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Global sea cucumber fisheries and aquaculture FAO’s inputs over the past few years

  • March 2015
  • Report number: FAN 53
  • Affiliation: FAO Aquaculture Newsletter
Authors:
Georgina Robinson at Scottish Association for Marine Science
Georgina Robinson
A. Lovatelli at Food and Agriculture Organization of the United Nations
A. Lovatelli
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Abstract

Sea cucumbers are a traditional delicacy prized by Chinese and other Asian consumers for their dietary and curative properties. In the international seafood trade, the processed body wall, known as bêche-de-mer or trepang, has been a globally important trade commodity since the 16th century. Since the 1950s, in response to strong market demand and increasing prices, sea cucumber fisheries have undergone a rapid global expansion. The collapse of stocks in traditional Indo-Pacific fishing grounds adjacent to the main market in Hong Kong SAR catalysed the search for new regions and species to exploit to satisfy the ever growing market demand. Sea cucumber fisheries are currently exploited in over 70 countries, stretching from polar to temperate and tropical zones, in industrial, semi-industrial and small-scale fisheries, however, exploitation in new regions is currently being documented. The recent fast-paced, export-driven overexploitation of sea cucumber fisheries has been unsustainable and in many cases too rapid for an effective management response. Sea cucumber fisheries have under gone rapid boom-and-bust cycles, such that currently more than half of global sea cucumber fisheries are considered depleted or overexploited. The collapse of sea cucumber stocks has forced moratoria on fishing or exports in 39 percent of sea cucumber fisheries globally, causing hardship to all actors in the value chain with no guarantee that stocks will recover in the future. Overexploitation is driving the risk of extinction of the most commercially valuable species, with 16 species now classified as " vulnerable " or " endangered " on the IUCN red list. Overexploitation of sea cucumber resources therefore poses a threat to livelihoods, biodiversity and ecosystem functioning.
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Thematic Articles
FAO Aquaculture Newsletter 53 2015 55
Sea cucumbers are a traditional delicacy prized
by Chinese and other Asian consumers for
their dietary and curative properties. In the
international seafood trade, the processed body
wall, known as bêche-de-mer or trepang, has
been a globally important trade commodity since
the 16th century. Since the 1950s, in response to
strong market demand and increasing prices, sea
cucumber sheries have undergone a rapid global
expansion. The collapse of stocks in traditional
Indo-Pacic shing grounds adjacent to the
main market in Hong Kong SAR catalysed the
search for new regions and species to exploit
to satisfy the ever growing market demand. Sea
cucumber sheries are currently exploited in over
70 countries, stretching from polar to temperate
and tropical zones, in industrial, semi-industrial
and small-scale sheries, however, exploitation in
new regions is currently being documented.
The recent fast-paced, export-driven
overexploitation of sea cucumber sheries has
been unsustainable and in many cases too rapid for
an effective management response. Sea cucumber
sheries have under gone rapid boom-and-
bust cycles, such that currently more than half
of global sea cucumber sheries are considered
depleted or overexploited. The collapse of sea
cucumber stocks has forced moratoria on shing
or exports in 39percent of sea cucumber sheries
globally, causing hardship to all actors in the
value chain with no guarantee that stocks will
recover in the future. Overexploitation is driving
the risk of extinction of the most commercially
valuable species, with 16 species now classied as
“vulnerable” or “endangered” on the IUCN1 red
list. Overexploitation of sea cucumber resources
therefore poses a threat to livelihoods, biodiversity
and ecosystem functioning.
Over the past decade, FAO has supported the
development of improved sea cucumber sheries
management and aquaculture globally through
the organisation of technical workshops and the
publication of technical reviews, manuals and
information guides. In 2003, FAO held a large
workshop on the advances in sea cucumber
aquaculture and management in Dalian, China
— the rst of its kind in this eld. Today, China
remains the world leader in sea cucumber
aquaculture with aquaculture production of
their temperate species, Apostichopus japonicus
(see FAO cultured aquatic species information
fact sheet at www.fao.org/shery/culturedspecies/
Stichopus_japonicus/en) exceeding 170 000
tonnes, surpassing production from capture
sheries. Juvenile A. japonicus are mass produced
in hatcheries under controlled conditions
and farmed to market size in a wide range of
production systems including sea ranching, pond
farming, intensive production in recirculating
aquaculture systems (RAS), as well as in oating
cages2. Aquaculture production of tropical sea
cucumbers has primarily focused on the most
valuable species Holothuria scabra, commonly
known as sandsh, which has an average market
price of USD303 kg-1 with prices reaching as high
as USD1668 kg-1 for a premium grade-A product.
Sandsh are an ideal culture species in low-cost
simple production systems in nearshore seagrass
beds as they are relatively sedentary, require no
additional feed and can be reared to market size
in approximately 12 months. Following more
than two decades of research, the hatchery,
Global sea cucumber sheries and aquaculture
FAO’s inputs over the past few years
Georgina Robinson1 and Alessandro Lovatelli2
1School of Marine Science and Technology, Newcastle University, Newcastle NE1 7RU, UK
2FAO Fisheries and Aquaculture Department, Aquaculture Branch, Rome, Italy
georgi.robinson@yahoo.com and Alessandro.Lovatelli@fao.org
Bêche de mer at the dried sea food market in Hong Kong
G. Clayden
nursery and grow-out technology is rather well
developed, however aquaculture production has
only recently emerged in the past ve years, with
current production limited to 130 tonnes per
annum. While commercial production is gaining
momentum, the majority of global aquaculture
production is derived from extensive production
systems including sea ranching, sea pen farming
and pond culture in countries ranging from
Madagascar to Fiji providing an alternative and/or
supplementary livelihood for coastal communities.
Sea cucumbers are excellent candidate extractive
organisms for co-culture or integrated multi-
trophic aquaculture as they feed principally on
organically rich substrates, including waste from
other species. Consequently, research is currently
focusing on how sea cucumbers can be integrated
into existing land-based and open-ocean culture
systems to improve the sustainability of current
aquaculture practices and reduce waste discharges.
While aquaculture is considered as the only viable
means of meeting future market demand, the
importance of managing existing sheries should
not be underestimated. Sea cucumber sheries
are inherently difcult to manage due to their
open-access, artisanal nature compounded by key
biological life-history characteristics that renders
sea cucumbers vulnerable to overexploitation and
unsuited to traditional management techniques.
In recognition of this, FAO published a technical
manual in 2010 based on an ecosystem approach
to managing sea cucumbers, accompanied by a
condensed guidebook containing prescriptive
advice and guidelines on putting the approach
into action. To compliment the manuals and assist
sheries agencies to design practical management
plans for sea cucumber sheries, FAO organised
a workshop series on Sea Cucumber Fisheries: an
Ecosystem Approach to Management (SCEAM).
The rst workshop for the Pacic region was
held in Fiji Islands in 2011, followed by a second
workshop for the Indian Ocean region held at
Zanzibar (Tanzania) in 2012.
In the Caribbean region, there is very little
information pertaining to the current status of
sea cucumber sheries. In a global FAO review of
sea cucumber sheries and trade, the majority of
the Caribbean countries were classied as having
no known shery or no available information.
In light of the recent serial overexploitation of
sea cucumber resources and the globalisation of
sea cucumber trade, there is a very real risk that
sheries will become depleted before management
interventions can be implemented. In some Latin
American countries, sea cucumber sheries have
already undergone boom-and-bust cycles, and
moratoria are currently in place in Costa Rica,
Ecuador, Panama and Venezuela and unregulated
and unreported (IUU) shing in the region is rife.
In order to address these knowledge gaps, a
workshop on Lionsh and Sea Cucumber
management was held on April 2014 in Havana,
Cuba. The workshop was organised by
INFOPESCA, in conjunction with FAO, the
Western Central Atlantic Fisheries Commission
(COPACO) and the Ministry of Food Industry of
Cuba (MINAL). The objective of the workshop
was to analyse the status of the sea cucumber
sheries by country, share experiences in resource
management and aquaculture, and provide a
perspective of the world market for this product.
It was generally agreed that the high value of
sea cucumber species is the key driver behind
overexploitation and illegal shing, which in some
cases is signicant. While some countries already
have management schemes in place, the problems
implementing sound sea cucumber management
regimes in situations of illegal, unreported and
Sea pen farming in Madagascar
56 201 FAO Aquaculture Newsletter 53
G. Robinson
K. Al-Rashdi
Freshly fished Holothuria scabra from Oman
unregulated (IUU) shing from neighbouring
countries was noted.
At the conclusion of the workshop a resolution
on sea cucumber sheries management and
aquaculture was made. Such resolution, that
calls for a series of coordinated actions, along
with information relating to the workshop,
including copies of all the presentations and
information relating to the management of sea
cucumber sheries, can be downloaded from the
INFOPESCA web site at: www.infopesca.org/
content/taller-sobre-pez-le%C3%B3n-y-pepino-
de-mar-0.
Sea cucumber aquaculture in the Caribbean is
currently underdeveloped, however the potential
exists for the development of sea cucumber
aquaculture as an alternative livelihood for coastal
communities and co-culture of with other target
species that are currently produced such as
mangrove oysters. The four-sided sea cucumber,
Isostichopus badionotus has been evaluated as
the most promising candidate for aquaculture
in the Caribbean given its high market value
(USD203–402 dry kg-1; FAO 2012), natural
densities in the wild and the wide range of habitats
it occupies. In addition, its reproductive biology
has already been studied and hatchery-reared
juveniles have been consistently produced under
controlled conditions in Mexico.
A number of positive outcomes have already
emerged from the workshop stemming from
increased awareness among participants of
the precarious nature of sea cucumber stocks
and interest in the potential for aquaculture
production of high value indigenous species.
In Bermuda, research and development to
optimise larval rearing and nursery culture of
I. badionotus is underway following the completion
of three successful spawning trials during the past
reproductive season (July-November). Following
lobbying from the University of West Indies, the
Fisheries Division in Barbados plans to introduce
a moratorium on sea cucumber harvesting
under new shing regulations and nally FAO
is assisting the Jamaican Government to draft a
Technical Cooperation Project which will provide
technical assistance for the development of stock
assessment methodologies, a national management
plan for sea cucumbers and technology transfer for
sea cucumber aquaculture.
For further information please contact:
Alessandro.Lovatelli@fao.org
1International Union for Conservation of
Nature
2Elsevier has just published the following book “The Sea
Cucumber, Apostichopus japonicus: History, Biology and
Aquaculture”.
FAO Aquaculture Newsletter 53 2015 57
List of FAO publications on sea cucumbers
Advances in sea cucumber aquaculture and management
http://www.fao.org/docrep/007/y5501e/y5501e00.htm
Sea cucumbers A global review of sheries and trade
http://www.fao.org/docrep/011/i0375e/i0375e00.htm
Managing sea cucumber sheries with an ecosystem approach
English - http://www.fao.org/docrep/012/i1384e/i1384e00.htm
Spanish - http://www.fao.org/docrep/013/i1384s/i1384s00.htm
Putting into practice an ecosystem approach to managing sea cucumber sheries
http://www.fao.org/docrep/013/i1780e/i1780e.pdf
Commercially important sea cucumbers of the world
http://www.fao.org/docrep/017/i1918e/i1918e.pdf
An Ecosystem Approach to Management in the Indian Ocean (SCEAM Pacic)
http://www.fao.org/docrep/015/i2658e/i2658e.pdf
An Ecosystem Approach to Management in the Indian Ocean (SCEAM Indian Ocean)
http://www.fao.org/docrep/018/i3223e/i3223e.pdf
A regional shellsh hatchery for the Wider Caribbean
http://www.fao.org/docrep/014/i2179e/i2179e00.htm
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Thematic Articles
... Increasing demand by consumers has thereafter led to overfishing and depletion of the natural stock of sea cucumbers including A. japonicus (Kazanidis et al., 2010;Purcell et al., 2013). As the wild populations decline, aquaculture of A. japonicus has increasingly expanded in the provinces of Liaoning, Shandong, Hebei and Fujian of China since the 1990s (Robinson & Lovatelli, 2015). Now, it has become an important economical culture species in China with an annual yield amounting to 180 thousand tons (Han et al., 2016). ...
... It has been widely used as a nutritive antioxidant in the feeds of terrestrial livestock (He et al., 2013). Furthermore, the beneficial effects of Se-yeast supplementation on growth performance have been reported on several aquatic animals including hybrid striped bass (Morone saxatili) (Cotter et al., 2008) and rainbow trout (Oncorhynchus mykiss) (Robinson & Lovatelli, 2015). ...
... In the present study, sea cucumbers fed diets with the supplementation of 0.5-1.5 mg/kg Se-yeast also showed a significant increase in the growth performance, digestive tract index, digestive enzyme activities as well as immune and antioxidant capacity. The beneficial effects of Se-yeast supplementation on growth performance have been previously reported on hybrid striped bass (Morone saxatili) (Cotter et al., 2008), rainbow trout (Oncorhynchus mykiss) (Robinson & Lovatelli, 2015) and Wuchang bream (Megalobrama amblycephala) (Long et al., 2017). It has been speculated that the increased bioavailability of organic Se occurs because it is transported through the intestine in an intact form to the target tissues (Ashmead & Zunino, 1992). ...
An evaluation on the selenium yeast supplementation in the practical diets of early juvenile sea cucumber ( Apostichopus japonicus ): Growth performance, digestive enzyme activities, immune and antioxidant capacity, and body composition
Article
Full-text available
  • Sep 2021
A 45-day feeding trial was carried out to investigate the effects of dietary selenium yeast (Se-yeast) on the survival, growth performance, activities of digestive enzymes and antioxidant enzymes, and body composition of early juvenile Apostichopus japonicus. Five isoprotic (15.6%) and isolipic (1.5%) feeds with graded levels of Se-yeast (0, 0.5, 1.0, 1.5 and 2.0 mg/kg) were formulated and randomly allocated to the early juvenile sea cucumbers (initial weight: 0.11 ± 0.01 g). The results showed that the weight gain rate (WGR) and relative visceral weight ratio (RVW) significantly increased as the Se-yeast supplementation increased from 0 to 1.0 mg/kg, and then reached a plateau with further increase in Se-yeast, while survival rate (SR) increased as the supplementation level of Se-yeast increased, and the lipase and amylase activities first significantly increased as the Se-yeast increased from 0 to 1.0 mg/kg, and then significantly decreased with the continuous supplementation of Se-yeast. The antioxidant capacity and nonspecific immunity were significantly elevated by the moderate level (0.5 and 1.0 mg/kg) of Se-yeast. Besides, the activities of immune-related enzymes and transcription of antioxidation-related genes were significantly elevated by the supplementation of Se-yeast. However, malonaldehyde contents were significantly reduced in the treatments with 0.5 and 1.0 mg/kg Se-yeast. The selenium content in the body wall of the sea cucumber showed a markedly increasing trend with increasing Se-yeast supplementation levels. Results above indicated that a moderate level (0.5–1.0 mg/kg) of Se-yeast enhanced the growth performance, digestive enzyme activities, antioxidant capacity and nonspecific immunity of early juvenile A. japonicus.
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... In the long term, overfishing might affect their reproduction cycles, which would slow their natural recovery process. The solution to this problem can be achieved through the development of aquaculture technology to rear sea cucumbers within their natural habitat (Robinson and Lovatelli, 2015). Aquaculture produced sea cucumber can be used for commercial purposes to meet the market demand, and has recently been used in the conservation effort, for instance in restocking activities (Indriana et al., 2017;Rizqi, 2018) The grow-out phase of sea cucumber aquaculture is mostly conducted in separate sites/facilities from its initial phases. ...
VARIATION OF TEMPERATURE AND ZEOLITE APPLICATION ON SIMULATED TRANSPORT OF CULTURED JUVENILE SEA CUCUMBER (Holothuria scabra)
Article
Full-text available
  • Feb 2022
Sea cucumber (Holothuria scabra) aquaculture practice required different sites for the juvenile and grow-out phase. While broodstock conditioning, spawning, and nursery phase were mostly conducted in an indoor hatchery, the juvenile needs to be reared outdoor in saltwater pond, sea pens, or ex-situ grow-out sites. However, information on optimal transport condition with regards to post-transport survival from the hatchery to the grow-out sites is limited. These gaps of knowledge required immediate research since the demand for sustainable sea cucumber culture is constantly increasing, whether for commercial or conservation (restocking) purposes. Therefore, the aim of this study is to investigate the effectiveness of transportation methods of juvenile sandfish by combining temperature and zeolite treatment. The variation of temperature (low and ambient) combined with the use of zeolite treatment on simulated transport condition of sea cucumber juvenile were evaluated in this study. This experiment used 3 (three) replicate groups consisting of 10 (ten) individual hatchery-produced sea cucumber juvenile (less than 0.1 g weight) held in 4 (four) different treatments of temperature and zeolite addition to medium water for 12 hours duration of simulated transport. The monitoring result of water quality (pH and ammonia) and the survival rate of sea cucumber juvenile observed within 7 (seven) days post-transport suggests that pH and survival rate were affected by the temperature regime and zeolite addition. The addition of zeolite and the increase of temperature tend to decrease pH values. However, the excessive decrease of temperature should be avoided during the transportation process as it tends to reduce the survival rate of sea cucumber juvenile.
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... This association of sea cucumbers with the seagrasses received considerable attention in recent times due to the intense fishing pressure on this vital resource in the wild (e.g., Mercier et al., 2000;Hamel et al., 2001;Domínguez-Godino et al., 2019), prompting authorities to seek for solutions aimed at restoring depleted stocks. Despite the restoration initiatives being undertaken to mitigate the depleting sea cucumber populations, managing the wild sea cucumber fisheries has been proven largely unsuccessful (e.g., Choo, 2008;Vincent and Morrison-Saunders, 2013;Robinson and Lovatelli, 2015). One of the causes for this failure is the general lack of understanding of the underlying mechanisms that characterize this trophic relationship. ...
A Review of Factors Influencing the Seagrass-Sea Cucumber Association in Tropical Seagrass Meadows
Article
Full-text available
  • Nov 2021
In the tropical ecosystem, sea cucumbers are associated with seagrass meadows in various ways, often forming a network of ecological interactions. From this myriad of interactions, the trophic relationship between the seagrasses and sea cucumbers has received recent attention with the advent of analytical techniques. However, little is understood about the exact mechanism by which seagrasses are sustaining the sea cucumber populations in the food chain, considering the high number of refractory components in seagrasses and the lack of digestive enzymes among sea cucumbers. This manuscript aims to review existing concepts in ecology concerning the association between tropical seagrasses and sea cucumbers to provide directions for research and management of this vital resource. We searched literature from electronic databases and identified key concepts concerning sea cucumber and seagrass communities based on geographic distribution, nutrient compositions, seagrass decomposition process, and trophic enrichments in the food chain. A conceptual model was then developed detailing the factors influencing the association between the seagrass meadows and sea cucumbers. Despite the limited published information on the seagrass–sea cucumber association, a synthesis of the current understanding of this topic is provided to address the declining sea cucumber populations in the tropical seagrass meadows. We suggest that the successful restoration of sea cucumber fisheries requires a thorough understanding of the seagrass decomposition process, which is vital to the diet of sea cucumbers.
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... This study focused on describing the extractive sea cucumber system and its integration into the red drum monoculture. H. scabra was chosen for co-culture with red drum since it is the most commonly cultured tropical sea cucumber species (Robinson and Lovatelli, 2015) and one of the edible sea cucumbers with a high commercial value . It is considered for aquaculture diversification on Mayotte (Cabinet Gressard consultants et al., 2013) and already cultured in the Indian Ocean (Madagascar). ...
Analyse environnementale intégrée pour le développement d’une aquaculture durable : scénarios de pisciculture marine dans le lagon de Mayotte
Thesis
  • Nov 2019
L’aquaculture marine a un fort potentiel de croissance permettant de faire face aux besoins alimentaires des populations actuelles et futures. Cependant, cette activité, incluant l’étape de production et celles de la chaîne de valeur en amont et en aval, est responsable de potentiels impacts environnementaux sur les écosystèmes locaux (ex. impact sur le benthos) ou globaux (ex. impact sur le changement climatique). Afin de minimiser ces impacts, il est nécessaire de développer des méthodes d’analyse environnementale avec une approche holistique. L’objectif général de cette thèse est de concevoir une méthode d’évaluation des impacts environnementaux à différentes échelles spatiales (locale, régionale, globale) en combinant des outils de modélisation à plusieurs échelles organisationnelles (individu, ferme, filière) et de l’analyse de scénarios. Cette méthode a été testée sur le cas d’étude de la pisciculture d’ombrine ocellée (Sciaenops ocellatus) dans le lagon de Mayotte. Trois scénarios de fermes ont été construits sur la base d’enquêtes. Le modèle FINS a été développé pour simuler le fonctionnement de ces fermes et estimer leurs émissions (solides et dissoutes). La dispersion et le dépôt des rejets solides ont été simulés avec le modèle NewDEPOMOD pour des scénarios de sites couvrant différentes conditions hydrodynamiques d’un secteur du lagon. La taille de la ferme, les choix de gestion et l’intensité des courants sont les facteurs prépondérants qui déterminent le niveau d’émission et/ou la dispersion des rejets et donc les potentiels impacts sur le benthos. Une évaluation par analyse du cycle de vie (ACV) a permis de comparer les impacts globaux d’un de ces scénarios de monoculture à ceux d’un système d’aquaculture multi-trophique intégré (AMTI) associant l’élevage du détritivore Holothuria scabra aux cages piscicoles. Ce système AMTI a montré une faible capacité de bioremédiation des rejets particulaires et des niveaux d’impacts globaux similaires à ceux du système en monoculture, en raison des limites de densité d’élevage pour le compartiment détritivore. Cette évaluation des impacts à différentes échelles spatiales a permis d’identifier les facteurs clés déterminant la durabilité environnementale des systèmes et pour lesquels des leviers d’actions pourraient être proposés.
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... Participants blamed falling prices for sea cucumber and seaweed farming on over promotion, supplier saturation and excess production. The literature, however, suggests that this is more a consequence of low quality production and processing, and the absence of Good Manufacturing Processes and Hazard Analysis Critical Control Point methods (Perez and Brown, 2012;Robinson and Lovatelli, 2015). Both issues illustrate the need to understand international market requirements and for external support for communities wishing to engage with them. ...
Building resilience in practice to support coral communities in the Western Indian Ocean
Article
Full-text available
Global environmental change and other site specific pressures (e.g. over fishing and pollution) are threating coral reefs and the livelihoods of dependent coastal communities. Multiple strategies are used to build the resilience of both coral reefs and reef dependent communities but the effectiveness of these strategies is largely unknown. Using the Western Indian Ocean (WIO) as a case study, this paper combines published literature and expert opinion elicited through a multi-stakeholder workshop to assess the intended and realised social and ecological implications of strategies commonly applied in the region. Findings suggest that all strategies can contribute to building social and ecological resilience, but this varies with context and the overall strategy objectives. The ability of strategies to be successful in the future is questioned. To support effective resilience policy development more nuanced lesson learning requires effective monitoring and evaluation as well as a disaggregated understanding of resilience in terms of gender, agency and the interaction between ecological and social resilience. Opportunities for further lesson sharing between experts in the region are needed.
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Metrologically sound comparison of trace-metal levels in sea cucumber tissues from different species and habitats
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Sea cucumbers are indicators of metal contamination in sea bottoms due to their low mobility and feeding behaviour. Comparing contaminations of specimens from different locations, habitats, and/or organs allows understanding of contamination processes and differences. However, the interpretation of these data is affected by the variability of contamination levels in specimens, the uncertainty of tissue analyses, and the complex correlation of mass fractions estimated by using the same calibration of the used instrumental method of analysis. This work presents a novel tool for the sound comparison of contamination levels of biota where all mentioned factors are considered to produce reliable and undisputable information on the studied system. The Monte Carlo simulation of uncertainty components, affecting the determination of mean contamination levels observed in selected types of tissues, allowed simulating mean contamination differences and determining if these are meaningful. This tool was used to assess the levels of Cd, Cu, Ni and Pb of animals collected in different locations of Sesimbra-Portugal. It was concluded that specimens that selectively consume macroalgae have larger contamination levels than animals feeding on sediment. The gut is the most contaminated organ suggesting intake from feeding is dominant. Three of the analysed animals have Pb mass fractions larger than a maximum admissible value for human consumption of 3 mg kg-1 with a probability larger than 2.5%.
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How does climate change affect a fishable resource? The case of the royal sea cucumber (Parastichopus regalis) in the central Mediterranean Sea
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  • Sep 2022
Holothurians or sea cucumbers are key organisms in marine ecosystems that, by ingesting large quantities of sediments, provide important ecosystem services. Among them, Parastichopus regalis (Cuvier, 1817) is one of the living sea cucumbers in the Mediterranean actively fished for human consumption mainly in Spain, where it is considered a gastronomic delicacy. In the Strait of Sicily (central Mediterranean Sea), this species is not exploited for commercial use even if it is used as bait by longline fishery. P. regalis is frequently caught by bottom trawling and discarded at sea by fishers after catch, and because of its capacity to resist air exposition (at least in cold months), it is reasonable to consider that it is not affected by fishing mortality. Having observed a significant decrease in abundance since 2018, the possible effects of some ecological factors related to current climate change (i.e., temperature and pH) were sought. Generalized additive models (GAMs) were applied to investigate the relationship among the abundance of P. regalis and environmental variables and fishing effort. Long time series of P. regalis densities (2008-2021) were extracted from the MEDITS bottom trawling survey and modeled as function of environmental parameters (i.e., salinity, dissolved oxygen, ammonium, pH, and chlorophyll a) and fishing effort (i.e., total number of fishing days per gross tonnage). Our results showed that this species prefers the soft bottoms (50-200 m) of the Adventure Bank and Malta Plateau, and its distribution changed over time with a slight deepening and a rarefaction of spatial distribution starting from 2011 and 2017, respectively. In addition, a positive relationship with pH concentration in surface waters during the larval dispersal phase (3-year lag before the survey) and nutrient concentration at sea bottom (1-year lag) has been found, suggesting that this species is sensitive to climate change Frontiers in Marine Science and food availability. This study adds new knowledge about the population dynamics of an unexploited stock of P. regalis under fishing impact and environmental under climate change in fisheries management.
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Spatial distribution of sea cucumber and their management effort in seagrass ecosystems in Buntal Island, Western Seram Regency
Article
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  • Jun 2021
Sea cucumbers belong in the Echinoderms and some of them have a high economic value. The demand for sea cucumber as an export commodity encourages multispecies hunting with various sizes. The objective of this research was to determine the ecological parameters and spatial distribution of sea cucumber. Sampling was conducted in Buntal Island waters from March to June 2017, using the belt transect method. The results showed that there were 12 species of sea cucumbers, of which the Holothuria atra has the highest potential value, density, and frequency of presence compared to Opheodesoma grisea from the 4 stations area. The species diversity index (H’) is in the medium category, the compatibility index (E) is in the stable community, the species dominance value (D) is low. The Morisita index value shows a uniform, random, and group distribution. The sea cucumber is found to distribute in almost all substrates i.e. sand, muddy sand, and sandy mud associated with seagrass. Three management strategies were proposed namely conservation and protection efforts, restrictions on the number and size of sea cucumber caught in a certain period, and improve the understanding and community knowledge of sustainability of the marine natural resources.
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IOP Conference Series: Earth and Environmental Science The fishery of sea-cucumber Holothuridae in Kilbat Village, Central Maluku Regency, Indonesia
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  • Jul 2021
Sea cumber is one of the valuable high economic resources. Worldwide, most sea cucumber fisheries are ineffectively managed, leading to declining stocks and potentially eroding the resilience of fisheries. The local fishermen of Kilbat Village have been exploiting sea cucumber for a long time with un-proper management pan. This study was aimed to investigate the utilization of sea cumber and assess its sustainability, and propose a sustainable management strategy. Field observation was used to analyze sea cucumber utilization, the Rapid appraisal to Fisheries (Rapfish) approach was used to assess its sustainability, whilst DPSIR was applied to perform a sustainable management strategy. The result shows that the local sea cucumber fishermen utilize sea cucumber as a source of income and self-consumption. The average sustainability was 61.17% of 100% sustainable scale and considered as fair sustain with institutional dimension being unsustain. There are 8 strategies proposed for sea cumber sustainable management with responses at D, P, S, and I level, A traditional indigenous knowledge ( sasi) has been proposed for sea cucumber community-based fishery management.
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Nursery culture of sandfish Holothuria scabra in sea-based floating hapa nets: Effects of initial stocking density, size grading and net replacement frequency
Article
Sea-based culture of early juvenile sandfish (Holothuria scabra) up to fingerling size (>2 g) using floating hapa nets has been confirmed as a viable nursery system in tropical countries such as the Philippines. However, production can be further optimized through more efficient rearing practices. In this study, we demonstrate the effects of initial stocking density, size grading and net replacement frequency during the culture of early juvenile sandfish in sea-based floating hapa bag nets (2 × 1 × 1 m). Testing different initial stocking density treatments ranging from 150 to 2000 early juveniles (4–10 mm; 0.02–0.06 g) per hapa net, we confirmed significantly faster growth (0.06–0.08 g d⁻¹) and higher survival (72–97%) in low densities (≤500 hapa⁻¹), compared to high densities (≥700 hapa⁻¹: 0.02–0.04 g d⁻¹; 67–80%). Low density culture can produce 2 g sandfish in about a month, while higher densities will require a 2–3 mo culture period to reach this size. Culture performance following size grading was also compared using three initial size classes (small, 0.05–0.99 g; medium, 1–1.99 g; and large, 2–3 g) and a mixed group (0.05–3.00 g). At 45 d, juveniles in pooled size-graded groups grew significantly faster (0.11–0.13 g d⁻¹) than those in the mixed group (0.01 g d⁻¹). Survival was significantly higher in the medium (85.3%) and large (84.7%) groups, than those in the small (54.4%) and mixed (45.6%) groups. However, size variation was not significantly mitigated by grading during the 45-d culture. Culture performance of sandfish was not significantly enhanced by more frequent net replacement for short-term rearing (30–45 d). Optimal results were gained from an initial stocking density of ≤500 early juveniles (5–10 mm) per floating hapa net which may be cultured in a month, without requiring net replacement and size grading to produce ≥2 g sandfish. However, in cases of high hatchery production, it is also feasible to adopt higher density stocking (e.g. >1000 hapa⁻¹), but will require longer culture duration (60–85 d), monthly net replacement and size-grading to attain the same size. Results of this study can help fine-tune management practices for nursery culture of sandfish in sea-based floating hapa net nurseries in order to boost production of fingerlings needed for aquaculture and restocking.
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