchs (sharks and rays) are highly threatened by fisheries, there are few studies that examine gear and fishery effects on catch composition and abundance across India, one of the top elasmobranch fishing nations globally. We assessed elasmobranch diversity, abundance, catch rates and fishery characteristics using landing surveys in Malvan on the central‐western coast of India, a major multi‐gear, multi‐species fishing centre, over three sampling periods from February 2018 to March 2020. We sampled 3145 fishing trips and recorded 27 elasmobranch species, of which nearly half are categorised as “Threatened” by the IUCN. In addition, we documented historical records by compiling information from identification guides, research papers, articles and reports. During the study period, the catch was dominated by small‐sized coastal species like the spadenose shark (Scoliodon laticaudus) and the scaly whipray (Brevitrygon walga). Trawlers accounted for 64.9% of the catch, highest by number, and captured smaller‐sized individuals. Nonetheless, artisanal and gillnet fisheries had higher catch per unit effort (CPUE) for rays (5.1 ± 1.0) and sharks (10 ± 1.0), respectively, and captured significantly larger‐sized individuals. Through generalised linear models, we found seasonal, gear and fishery effects on the abundance and size of commonly caught species. The presence of neonates and gravid females of multiple species also suggests nursery grounds in this region. Historically, 141 species have been recorded in this region, and a comparison with current catch suggests a shift in elasmobranch community structure and potential mesopredator release. This study emphasises the importance of gear and species‐specific research for conservation planning at the local level and suggests the need for management strategies with fisher cooperation.
... Sciaenid species are globally distributed and comprise one of the most important groups of fish, supporting many commercial and recreational fisheries worldwide (Fisher et al., 1981;Griffiths & Hecht, 1995a, 1995bOlsen et al., 2018;Paxton & Eschmeyer, 1994;Silberschneider & Gray, 2005). Unfortunately for many species, a lack of life history information during fishery exploitation, coupled with slow growth, late size and age at maturity, and spawning aggregations increasing susceptibility to large catches, has led to a severe depletion of many sciaenid stocks (Sadovy & Cheung, 2003). ...
... The large sizes attained by many species within the family make them highly prized and targeted within recreational and commercial fisheries (Sadovy & Cheung, 2003). Reaching sexual maturity at large sizes also results in a predisposed risk to overfishing and significant declines during the last few decades have been reported for several species e.g. ...
Worldwide there have been declines in stocks of exploited sciaenids. Despite a long history of exploitation, there has been no study of the life history characteristics of the fishery‐important sciaenid, teraglin, Atractoscion atelodus. This study describes the reproductive characteristics of A. atelodus within the major area of its distribution and fishery, New South Wales (NSW) Australia. Characteristics studied included the size and age at maturity, fecundity, spawning mode and season, and these are compared to congeneric species. Atractoscion atelodus displays year‐round batch spawning behaviour with asynchronous oocyte development and indeterminate fecundity. This is unusual for sciaenids, which typically display spring‐summer spawning and only over a few months. The length and age at which 50% of the population matures for both males and females is 36 cm fork length (FL) and 1 year, a smaller size compared to other closely related sciaenids. While the species displays resilient reproductive characteristics such as protracted year‐round spawning, constant supply of vitellogenic oocytes and relatively small/young age at maturity, there are also characteristics that make it susceptible to over‐exploitation. These include highly female skewed sex ratios, as well as their schooling and voracious feeding behaviour leading to the potential for high catch rates.
... The fish is believed to perform seasonal migration and aggregation probably in response to reproduction cycles (Dhawan, 1971) and/or food availability (Thomas and Kunju, 1981). Unfortunately, fish that show aggregation behaviour are typically vulnerable to overfishing and excessive targeting, especially during spawning aggregation, which could be detrimental for such species (Sadovy and Cheung, 2003), as has been the case in Australia with reduction in total length and an abundance of smaller size groups in the catches, and a declining size at maturity (Phelan et al., 2008;Leigh et al., 2022). ...
Introduction
This study evaluates the feasibility of culturing the high-value marine fish Protonibea diacanthus in a polyculture system with Indian pompano ( Trachinotus mookalee ) using a marine cage culture setup. The study aims to determine growth performance, feed efficiency, and the potential of P. diacanthus as a candidate species for polyculture.
Methods
Wild-caught P. diacanthus were reared in six high-density polyethylene sea cages (Inner Diameter: 6 m; Outer Diameter: 7 m; Depth: 4.5 m; Area: 28.29 m²; Volume: 127.29 m³). Two experimental groups were established: Group-1 with 90 individuals (average weight: 130.15 ± 6.39 g) and Group-2 with 90 individuals (average weight: 287.80 ± 16.90 g). Each group was divided into three cages (30 fish/cage) and reared in triplicate with T. mookalee (2,500 fish/cage, average weight: 31.12 ± 1.17 g). The fish were cultured for 148 days and fed a commercial diet (40% crude protein, 10% crude lipid). Growth indices and feed efficiency indices were analyzed, and growth of the fish was modeled using von Bertalanffy Growth Function (VBGF).
Results
Growth performance indices, including total length gain, body weight gain, and specific growth rate, were significantly higher in Group-1 (P ≤ 0.05). Feed efficiency indices (feed conversion ratio, feed efficiency ratio, and protein efficiency ratio) did not differ significantly between the groups (P > 0.05). VBGF modeling estimated P. diacanthus asymptotic length (L ∞ ) at 164.21 ± 3.58 cm, asymptotic weight (W ∞ ) at 44,070.19 ± 2811 g, growth coefficient (K) at 0.30 ± 0.01 yr ⁻¹ and t₀ at -0.005 ± 0.02 yr. The growth performance index (ϕ’) was calculated at 1.91, surpassing values reported for wild populations. Polyculture with P. diacanthus did not significantly affect the growth or feed utilization of T. mookalee (P > 0.05).
Discussion and conclusion
The results indicate that P. diacanthus exhibits superior growth under marine cage culture conditions, with a high growth performance and compatibility in polyculture systems. These findings support the potential of P. diacanthus as a viable candidate for integration into commercial polyculture systems.
... Species with economic value face additional risks, not only from direct exploitation that hampers population regeneration but also from the removal of individuals from wild populations [9][10][11]. Theoretical studies have predicted a loss of alleles and reduced heterozygosity in overexploited populations [12,13]. ...
... Several factors have been identified as responsible for the decline of natural populations and fishery captures of Sciaenids: i) Anthropic pollution in Robins and Ray (1986); i ern and esbaugh (2018); j Reagan (1985); k Frimodt (1995); l chao (1995); m Ross et al. (1995);n waggy et al. (2006); p caverivière and Andriamirado (1997); q schneider (1990); r Ruiz-Jarabo et al. (2018); s estuaries; ii) reduced river discharge; iii) climate change; iv) overfishing; v) illegal trade of their valuable swim bladder; and vi) the capture of many adults before spawning due to the ease of locating large mature fish by courtship sound production (Sadovy and Cheung 2003;Fernández Carvajal 2013;Moreno-Díaz and Alfaro 2018;Bolgan et al. 2020). In contrast to their decline in fisheries, aquaculture production of the Sciaenidae family has increased and partially replaced the decrease in fisheries, with a production of 367,578.4 ...
Sciaenidae is the family of marine fish that has the highest aquaculture growth and production in the world. In this study, the global production, historical characteristics, biological aspects, and aquaculture technologies used for the Sciaenid species with the highest aquaculture production were compiled and analyzed to determine the success factors and bottlenecks that favored these species aquaculture development. This study also presents the state of technological aquaculture development in Sciaenid species in Latin America. The principal Sciaenid aquaculture species are large yellow croaker (Larimichthys crocea), red drum (Sciaenops ocellatus) and meagre (Argyrosomus regius), which together contribute 99.9% of the global aquaculture production of Sciaenid species. The aquaculture success of these three species is attributed to their suitable biology for aquaculture, high consumer demand, good market prices, government support, and prior empirical and/or scientific knowledge with other species that was transferrable to Sciaenidae, however, the aquaculture development of these species has not been free of errors. Principal bottlenecks in development include poorly planned marine spatial planning, the introduction of exotic species, the excessive use of fresh seafood-based feeds (especially in China), and inadequate genetic selection programs. In Latin America, eleven Sciaenidae species with biological attributes similar to the three established aquaculture species are being investigated. The technologies for the totoaba (Totoaba macdonaldi) and the Chilean croaker (Cilus giberti) are the most advanced. The technology developed and the positive and negative experiences of the Sciaenid aquaculture industry identified in this review should be considered to assist government decision-making for research and development of aquaculture in the family Sciaenidae.
... Currently, only 3.5% of China's marine area is covered by its marine protected areas (MPAs), and these are often poorly managed (Hu et al., 2020;Zhang et al., 2017). Iconic marine species have been heavily threatened or even become functionally extinct in China's seas (Chen et al., 2009;Kang et al., 2021;Lin et al., 2022;Sadovy & Cheung, 2003). To the best of our knowledge, the number of Chinese scientists and NGOs focusing on marine conservation is minimal. ...
Plain language summary
Protecting our oceans, which serve as an important life‐support system for humans, presents a significant challenge that needs both science‐based conservation decisions and strong support from multiple stakeholders. However, marine conservation strategies often prioritize environmental and ecological goals above social factors and human dimensions, even though these elements are essential to successful conservation efforts. Scientists and nongovernmental organizations (NGOs) play vital roles in science communication and conservation practices and significantly influence the decision‐making of various stakeholders, including policymakers, conservation managers, and the public. Therefore, understanding the potential social influence of scientists and NGOs on marine conservation, as well as identifying the driving factors behind this influence, is critical for enhancing their impact on societal attitudes and achieving more efficient marine conservation and other successful outcomes. In this context, we present China as a case study to introduce a new framework for identifying the factors and potential causal pathways that affect the social influence of scientists and NGOs on the decision‐making processes of multiple stakeholders in marine conservation. Our research showed that both communication capability and annual funding have strong positive effects on the potential social influence of scientists and NGOs in marine conservation, despite being through different pathways. This finding highlights the importance of these factors in achieving social influence. The novel framework we propose provides a new approach for global researchers to examine the social influence of scientists and NGOs in nature conservation. Ultimately, this framework aims to facilitate science‐based conservation policymaking and actions, helping to achieve the targets of the Kunming‐Montreal Global Biodiversity Framework.
... A clear example of the impact of such threats can be observed in the case of its sister species, Bahaba taipingensis, which is endemic to China. The intensive use of bottom trawling has resulted in high juvenile mortality and has ultimately led to the commercial extinction of B. taipingensis, warranting its listing as critically endangered (CR) on the IUCN Red List of Threatened Species (Sadovy & Cheung, 2003;Moore, 2012;Liu, 2020). ...
The Spine Bahaba (Bahaba polykladiskos), locally known as 'Gelama Tirusan,' is a member of the Sciaenidae fish family that is distributed across Southeast Asia, reaching as far as North Australia. This species is renowned for its swim bladder, which produces a distinctive loud sound. Despite its distribution in Southeast Asia, no previous studies have reported the presence of the Spine Bahaba in Peninsular Malaysia. This research aims to document the first-ever record of B. polykladiskos in Muar River, Johor, and provide ethnoichthyological insights regarding this species. The ethnoichthyological data were collected using a convenience snowball sampling technique, involving the collection of information from communities residing in the Muar area. In total, 47 respondents participated in the study. The results indicate that a majority of the respondents were familiar with (98%) and had encountered (94%) B. polykladiskos in both the Muar River and the local fish market. The study also documented the demand and trade associated with B. polykladiskos in Muar, with recorded prices ranging from RM 20 to RM 11,500 per fish. Furthermore, this research provides an introductory description of the uses and perceived benefits of B. polykladiskos in traditional medicine, particularly in relation to sexual prowess among male respondents. The study successfully establishes a baseline information for B. polykladiskos in Peninsular Malaysia using an ethnoichthyological approach, thus extending the known geographical distribution of this distinctive species.
... Given their characteristic K-selected life history traits (i.e., slow growth, late maturity and low fecundity), these species are typically more vulnerable to anthropogenic impacts, and substantial population declines. Two of the largest sciaenids (Totoaba macdonaldi and Bahaba taipingensis), for example, were almost driven to extinction by a combination of overfishing and environmental changes [20,21]. ...
Background
The meagre, Argyrosomus regius, is a large coastal predatory fish inhabiting waters from the north-eastern Atlantic and Mediterranean Sea, where it is targeted by commercial and recreational fisheries. Previous genetic studies have found an unexpectedly high population differentiation not only between the Atlantic and the Mediterranean, but also along the Atlantic coast. However, the reasons underpinning this genetic barrier remained unclear. Likewise, even though the species is amongst the world’s largest marine teleosts, knowledge about its movement ecology and migratory behaviour remains notably scarce, and primarily reliant on fisheries-dependent data.
Methods
In this study, we used a combination of acoustic telemetry and pop-up satellite archival tags to investigate the movements of 22 adult meagre (70–143 cm total length) along the Southwestern coast of the Iberian Peninsula.
Results
Our results strongly suggest that the previously reported genetic differentiation is not maintained by limited adult dispersal/movement, as hypothesized. On the contrary, we documented some of the longest individual annual migrations ever recorded for a coastal teleost, up to > 2000 km, with frequent back-and-forth movements between the West and Southern Iberian coasts. Moreover, their detected regional movement patterns support the existence of a marked seasonal behavioural shift, with individuals being less active and moving to deeper waters during winter, and are consistent with spawning philopatry associated to their summer reproductive movements. Finally, we identified putative aggregation areas that may harbour important feeding/overwintering grounds.
Conclusions
These findings shed new light on the movement and behaviour patterns of meagre that may be of particular importance for the conservation and spatial management of this species throughout its range, and open the door to further research on functional connectivity.
... This results in shifting baseline syndrome, whereby once species cease to be encountered on a regular basis, they are rapidly forgotten by local communities (Turvey et al. 2010). If such species have not previously been scientifically documented, it can then be difficult to assess their historical range and potential for recovery (Sadovy & Cheung 2003, Webb & Mindel 2015. ...
Globally, sawfishes are amongst the most threatened of all sharks and rays, but a paucity of current data on their presence and status has limited conservation action in many countries. Whilst 2 sawfish species, Pristis pristis and P. zijsron, were historically present in the Philippines, a lack of recent reports suggests that they may have become extremely rare. To determine the current status of sawfishes in the Philippines, interviews were conducted with 106 fishers, fish brokers and fisheries officers at 31 sites in 2016. Interviewees confirmed that sawfishes had inhabited Laguna de Bay and the Agusan and Cagayan Rivers in the past, but the majority of interviewees had last seen a sawfish several decades ago. The most recent observations of a sawfish reported during interviews were in 2014, at the estuary of the Tamontaka River, Mindanao, and at Mercedes fish port, Bicol. After the study, photographic evidence of the landing in 2015 of a largetooth sawfish in Zamboanga Peninsula was published on social media. The considerable degradation and modification of freshwater ecosystems, mangrove loss, coastal degradation, fishing pressure and widespread bottom trawling since the 1940s have all likely contributed to sawfish declines. This study confirms that sawfishes, previously abundant in the Philippines, are now extremely rare or locally extinct. Bottlenose wedgefish Rhynchobatus australiae were observed at Mercedes port during the study and interviewees stated that they are landed regularly. Given the Critically Endangered status of this species, this fishery likely needs immediate management.
... Even when a species becomes so rare that it cannot, alone, support livelihoods, opportunistic exploitation, while targeting more common species, will ensure that population decline continues (Branch et al., 2013). For example, Chinese bahaba (Bahaba taipingensis) is a highly soughtafter fish for use in traditional Chinese medicine, but fishers seeking this species must make their living off other species because only a few are caught each year (Sadovy and Cheung, 2003). The anthropogenic Allee effect, an explicitly biocultural model of extinction risk, is particularly applicable to "collectable" exotic species (Siriwat et al., 2019) or their products, as in the example of traditional Chinese medicine highlighted above (but see Mateo-Martín et al., 2023). ...
Human responses to impending extinctions are complex, highly dependent on cultural and socioeconomic context, and have typically been far less studied than the ecological and genetic aspects of extinction. Specifically, the way in which science and societies respond to population decline, extirpation, and species extinction can also have a profound influence on whether a species goes extinct, either positively or negatively. For example, while some rare species suffer higher extinction risk the rarer they become, some charismatic species benefit from significantly higher conservation effort and elevated levels of scientific research. A more comprehensive and nuanced understanding of which species will go extinct, and which will be ‘rescued’ by conservation and stewardship efforts, requires an explicit interdisciplinary, biocultural approach to extinction that draws on expertise from the natural and social sciences, and dialogue with holders of different knowledge systems, and in particular with Indigenous Peoples and local communities. Ultimately, many currently threatened species will only go extinct if society allows it to occur, either through a lack of motivation, knowledge, resources, or local conservation capacity.
... Chinese bahaba (Bahaba taipingensis), a member of the Sciaenid family, is one of the largest croakers. This species has a geographical distribution in the estuary areas from the Yangtze River southwards to Hong Kong in China [23]. As an endemic commercial species, the Chinese bahaba was overfished due to its economic value. ...
Chinese bahaba (Bahaba taipingensis) is a critically endangered fish species, which can produce sounds like other Sciaenidae species. In this study, sounds produced by sexually mature Chinese bahaba were recorded during the reproduction season for the first time. Two distinct types of sounds were observed during the reproduction season, termed as single drum and fast drum trains calls. Single drum callings occurred as a series of trains with rapid pulses, while fast drum trains callings were mainly made of a single signal. The single drum and fast drum trains had a peak frequency of 77.8 ± 16.2 Hz and 79.1 ± 8.7 Hz, respectively. Statistical analysis suggested significant differences in −3 dB bandwidth, signal duration, and root-mean-square sound pressure levels, except for peak frequency (p < 0.05) between single drum and fast drum trains sounds. Single drum occurred mainly before dawn (period range from 0:00 to 6:00 am) and less frequently after dusk (18:00-24:00 pm), and the fast drum trains occurred after dawn (6:00 am to 12:00 pm) and dusk (18:00 pm to 24:00 pm). Considering the abundance of Chinese bahaba has significantly declined, passive acoustic monitoring provides a non-invasive and low-cost effective tool to monitor sound production during reproduction season, which may help to facilitate aquaculture management and fishery population conservation in the future.
... Although sciaenids have a relatively high fecundity, which would be of value when their stocks are heavily exploited (Musick, 1999;Powles et al., 2000), there are examples of some members of this family being particularly vulnerable to fishing. For example, Totoaba macdonaldi has been fished to extinction in southern China (Sadovy and Cheung, 2003) and Argyrosomus regius is now no longer caught in the Wadden Sea (Wolff, 2000a;2000b). ...
... The writings of Aristotle, Athanaeus and Pliny describe sound production from whales, fish and crustaceans from ancient times (Schevill et al., 1962). Since ancient times shoals of fish have been located underwater by listening with the unaided ear a practice which continued into modern times by Indigenous peoples and Chinese fishers (Sadovy and Cheung, 2003;Schevill et al., 1962). During the 19th Century scientists began to investigate species of fish which could produce sound, investigating the anatomical sound-making structures and speculating as to function (Schevill et al., 1962). ...
We review the current knowledge of the biodiversity of the ocean as well as the levels of decline and threat for species and habitats. The lack of understanding of the distribution of life in the ocean is identified as a significant barrier to restoring its biodiversity and health. We explore why the science of taxonomy has failed to deliver knowledge of what species are present in the ocean, how they are distributed and how they are responding to global and regional to local anthropogenic pressures. This failure prevents nations from meeting their international commitments to conserve marine biodiversity with the results that investment in taxonomy has declined in many countries. We explore a range of new technologies and approaches for discovery of marine species and their detection and monitoring. These include: imaging methods, molecular approaches, active and passive acoustics, the use of interconnected databases and citizen science. Whilst no one method is suitable for discovering or detecting all groups of organisms many are complementary and have been combined to give a more complete picture of biodiversity in marine ecosystems. We conclude that integrated approaches represent the best way forwards for accelerating species discovery, description and biodiversity assessment. Examples of integrated taxonomic approaches are identified from terrestrial ecosystems. Such integrated taxonomic approaches require the adoption of cybertaxonomy approaches and will be boosted by new autonomous sampling platforms and development of machine-speed exchange of digital information between databases.
... The large demand for fish maws from croakers has put some species at risk of overfishing or extinction. For example, Chinese bahaba is one of the largest croakers, reaching 2 m in length (18). Maws from Chinese bahaba are usually very large and thick and are always highly valued. ...
Fish maws (dried swim bladders) have long been used for medicinal tonics and as a valuable food resource in Southeast Asia. However, it is difficult to identify the original species of fish maws sold in markets due to a lack of taxonomic characteristics. In the present study, 37 kinds of commercial fish maws from various medicinal material markets were examined, and gene sequences were successfully obtained from ca. 95% of the samples. Partial sequences of the 16S rRNA gene and cytochrome c oxidase I (COI) gene were obtained and used to investigate the origin of these commercial fish maws. Thirty-five specimens belonged to nine species: five croakers and four noncroakers. All species identification was supported by both high homogeneity (98 to 100%) and clear clustering with low within-group Kimura two-parameter divergence scores (0 to 0.04 for 16S rRNA and 0 to 0.07 for COI) and high between-group divergence scores (0.07 to 0.15 for 16S rRNA and 0.11 to 0.24 for COI). Croakers were the predominant species, accounting for 74% of the total fish maw specimens. The large demand for croakers has put some species at the risk of extinction due to overfishing. As a valuable food, fish maw has progressively become more popular and has been used as a substitute for shark fin. The identification results allowed us to learn more about the fish species available on the fish maw market and provided an indicator for possible control of threatened or endangered fish species. A probable correlation between the molecular characteristics and morphological features of fish maws was also found and could provide both consumers and merchants with an important reference for identifying the origin of fish maws.
HIGHLIGHTS
... The mapping and management of the areas in which reproductive aggregations occur are essential for the maintenance of stocks. Without protection, the exploitation of these areas can lead to the rapid exhaustion of fishery stocks (Sadovy and Cheung, 2003;Sala et al., 2003). This emphasizes the need to identify the areas in which reproductive aggregations of L. purpureus form off the Amazon coast, in order to develop adequate fishery management strategies. ...
The Southern red snapper, Lutjanus purpureus, is a valuable economic resource, especially in international market. However, no recent data are available on the reproductive biology of this species in Brazilian waters, in particular, the stock found on the Amazon reef. The present study evaluated the population structure and reproductive biology of L. purpureus, and the volume of the catch of juveniles taken by the local commercial fisheries. A total of 923 specimens were analyzed, of which, 577 were female and 346 male (sex ratio: 0.6:1; p < 0.05). The analysis of the gonadosomatic index (GSI) and the distribution of maturation stages indicated that the males and females are able to reproduce throughout the year, however the reproductive peak occurs simultaneously with the increase in the water discharge of the Amazon River. The spawning females were registered in the study area, indicating that L. purpureus does not perform long distance reproductive migrations, different from the previously proposed. The Fork length at first sexual maturation (FL50) was estimated to be 35.2 cm in the males and 32.1 cm in the females. The high frequency of juveniles (< FL50) captured by the commercial snapper fleet using longlines (33.67% of the total catch) and traps (42.1%) indicates the poor selectivity of the fishing gear used by the snapper fleet, which may contribute to the accelerated depletion of the L. purpureus stock. Although the results of this study show a catch percentage of juveniles >50%, it is still a significant percentage of juveniles that are being caught due to little or no guidance and enforcement of fishing gear to ensure compliance with current legislation. Considering the data presented in this study and the current situation of declining fish stocks of L. purpureus, an assessment is recommended for the inclusion of the species in the IUCN Red List of Threatened Species, which is currently a species categorized as “vulnerable” in the Brazilian Red List.
... The EU began to deal with deep-sea fisheries in 1992, as a result of assessments carried out by the International Council for the Exploration of the Sea (ICES), who stated that most of the deep-water species of commercial interest were overfished [28]. The current scientific evidence suggests that many deep-sea fish stocks are being exploited beyond sustainable levels [23,[29][30][31][32], thus emphasising the need to improve the management of these species [3,[32][33][34][35]. ...
As part of the “Innovations in the Food System: Exploring the Future of Food” Special Issue, this paper briefly reviews studies that highlight a link between deep-sea fishery resources (deep-sea food resources) and vulnerable marine ecosystems (VME), species, and habitats in the Mediterranean Sea, providing new insights into changes in commercial and experimental catches of the deep-sea fishery resources in the central Mediterranean over the last 30 years. About 40% of the total landing of Mediterranean deep-water species is caught in the central basin. Significant changes in the abundance of some of these resources with time, sea-bottom temperature (SBT), and fishing effort (FE) have been detected, as well as an effect of the Santa Maria di Leuca cold-water coral province on the abundance of the deep-sea commercial crustaceans and fishes. The implications of these findings and the presence of several geomorphological features, sensitive habitats, and VMEs in the central Mediterranean are discussed with respect to the objectives of biodiversity conservation combined with those of management of fishery resources.
... Species within the family Sciaenidae support many significant commercial and recreational fisheries worldwide (Froese & Pauly, 2019) and are highly prized owing to the large sizes they attain (Sadovy & Cheung, 2003). Numerous species (Sciaenops ocellatus, Ross et al., 1995;Argyrosomus japonicus, Silberschneider & Gray, 2005; Totoaba macdonaldi, Potts et al., 2010; Argyrosomus inodorus, Griffiths, 1997; Atractoscion nobilis Hervas et al., 2010) have experienced substantial declines in fishery landings because of the large size that sexual maturity is reached. ...
Growth rates and other age‐related population characteristics are essential parameters underpinning management of a stock. This is the first study to estimate length‐at‐age of Atractoscion atelodus (family Sciaenidae) in New South Wales (NSW), despite the species being exploited since the 1940s. The aim of the current study was to quantify the age‐based biological characteristics of A. atelodus and in particular: (a) validate the use of sagittal otoliths to quantify age; (b) estimate the growth rates and longevity of males and females; (c) examine geographical variation in age and growth; (d) document the age composition in commercial landings and (e) estimate mortality rates. A. atelodus is relatively fast growing, reaching 40 cm fork length (LF) in the first year of life and living to at least 14 years. Growth was significantly different between sexes, with modelled asymptotic lengths of females (L∞ = 84.6 cm LF) greater than males (L∞ = 69.0 cm LF). Growth rates were also significantly different between northern and southern populations. Fish sampled from the southern region were younger and faster growing than those sampled in the northern region, supporting the counter‐gradient growth theory and the influence of upwelling providing greater nutrient and food availability. The commercial fishery was predominantly based on young fish <3 years. with few (c. 5%) greater than 5 years. Fishing mortality estimates (F = 0.42) were similar to natural mortality estimates (M = 0.44). The age‐based parameters estimated in the present study suggest that A. atelodus should be relatively resilient to fishing; nonetheless, the sizes and ages in landings are indicative of a stock heavily fished. The fishery is experiencing truncated age distributions and appears to be largely recruitment driven, increasing susceptibility to overexploitation. Determining geographical differences in growth rates of a population has important implications when considering impacts of anthropogenic drivers such as global warming and overexploitation and is important to determine in managing exploited fish populations.
... Dans ce sens, les espèces de grandes tailles sont donc plus facilement affectées car plus susceptibles d'être pêchées et aussi plus vulnérables car leur cycle biologique est plus long. En effet, les espèces les plus grandes ont besoin de plus de temps pour atteindre la maturité sexuelle et se reproduire (Denney et al., 2002) ce qui les rend d'autant plus sensibles à la surpêche (Sadovy and Cheung, 2003). Si le seuil critique est dépassé et le stade de surpêche atteint, la population n'est plus exploitable au risque de la voir disparaitre totalement. ...
Dans le contexte actuel de surpêche et de réchauffement climatique, il est nécessaire d’adopter une gestion écosystémique des ressources halieutiques. Ce travail de thèse apporte des éléments de réponse à cette problématique en se penchant sur le cas de la pêcherie crevettière guyanaise et de son impact sur les communautés de poissons associées. Comme dans la plupart des régions tropicales, les eaux côtières de Guyane se sont réchauffées d’environ 1°C entre 1990 et 2017. En revanche, comme dans peu d’endroits au monde, la pression de pêche s’est quasiment effondrée sur cette même période. Ce cas d’étude est donc une bonne opportunité pour comprendre la réaction des communautés de poissons de cette région tropicale après une diminution progressive et à grande échelle de la pression de pêche dans un contexte de réchauffement climatique. Les résultats de ce travail montrent que les facteurs environnementaux jouent un rôle dominant dans la structuration des communautés de poissons marins en Guyane. Les analyses montrent notamment des augmentations de certains indicateurs de diversité, une augmentation du spectre des tailles maximales théoriques des espèces et une augmentation de la redondance fonctionnelle qui est un facteur clé pour la stabilité des peuplements. Ces éléments témoignent d’une restructuration des communautés et mettent en avant leur capacité à retrouver un état riche et stable en une période relativement courte d’une douzaine d’années voire moins. On observe néanmoins une tropicalisation des communautés qui pose des questions sur l’évolution future de la diversité des écosystèmes tropicaux au regard des différents scénarios climatiques.
... Totoaba is currently listed as critically endangered by the Convention on International Trade in Endangered Species of Wild Fauna and Flora and the International Union for Conservation of Nature and is listed under the U.S. Endangered Species Act and the Mexican norm for threatened species (NOM-059-SEMARNAT-2010), which includes species considered at risk of extinction (Scientific Authority CITES Mexico 2001;DOF 2010;Valenzuela-Quiñonez et al. 2015). A recent increase in the illegal harvest of totoaba is a consequence of the near extinction of the yellow croaker or Chinese bahaba (Bahaba taipingenisis) in China (Sadovy & Cheung 2003). The dried swim bladders of totoabas and bahabas are similar in size and appearance and can garner prices from US$1,500 to US$20,000/kg dried on the black market in China (CITES 2016; Cisneros-Mata et al. 2020). ...
... The statistical approaches used to infer extinctions are typically based on time series of sightings data, which are difficult to obtain for wide-ranging species, particularly marine fishes (10,11). As a consequence, marine extinctions have been overlooked, as many marine populations have been exploited to the point of collapse long before monitoring began (9,12,13). ...
Extinctions on land are often inferred from sparse sightings over time, but this technique is ill-suited for wide-ranging species. We develop a space-for-time approach to track the spatial contraction and drivers of decline of sawfishes. These iconic and endangered shark-like rays were once found in warm, coastal waters of 90 nations and are now presumed extinct in more than half (n = 46). Using dynamic geography theory, we predict that sawfishes are gone from at least nine additional nations. Overfishing and habitat loss have reduced spatial occupancy, leading to local extinctions in 55 of the 90 nations, which equates to 58.7% of their historical distribution. Retention bans and habitat protections are urgently necessary to secure a future for sawfishes and similar species.
Available at: https://advances.sciencemag.org/content/7/7/eabb6026
... The global demand for marine animal products such as shark fins (Clarke et al., 2006), swim bladders (Sadovy and Cheung, 2003;Clarke, 2004), and ray gill plates (White et al., 2006;Ward-Paige et al., 2013) is unsustainable (Berkes et al., 2006;Lenzen et al., 2012). Particularly for the slower life history species has the intense fishing exploitation that targets these demands resulted in population declines and increased risks of extinction, sometimes with synergistic effects of environmental conditions (Jennings et al., 1999;Schindler et al., 2002). ...
Understanding why different life history strategies respond differently to changes in environmental variability is necessary to be able to predict eco-evolutionary population responses to change. Marine megafauna display unusual combinations of life history traits. For example, rays, sharks and turtles are all long-lived, characteristic of slow life histories. However, turtles also have very high reproduction rates and juvenile mortality, characteristic of fast life histories. Sharks and rays, in contrast, produce a few live-born young, which have low mortality rates, characteristic of slow life histories. This raises the question if marine megafaunal responses to environmental variability follow conventional life history patterns, including the pattern that fast life histories are more sensitive to environmental autocorrelation than slow life histories. To answer this question, we used a functional trait approach to quantify for different species of mobulid rays, cheloniid sea turtles and carcharhinid sharks – all inhabitants or visitors of (human-dominated) coastalscapes – how their life history, average size and log stochastic population growth rate, log(λs), respond to changes in environmental autocorrelation and in the frequency of favorable environmental conditions. The faster life histories were more sensitive to temporal frequency of favourable environmental conditions, but both faster and slower life histories were equally sensitive, although of opposite sign, to environmental autocorrelation. These patterns are atypical, likely following from the unusual life history traits that the megafauna display, as responses were linked to variation in mortality, growth and reproduction rates. Our findings signify the importance of understanding how life history traits and population responses to environmental change are linked. Such understanding is a basis for accurate predictions of marine megafauna population responses to environmental perturbations like (over)fishing, and to shifts in the autocorrelation of environmental variables, ultimately contributing toward bending the curve on marine biodiversity loss.
... Totoaba is currently listed as critically endangered by the Convention on International Trade in Endangered Species of Wild Fauna and Flora and the International Union for Conservation of Nature and is listed under the U.S. Endangered Species Act and the Mexican norm for threatened species (NOM-059-SEMARNAT-2010), which includes species considered at risk of extinction (Scientific Authority CITES Mexico 2001;DOF 2010;Valenzuela-Quiñonez et al. 2015). A recent increase in the illegal harvest of totoaba is a consequence of the near extinction of the yellow croaker or Chinese bahaba (Bahaba taipingenisis) in China (Sadovy & Cheung 2003). The dried swim bladders of totoabas and bahabas are similar in size and appearance and can garner prices from US$1,500 to US$20,000/kg dried on the black market in China (CITES 2016; Cisneros-Mata et al. 2020). ...
The illegal harvest of marine species within exclusive economic zones can have a strong impact on the function of local ecosystems and livelihoods of coastal communities. The complexity of these problems is often overlooked in the development of solutions, leading to ineffective and sometimes harmful social and environmental outcomes. One‐dimensional, oversimplified perspectives can lead to conservation prescriptions that exacerbate social stressors. This is particularly critical in the case of international illegal trade of endangered, high‐value species, which generate a value chain in which artisanal fishers are the first operational and often the weakest link of an intricate web. We examined 2 illegal fisheries, totoaba (Totoaba macdonaldi) and sea cucumber (Isostichopus badionotus and Holothuria floridana), in Mexico. Although these are 2 separate and independent fisheries, important ecological (resource condition, fishery impacts at the ecosystem level) and social (governance, markets) similarities improve understanding of their complexity. Our findings are relevant globally and show the need for interdisciplinary decision‐making groups, community engagement, and the development of demand reduction measures.
The increased illegal fishing to supply swim bladders is the current threat to the Totoaba macdonaldi, due to the high commercial value of swim bladders. Species identification is the foundation of the endangered animal protection. Limited by the sophisticated thermal cycling, specialized machine, and sequencing costs, DNA barcoding might not better satisfy the needs of on-site inspection to the efficiency, convenience, and low cost, although it has reliable results and has been widely used. It is necessary to establish a convenient, rapid, sensitive, and accurate method for customs to inspect the swim bladders in legal or illegal trade on site. In this study, we introduce real-time fluorescence-based recombinase-aided amplification (RF-RAA) into species identification of swim bladders. Specific primers and probes targeted to Totoaba macdonaldi were designed and the reaction temperature and time were screened. It was applied to the forensic identification of swim bladders confiscated by custom after its sensitivity and specificity were verified. The results showed that (1) the primers of TMcytB F1 and TMcytB R3 targeted to the Cytb had a good amplification at 39°C, 30 cycles (15 min) with good repeatability and stability; (2) the method had good specificity and no cross-reaction with other 22 swim bladder originated species; (3) the lowest detectable limit (LDL) of this method was 3.7×101 copies/μL; (4) about 1.836 kg of all the swim bladders confiscated by Shenzhen customs on 2022 were identified to be Totoaba macdonaldi by using this method. This study provides an effective species identification alternative for competent authorities to tackle the illegal import and market regulation of totoaba swim bladders.
Marine fish diversity in the Beibu Gulf from 2014 to 2022 was analyzed, using various methods including at-sea fisheries resource surveys, fishing port surveys, underwater survey techniques, and data from literature, books, and databases, from which 1 059 fish species across 40 orders, 166 families, and 503 genera were identified. Among them, Acanthuriformes displayed the highest diversity, followed by Carangiformes and Perciformes. Notably, eight alien species were found in the Beibu Gulf. The International Union for Conservation of Nature (IUCN) Red List assessment revealed 51 threatened species, primarily cartilaginous fish. Taxonomic changes affected 88.70% of species due to classification adjustments, misidentifications, and junior synonymy. This study contributed new data of the gulf, including one additional order, six new families, 34 new genera, and 81 new species, emphasizing the dynamic nature of marine ecosystems. Fish diversity in the gulf was relatively lower than the broader South China Sea, attributed to limited habitats and survey methods. Different survey methods, such as gill nets, trap nets, and underwater cameras, yielded varying results. Ocean currents may have transported deep-sea species into the Beibu Gulf, leading to accidental records. Research gaps exist in unexplored areas, warranting further investigation. Therefore, the Beibu Gulf hosts significant marine biodiversity, but taxonomic challenges and undiscovered species require new research and conservation efforts.
While haplotype‐specific genetic load shapes the evolutionary trajectory of natural and captive populations, mixed‐haplotype assembly and genotyping hindered its characterization in diploids. Herein, we produced two phased genome assemblies of the critically endangered fish Chinese Bahaba ( Bahaba taipingensis , Sciaenidae, Teleostei) and resequenced 20 whole genomes to quantify population genetic load at a haplotype level. We identified frame‐shifting variants as the most deleterious type, followed by mutations in the 5′‐UTR, 3′‐UTR and missense mutations at conserved amino acids. Phased haplotypes revealed gene deletions and high‐impact deleterious variants. We estimated ~1.12% of genes missing or interrupted per haplotype, with a significant overlap of disrupted genes (30.35%) between haplotype sets. Relative proportions of deleterious variant categories differed significantly between haplotypes. Simulations suggested that purifying selection struggled to purge slightly deleterious genetic load in captive breeding compared to genotyping interventions, and that higher inter‐haplotypic variance of genetic load predicted more efficient purging by artificial selection. Combining the knowledge of haplotype‐resolved genetic load with predictive modelling will be immensely useful for understanding the evolution of deleterious variants and guiding conservation planning.
A key aspect of the sustainable management of commercially important coastal pelagic fish stocks is the identification
of the spatio-temporal dynamics of aggregation behaviour. An exemplary case species is the greater
amberjack, Seriola dumerili. This top-predator is an important commercial resource exploited by recreational and
commercial fisheries worldwide. Greater amberjack is known to form aggregations during important stages of its
life-history, making it highly vulnerable to overfishing with potential consequences to its conservation. To
improve the limited knowledge on the spatio-temporal aggregation areas of this important resource, this study
combined fishing fleet dynamics (Vessel Monitoring System records), environmental and landing data into a
species distribution model to predict such vulnerable events in space and time around the Balearic Islands. Our
results indicated that S. dumerili aggregations were generally encountered in coastal areas at shallow depths
(<100 m), low salinities, low chlorophyll concentrations, and weak meridional and zonal current velocities
around the Balearic Islands. The preference for these environmental variables and processes is probably related
to searching for an optimal scenario that maximises the success of larval development and survival of its
offspring. Moreover, the distribution model suggested the possibility of a longer spawning period than previously
predicted. This research demonstrates the use of a perceptive statistical tool that efficiently combines fisheriesdependent
data and environmental data to highlight essential factors that influence the aggregation behaviour of
S. dumerili and thus provides essential information for the conservation and sustainable exploitation not only of
the greater amberjack, but also for other gregarious species highly-vulnerable to fishing by their aggregation
behaviour.
Coral reefs are the 'rain forests' of the ocean, containing the highest diversity of marine organisms and facing the greatest threats from humans. As shallow-water coastal habitats, they support a wide range of economically and culturally important activities, from fishing to tourism. Their accessibility makes reefs vulnerable to local threats that include over-fishing, pollution and physical damage. Reefs also face global problems, such as climate change, which may be responsible for recent widespread coral mortality and increased frequency of hurricane damage. This book, first published in 2006, summarises the state of knowledge about the status of reefs, the problems they face, and potential solutions. The topics considered range from concerns about extinction of coral reef species to economic and social issues affecting the well-being of people who depend on reefs. The result is a multi-disciplinary perspective on problems and solutions to the coral reef crisis.
Coral reefs are the 'rain forests' of the ocean, containing the highest diversity of marine organisms and facing the greatest threats from humans. As shallow-water coastal habitats, they support a wide range of economically and culturally important activities, from fishing to tourism. Their accessibility makes reefs vulnerable to local threats that include over-fishing, pollution and physical damage. Reefs also face global problems, such as climate change, which may be responsible for recent widespread coral mortality and increased frequency of hurricane damage. This book, first published in 2006, summarises the state of knowledge about the status of reefs, the problems they face, and potential solutions. The topics considered range from concerns about extinction of coral reef species to economic and social issues affecting the well-being of people who depend on reefs. The result is a multi-disciplinary perspective on problems and solutions to the coral reef crisis.
Coral reefs are the 'rain forests' of the ocean, containing the highest diversity of marine organisms and facing the greatest threats from humans. As shallow-water coastal habitats, they support a wide range of economically and culturally important activities, from fishing to tourism. Their accessibility makes reefs vulnerable to local threats that include over-fishing, pollution and physical damage. Reefs also face global problems, such as climate change, which may be responsible for recent widespread coral mortality and increased frequency of hurricane damage. This book, first published in 2006, summarises the state of knowledge about the status of reefs, the problems they face, and potential solutions. The topics considered range from concerns about extinction of coral reef species to economic and social issues affecting the well-being of people who depend on reefs. The result is a multi-disciplinary perspective on problems and solutions to the coral reef crisis.
Coral reefs are the 'rain forests' of the ocean, containing the highest diversity of marine organisms and facing the greatest threats from humans. As shallow-water coastal habitats, they support a wide range of economically and culturally important activities, from fishing to tourism. Their accessibility makes reefs vulnerable to local threats that include over-fishing, pollution and physical damage. Reefs also face global problems, such as climate change, which may be responsible for recent widespread coral mortality and increased frequency of hurricane damage. This book, first published in 2006, summarises the state of knowledge about the status of reefs, the problems they face, and potential solutions. The topics considered range from concerns about extinction of coral reef species to economic and social issues affecting the well-being of people who depend on reefs. The result is a multi-disciplinary perspective on problems and solutions to the coral reef crisis.
Coral reefs are the 'rain forests' of the ocean, containing the highest diversity of marine organisms and facing the greatest threats from humans. As shallow-water coastal habitats, they support a wide range of economically and culturally important activities, from fishing to tourism. Their accessibility makes reefs vulnerable to local threats that include over-fishing, pollution and physical damage. Reefs also face global problems, such as climate change, which may be responsible for recent widespread coral mortality and increased frequency of hurricane damage. This book, first published in 2006, summarises the state of knowledge about the status of reefs, the problems they face, and potential solutions. The topics considered range from concerns about extinction of coral reef species to economic and social issues affecting the well-being of people who depend on reefs. The result is a multi-disciplinary perspective on problems and solutions to the coral reef crisis.
Coral reefs are the 'rain forests' of the ocean, containing the highest diversity of marine organisms and facing the greatest threats from humans. As shallow-water coastal habitats, they support a wide range of economically and culturally important activities, from fishing to tourism. Their accessibility makes reefs vulnerable to local threats that include over-fishing, pollution and physical damage. Reefs also face global problems, such as climate change, which may be responsible for recent widespread coral mortality and increased frequency of hurricane damage. This book, first published in 2006, summarises the state of knowledge about the status of reefs, the problems they face, and potential solutions. The topics considered range from concerns about extinction of coral reef species to economic and social issues affecting the well-being of people who depend on reefs. The result is a multi-disciplinary perspective on problems and solutions to the coral reef crisis.
Coral reefs are the 'rain forests' of the ocean, containing the highest diversity of marine organisms and facing the greatest threats from humans. As shallow-water coastal habitats, they support a wide range of economically and culturally important activities, from fishing to tourism. Their accessibility makes reefs vulnerable to local threats that include over-fishing, pollution and physical damage. Reefs also face global problems, such as climate change, which may be responsible for recent widespread coral mortality and increased frequency of hurricane damage. This book, first published in 2006, summarises the state of knowledge about the status of reefs, the problems they face, and potential solutions. The topics considered range from concerns about extinction of coral reef species to economic and social issues affecting the well-being of people who depend on reefs. The result is a multi-disciplinary perspective on problems and solutions to the coral reef crisis.
Coral reefs are the 'rain forests' of the ocean, containing the highest diversity of marine organisms and facing the greatest threats from humans. As shallow-water coastal habitats, they support a wide range of economically and culturally important activities, from fishing to tourism. Their accessibility makes reefs vulnerable to local threats that include over-fishing, pollution and physical damage. Reefs also face global problems, such as climate change, which may be responsible for recent widespread coral mortality and increased frequency of hurricane damage. This book, first published in 2006, summarises the state of knowledge about the status of reefs, the problems they face, and potential solutions. The topics considered range from concerns about extinction of coral reef species to economic and social issues affecting the well-being of people who depend on reefs. The result is a multi-disciplinary perspective on problems and solutions to the coral reef crisis.
Coral reefs are the 'rain forests' of the ocean, containing the highest diversity of marine organisms and facing the greatest threats from humans. As shallow-water coastal habitats, they support a wide range of economically and culturally important activities, from fishing to tourism. Their accessibility makes reefs vulnerable to local threats that include over-fishing, pollution and physical damage. Reefs also face global problems, such as climate change, which may be responsible for recent widespread coral mortality and increased frequency of hurricane damage. This book, first published in 2006, summarises the state of knowledge about the status of reefs, the problems they face, and potential solutions. The topics considered range from concerns about extinction of coral reef species to economic and social issues affecting the well-being of people who depend on reefs. The result is a multi-disciplinary perspective on problems and solutions to the coral reef crisis.
Coral reefs are the 'rain forests' of the ocean, containing the highest diversity of marine organisms and facing the greatest threats from humans. As shallow-water coastal habitats, they support a wide range of economically and culturally important activities, from fishing to tourism. Their accessibility makes reefs vulnerable to local threats that include over-fishing, pollution and physical damage. Reefs also face global problems, such as climate change, which may be responsible for recent widespread coral mortality and increased frequency of hurricane damage. This book, first published in 2006, summarises the state of knowledge about the status of reefs, the problems they face, and potential solutions. The topics considered range from concerns about extinction of coral reef species to economic and social issues affecting the well-being of people who depend on reefs. The result is a multi-disciplinary perspective on problems and solutions to the coral reef crisis.
The blackspotted croaker (Protonibea diacanthus) is an endangered coastal marine fish. It is also a valuable species that is cultured on the southeast coast of China. While some genetic studies have been conducted to protect this species, genomic resources are lacking. Here, we report a chromosome-scale assembly of P. diacanthus genome by high-depth genome sequencing, assembly, and annotation. The genome scale was 635.69 Mb with contig and scaffold N50 length of 3.33 Mb and 25.60 Mb, respectively. Hi-C scaffolding of the genome resulted in 24 chromosomes of 94.15% total genome. We predicted 23,971 protein-coding genes. In addition, we constructed a phylogenetic tree using 2755 single-copy gene families and identified 462 unique gene families in P. diacanthus genome compared to three other sciaenids. What's more, from the analysis of gene families, we found that several gene families related to innate immunity were significantly expanded in the blackspotted croaker genome compared to other teleost genomes. The high-quality genome can improve our understanding of the molecular mechanisms behind economically valuable traits and provide insights into characteristics of the immune system.
Fishers have detailed knowledge of their resources, their environment, and their fishing practices that is rarely systematically collected. We conducted three types of interviews with coastal Newfoundland fishers to identify the range of information available, to see if it could be quantified, and to explore its potential for reconstructing trends within fisheries. These fishers have many terms for Atlantic cod (Gadus morhua), each associated with characteristic patterns of seasonal movement and availability to gear and indicating the location of several coastal spawning areas. They described a variety of changes in fishing practice. Of the four changes that could be quantified, all contributed to decadal-scale increases in catch efficiency prior to 1992, while change in catch per unit of effort for cod was consistently negative at decadal scales. For these fishers' lumpfish (Cyclopterus lumpus) roe fishery, catch per unit of effort was consistently negative in the 1990s. We describe ways to access the large reservoir of information held by fishers, the use of several cross-checks to identify consistent patterns, and the use of trends and patterns to broaden the basis for interpreting quantitative surveys used in fisheries assessment. Local information from resource users can be assembled in forms usable in quantitative stock assessments.
Human impacts on the world's oceans have been substantial, leading to concerns about the extinction of marine taxa.We have compiled 133 local, regional and global extinc-tions of marine populations. There is typically a 53-year lag between the last sighting of an organism and the reported date of the extinction at whatever scale this has occurred. Most disappearances (80%) were detected using indirect historical compara-tive methods, which suggests that marine extinctions may have been underestimated because of low-detection power. Exploitation caused most marine losses at various scales (55%), followed closely by habitat loss (37%), while the remainder were linked to invasive species, climate change, pollution and disease. Several perceptions concerning the vulnerability of marine organisms appear to be too general and insu¤ciently con-servative. Marine species cannot be considered less vulnerable on the basis of biological attributes such as high fecundity or large-scale dispersal characteristics. For commer-cially exploited species, it is often argued that economic extinction of exploited popula-tions will occur before biological extinction, but this is not the case for non-target species caught in multispecies ¢sheries or species with high commercial value, espe-cially if this value increases as species become rare. The perceived high potential for recovery, high variability and low extinction vulnerability of ¢sh populations have been invoked to avoid listing commercial species of ¢shes under international threat criteria. However, we need to learn more about recovery, which may be hampered by negative population growth at small population sizes (Allee e¡ect or depensation) or ecosystem shifts, as well as about spatial dynamics and connectivity of subpopulations before we can truly understand the nature of responses to severe depletions. The evidence sug-gests that ¢sh populations do not £uctuate more than those of mammals, birds and but-ter£ies, and that ¢shes may exhibit vulnerability similar to mammals, birds and butter£ies. There is an urgent need for improved methods of detecting marine extinc-tions at various spatial scales, and for predicting the vulnerability of species.
growth and late maturity Severe population declines have been documented for several snappers and groupers (Lutjanidae, Serranidae) in the Atlantic and the Gulf of California, several rockfishes (Sebastinae) in the Pacific, and some sharks (Selachei), skates (Rajidae), and sawfishes (Pristidae). Regulatory agencies should be apprised that these groups are extraordinarily vulnerable, and priority management should be given to these species, The greatest threat to many long-lived marine species may be bycatch (including regulatory dis- card) in fisheries,tar geting other, often more-productive species. Regulatory,agencies must monitor bycatch of long-lived species and move to implement conservation actions if population declines are recorded. The most effective management strategy for some species taken as bycatch and for tar- geted species such as deeper-water groupers and Pacific rockfishes, may be establishment of large, protected marine reserves to supplement traditional management practices outside of the protected areas. The AFS supports the development, use, and evaluation of large marine reserves or Marine Protected Areas to protect and rebuild vulnerable populations. These reserves must have clearly defined goals, include a wide variety of environmental conditions, be of sufficient number to pro- tect marine ecosystems within each region, allow adaptive management, and be large enough to be self-sustaining. The AFS encourages its members to become involved by providing technical infor- mation needed for protection of at-risk marine stocks to international , federal, state, and provincial policy makers, so decisions are made on a scientific, rather than emotional or political, basis.
This initiative was supported by grants to AFS and the Virginia Institute of Marine Science by the Pew Charitable Trusts, NMFS Office of Protected Resources, National Fish and Wildlife Foundation, The Munson Foundation and the Homeland Foundation, J.A. Musick, Principal investigator.
Quantitative criteria used to assign species to categories of extinction risk may,seriously overestimate these risks for marine,fishes. Contemporary,perception is that marine,fishes may,be less vulnerable to extinction than other taxa, because of great natural variability in abundance, high fecundity, rapid population growth, and an intrinsically high capability of recovering from low population size. Contrary to perception, however, there appears to be generally little theoretical or empirical support for the hypotheses,that marine,fish are more,likely to experience large reductions in population size, to produce unusually high levels of recruitment, to have higher reproductive rates, or to recover more,rapidly from,prolonged,population declines than nonmarine,fishes. Although existing population-decline criteria may not accurately reflect probabilities of biological extinction, they do appear to reflect the converse—population re - covery. Insufficient support for contemporary perceptions of their susceptibility to extinction, coupled with caveats as - sociated with the assignment of extinction risk, suggest that significant increases in the population-decline thresholds used to assign marine,fishes to at-risk categories would,be inconsistent with a precautionary approach,to fisheries man,- agement,and the conservation of marine,biodiversity. Résumé : Il est possible que les critères quantitatifs qui servent à placer les espèces de poissons marins dans les
A change in attitude is urgently required to provide credibility to, and to devise methods for, combining and utilizing non-scientific information (local knowledge) together with more typical scientific data. In the midst of vast uncertainty about fish stocks, the climate is right for this change in attitude. Expert systems offer one tool to combine different sources of information in a meaningful way. We believe that through the simple communication required to gather knowledge for an expert system, the development of mutual respect will foster cooperation and responsibility of resource users, scientists and managers, thus providing the basis for improved and more responsible management.
Jean Baptiste de Lamarck and Thomas Huxley, two of the foremost thinkers of the 18th and 19th centuries, believed that humanity could not cause the extinction of marine species. Their opinions reflected a widespread belief that the seas were an inexhaustible source of food and wealth of which people could barely use a fraction. Such views were given weight by the abundant fisheries of the time. Additionally, the incredible fecundity and wide distributions of marine fishes, combined with limited exploitation, provided ample justification for optimism. The ideas of Huxley and Lamarck persist to this day, despite a sea change in the scale and depth of our influence on the oceans. Marine species could be at a far greater risk of extinction than we have assumed.
The dusky kob Argyrosomus japonicus is an important linefish species that is abundant in South African waters between Cape Agulhas and the Moçambique border. The juveniles (Y/R) and spawner biomass-per-recruit (SB/R) models were applied to the South African dusky kob stock, with accommodation for different inshore (Finshore) and offshore (Foffshore) fishing mortality. It is shown that, as a result of high juvenile mortality (Finshore = 4–6-fold FSB25 and 6–10-fold FSB40), dusky kob were exploited far beyond optimal (FSB40) and threshold (FSB25) fishing limits, and that SB/R was 1.0 – 4.5% of the pristine value. This is indicative of severe stock depletion and of recruitment overfishing. Based on the bag frequencies of 16 367 angler outings, it is clear that the current recreational bag limit of 10 fish·angler−1·day−1 does not limit fishing effort. Three alternative management scenarios (combinations of Finshore and minimum size at first capture) are discussed, which elevate SB/R above 25%SB/RF=0, increase Y/R beyond current levels, and equitably apportion Y/Rinshore and Y/Roffshore. Whereas it would take about 41 years for any of the alternative scenarios to attain maximum SB/R, a 3-fold increase is expected after 9 years and a 6.0 – 6.4-fold increase after 20 years. The increase in spawner biomass associated with the alternative strategies is expected to increase both inshore and offshore yield dramatically (as a result of higher recruitment), even though Y/Rinshore would be 69 – 70% of its current value. It is concluded that, because of the susceptibility of A. japonicus to recruitment overfishing, the species may have been overexploited in fisheries throughout its wide distributional range, and that accurate life history data and assessment-based regulations are essential for successful long-term management.
The life history of Argyrosomus japonicus off the east coast of South Africa was studied using biological, size composition and tagging data from fish caught in the estuaries, surf zone and nearshore marine environment of three coastal regions. Capture methods included hook and line (all habitats), seine-netting (estuaries and surf zone), and gill-netting and trawling (estuaries only). Median total length (TL) at maturity was 920 mm (5 years) for males and 1 070 mm (6 years) for females. All males > 1 100 mm TL (7 years) and all females > 1 200 mm TL (8 years) were mature. Adult fish are found predominantly in the nearshore marine environment, but they also frequent estuaries and the surf zone. Spawning takes place in the nearshore environment, from August to November in KwaZulu/Natal, and from October to January in the Southern and South-Eastern Cape regions. A large proportion of the adult population migrates to KwaZulu/Natal to spawn, although spawning may continue on their return to the Cape. Early juveniles of 20–30 mm (∼4 weeks) are recruited into turbid estuaries along the entire East Coast. They remain in the upper regions of the estuaries until they grow to about 150 mm. Juveniles > 150 mm are found in estuaries and in the surf zone. Fish A. japonicus to evolve a life history with a large size at maturity, thereby "pre-adapting" it to a migratory life-style. The life history of A. japonicus, including late maturity, the use of estuarine and surf-zone nursery areas, and a migratory adult population which forms concentrated spawning aggregations, is particularly vulnerable to the activities of man.
The genetic diversity of both wild and rearedpseudosciaena crocea (Richardson) collected from Guan-Jing-Yang in Ningde, China in May 1999 was investigated by random amplified polymorphic DNA (RAPD) in the present study. The polymorphism and mean difference of the wild population as revealed by RAPD were 18.9% and 0.0960 respectively, and those of the reared stocks were relatively lower, with 16.7% in polymorphism and 0.0747 in mean difference. The genetic distance between the two stocks was 0.0041. From the comprehensive investigation, the main reasons for the loss of genetic diversity were probably overfishing, small number of parents as broodstocks and the debatable artificial ranching. Results from this study also showed that the large yellow croaker populations distributed along Fujian coastal waters including Guan-Jing-yang still potentially wide genetic variability. It is suggested that genetic management and prevention should be scientifically conducted in order to maintain and improve the genetic diversity of theP. crocea population.
The five principal food finfishes that made up more than 50% of the total catch of food finfishes in the Middle Atlantic region, from New York to Virginia, about 25 years ago were: Atlantic croaker (Micropogonias undulatus), weakfish (Cynoscion regalis), scup (Stenotomus chrysops), summer flounder (Paralichthys dentatus), and black sea bass (Centropristis striata). Of these, only black sea bass had not clearly declined in abundance up to that time. Subsequently, the Middle Atlantic region has shown the greatest proportional decline in landings and their total value of any coastal region of the United States, except for the Great Lakes. From 1929 to 1983, 16 different species ranked among the top five by weight. Whereas abundance of many species changed from natural causes, the major species also suffered from overfishing. In their place, new species of lesser value such as silver hake (Merluccius bilinearis) have been harvested more effectively. Even with these additional species the total catch of food finfishes has declined about 50% for the region since the peak in 1945. Pound nets and otter trawls have been the principal gears taking food finfishes in the Middle Atlantic region from 1908 to the present. Yet the percentage of the catch by each gear has changed drastically. Pound nets accounted for more than 50% of the catch from 1908 to 1939, but for only 7% in 1983. Otter trawls were infrequently used until the early 1930s; by the 1980s they were taking about 70% of all food finfishes. The present condition in the Middle Atlantic region suggests that further action is required by the Middle Atlantic Fishery Management Council and individual states to reverse the decline in the fisheries.
We conducted a literature review on the biology, ecology, fishery, and protection of totoaba (Totoaba macdonaldi), an endemic, threatened fish of the Gulf of Calfornia, Mexico. Reinterpretation and integration of published and unpublished information enabled us to confirm and estimate specific biological parameters of the totooba, make hypothetical constructs of its life history, and to propose ideas for its preservation. In specific, we found (1) that the mean age of first reproduction of male and female totoaba are 6 and 7 years, respectively; (2) that the intrinsic rate of natural mortality was estimated as 0.268 per year and (3) that in the mid 1980s an estimated 120,300 juveniles died each year in the shrimp fishery by-catch and 6200 adults (26 kg average weight) died due to poaching. The parameters of an individual growth model for juveniles and adults were also estimated. Decreased spring water input from the Colorado River into the Gulf of California may have caused a contraction of the spawning season and a reduction of the carrying capacity of juvenile totoaba. An increase in annual survival during recent years indicates recovery of the stock that might be related to protection of adults. We argue that habitat restoration, which includes the elimination of growth and recruitment over-fishing, is critical to increasing numbers of totoaba, and thereby lifting the fishing ban, and to the delisting of totoaba.
Conservation biologists and natural resource managers are both working to maintain species, but their approaches and priorities differ. The contrast was highlighted when the World Conservation Union (IUCN) listed some commercial fish species, such as the Atlantic cod (Gadus morhua), in the 1996 Red List of Threatened Animals. These species qualified under IUCN’s criteria because they had undergone a marked decline in abundance. Disagreements over these listings revealed fundamental differences between resource managers and conservation biologists. Resource managers aiming to maximize continuing yields using specific, explicit, and data-rich models, generally have not considered risk assessment and sometimes face the necessity for political compromises. Conservation biologists generally consider a wide diversity of species and operate in a data-poor and precautionary context with an overall aim of minimizing extinction risk. The IUCN Red List is an extreme case in point and uses simple criteria for evaluating the conservation status of all species. Under these circumstances, it can do little more than indicate a species’ status in order to prompt further investigation by the appropriate body. We suggest that productive collaboration between conservation biologists and resource managers will start with an understanding of these different perspectives and will benefit from common interests in precautionary approaches, ecosystem approaches, and adaptive management studies.
Since the 1990s, artificial propagation and breeding technique of marine fish in China have developed by way of increasing
species and fry numbers, with special stress laid on valuable species. Large quantities of artificial fry can meet the needs
of both marine cage culture and pond culture for most species. Experimental results obtained by scientists have been put into
use in actual production. Fish fry production has entered a period of sustainable development. So far, at least 44 species
(21 families) of marine fish have been successfully bred in China. The artificial fry number of large yellow croaker (Pseudosciaena crocea) exceeded 300 million in 1999. The species whose artificial fry numbers have each surpassed 10 million annually are red drum
(Sciaenops ocellatus), Japanese seabass (Lateolabrax japonicus), cuneate drum (Nibea miichthioides), spring spawning red seabream (Pagrosomus major) and threebanded sweetlip (Plectorhynchus cinctus). Millions of artificial fry are bred annually in the species of black porgy (Sparus macrocephalus), Russell's snapper (Lutjanus russelli), javelin grunt (Pomadasys hasta), miiuy croaker (Miichthys miiuy) and skewband grunt (Hapalogenys nitens). The fish in the family Sciaenidae are the main species in artificial propagation and breeding. Some problems and prospects
on marine fish culture and stock enhancement are also discussed and some proposals for sustainable development are put forward
in this article.
For many of the worlds pelagic stocks, structure, dynamics and mesoscale distribution of fish shoals has considerable importance to central issues in fisheries management; stock structure, stock assessment, resilience and harvest control. A model is presented here, that attempts to bridge existing gaps in our basic understanding of the biological and ecological mechanisms underpinning the behavioural responses of herring, and how these govern spatial dynamics of shoals. The model, CLUPEX, is developed in the framework of an expert system and utilises fuzzy logic to capture and integrate scientific and local knowledge in the form of heuristic rules. Using input on biotic and abiotic environmental conditions, CLUPEX uses the rules to provide quantitative and qualitative predictions on the structure, dynamics and mesoscale distribution of shoals of migratory adult herring during different stages of their annual life cycle. Test predictions corresponded well with observed patterns, although accuracy for specific circumstances may be limited by the resolution of the knowledge. However, by adding specific local knowledge and adjusting weighting parameters, CLUPEX can be adapted to provide more accurate and precise predictions. The user interface combines hypertext and an explanation facility that is fully cross-referenced to a database, to provide an intuitive and transparent feel rarely found in more traditional analytical models.
Managing most marine finfisheries to achieve optimum yields is an unattainable dream. Protecting these resources from serious depletion through precautionary management seems the only practical option. But even this is of limited application if we demand scientific data for each managed fishery. There are too few researchers to do the work and, in any event, such research would usually not be cost-effective. Thus, we need not merely precautionary management; we need data-less management.
Are extinctions of marine vertebrates as rare and unlikely as current data indicate? Long-term research surveys on the continental
shelf between the Grand Banks of Newfoundland and southern New England reveal that one of the largest skates in the northwest
Atlantic, the barndoor skate (Raja laevis), is close to extinction. Forty-five years ago, research surveys on St. Pierre Bank (off southern Newfoundland) recorded
barndoor skates in 10% of their tows; in the last 20 years, none has been caught, and this pattern of decline is similar throughout
the range of the species.
The coherent RAKE reception of wideband code division multiple
access (W-CDMA) signals with complex spreading is considered. A general
multipath-fading channel model is assumed. A dedicated pilot channel,
which is separate from the data channels, is used for the purpose of
channel estimation. Based on a digital implementation, the coherent
demodulation scheme is presented. Pilot channel estimation error, due to
multiple access and multipath interference, is studied. The system
performance is evaluated by means of the bit error rate (BER). The
analysis shows that the error of channel estimation significantly
degrades system performance and can be effectively suppressed by low
pass filters (LPFs). A discussion on the envelope variation of complex
spread signals is also included, which illustrates that the complex
spread signal has a more stable envelope than the dual-channel spread
signal. The power ratio of pilot to data channels should be chosen in
the range of 0.2 to 0.4 (or -7 to -4 dB), in order to achieve maximum
system capacity
Fisheries Problems in theYellow and East China Seas
- T Kawasaki
Kawasaki, T. (1987) Fisheries Problems in theYellow and East China Seas. Environment and Policy Institute East^West Center, Honolulu, Hawai WP-88^2. November,1997.
Freshwater Fishes of Guangdong Province, China
- H.-L Wu
Wu, H.-L. (1991) Freshwater Fishes of Guangdong Province, China. Science and Technology Press, Guangdong. [In Chinese].
A Synopsis of the Fishes of China. Reprinted Volumes 2
- H W Fowler
Fowler, H.W. (1972) A Synopsis of the Fishes of China. Reprinted Volumes 2. Reprinted byAntiquariaat Junk, Dr. R.
Schierenberg and Sons, N.V., the Netherlands.
Fish air-bladders of commercial value in China Attitudes toward sus-tainability and extinction
- S Y Lin
- G M Mace
- E J Hudson
Lin, S.Y. (1939) Fish air-bladders of commercial value in China. The Hong Kong Naturalist, 9 (April),108^118. Mace, G.M. and Hudson, E.J. (1999) Attitudes toward sus-tainability and extinction. Conservation Biology 13, 242^ 246.
Totoaba: sacrifice in the Gulf of California
- Hendrickson J.R.
Hendrickson, J.R. (1979) Totoaba: sacri¢ce in the Gulf of Cali-fornia. Oceans September,14^18.
Historical extinctions in the sea Near extinction of a large, widely distributed ¢sh The Fishes of Zhejiang
- J T Carlton
- J B Geller
- M L Kudla
- E A Norse
- J M Casey
- R A Myers
Carlton, J.T., Geller, J.B., Reaka-Kudla, M.L. and Norse, E.A. (1999) Historical extinctions in the sea. Annual Review of Ecology and Systematics 30,515^538. Casey, J.M. and Myers, R.A. (1998) Near extinction of a large, widely distributed ¢sh. Science 281,690^692. Cheng, C.Y. (ed.) (1989) The Fishes of Zhejiang. Science Press, Beijing, China. [In Chinese].
Essay on South China's boat people. Asian Folklore and Social Life Monographs 2,119^120. British Museum Life Study Society
- E N Anderson
Anderson, E.N. (1972) Essay on South China's boat people.
Asian Folklore and Social Life Monographs 2,119^120.
British Museum Life Study Society (available at http://
ourworld.compuserve.com / homepages/BMLSS /drum-¢sh. htm; accessed on July 2002).
Fishes of Fujian Province, China Vulnerable ¢sh and traditional knowledge Y Life history and conservation of Totoaba macdonaldi World Currency Year Book. Interna-tional CurrencyAnalysis Inc Extinction vulnerability in marine populations
- Y.-T Chu
- H.-L Wu
- W L Cheung Cisneros-Mata Sadovy
- M A Montemayor-Lopez
- G And Roman-Rodriguez
Chu, Y.-T. and Wu, H.-L. (1985) Fishes of Fujian Province, China, Vol. 2. Science and Technology Press, Fujian. [In Chinese]. Vulnerable ¢sh and traditional knowledge Y Sadovy & W L Cheung Cisneros-Mata, M.A., Montemayor-Lopez, G. and Roman-Rodriguez, M.J. (1995) Life history and conservation of Totoaba macdonaldi. Conservation Biology 9 (4),806^814. Cowitt, P.P. (ed.) (1984) World Currency Year Book. Interna-tional CurrencyAnalysis Inc. Brooklyn, NY. Dulvy, N.K., Sadovy,Y. and Reynolds, J.D. (2003) Extinction vulnerability in marine populations. Fish and Fisheries 4, 25^64.
Extinction risk in the sea The threat of ¢shing to highly fecund ¢shes The sciaenid ¢shes (croakers or drums
- C M Roberts
- J P Hawkins
- Y E Sadovy
Roberts, C.M. and Hawkins, J.P. (1999) Extinction risk in the sea. Trends in Ecology and Evolution 14 (6), 241^246. Sadovy, Y. (2001) The threat of ¢shing to highly fecund ¢shes. Journal of Fish Biology 59 (Suppl. A),90^108. Trewavas, E. (1977) The sciaenid ¢shes (croakers or drums) of the Indo-West Paci¢c. Transactions of the Zoological Society of London 33, 253^541.
History of Fisheries in Hong Kong in the 20th Century and Reconstruction of the Inshore Marine Ecosystem in Hong Kong in the 1950s
- W L Cheung
Cheung,W.L. (2001) History of Fisheries in Hong Kong in the
20th Century and Reconstruction of the Inshore Marine
Ecosystem in Hong Kong in the 1950s. M. Phil thesis,
University of Hong Kong, Hong Kong,186 pp.
Endangered, vulnerable and rare marine ¢shes and animals
- P S B R James
James, P.S.B.R. (1994) Endangered, vulnerable and rare marine ¢shes and animals. In:Threatened Fishes of India (Proceedings of the National Seminar on Endangered
Species). P.V. Dehadrai, P. Das and S.R.Verma, eds. India
Nature Conservators, Muza¡arnagar, pp. 271^295.
Anthropological Studies No
- E N Anderson
Anderson, E.N. (1970) Anthropological Studies No. 4 (ed.W.H.
Goodenough). American Anthropological Association,
Washington, D.C.
A new sciaenid from southeastern China
- Herre A.W.
Herre, A.W. (1935) A new sciaenid from southeastern China.
Lingnan ScienceJournal14 (4),603^604.
Combining local and scienti¢c knowledge Distribution and Sound Charac-teristics of Argyrosomus
- S Mackinson
- L Nottestad
- H K Mok
- H Y Yu
MacKinson, S. and Nottestad, L. (1998) Combining local and scienti¢c knowledge. Reviews in Fish Biology andFisheries 8,481^490. Mok, H.K. and Yu, H.Y. (2002) Distribution and Sound Charac-teristics of Argyrosomus. sp. Abstracts of the 91st Annual Meeting of the Ichthyological Society of Taiwan, p.74.
Fishes from Kwangtung Province and Hainan Is China
- Herre A.W.
Herre, A.W. (1932) Fishes from Kwangtung Province and Hainan Is China. Lingnan ScienceJournal11 (3), 423^443.
Marine, estuarine, and diadromous ¢sh stocks at risk of extinction in North America (exclusive of Paci¢c Salmonids) Fisheries Fisheries assessment: what can be learned from interviewing resource users? Assessment of Hong Kong's inshore ¢shery resources
- J A Musick
- M M Harbin
- S A Berkeley
Musick, J.A., Harbin, M.M., Berkeley, S.A. et al. (2000) Marine, estuarine, and diadromous ¢sh stocks at risk of extinction in North America (exclusive of Paci¢c Salmonids). Fisheries 25 (11),6^30. Neis, B., Scheider, D.C., Lawrence, F., Haedrich, R.L., Fischer, J. and Hutching, J.A. (1999) Fisheries assessment: what can be learned from interviewing resource users? Canadian Journal of Fisheries and Aquatic Science 50, 1949^1963. Pitcher,T.J.,Watson, R., Courtney, A.M. and Pauly, D. (1998) Assessment of Hong Kong's inshore ¢shery resources. Fisheries Centre Research Reports 6 (1),1^168. Quero, J.C. (1989) Le maigre, Argyrosomus regius (Asso) (Pisces, Sciaenidae) en Mediterraneë occidentale. Bulle-tin Societe¨ de France114 (4): [In French].
Management of South African dusky kob Argyrosomus japonicus (Sciaenidae) based on pre-recruit models Historyand conditionof food ¢n¢sheries in the Middle Atlantic region compared with other sections of the coast
- M H Gri¤ths
Gri¤ths, M.H. (1997) Management of South African dusky kob Argyrosomus japonicus (Sciaenidae) based on pre-recruit models. South African Journal of Marine Science 18, 213^228. HcHugh, J.L. andConover, D.O. (1986) Historyand conditionof food ¢n¢sheries in the Middle Atlantic region compared with other sections of the coast. Fisheries11 (5),8^13.
The demersal ¢shery resources Agriculture and Fisheries Department
- C K Chong
Chong, C.K. (1984) The demersal ¢shery resources. In: Hong KongWaters (MRRD/WP/1/85, Agriculture and Fisheries Department, Hong Kong Government, Hong Kong,1984).
Precious and rare aquatic animals in China (Bahaba Flavolabiata (Lin.). Zhejiang Scienti¢c and Technical Publishers, China, pp.53^54
- S Y Hui
Hui, S.Y. (1987) Precious and rare aquatic animals in China
(Bahaba Flavolabiata (Lin.). Zhejiang Scienti¢c and Technical Publishers, China, pp.53^54. [In Chinese].
A New Revision of the Ichthyotoxic and Medicinal Fishes of China
- H L Wu
Wu, H.L. (2001) A New Revision of the Ichthyotoxic and
Medicinal Fishes of China. Agriculture Press of China,
Beijing, China. [In Chinese].
in Taiping, on separate occasions, prices were: US$ 14 493 (RMB 120 000) per 50 kg ¢sh
- Guangdong Taiping
- Province
2000
Taiping,
Guangdong
Province, PRC
In 2000 in Taiping, on separate occasions, prices were: US$ 14 493 (RMB
120 000) per 50 kg ¢sh (240 000 RMB and US$ 28 986 kg À1 of swimbladder);
PRC One ¢sh 1.5 m and 66.5 kg sold to Taiwan at US$ 24 155
- Hong Kong Trader Talking To Mr Kwan Sai-Ping
Hong Kong trader talking to Mr Kwan
Sai-ping, late 2000.
2001
Zhejiang, PRC
One ¢sh 1.5 m and 66.5 kg sold to Taiwan at US$ 24 155 (RMB 200 000) ^
re£ecting the price of the swimbladder (newspaper article).