Overexploitation and More Than a Decade of Failed Management Leads to No Recovery of the Galápagos Sea Cucumber Fishery

Ramírez-González, Jorge; Moity, Nicolás; Andrade-Vera, Solange; Reyes, Harry

doi:10.3389/fmars.2020.554314

Cited by 15 publications

(13 citation statements)

References 20 publications

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“…However, it was reported that 1.3 tons of sea cucumbers were harvested in 2014 from the coasts of Itoman City, which includes the Odo coastal area ( Okinawa General Bureau, 2017 ), and therefore we speculate that there were substantial amounts of LEC sea cucumbers present at least in the very recent past around Odo. The gap observed between past reports and the current study may be due to slow population recovery after over-exploitation, which has been reported in previous research ( Uthicke, Welch & Benzie, 2004 ; Friedman et al, 2011 ; Rehm et al, 2014 ; Ramírez-González et al, 2020 ). The majority of sea cucumbers are gonochoric broadcast spawners ( Babcock et al, 1992 ; Mercier & Hamel, 2009 ) with low mobility, and thus considered vulnerable to drastic population size declines due to the “allee effect” ( Purcell et al, 2011 ).…”

Section: Discussioncontrasting

confidence: 89%

“…In other words, once a population size becomes too low, the population can no longer maintain itself and recruitment from elsewhere is needed. However, it has been suggested that there may be no sexual recruitment in sea cucumbers as juveniles are typically not observed in coastal reef areas ( e.g ., H. atra at Taiwan, Chao, Chen & Alexander, 1994 ; H.atra and S. chloronotus at Great Barrier Reef, Uthicke, 2001b ; H. nobilis at Great Barrier Reef, Uthicke & Benzie, 2002 ), therefore local population recovery may take much longer than expected ( Uthicke, Welch & Benzie, 2004 ; Ramírez-González et al, 2020 ).…”

Section: Discussionmentioning

confidence: 99%

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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: Discussioncontrasting

confidence: 89%

Section: Discussionmentioning

confidence: 99%

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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“…Wild sea cucumber stocks are easily affected by fisheries, and marine reserves can assist in conserving their declining populations (Uthicke and Benzie, 2000;Anderson et al, 2011;Purcell et al, 2012Purcell et al, , 2013Wolfe and Byrne, 2017;Ramírez-González et al, 2020). In Ngardmau State, Palau, a decline in sea cucumber abundance occurred in one area open to fishing, while recovery occurred within a marine reserve (Rehm et al, 2014).…”

Section: Abundancementioning

confidence: 99%

“…Nowadays most tropical sea cucumber species have been overexploited, especially in China, because of increased demand for their product. This overexploitation could indirectly, deleteriously affect marine ecosystems (Purcell et al, 2012;Harith et al, 2018;Huang et al, 2018;Ramírez-González et al, 2020). While H. leucospilota is an abundant species in tropical and subtropical waters, and not in danger of extinction like other commercially fished species (e.g., Stichopus horrens), it is severely threatened by overexploitation and environmental degradation (Purcell et al, 2012;Harith et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

The Effects of Hypoxia and Anthropogenic Disturbance on the Distribution, Abundance and Recruitment of the Sea Cucumber Holothuria leucospilota at the Mouth of a Subtropical Bay, China

Zhang

Zhou

et al. 2021

Front. Mar. Sci.

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Despite the commercial importance of the sea cucumber Holothuria leucospilota increasing in recent years, little is known of its spatial distribution and ecology in the South China Sea. We investigate the distribution, abundance, and recruitment of H. leucospilota from 2017 to 2020 at two sites (S1 and S2) in Daya Bay, a typical subtropical bay which is strongly influenced by human activities in the South China Sea. We report hypoxia to drive H. leucospilota from deeper into shallower waters with higher DO concentrations at the mouth of Dapeng Cove in Daya Bay (S1), particularly during summer. Population size at S1 decreased by 90% from 2017 levels, before this area was opened to the public in 2018; recruitment was not observed by August (summer) of 2020. In contrast, in summers of 2017 and 2020, H. leucospilota abundance at S2, a protected open-water area, increased by 84%, and the proportion of small-sized (recently recruited) sea cucumber in the population increased by 20%. Severe summer hypoxia at S1 could negatively influence H. leucospilota spawning and larval settlement, which combined with depletion of broodstock because of fishing pressure and/or hypoxia-induced mortality, could inhibit recruitment. In contrast, higher DO concentrations and abundant broodstock during summer (the breeding season) favoured recruitment of H. leucospilota at S2. Overall, hypoxia and anthropogenic disturbance impede recovery of H. leucospilota at S1, while at the protected S2, larvae may be released to settle in nearby areas. It is imperative to develop a better understanding of the biology, ecology and conservation of tropical sea cucumbers in China.

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“…In response to the market demand, the fishery of sea cucumbers have shifted to new target species as the Mediterranean ones (Gonzaĺez-Wangüemert et al, 2014;Gonzaĺez-Wangüemert et al, 2018). In many cases, the sea cucumber harvesting increased without an adequate management, which, coupled with the illegal catches, caused the collapse of several stocks (Toral-Granda et al, 2008;Anderson et al, 2011;Purcell, 2014, Gonzaĺez-Wangüemert et al, 2018Ramıŕez-Gonzaĺez et al, 2020a). One of the main causes of the failure of sea cucumber management can also be a reflection of severe knowledge gaps on basic biological and ecological attributes, and their reproductive biology.…”

Section: Introductionmentioning

confidence: 99%

New insights upon the reproductive biology of the sea cucumber Holothuria tubulosa (Echinodermata, Holothuroidea) in the Mediterranean: Implications for management and domestication

et al. 2022

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Holothuria tubulosa is one of the most common sea cucumber species inhabiting the Mediterranean Sea. Due to its commercial interest for the international market, it has been harvested without proper management causing the overexploitation of its stocks. Inadequate management is also caused by lack of information on basic biology and ecology not allowing the estimating of the species vulnerability and resilience to growing anthropogenic pressures. In this paper, we have investigated basic life-history traits of H. tubulosa (population structure and reproductive cycle) in a population of Central-Western Mediterranean (Sardinia, Italy). A macroscopic maturity scale for both sexes was defined through an instrumental colorimetric analysis of the gonads and the ramification level of the gonad’s tubules, subsequently confirmed by histological analysis. The seasonal trend of the Gonado-Somatic Index, the changes in color of the gonads and tubules ramification indicated that the spawning period of H. tubulosa was concentrated in summer with a peak in late August, closely related to the increase in water temperature. A synchronous development of the gonads, with a unique and short reproductive event during the year, was also detected. In conclusion, this study provides new evidence on the biological and ecological features of H. tubulosa, essential data for developing a scientifically-based stock assessment as well as conservative management at a local scale. Finally, we provided basic information for the domestication of broodstock in a conservative hatchery.

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Overexploitation and More Than a Decade of Failed Management Leads to No Recovery of the Galápagos Sea Cucumber Fishery

Cited by 15 publications

References 20 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

The Effects of Hypoxia and Anthropogenic Disturbance on the Distribution, Abundance and Recruitment of the Sea Cucumber Holothuria leucospilota at the Mouth of a Subtropical Bay, China

New insights upon the reproductive biology of the sea cucumber Holothuria tubulosa (Echinodermata, Holothuroidea) in the Mediterranean: Implications for management and domestication

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