Holothuria Mammata Research Articles

Estimating age and growth parameters for three commercial NE-Atlantic sea cucumbers, Holothuria mammata, H. forskali and H. arguinensis, in a marine protected area

Sea cucumbers, integral components of benthic ecosystems, have become subjects of scientific scrutiny owing to their intricate morphology and ecological importance. Due to increasing demand, several species of these echinoderms have become overexploited. As a consequence, NE-Atlantic species became new targets for the international markets. There is a vital need for comprehensive biological data to establish and enhance holothurian fisheries management. In the absence of such data, there is a risk of ineffective fisheries regulations, particularly for susceptible commercial species in the NE-Atlantic, which could lead to overexploitation. Establishing effective fisheries regulations requires a foundation of fundamental biological information, such as growth rates from target populations. This work aims to determine the growth parameters for three commercial sea cucumber species from the NE-Atlantic, in a marine protected area, Holothuria mammata, H. forskali and H. arguinensis. This presents a challenge, as sea cucumbers lack significant calcified structures for age determination, and assessing size is complicated because of their body size plasticity. Thus, a von Bertalanffy model was fitted to length-frequency data using the ELEFAN method with the simulated annealing procedure. Underwater length measurements of the three sea cucumber species, in a relaxed state, were systematically recorded over a span of 18 months, with measurements taken every 1.5 months. The results provide the growth parameters of each species. Models considering seasonal growth were better fits to the data. The three species had different growth rates and periods of no growth coincided with the reproductive season. Mortality was lower for the species growing slower. This is crucial information to support decision-making processes regarding stock management, such as setting limits to fisheries considering stock condition associated with environmental variability.

How Biological Activity in Sea Cucumbers Changes as a Function of Species and Tissue.

Biological activity and bioactive compound content in sea cucumbers was assessed, considering Parastichopus regalis, Holothuria mammata, Holothuria forskali, and Holothuria arguinensis as species and intestine, muscle band, respiratory tree, body wall, and gonads as tissues. P. regalis had the lowest content in phenolic compounds and antioxidant activity in contrast to Holothuria species. In the respiratory tree, the highest phenolic concentration was recorded in H. arguinensis, 76.4 ± 1.2 mg GAE/100 g dw vs. 21.0-49.0 mg GAE/100 g dw in the other species. H. arguinensis had the highest DPPH and FRAP results in the gonads, 13.6 ± 0.7 mg AAE/100 g dw vs. 2.6-3.5 mg AAE/100 g dw and 27.1 ± 0.3 μmol Fe2+/g dw vs. 8.0-15.9 μmol Fe2+/g dw, respectively. Overall, P. regalis biomass presented the highest anti-inflammatory activity levels and H. arguinensis the lowest anti-inflammatory levels. The respiratory tree was the most anti-inflammatory (measured by the inhibition of cyclooxygenase-2, COX-2) tissue in H. mammata and H. forskali (also the muscle band in this case), 76.3 ± 6.3% and 59.5 ± 3.6% COX-2 inhibition in 1 mg/mL aqueous extracts, respectively. The results demonstrated a variable bioactive potential and advantage in targeting antioxidant properties in the muscle band and anti-inflammatory activity in the respiratory tree, which may constitute a starting point for a biorefinery approach envisaging multiple applications.

Barcoding (COI) Sea Cucumber Holothuria mammata Distribution Analysis: Adriatic Rare or Common Species?

The overexploitation of the western Pacific Ocean has expanded the sea cucumber fishery into new regions to supply the Asian market. In 2013, sea cucumbers were removed from the Croatian marine protected species list, and commercial fishery took place for a short period (2017-2018) in the Eastern Adriatic Sea. However, holothuroid species are difficult to distinguish. Holothuria mammata is a species that has rarely been reported in this region and strongly resembles the common species Holothuria tubulosa. This is the first study to assess the genetic diversity of sea cucumbers in the Adriatic Sea using genetic barcoding of the mitochondrial gene cytochrome c oxidase subunit 1 (COI). Specimens for barcoding were collected from the northern and central Adriatic, along with a specimen that had been previously identified as H. sp. cf. mammata based on its morphological characteristics. While genetic analyses showed identified this specimen as H. tubulosa, 30% of the collected specimens were genetically identified as H. mammata. These results call into question the historically accepted sea cucumber assemblage in the Adriatic Sea, which regarded H. mammata as a rare species and generally disregarded its presence in large census studies. Such species distribution data are extremely important in developing and monitoring a sustainable fishery.

Türkiye'nin Ege Denizi kıyılarında Holothuria tubulosa (Gmelin, 1790) ve Holothuria polii (Delle Chiaje, 1823) popülasyon yoğunluğunun av yapılan ve yapılmayan alanlar arasındaki karşılaştırılması

Increasing demand from the Asian market first led to the collapse of economically valuable sea cucumber stocks in the Indo-Pacific, and then demand shifted to lower value Mediterranean species. The effect of this change in sea cucumber stocks in Türkiye started to be seen after the 2010s. To address it, we carried out a study to compare the population density of the most caught Holothuria tubulosa and Holothuria polii species between exploited and non-exploited areas in the Aegean Sea coast of Türkiye. The study was carried out between September 2018 and March 2020 at 4 stations, two of which are in Çandarlı Bay, where sea cucumber fishing is free, and two in İzmir Bay, where it is prohibited. Samplings between 0-20 m depths were carried out with underwater transect line technique, and at depths deeper than 20 m, with beam trawling operations. A total of 6 sea cucumber species were identified, including Holothuria mammata, Holothuria sanctori, Parastichopus regalis and Holothuria forskali species, apart from the target species H. tubulosa and H. polii. Only one P. regalis individual was recorded in the samplings in waters deeper than 20 m. The mean densities of H. tubulosa and H. polii were found to be higher in İzmir Bay stations than in Çandarlı Bay (p<0.05). The results of this study clearly reveal that the population density of sea cucumber in sampling areas has decreased tens of times compared to the last 5 years.

Elemental composition and in vitro bioaccessibility assessment of holothuroids

The elemental composition and bioaccessibility of the wild holothuroids Holothuria arguinensis, Holothuria forskali, and Holothuria mammata was studied. Nutritional and toxicological aspects were evaluated. H. mammata was the richest in Mn, Ni, As, Cd, Pb, and Hg; H. forskali had the highest Cu and I contents, 4.12–4.93 mg/kg dw and 28.02–28.26 mg/kg dw, respectively; and Summer H. arguinensis had high Se content, 4.26 ± 0.08 mg/kg dw. Holothuroids as food may be a dietary Se and I source, with Pb as main hazard. In order to meet the Se Recommended Daily Allowance (RDA), 15–18 g of dried H. arguinensis and 18–33 g of dried H. mammata would have to be consumed everyday. For I, 10 g of dried H. arguinensis, 6–11 g of dried H. forskali, and 20–21 g of dried H. mammata everyday would be required to achieve the I Dietary Recommended Intake (DRI). For meeting Cu dietary requirements, consumption frequencies would have to exceed 330 g dw/day in the most favourable case (Winter H. forskali). Regarding other essential elements, quantities would be much higher. Regarding contaminants, a consumption above 20–21 g/day of dried H. mammata would constitute a Pb risk. Overall, holothuroids can substantially contribute to elemental nutritional requirements.

Reproductive Biology of the Sea Cucumber Holothuria mammata (Echinodermata: Holothuroidea).

Simple SummaryHolothuria mammata is one of the sea cucumber species with high commercial value and great demand in Asian markets; however, the existent knowledge about the biology and ecology of this species is scarce. This study aims to describe the reproductive cycle of H. mammata in a coastal area of southwest Portugal through monthly collections of biometric data and environmental data. The sex ratio of H. mammata was 1:1.2 (male:female), and the size at first sexual maturity was 142 mm for males and 167 mm for females. Gonad development began when days had a shorter photoperiod and lower seawater temperature, and spawning occurred later, with longer photoperiod and higher seawater temperature and chlorophyll-a concentrations. This study is essential to increase the biological and ecological knowledge of the populations of H. mammata, create conditions for the domestication of broodstock in captivity and create precise measures for the conservation of ecosystems.Holothuria mammata is one of the most valuable species of sea cucumber, as well as one of the main target species harvested in the Mediterranean and NE-Atlantic regions. This study aims to describe the reproductive cycle of H. mammata in a coastal area of southwest Portugal. Monthly samplings were carried out for 19 months, with the concomitant collection of environmental data and biometric data. H. mammata had a sex ratio of 1:1.2 (male:female) and a size at first maturity of 142 mm for males and 167 mm for females. The gonadosomatic index (GI) peaked between April and May for both sexes. Gonad development started when days had a shorter photoperiod (9 to 13 h of sunlight) and lower seawater temperature (<15 °C), and spawning occurred later, with longer photoperiod (13 to 15 h of sunlight) and higher seawater temperature (>15 °C) and chlorophyll-a concentrations. The development of new studies to increase the biological and ecological knowledge of the populations of H. mammata is essential to create conditions for the domestication of broodstock in captivity, to allow the development of fishing regulations based on informed decisions and to create precise measures for the conservation of ecosystems.

Modelling the Distribution of a Commercial NE-Atlantic Sea Cucumber, Holothuria mammata: Demographic and Abundance Spatio-Temporal Patterns

There is an increasing demand for sea cucumbers, for human consumption, mainly from Asian markets and, as a consequence, NE-Atlantic species are now new targets for exploitation and exportation. Holothuria mammata is one of the most valuable species in Europe. However, the lack of historical economic interest in this species in most European countries has also led to a lack of studies concerning biological and ecological aspects on wild populations and this is a major issue for stock management. This study aims to determine the temporal and spatial patterns of distribution of H. mammata, considering its abundance and demographic structure in a NE-Atlantic area, SW Portugal, as a function of environmental conditions. For that, a population from a marine protected area was followed for 1 year at 1.5-month intervals. Throughout the coastal area, six sites were selected and at each sampling campaign three random transects per site and substrate (rock and sand) in which all H. mammata individuals were counted and measured. For each site and survey several environmental parameters of interest, from the water column, the sediment and substrate cover, were also measured. Generalized Linear Models were used to model the spatial and temporal distribution of the species according to environmental conditions, to determine the species’ habitat preferences. The distribution models indicate that abiotic and biotic parameters of the water column are not the main drivers shaping the distribution of H. mammata. The species has a patchy distribution, and its habitat preferences depend on environmental stability, the presence of shelter and habitat complexity, which is more important for smaller, more vulnerable, individuals, while bigger size classes tend to venture more into less stable environments in an opportunistic fashion. The knowledge of these population traits is determinant to develop stock management measures, which are now urgent to prevent the depletion of commercial sea cucumber populations in the NE-Atlantic. Sustainable fisheries policies should be developed and start by considering to delimit fishing areas and periods, considering the species spatial and temporal distribution patterns.

Allometric relationships to assess ontogenetic adaptative changes in three NE Atlantic commercial sea cucumbers (Echinodermata, Holothuroidea)

Holothuria arguinensis, Holothuria mammata and Holothuria forskali are three common sea cucumber species found in the NE Atlantic, traded in international markets and susceptible to capture. Allometric relationships reveal if the scaling relationships between biometric characters are proportional with growth, being a useful tool to understand species growth strategies. Allometric relationships of the three species were estimated and compared between them and with populations from different regions. These allometric relationships revealed that the three species have negative allometric growth. However, they have different growth strategies between them and reveal different regional intra-specific growth strategies when compared to other populations, suggesting ontogenetic adaptation as a consequence of external factors.

Length-weight relationships and condition factor of four different sea cucumber species in the Aegean Sea

In this study, the gutted length-weight relationships and condition factor of the 4 Holothuria species (Holothuria tubulosa, Holothuria polii, Holothuria mammata and Holothuria sanctori) living in the Aegean Sea were determined.&#x0D; The sea cucumber samples were obtained between November 2014 and December 2018 by SCUBA and Hookah diving systems in the Aegean Sea. Identification of the species were based on morphometric characteristics only. Total gutted length (GL) and weight (GW) of each individual were recorded with an accuracy 0.1 cm and 0.01 g, respectively.&#x0D; During the sampling period, a total number of 18248 sea cucumber individuals belonging to four species were collected and measured. Mean gutted length and weight were found to be 13.20+3.44 cm and 66.34+30.93 g for H. tubulosa, 10.45+2.06 cm and 49.33+19.68 g for H. polii, 13.07+3.86 cm and 68.08+36.73 g for H.mammata, 18.62+3.02 cm and 102.34+21.76 g for H. sanctori, respectively. Negative allometric growth was estimated for all the four species with the “b” values ranging from 1.104 to 1.804.

Density and Biomass of Commercial Sea Cucumber Species Relative to Depth in the Northern Aegean Sea

Distribution and biomass of Holothuria tubulosa, Holothuria polii and Holothuria mammata in the Northern Aegean Sea were investigated in various depths (5 m, 10 m, and 15 m). Samples were collected by SCUBA or hookah diving systems from eleven stations, covering 2100 m2 area. Number of 5500, 3771 and 2742 were sampled at 5, 10 and 15 m depth, respectively. The gutted weight and length of the samples collected from 5, 10 and 15 m depth were 47.97 g and 11.00 cm, 61.99 g and 12.38 cm, and 63.41 g and 12.28 cm, respectively. The sea cucumber biomass and density were calculated as 125.65 g/m2 and 2.62 individuals/m2 at 5 m depth, 111.35 g/m2 and 1.8 individuals/m2 at 10 m depth, and 82.8 g/m2 and 1.31 individuals/m2 at 15 m depth. It was concluded that the mean weight of the studied commercial sea cucumber species increases by depth.

Does space matter? Optimizing stocking density ofHolothuria arguinensisandHolothuria mammata

Stocking density is an important factor affecting growth in aquaculture. The main objectives of this study are to evaluate the effects of different stocking densities on Holothuria arguinensis and Holothuria mammata's growth and determine the optimal density. Four different stocking densities were selected for H. arguinensis (1, 3, 5 and 7 ind/0.2 m2) and three for H. mammata (6, 10 and 12 ind/0.5 m2). Growth (specific growth rate (SGR) and growth rate (GR)), weight change, coefficient of variation and productivity were estimated, additionally the feeding rate on H. mammata. Growth on H. arguinensis decreased as the stocking density increased, showing the higher growth at the stocking density of 1 ind/0.2 m2 (SGR: 1.24%/day ± 0.16 and GR: 0.94 g/day ± 0.05), with a 104.65% (±9.98) of weight change. The best H. mammata growth was registered at 10 ind/m2 (SGR: 0.56% ± 0.04%/day and GR: 0.48 ± 0.04 g/day) and 25.48% (±1.52) of weight change. H. mammata feeding rate decreased as stocking density increased. Crowding stress could be considered the main factor affecting the sea cucumbers growth and performance on our study. The optimal stocking density for H. arguinensis and H. mammata under tank-based conditions were established as 1 ind/0.2 m2 and 5 ind/0.5 m2 respectively. The critic biomass for H. arguinensis (471.65 g/m2) and for H. mammata (988.11 g/m2) were reached during the experiment at the fourth and fifth weeks respectively. Therefore, to ensure and increase growth of these species under tank, their biomass should be maintained under those thresholds.

Non-destructive tissue sampling and the use of PCR-RFLPs in two edible sea cucumbers from the north-eastern Atlantic, Holothuria mammata Grube, 1840 and H. sanctori Delle Chiaje, 1823 (Echinodermata: Holothuroidea)

Historically, the harvest and consumption of sea cucumbers have been largely restricted to Asian countries. Recently, however, the western world has witnessed a rapid growth of holothurian-related industries, and Holothuria mammata Grube, 1840 and H. sanctori Delle Chiaje, 1823 are now being commercially harvested in European and North African countries. The identification of holothurian species tends to be difficult and time-consuming, and in many cases needs experienced taxonomists. We suggest a simple non-destructive DNA sampling, using tube feet or oral tentacles from these two species. We also describe a simple and fast method of diagnose based on polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) using restriction nuclease Sau3AI on 16S rRNA fragments. The use of RFLPs to rapidly and inexpensively identify species with no need for taxonomical or genetic expertise could prove a valuable asset for conservation and fishery purposes targeting commercially harvested animals such as the holothurians in the north-east Atlantic and the Mediterranean Sea.

Outlanders in an unusual habitat : Holothuria mammata (Grube, 1840) behaviour on seagrass meadows from Ria Formosa (S Portugal)

Holothuria mammata is one of the new target species from the Mediterranean and Atlantic. Usually, it inhabits rocky bottoms, staying in crevices and holes during the day and leaving them in the night for feeding on sandy bottoms. However, it can be found in unusual habitats such as seagrass with diurnal and nocturnal feeding. This study provides information for the first time on the behaviour, density and small scale distribution of H. mammata in a seagrass habitat from Ria Formosa (S Portugal). To reach these aims, a mark/recapture methodology was used. Abundance was estimated through R statistical software v.2.15.3 (package “Rcapture”). The minimum area method was applied in GRASS GIS v.6.4.2 for home range. Size distribution was estimated applying a ShapiroWilk test. Rayleigh test for randomness was applied to study the directionality of movements. A circular one-way ANOVA was used to test for differences in movement direction. Capture probability was higher on seagrass than sand and the total length of the individuals ranged from 13 to 25cm. Movement speed was between 4.7 and 14.7 m day-1. Movements were not directional. H. mammata differs in its behaviour from the related Holothuria arguinensis occurring in the same habitat.

Interactions and accumulation differences of metal(loid)s in three sea cucumber species collected from the Northern Mediterranean Sea

This study was conducted on Holothuria polii, Holothuria tubulosa, and Holothuria mammata collected from five stations with different depths in the Northern Mediterranean Sea. The body walls and guts of these holothurians were examined in terms of interactions of 10 metals (iron (Fe), copper (Cu), manganese (Mn), zinc (Zn), chromium (Cr), cobalt (Co), vanadium (V), nickel (Ni), cadmium (Cd), and lead (Pb)) and one metalloid (arsenic (As)) using a multivariate analysis, and interspecies differences were determined. The multivariate analysis of variance (MANOVA) revealed significant differences between the species in terms of metal(loid) accumulations. The principal component analysis (PCA) showed a more association between H. tubulosa and H. polii with regard to the accumulation. The cluster analysis (CA) located Pb concentrations of the guts to the farthest place from all elements regardless of the species. A correlation analysis displayed that the element concentrations of the guts were more closely related to each other compared with those of the walls. The most inconsistent element in terms of correlations was the gut Fe contents. Accordingly, while Fe concentrations of H. mammata and H. tubulosa were correlated with all elements (except Pb) in divalent metal transporter 1 (DMT1) (divalent cation transporter 1 (DCT1) or natural resistance-associated macrophage protein 2 (NRAMP2)) belonging to the NRAM protein family, this was not the case in H. polii. Consequently, significant relationships between accumulated metal(loid)s that changed by tissues and sea cucumber species were observed.

Novel polymorphic microsatellite loci for a new target species, the sea cucumber Holothuria mammata

With traditional finfish fisheries declining and pushing transition to new invertebrates target species, sea cucumbers have been heavily explored, suffering global overexploitation and worldwide depletion of their stocks.Nowadays, holothurians from the Mediterranean Sea and NE Atlantic Ocean are being exported to Asian markets. The scarce knowledge about their biology, population dynamics, ecology and genetics, is promoting defective management of their fisheries.We report the development of 9 novel polymorphic microsatellites markers for Holothuria mammata and characterized them by testing in three different sample locations. All nine microsatellites revealed high polymorphism and diversity, with high number of alleles, ranged from 11 to 22 and expected heterozygosity, between 0.52 and 0.92. Significant genetic differentiation was found between populations.These microsatellites are providing valuable information which could be applied to fisheries management including, identification of stocks, assessment of their genetic diversity, estimation of gene flow and monitoring the fishery effects on exploited populations.

Setting preliminary biometric baselines for new target sea cucumbers species of the NE Atlantic and Mediterranean fisheries

Commercial interest on sea cucumber species from the NE Atlantic and the Mediterranean is increasing. Holothuria polii, Holothuria tubulosa, Holothuria mammata and Holothuria arguinensis are the new target species. The scarce biological and ecological knowledge on these species along their geographical distribution, is a major problem for their fisheries management. To address it, we carried out a morphometric study to describe the baseline population size structure, focused on the length–weight relationship and size–weight distribution.In the NE Atlantic, the largest mean size and heaviest mean weight of H. mammata and H. arguinensis were found in localities with upwelling, but another factors could be influencing on these results. In the Mediterranean, Girona and Mallorca showed the heaviest specimens of H. polii, H. tubulosa and H. mammata, and the smallest were registered in Crete and Kusadasi. Significant differences in length and weight between populations were found for each species. These results could be linked with local environmental conditions. Size frequency distribution was multimodal for all species except for H. mammata; the weight frequency distribution was only unimodal for H. polii and H. mammata.This study provides novel data, helpful for stock and population assessment which could support the implementation of effective management for the European sea cucumber target species.

Assessment of sea cucumber populations from the Aegean Sea (Turkey): First insights to sustainable management of new fisheries

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.

The taxonomic status of some Atlanto-Mediterranean species in the subgenusHolothuria(Echinodermata: Holothuroidea: Holothuriidae) based on molecular evidence

Molecular and morphological data were used to evaluate the taxonomic status of the species Holothuria tubulosa Gmelin, 1790, Holothuria stellati Delle Chiaje, 1823, Holothuria mammata Grube, 1840, and Holothuria dakarensis Panning, 1939, belonging to the nominate subgenus Holothuria (Holothuria) (family Holothuriidae) from the Mediterranean Sea and Atlantic Ocean. A 16S rRNA marker distinguished three well-supported clades with clear genetic differentiation amongst them. The morphometric characters, although they reflected the clades, showed great variability, and some specimens from different clades overlapped. The morphological data and the literature suggest that the clades correspond to H. dakarensis (from Cape Verde Islands), H. mammata (from the AtlantoMediterranean area) and H. tubulosa (from the Mediterranean Sea). Holothuria stellati is considered here to be a junior subjective synonym of H. tubulosa. Great morphological intraspecific variation within H. tubulosa and H. mammata explains the confusion in the literature. Holothuria tubulosa includes specimens with distinctive ossicles, but others are similar to H. mammata. In these cases, the presence or absence of Cuvierian tubules proved a reliable indicator to the identity of these species; unfortunately this character is difficult to assess in preserved material. According to the results of discriminant analysis we propose a set of ossicle morphometric variables that permit the optimum assignation of individuals to the clades. Our results present a new perspective on the taxonomic status of species in Holothuria (Holothuria), and show how a molecular approach, combined with a morphological approach, can solve taxonomic problems.