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The larvicidal property of sea cucumbers collected from Pointes aux Feuilles, Mauritius was assessed. The sea cucumbers were morphologically identified as Holothuria atra (Halodeima) Jaeger 1833, Bohadschia vitiensis Semper 1868, and Holothuria sp. In this study, water and methanol were used for the extraction of the sea cucumber body wall. All extracts showed larvicidal potential against 3rd intar wild Aedes larvae with the highest toxicity observed in Holothuria atra extract. Chemical screening of the extracts revealed the presence of saponins, steroids and terpenoids. The biological activity of the extracts could certainly be attributed to the presence of saponins and glycosides. This study indicates the need for further exploration of the marine organisms as a source of new molecules with larvicidal/insecticidal properties. [ABSTRACT FROM AUTHOR]

Holothuria leucospilota or locally known as “Patola” is currently considered the most abundant sea cucumber species in Malaysia. This coral reef-dwelling species is not in danger of extinction in comparison to commercial sea cucumbers such as “gamat.” However, overfishing activities in addition to lack of fishing regulations in Malaysia could put this species at risk of extinction in the future. It is important to conduct research on the sea cucumber community in Sarawak because the data can be used as reliable information for future research. Therefore, this study is carried out to quantify and estimate the Holothuria leucospilota population from an intertidal area of Satang Besar Island, Sarawak, Malaysia. Ten stations surrounding the island were selected as the location for this study. A total number of 203 individuals of Holothuria leucospilota were recorded and estimation of the population that inhabits the island’s intertidal area was 609 individuals. RELATE test showed relationships between species population and water parameters, namely, temperature, salinity, and pH. Results from this study are important as a baseline data that might contribute to the sustainable management of Sarawak, Malaysia’s sea cucumber in the future. Future work suggestions include addition of subtidal samples and other factors, namely, seawater nutrients and feeding environment, that should be done to better understand the population. [ABSTRACT FROM AUTHOR]

The biological characteristics of the sea cucumber, Isostichopus badionotus (Selenka, 1867), which include slow movement, late sexual maturity, densitydependent reproduction, and a low recruitment rate, make it vulnerable to overexploitation. Since 1999, Cuba has been harvesting this species, and maintaining this activity at a profitable level. Of the six fishing zones in which the species is caught, the yield in the southern Camagüey zone in the southeast region produces the greatest biomass. Fisheriesdependent and -independent indices were combined to evaluate status and develop strategies for fisheries management off the southern coast of Camagμey. This entailed establishing quantitative benchmarks using catch and effort data from the Santa Cruz del Sur enterprise for the period 2003-2014. There was a reduction in sea cucumber biomass and abundance during this period, and catch rates have been above maximum sustainable yield for the last 3 yrs. We propose that the quotas based on 15%-25% of the fishing potential be reduced to 10%. We recommend applying quotas only in those places where the densities are higher than 0.45 cucumbers per 100 m2 and closing fisheries where the density is lower. The application of the dynamic surplus production model, together with independent indicators of the fishery, are useful tools for management of the species and should be applied to the sea cucumber fisheries around the island. [ABSTRACT FROM AUTHOR]

The Japanese sea cucumber Apostichopus japonicus plays important ecological and economic roles in the coastal areas of Japan. Here, we aim to reveal the relation between habitat characteristics and density of juvenile and adult sea cucumbers in Maizuru Bay. Density of adult sea cucumbers was estimated by underwater visual surveys and bottom trawls and that of newly settled individuals by seedling collectors distributed in the bay. The physical environment of the sea bottom was evaluated from median diameter, total organic carbon, total nitrogen, carbon-to-nitrogen ratio, carbon isotope ratio, nitrogen isotope ratio, depth, slope, and distance from the coastline. Adult sea cucumber density was higher in the east side than the west side of Maizuru Bay, the former having a no-take zone for sea cucumbers. Juvenile sea cucumbers were most abundantly collected in the central part of the bay. High organic matter from the sea, short distance from the coastline, and high seabed gradient (steepness) had a positive effect on the density of adult sea cucumbers, and depth had positive effects on their body size. We suggest that sustainable management of sea cucumbers can be achieved by a combination of the establishment of no-take zones and increased protection of nursery habitats. [ABSTRACT FROM AUTHOR]

Due to the heavy exploitation of holothurians over the last few decades, it is necessary to implement fishing regulations aimed at reversing this situation. Holothurians require specific regulations that take into account their biology and ecology. Their behavior to group and form patches as a strategy for feeding, defense and reproduction, makes them vulnerable to overfishing. The higher the population density, the higher the catchability coefficient, and because they are sedentary organisms, the catchability does not change significantly until the density is very low. Hence, the stock assessment of holothurians can be improved by analyzing their spatial distribution. This paper proposes a stock assessment technique that considers the spatial distribution pattern of the sea cucumber Isostichopus badionotus from Yucatan, Mexico. A bioeconomic spatial model was developed to explain the interactions between fishing effort allocation, quasi-profits and the population in the short term. Because of the high price of the species and the low production costs, artisanal fishers preferred to maximize short-term quasi-profits, rather than the long-term benefits they could gain with low fishing mortality rates. [ABSTRACT FROM AUTHOR]

Tropical aspidochirotid holothuroids are among the largest coral reef invertebrates, but gaps remain in our understanding of their ecological roles in lagoon sediment habitats, a vast component of coral-reef ecosystems. Stichopus herrmanni, listed as vulnerable (IUCN), is currently a major fishery species on the Great Barrier Reef (GBR) and throughout the Indo-Pacific. It is critical to characterise how this species interacts with its environment to understand how its removal may impact ecosystem functionality. We investigated seasonal variation in movement, bioturbation, feeding and gonad development of S. herrmanni over 3 yr at One Tree Reef, which has been a no-take area for decades. We determined the direct influence of the deposit-feeding activity of S. herrmanni on sediment turnover and granulometry, and on the abundance of infauna and benthic productivity in a comprehensive in situ analysis of tropical holothuroid feeding ecology. This species is highly mobile with identifiable individuals exhibiting site fidelity over 3 yr. With the potential to turn over an estimated 64-250 kg individual yr, S. herrmanni is a major bioturbator. Stichopus herrmanni is a generalist feeder and influences trophic interactions by altering the abundance of infauna and microalgae. Stichopus herrmanni exhibited decreased feeding activity and gonad development in winter, the first documentation of a seasonal disparity in the bioturbation activity of a tropical holothuroid. Sediment digestion and dissolution by S. herrmanni has the potential to influence seawater chemistry, a particularly important feature in a changing ocean. Our results provide essential baseline data on the functional roles of this ecologically important species to inform development of ecosystem-based bêche-de-mer fisheries management on the GBR. [ABSTRACT FROM AUTHOR]

Sea cucumbers are increasingly exploited for human consumption and for their curative properties, and many wild populations are now depleted or in danger of extinction. While aquaculture is seen as an alternative to fisheries and as a mean to restore wild populations, more knowledge is needed on their reproductive strategies to render this practice efficient, notably for fissiparous holothurians, which are some of the mobile animals able of asexual reproduction by transverse fission. Little information is available on their population genetic diversity and structure. Here, the clonal structure of populations of the fissiparous sea cucumber Stichopus chloronotus has been investigated using nine microsatellite loci and a random sampling, at different spatial (intra-reef and inter-reef) and temporal (inter-season and inter-year) scales. Our findings highlight the importance of asexual reproduction in maintaining these populations, and the prevalence of the 'initial seedling recruitment' strategy (ISR), leading to a high stability of clonal composition over seasons and years. It also seemed that clonal propagation was limited to the reef scale (<10 km) while reefs were connected by sexual dispersal. This is the first time that clonal structure in sea cucumbers has been studied at such a fine scale, with a specific sampling strategy. It provides key findings on the genetic diversity and structure of fissiparous sea cucumbers, which will be useful for the management of wild populations and aquaculture. [ABSTRACT FROM AUTHOR]

The suspension-feeding sea cucumber Cucumaria frondosa is widely distributed in cold waters and is commercially exploited in the North Atlantic. While the species is considered to have potential for aquaculture, its feeding and reproductive biology differs markedly from that of currently cultivated sea cucumbers. Here, for the first time, the influence of food sources on the condition of C. frondosa was experimentally tested. Individuals were fed with either diatoms or fish eggs for 3 months. Specific growth rate ( SGR), organ indices, fecundity, gonad maturity and profiles of lipids and fatty acids ( FA) in tissues were compared among treatments and with sea cucumbers collected from the field. Individuals fed with fish eggs showed higher SGR and organ indices than all other treatments. The highest proportion of large oocytes was also found in gonad tubules of females from the fish egg treatment, although individuals fed with diatoms were the only ones in which spontaneous spawning occurred. Moreover, gonad and muscle tissues of sea cucumbers from the fish egg treatment presented the highest levels of lipids and essential FA. In contrast, non-fed sea cucumbers showed negative SGR, relatively low female fecundity and low concentrations of lipids and FA in tissues. While the fish egg diet presented several obvious benefits, phytoplankton remains an important source of carotenoids, which are vital for vitellogenesis in echinoderms. This indicates that mixed diets rich in lipids, essential FA and carotenoids can be further investigated to optimize growth and reproductive output of this species in captivity. [ABSTRACT FROM AUTHOR]

Populations of sea cucumbers, including the Japanese common sea cucumber Apostichopus japonicus, have been seriously depleted worldwide due to overfishing. Mark-recapture study is an efficient means of collecting ecological data. However, the use of such a method in sea cucumbers is difficult because they lack hard tissues in the body wall. Here we tested the viability of various tagging methods on A. japonicus. First, we applied conventional tags using four different methods [single spaghetti (T-bar) tagging, double spaghetti tagging, ribbon tagging, and Atkins tagging] to ten individuals per method in aquaria for 14 days. Of the methods used, single spaghetti tagging had the highest retention rate. Then we examined the retention rate of single spaghetti tags on ten individual sea cucumbers for up to approximately 6 months in rearing conditions. The single spaghetti tagging method showed a retention rate of 100% over at least 7 days, and 50% of the tags remained embedded after 56 days. The longest duration of tag retention was 174 days, at which time the experiment was terminated. These results indicate that single spaghetti tagging is reliable for both short- and longer-term studies, making it a useful tool for ecological and conservation studies in sea cucumbers. [ABSTRACT FROM AUTHOR]

The brown sea cucumber Isostichopus fuscus (Ludwig, 1875) has been subjected to strong fishing pressure and is currently considered an endangered species by the IUCN Red List of Threatened Species. Spatial and temporal variations in density were analysed and population parameters of I. fuscus were estimated in three localities of the Southern Mexican Pacific. Density was estimated using circular transects covering a 300 m2 area in each locality. Body length and weight were also measured. The mean density was 0.018 ± 0.013 individuals·m−2, and was statistically significantly lower during summer. The mean length and weight were 22.4 ± 3.8 cm and 396 ± 130 g, respectively, and statistically significant differences were found among localities. The weight-length relationship was W = 0.28·L1.32 and the mean relative condition index (Kn) = 1.04 ± 0.31. The von Bertalanffy growth equation was Lt = 38.7·(1-exp(−0.4·t)). The lowest values of length, weight and age were found at Dos Hermanas, suggesting that this locality could be favorable for the settlement of larvae and recruitment and growth of juveniles. The present study is the second to estimate densities of I. fuscus and the first one to publish data on size structure and growth for the population at Bahias de Huatulco. The densities were so low in the three sampled localities that none of them would be able to support a fishery, even under a sustainable management scheme. The information collected in the present study could be helpful for management programs of the Huatulco National Park, as all the data used for these currently come mainly from the populations of I. fuscus in the Gulf of California. [ABSTRACT FROM AUTHOR]

Populations of tropical sea cucumbers, harvested for bêche-de-mer, are in a perilous state of conservation, yet there remains a paucity of information on the biology of many harvested species. We examined the population biology of the commercially important curryfish, Stichopus herrmanni, across 2 years on Heron Reef, a protected zone in the Great Barrier Reef ( GBR) Marine Park. Stichopus herrmanni, a species recently listed as vulnerable to extinction, is a major target species for the fishery operating in the GBR. The size class distribution and density of S. herrmanni were documented for six sites across Heron Reef. There was distinct spatial variation in the size and density of S. herrmanni across sites, with no significant difference between the 2 years. The smallest individuals found were 10 cm long, some of the only juvenile S. herrmanni documented in nature. Juvenile and sub-adult populations were found along the leeward reef edge of Heron Reef, a habitat characterized by shallow channels of sand between inter-tidal coral reef and crustose coralline algae ( CCA). Juvenile nurseries of sea cucumbers are rarely observed in nature, making this an important observation for understanding the recruitment and population biology of S. herrmanni. The presence of juveniles in the consolidated CCA habitat each year in autumn following the summer spawning period, and the absence of small individuals several months later in spring, suggests an ontogenetic migration or displacement of these individuals to adult habitat. The distribution of larger S. herrmanni suggests intra-reef connectivity and migration into deeper lagoon areas. This study contributes to understanding the population dynamics of this vulnerable species, a consideration for fisheries management in light of increasing global harvest. [ABSTRACT FROM AUTHOR]

Because of its high nutritional value and health benefits, aquaculture production of Apostichopus japonicus in China is the largest of any single species. Therefore, the development of new farming methods is of considerable significance. In this study, discarded oyster shells have been used to create an artificial reef for the culture of this species. The results have shown that from 6th March 2009 to 26th November 2009, the wet weight of sea cucumber increased from 49.57 ± 1.16 to 79.87 ± 1.46 g ind−1. Between 16th July and 18th October, the specific growth rate and daily weight gain of A. japonicus differed significantly from other periods. Population density was higher within the reef compared with outside the reef area, and the difference was significant ( P < 0.01). The maximum distance between A. japonicus individuals within the reef area on 3rd March and 16th July was 65.0 ± 3.3 and 62.9 ± 4.4 cm, respectively, but the difference was not significant ( P > 0.05). The diatom species attached to the oyster shells were similar to those found in the stomach content of A. japonicus. In conclusion, the oyster-shell reef provides a suitable habitat and shelter for the culture of the sea cucumber, A. japonicus. [ABSTRACT FROM AUTHOR]

The eastern Gulf of Mexico is a complex mosaic of coral reefs and epibenthic communities. Although it is a large area of approximately 225,000 km2, only a small portion sustains viable coral reefs. In the lower margins of the eastern Gulf of Mexico (Key West to Dry Tortugas, 24°33'N), the coral reef communities are speciose and very similar to Caribbean coral reefs. Controlling factors influencing the distribution of the hydrozoan Millepora and Scleractinian species include climate, the lack of a consistent current system to support larval transport, and stochastic disturbances, such as red tide-harmful algal blooms, hurricanes, and winter frontal passages. In the eastern Gulf of Mexico region north of 26°N (Naples), the fauna is more eurytopic; characteristic species inhabiting the rocky hard bottom include Cladocora arbuscula (Lesueur, 1820), Siderastrea radians (Pallas, 1766), Solenastrea hyades (Dana, 1846), Manicina areolata (Linnaeus, 1758), and Isophyllia sinuosa (Ellis and Solander, 1786). Isolated locations, such as the Florida Middle Grounds and Pulley Ridge, sustain the more reef-dwelling-stenotopic species: Leptoseris cuccullata (Ellis and Solander, 1786); Dichocoenia stokesi Milne-Edwards and Haime, 1848; and Meandrina meandrites (Linnaeus, 1758). The present study focuses on the Hourglass collection of Scleractinian coral samples collected from August 1965 through November 1967 in the eastern Gulf of Mexico offshore of Tampa Bay (27°35'N) and Sanibel Island (26°24'N), from 6 to 73 m depths. [ABSTRACT FROM AUTHOR]

Sea cucumbers are dominant invertebrates in several ecosystems such as coral reefs, seagrass meadows and mangroves. As bioturbators, they have an important ecological role in making available calcium carbonate and nutrients to the rest of the community. However, due to their commercial value, they face overexploitation in the natural environment. On top of that, occurring ocean acidification could impact these organisms, considered sensitive as echinoderms are osmoconformers, high-magnesium calcite producers and have a low metabolism. As a first investigation of the impact of ocean acidification on sea cucumbers, we tested the impact of short-term (6 to 12 days) exposure to ocean acidification (seawater pH 7.7 and 7.4) on two sea cucumbers collected in SW Madagascar, Holothuria scabra, a high commercial value species living in the seagrass meadows, and H. parva, inhabiting the mangroves. The former lives in a habitat with moderate fluctuations of seawater chemistry (driven by day-night differences) while the second lives in a highly variable intertidal environment. In both species, pH of the coelomic fluid was significantly negatively affected by reduced seawater pH, with a pronounced extracellular acidosis in individuals maintained at pH 7.7 and 7.4. This acidosis was due to an increased dissolved inorganic carbon content and pCO of the coelomic fluid, indicating a limited diffusion of the CO towards the external medium. However, respiration and ammonium excretion rates were not affected. No evidence of accumulation of bicarbonate was observed to buffer the coelomic fluid pH. If this acidosis stays uncompensated for when facing long-term exposure, other processes could be affected in both species, eventually leading to impacts on their ecological role. [ABSTRACT FROM AUTHOR]

Fatty acids (FAs) provide energy and also can be used to trace trophic relationships among organisms. Sea cucumber Apostichopus japonicus goes into a state of aestivation during warm summer months. We examined fatty acid profiles in aestivated and non-aestivated A. japonicus using multivariate analyses (PERMANOVA, MDS, ANOSIM, and SIMPER). The results indicate that the fatty acid profiles of aestivated and non-aestivated sea cucumbers differed significantly. The FAs that were produced by bacteria and brown kelp contributed the most to the differences in the fatty acid composition of aestivated and nonaestivated sea cucumbers. Aestivated sea cucumbers may synthesize FAs from heterotrophic bacteria during early aestivation, and long chain FAs such as eicosapentaenoic (EPA) and docosahexaenoic acid (DHA) that produced from intestinal degradation, are digested during deep aestivation. Specific changes in the fatty acid composition of A. japonicus during aestivation needs more detailed study in the future. [ABSTRACT FROM AUTHOR]

We developed a species-specific PCR method to identify species among dehydrated products of 10 sea cucumber species. Ten reverse species-specific primers designed from the 16S rRNA gene, in combination with one forward universal primer, generated PCR fragments of ca. 270 bp length for each species. The specificity of the PCR assay was tested with DNA of samples of 21 sea cucumber species. Amplification was observed in specific species only. The species-specific PCR method we developed was successfully applied to authenticate species of commercial products of dehydrated sea cucumber, and was proven to be a useful, rapid, and low-cost technique to identify the origin of the sea cucumber product. [ABSTRACT FROM AUTHOR]

Abstract: Sea cucumber stocks have been overfished in many countries. As a consequence, several species (Holothuria polii, Holothuria tubulosa and Holothuria mammata) are now caught in Turkish waters without adequate knowledge on their biology and ecology. Here, we address their morphometry, relationships among gutted length and weight, population dynamics, temporal evolution of catches, and we provide the first insights about technical aspects of their fisheries. The largest size classes of H. polii are missing from our sampling collection, possibly due to the heavy fishery pressure on this species. Significant differences in the eviscerated length and weight were found among the Turkish sampled localities for H. polii and H. tubulosa, respectively. These differences could be explained by higher food availability in some areas and/or differential fishery pressure. The size and weight of H. tubulosa specimens were smaller than those registered for the same species in Greek waters, where this species is not fished. All the studied species showed allometric growth. In the last two years, the sea cucumber fishery in Turkey has been increasing rapidly, reaching a total production of ca. 555 000 kg in 2012 (80% H. polii and 20% H. tubulosa plus H. mammata). For a correct management of these species, we recommend: 1) the re-establishment of species-specific closed fishery season according to the specific reproductive cycle; 2) the assessment of the exploited stocks from the Northern Turkish coasts with estimates of recovery time of their populations; 3) the reduction of fishery efforts, mainly on H. polii and H. tubulosa and 4) the establishment of protected areas (where sea cucumber fisheries are forbidden) to conserve healthy populations which will favour the recruitment on nearby areas. [Copyright &y& Elsevier]

Presented here is a new deep-sea association between the polynoid,Eunoe bathydomus(Ditlevsen, 1917) and the holothurianDeima validum validumThéel, 1879 from the Mid-Atlantic Ridge, North Atlantic. For the first time in the deep-sea two polynoid specimens have been found on a single holothurian host. Genetic data in this study show thatE. bathydomushas a distribution ranging across the Mid-Atlantic Ridge over a distance of 72 km, which could have been facilitated by hitchhiking on holothurians, although the main ecological benefits for being associated with a host remain unclear. Additional taxonomic records of polynoid species recovered during remotely operated vehicle Isis sampling during theRRS James Cookcruise JC48 in summer of 2010 are also presented. [ABSTRACT FROM AUTHOR]

The article presents a study which describes four new Antarctic holothuroid species of sea cucumbers from Admiralty Bay in King George Island. Among of the species described are Dendrelasia sicinski, Cucumariid Staurocucumis krzysztofi, and provisionally-assigned thyonid Allothyone presleri. An overview of halothuroid taxa from Admiralty Bay is given, along with the materials and methods of the study.

Abstract: A feeding experiment was conducted to determine effects of Hanseniaspora opuntiae C21 on immune response and disease resistance against Vibrio splendidus infection in juvenile sea cucumbers Apostichopus japonicus. Sea cucumbers were fed with either diets containing C21 at 104, 105 and 106 CFU g−1 feed or a control diet for 30–50 days, respectively. After feeding for 30 days and 45 days, five sea cucumbers from each tank were sampled for immunological analyses. Results indicated that C21 significantly improved the phagocytic activity in coelomocytes of sea cucumbers (P < 0.05). Moreover, C21 administration significantly enhanced lysozyme (LSZ), phenoloxidase activity (PO), total nitric oxide synthase (T-NOS), superoxide dismutase (SOD), alkaline phosphatase (AKP) and acid phosphatase (ACP) activities in coelomic fluid, and LSZ, T-NOS, AKP and ACP activities in coelomocytes lysate supernatant (CLS) of sea cucumbers (P < 0.05). After feeding for 45 days, 10 sea cucumbers from each dose group were challenged with V. splendidus NB13. Cumulative incidence and mortality of sea cucumbers fed with C21 were found to be lower than those of control group. After feeding for 50 days, sea cucumbers in 104 CFU g−1 C21 treatment and control tanks were subjected to acute salinity changes (from 30 to 20) for 24 h in the laboratory, and the immunological parameters were measured to evaluate the immune capacities of the A. japonicus. Phagocytic, LAZ and T-NOS activities of C21-treated group were higher than those of control group, indicating that salinity stress tolerance of sea cucumber was enhanced by C21. The present results showed that a diet supplemented with C21 could stimulate the immune system of juvenile A. japonicus thus enhancing their resistance against V. splendidus. [Copyright &y& Elsevier]

Ilyphagus Chamberlin, 1919 includes abyssal, fragile benthic species. Most species have large cephalic cages but chaetae are brittle and easily lost which may explain why the original definition included species with a cephalic cage or without it. The type species, I. bythincola Chamberlin, 1919, together with another species (I. pluto Chamberlin, 1919) were described as lacking a cephalic cage whereas a third species (I. ascendens Chamberlin, 1919) was described with one. To clarify this situation, all available type and non-type materials were studied. Ilyphagus is redefined to include species with digitiform bodies, abundant filiform papillae and a thin body wall; their neurochaetae are thick, anchylosed aristate spines, and all species have a cephalic cage (in the type species the presence of a cage is inferred from the remaining chaetal scars). Ilyphagus pluto, which also lacks a a cephalic cage is determined here to be a holothurian. The redefined genus contains I. bythincola (incl. I. ascendens), I. coronatus Monro, 1939, I. hirsutus Monro, 1937, and I. wyvillei (McIntosh, 1885). [ABSTRACT FROM AUTHOR]

Widespread overfishing threatens the sustainability of sea cucumber fisheries and the important role they play in the livelihoods of coastal fishers. The SCEAM Pacific workshop was jointly funded and coordinated by the FAO, the Australian Centre for International Agricultural Research, the Secretariat of the Pacific Community and Southern Cross University in November 2011. The workshop brought together fishery managers from 13 Pacific island countries to foster improved management plans for PACIFIC sea cucumber fisheries. Seminars by the workshop facilitators presented contemporary fisheries science and new paradigms for management. Pre-workshop questionnaires, workgroup sessions and plenary discussions were used to help participants decide on appropriate objectives, regulatory measures and management actions for each fishery. The workshop outputs given in this report reveal the constraints and issues facing Pacific sea cucumber fisheries, and the proposed management changes and research priorities of the fishery managers. [ABSTRACT FROM AUTHOR]

Effective nursery diets can greatly reduce the cost of producing juvenile sea cucumbers for release to aquaculture or restocking programs. However, methods for systematically testing the bioavailability of artificial diet ingredients for sea cucumbers are poorly developed, and consequently, there has been little research in this field. The current study presents methods developed to test the suitability of common carbohydrate and protein sources for inclusion in artificial diets for juvenile Australostichopus mollis. Apparent digestibility of carbohydrates was moderate and did not exceed 50% for any carbohydrates assayed. Wheat starch and carrageenans showed the highest digestibility amongst carbohydrates. Differences in apparent digestibility were not reflected in growth performance of juvenile A. mollis fed carbohydrate diets; overall growth performance was poor for all diets. Artificial protein sources consistently exhibited higher apparent digestibility, ranging from 75.1% for fish meal to 98.1% for casein. Low-cost protein sources, like meat meal, show promise for future use in artificial diet formulation. However, delivering high protein content may reduce ingestion rates and thereby lower overall digestive efficiency in juveniles. Results show that artificial carbohydrate sources have some potential as diet constituents for juvenile sea cucumbers but are unsuitable as primary energy sources. Future testing of artificial carbohydrate sources for A. mollis may require predigestion to improve digestibility. [ABSTRACT FROM AUTHOR]

In Kievka Bay of the Sea of Japan, the population of the Japanese sea cucumber Apostichopus japonicus inhabits the areas of coarse sediments and complex bottom topography. These distributional patterns are closely related to the species' ecology, i.e., to the demand for protection against the wave turbulence. The aggregationing coverage of the sea cucumber population is about 80 hectares, where ∼200 thousand animals were accounted for in the last years. The aggregation's area varies during the year, which is closely related to the species' biological peculiarities, such as their behavioral patterns and the redistribution of their food resources. A significant increase of the juvenile population occurred after the farm-reared sea cucumber spat were released in 2003. [ABSTRACT FROM AUTHOR]

Identifying rates of change in the abundance of sea cucumbers under differing management regimes is fundamental to estimating commercial yields, identifying ecological interactions and facilitating management. Here, we review the status of sea cucumber stocks from a range of Pacific Island countries (Samoa, Tonga, Palau, Fiji and Papua New Guinea), some of which have had a moratorium on exports for up to a decade. We use a time-series approach to look at variation in sea cucumber presence, coverage and density from survey and re-survey data. Results give an appreciation of variation between 'high' status (less impacted) and depleted stocks. Survey data show marked declines in coverage and abundance as a result of artisanal fishing activity, and although species groups were not lost at a country level, local extirpation and range restriction was noted. Resilience and 'recovery' following cessation of fishing varied greatly, both among locations and among the species targeted. Worryingly, even after extended periods of moratorium, the density of some species was markedly low. In many cases, the densities were too low for commercial fishing, and may be at a level where the effective population size is constrained due to 'Allee' affects. From these results, we suggest that management regimes presently employed are generally not well aligned with the level of response to fishing mortality that can be expected from sea cucumber stocks. New adaptive, precautionary approaches to management are suggested, which would allow more timely interventions to be made, while refined information on stock dynamics is sought. [ABSTRACT FROM AUTHOR]

The dermis of sea cucumbers is a catch connective tissue or mutable collagenous tissue that shows large changes in stiffness. Extensive studies on the dermis revealed that it can adopt three different states having different mechanical properties that can be reversibly converted. These are the stiff, standard and soft states. The standard state is readily produced when a dermal piece is immersed in the sea water containing Ca2+, whereas the soft state can be produced by removal of Ca2+. A stiffening protein, tensilin, has been isolated from some sea cucumbers (Cucumaria frondosa and Holothuria leucospilota). Although tensilin converts the state of the dermis from soft to standard, it cannot convert from standard to stiff. In this study, we isolated and partially purified a novel stiffening factor from the dermis of Holothuria leucospilota. The factor stiffened the dermis in normal artificial sea water (ASW) but did not stiffen the soft dermis in Ca2+-free ASW. It also stiffened the dermis that had been converted to the standard state in Ca2+-free ASW by the action of tensilin. These results suggest that the factor produces the stiff dermis from the standard state but cannot work as a stiffener on the soft dermis. Its addition to longitudinal muscles of the sea cucumber produced no effects, suggesting that its effect is specific to the catch connective tissue. Its stiffening activity was susceptible to trypsin, meaning that it is a polypeptide, and its molecular mass estimated from gel filtration chromatography was 2.4kDa. [ABSTRACT FROM AUTHOR]

The article presents a study which investigated the population density, activity and bioturbation contribution of the sea cucumber Holothuria whitmaei on Ningaloo Reef, Western Australia. A number of methods were used including stratified manta tows and blanket manta tows and both recorded population densities between 11.4 and >100 individuals ha-1. According to the researchers, they had difficulty characterizing temporal patterns of feeding, but rates of sediment egestion were in many cases higher in the morning. According to them, the presence of species aggregates has impacted density estimates.

Abstract: Echinoderms possess a variety of cells populating the coelomic fluid; these cells are responsible for mounting defense against foreign agents. In the sea cucumber Holothuria glaberrima, four different coelomocyte types were readily distinguished using morphological, histochemical and physiological (phagocytic activity) parameters: lymphocytes, phagocytes, spherulocytes and “giant” cells (listed in order of abundance). Monoclonal antibodies generated against sea cucumber tissues and one polyclonal against sea urchin mayor yolk protein (MYP) were also used to characterize these cell populations. The effects of several pathogen-associated molecular patterns (PAMPs): Lipopolysaccharides from Escherichia. coli (LPS), heat-killed Staphylococcus aureus (SA) and a synthetic dsRNA were studied on coelomocyte cell populations. PAMPs increased the phagocytic activity of the holothurian coelomocytes, and were able to induce selective immune responses in several of these populations, demonstrating the ability of the sea cucumber to respond to a different variety of immune challenges. Overall, these results show the variety of cells that populate the coelomic fluid of the holothurian and demonstrate their involvement in immune reactions. These animals represent an untapped resource for new findings into the evolution and development of the immune response not only in invertebrates but also in phylogenetically shared reactions with vertebrates. [Copyright &y& Elsevier]

The sea cucumber stocks off the east and northwest coasts of Sri Lanka were estimated by surveying 1307 km2 and 1779 km2 by an underwater visual census (UVC) in June and October 2008 respectively. The presence of twenty-five sea cucumber species belonging to seven genera; Actinopyga, Bohadschia, Holothuria, Pearsonothuria, Stichopus, Thelenota and Acaudina was identified in five hundred sampling sites randomly selected in each area. The overall average density (± SD) of sea cucumbers was higher in the northwest (350 ± 648 ind ha-1) than in the east (90 ± 130 ind ha-1) and low-value species were predominant in both survey areas (79 ± 125 ind ha-1 in the east, 244 ± 488 in the northwest) when compared with medium (10 ± 34 ind ha-1, 105 ± 175 ind ha-1, respectively) and high-value category (<2 ind ha-1). The estimated total biomass in the northwest (13 024 t) was roughly four times greater than the east (3027 t). Holothuria edulis was the most abundant species in numbers while Holothuria atra had the highest stock biomass in both areas. Sea cucumber densities were significantly different among the habitat (p < 0.001) and depth categories. The highest density was reported in rocky habitat associated with seagrass and / or macroalgae. The density of low-value species was significantly high in 1–10 m depth category (p < 0.001) in the northwest while other commercial groups were dominant in 20–30 m depth range in both areas. Temporal banning of the fishery for high and medium-value species would be a better management option to avoid further stock depletion. [ABSTRACT FROM PUBLISHER]

Megafaunal organisms play a key role in the deep-sea ecosystem functioning. At 3500m depth in the Nazaré Canyon, NE Atlantic, very high abundances of the infaunal holothurian Molpadia musculus were found. Sediment samples and holothurians were collected by ROV and experiments were conducted in situ in incubation chambers. The biochemical composition of the sediment (in terms of proteins, carbohydrates and lipids), the holothurians' gut contents and holothurians' faecal material were analysed. In the sediments, proteins were the dominant organic compound, followed by carbohydrates and lipids. In the holothurian gut contents, conversely, protein concentrations were higher than the other compounds and decreased significantly as the material passed through the digestive tract. About 33±1% of the proteins were digested already in the mid gut, with a final digestion rate equal to 67±1%. Carbohydrates and lipids were ingested in smaller amounts and digested with lower efficiencies (23±11% and 50±11%, respectively). As a result, biopolymeric C digestion rate was on average 62±3%. We also calculated that the entire holothurians' population could remove from the sediment about 0.49±0.13 g biopolymeric C and 0.13±0.03 gNm-2 d-1. These results suggest that the M. musculus plays a key role in the benthic tropho-dynamics and biogeochemical processes of the Nazaré Canyon. [ABSTRACT FROM AUTHOR]

The article presents a study regarding Holothurian populations in the atolls of Chagos Archipelago including Diego Garcia, Salomon and Great Chagos Bank. The study assessed the Holothurian populations in the atolls with the use of two complementary field methodologies. It mentions that the results of the study show that the mean Holothurian abundance did not surpass 3.5 and 5.2 individual transects. Moreover, the results also indicate heavy and illegal Holothurian populations harvesting.

The article discusses the brief description on the investigation on the ecology of the Pacific fringing reef at Nombur, Gaua Island in New Hebrides. The investigation focuses on the zonation in the distribution of the Holothurians that flourish on the reef. The reef composes different coral species which gives its name to the zone inlcuding the Montipora zone, the Porites zone, the boulder zone channel and the Goniastraea zone. The investigation based on the following account of each zone, which has a characteristic Holothurian, proves that they were far from being distributed at random.

Sea cucumber populations are declining worldwide through overfishing. This is also the case for the greenfish Stichopus chloronotus in spite of its moderate commercial value. We studied asexual propagation of this fissiparous species at different geographic scales as well as the genetic population structure within and among two marine provinces: the Western Indian Ocean and the Tropical Southwestern Pacific. A total of 18 populations (n = 809 individuals) were sampled in both provinces encompassing three ecoregions (New Caledonia, western and northern Madagascar, Mascarene Islands) and genotyped using nine microsatellite loci, allowing the identification of repeated multi-locus genotypes. Populations presented low clonal richness with few clones and a high number of individuals per clone. No clones were shared among different islands. Within islands, members of the same clone could be found 3–15 km apart, indicating that asexual reproduction allows population maintenance at reef scales. Assignment tests and individual-based networks identified two isolated New Caledonian populations, while a third population was less differentiated to those from the Western Indian Ocean than to the two former. Regional ocean currents could explain these patterns. Within the Western Indian Ocean, differentiation indices were always high, indicating restricted gene flow among populations. Possible overfishing of S. chloronotus stock is evidenced by very low sample sizes (and in some cases, the absence) in spite of high sampling efforts [all around New Caledonia, Chesterfield/Bampton/Bellona Plateau (Coral Sea), north-east of Madagascar, Scattered Islands (Mozambique Channel)]. [ABSTRACT FROM AUTHOR]

The article discusses research reported by marine ecologists Heike Lotze, Sean Anderson, and colleagues that quantified the global population of sea cucumbers, as reported online December 30, 2010 in the journal "Fish and Fisheries."