Higher Genetic Diversity of the Common Sea Cucumber Holothuria (Halodeima) atra in Marine Protected Areas of the Central and Southern Ryukyu Islands

Hamamoto, Kohei; Soliman, Taha; Poliseno, Angelo; Fernández-Silva, Iria; Reimer, James Davis

doi:10.3389/fcosc.2021.736633

Cited by 13 publications

(8 citation statements)

References 62 publications

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“…Among sites, Aka showed the highest number of individuals (131 individuals) and density (0.0903 ind/m 2 ) of H. atra , and this site is within Keramashoto National Park (see Fig. 1 for its location), which was reported recently to harbor the highest genetic diversity of this species ( Hamamoto et al, 2021 ). As well, Manza, which showed the second highest COI genetic diversity ( Hamamoto et al, 2021 ) and had the second highest total individual numbers following Aka, and third highest total population density among sites in the current study, is within a quasi-national park.…”

Section: Discussionmentioning

confidence: 69%

“…1 for its location), which was reported recently to harbor the highest genetic diversity of this species ( Hamamoto et al, 2021 ). As well, Manza, which showed the second highest COI genetic diversity ( Hamamoto et al, 2021 ) and had the second highest total individual numbers following Aka, and third highest total population density among sites in the current study, is within a quasi-national park. Combined, these facts may indicate this species is comparatively better conserved within parks.…”

Section: Discussionmentioning

confidence: 86%

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Shallow epifaunal sea cucumber densities and their relationship with the benthic community in the Okinawa Islands

Hamamoto

Poliseno

Soliman

et al. 2022

PeerJ

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Sea cucumbers are important ecological engineers in marine ecosystems. However, the fishery demand of some species, especially large-epifaunal and commercially used (LEC) sea cucumbers, has risen drastically, resulting in serious depletion of local populations for many species. Despite this problem, basic ecological data on sea cucumbers, such as population densities and preferred habitats, are often still insufficient. Here, we report on the population densities of multiple LEC sea cucumber species, and their ambient benthic communities at eight sites around Okinawa Islands. Further, we discuss the correspondence between sea cucumber densities and the surrounding coral communities. Our results show two sites within national or quasi-national parks, Aka and Manza, where stricter rules have been placed on fisheries and land reclamation compared to other areas, had the highest and third highest sea cucumber population densities among sites, respectively. Holothuria atra was observed at all survey sites and made up the majority of sea cucumber populations at all sites except for Chatan and Sesoko, where Holothuria leucospilota and Stichopus chloronotus were most abundant, respectively. Regarding the relationships between benthic composition and LEC sea cucumber species, S. chloronotus was significantly correlated with dead corals, scleractinian corals, and coralline algae. As well, H. leucospilota had significant correlations with rubble. Although there were no significant correlations between any specific scleractinian coral genus and sea cucumber densities, S. chloronotus was marginally insignificant with Platygyra and Psammocora. Notably, medium- to highly valued species were sparse in our surveys, and most of them appeared at only one site. Additionally, at one site (Odo), only three LEC sea cucumber individuals were observed. Combining these facts with relatively low population densities around the Okinawa Islands compared to densities reported in previous research from the Indo-West Pacific Ocean region, we conclude that Okinawan LEC sea cucumber populations have been and are being impacted by high levels of direct (e.g., overexploitation, as well as coastal development) and indirect anthropogenic pressure (e.g., decreasing water quality). To address the current situation, repeated monitoring and more detailed investigations to reveal the drivers that determine LEC sea cucumber species aggregations and population densities are urgently needed, along with more robust management of remaining LEC sea cucumber populations.

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Section: Discussionmentioning

confidence: 69%

Section: Discussionmentioning

confidence: 86%

Shallow epifaunal sea cucumber densities and their relationship with the benthic community in the Okinawa Islands

Hamamoto

Poliseno

Soliman

et al. 2022

PeerJ

Self Cite

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“…While that study showed that habitat also influenced holothurian presence, the authors concluded that MPAs may help conserve high densities of economically important holothurians. Another study has demonstrated higher genetic diversity of H. atra within an MPA (Hamamoto et al, 2021). In general, no-take MPAs have not been designed specifically for holothurians (Cariglia et al, 2013), and the use of MPAs for holothurian conservation warrants further consideration (Hamel et al, 2022).…”

Section: Holothurians Fishing and Mpa Effectsmentioning

confidence: 99%

Boom‐and‐bust cycles of holothurian (sea cucumber) populations in the Chagos Archipelago: An indication of poaching or natural processes?

Widman

Collins

Evans

et al. 2023

Aquatic Conservation

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The Chagos Archipelago is a remote Indian Ocean atoll of international conservation significance. Holothurians (sea cucumbers) are a major resource and influence reef health. Past populations have fluctuated from poaching and natural events. Visual censuses of holothurians were conducted in 62 shallow‐water transects within four atolls of Chagos in 2014, 4 years after creation of the Marine Protected Area, to determine its possible influence on holothurians. Comparison with data from the same locations in 2006 and 2010, using the same methodologies, showed significant overall population decline at Diego Garcia, recovery at Salomon (significant) and Peros Banhos (not significant), and no significant change on the Great Chagos Bank. The median abundance of Holothuria atra and Bohadschia sp(p.) decreased at Diego Garcia, while that of Stichopus chloronotus increased at Diego Garcia and Salomon atolls. Changes for other species were less marked. Diego Garcia, Salomon and Peros Bahnos showed a decline in diversity (no. of holothurian taxa and/or Shannon index, H), but diversity has been relatively stable on the Great Chagos Bank. All atolls, except Diego Garcia, are uninhabited and illegal fishing of holothurians, principally by Sri Lankan fishers, appears to have eased since 2005/2006, based on evaluation of 299 patrol survey reports. This may have led to the recovery or stabilization of populations in the outer atolls of Salomon, Peros Banhos atolls and the Great Chagos Bank. The reasons for holothurian decline at Diego Garcia, where exploitation is also prohibited (but cannot be ruled out), are unclear. Population patterns on all islands may reflect both natural fluctuations and disturbance events, including changing exploitation pressure. Conservation requirements include periodic re‐censusing of holothurians and ongoing monitoring of illegal fishing to help safeguard populations and the integrity of the Marine Protected Area.

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“…The ndings largely supported the presence of genetic variations within populations of H. fuscogilva. Moreover, the observation with AMOVA was also the case with species within its genera, among them, being H.scabra (Gardner & Fitch, 2012; Ravago-gotanco & Kim, 2019), H. mammata (Valente et al, 2015)d halodeima (Hamamoto et al, 2021), all showing high variation at the intra-population level. The variation in intrapopulation levels could be explained by the possibility of high gene ow among the locations that make up the populations, as was also suggested for H. polii populations sampled within their smaller geographic scales (Vergara-Chen et al, 2010).…”

Section: Phylogeneticsmentioning

confidence: 81%

Population genetic structure of white teatfish, Holothuria fuscogilva in south-coast, Kenya

Karan

Fulanda

Mkare

et al. 2023

Preprint

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The white teatfish, Holothuria fuscogilva, is widely distributed in coastal areas, including waters around coral reefs and seagrasses in the Indo-Pacific. In Kenya, the species is distributed in shallow reefs, with higher landings reported from the Vanga-Shimoni-Msambweni seascape on the Kenyan south coast. The present study investigated the genetic structure and effects of fishing pressure on genetic diversity of H. fuscogilva populations from three fish landing sites in south-coast Kenya, using an analysis of the mitochondrial cytochrome oxidase sub-unit I (COI) gene. Muscle tissues were obtained for a total of 60 individuals collected from three sites. Genomic DNA was extracted from the ethanol stored samples using commercial DNA extraction kit method. DNA samples for 47 samples were able to amplify using the polymerase chain reaction method (PCR). High-quality PCR products yielding high-quality sequences, producing 22 haplotypes with high haplotype diversity but low nucleotide diversity (h = 0.922, π = 0.008). The northernmost site, Gazi, reported higher genetic diversity (h = 0.933) than other populations. The genetic structure was analyzed using Analysis of Molecular Variance (AMOVA), a comparison of the genetic differentiation between populations using Fixation Indices (FST) based on Wright's F-statistics. AMOVA showed the highest proportion of variation within the populations than among the populations. The fixation index FST showed a lack of structure among H. fuscogilva (FST = 0.01186, p. value = 0.29069). The H. fuscogilva populations at the three study sites along Kenya's south coast appear to have genetic connectivity but no significant genetic structure. The genetic structure estimates and intra-population genetic diversity depict a robust population that can regenerate lost individuals after a fishing event. This study has generated information on genetic structure and the status of genetic diversity of H. fuscogilva under fishing pressure in south-coast Kenya. The study has provided genetic information to elucidate population genetic structure along the Kenya south-coast that is critical in guiding the formulation of sound harvest strategies and conservation management policies for the H. fuscogilva species.

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Higher Genetic Diversity of the Common Sea Cucumber Holothuria (Halodeima) atra in Marine Protected Areas of the Central and Southern Ryukyu Islands

Cited by 13 publications

References 62 publications

Shallow epifaunal sea cucumber densities and their relationship with the benthic community in the Okinawa Islands

Shallow epifaunal sea cucumber densities and their relationship with the benthic community in the Okinawa Islands

Boom‐and‐bust cycles of holothurian (sea cucumber) populations in the Chagos Archipelago: An indication of poaching or natural processes?

Population genetic structure of white teatfish, Holothuria fuscogilva in south-coast, Kenya

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