Effects of fishery protection on biometry and genetic structure of two target sea cucumber species from the Mediterranean Sea

Sea cucumber fisheries are now occurring in most of the tropical areas of the world, having expanded from its origin in the central Indo-Pacific. Due to the overexploitation of these resources and the increasing demand from Asian countries, new target species from Mediterranean Sea and northeastern Atlantic Ocean are being caught. The fishery effects on biometry and genetic structure of two target species (Holothuria polii and H. tubulosa) from Turkey, were assessed. The heaviest and largest individuals of H. polii were found into the non-fishery area of Kusadasi, also showing the highest genetic diversity. Similar pattern was detected in H. tubulosa, but only the weight was significantly higher in the protected area. However, the observed differences on the fishery effects between species, could be explained considering the different percentage of catches (80% for H. polii and 20% for H. tubulosa)

The History of Makassan Trepang Fishing and Trade

The Malayan term trepang describes a variety of edible holothurians commonly known as sea cucumbers. Although found in temperate and tropical marine waters all over the world, the centre of species diversity and abundance are the shallow coastal waters of Island Southeast Asia. For at least 300 years, trepang has been a highly priced commodity in the Chinese market. Originally, its fishing and trade was a specialized business, centred on the town of Makassar in South Sulawesi (Indonesia). The rise of trepang fishing in the 17th century added valuable export merchandize to the rich shallow seas surrounding the islands of Southeast Asia. This enabled local communities to become part of large trading networks and greatly supported their economic development. In this article, we follow Makassan trepang fishing and trading from its beginning until the industrialization of the fishery and worldwide depletion of sea cucumbers in the 20th century. Thereby, we identify a number of characteristics which trepang fishing shares with the exploitation of other marine resources, including (1) a strong influence of international markets, (2) the role of patron-client relationships which heavily influence the resource selection, and (3) the roving-bandit-syndrome, where fishermen exploit local stocks of valuable resources until they are depleted, and then move to another area. We suggest that understanding the similarities and differences between historical and recent exploitation of marine resources is an important step towards effective management solutions

The cost of being valuable: predictors of extinction risk in marine invertebrates exploited as luxury seafood

Extinction risk has been linked to biological and anthropogenic variables. Prediction of extinction risk in valuable fauna may not follow mainstream drivers when species are exploited for international markets. We use results from an International Union for Conservation of Nature Red List assessment of extinction risk in all 377 known species of sea cucumber within the order Aspidochirotida, many of which are exploited worldwide as luxury seafood for Asian markets. Extinction risk was primarily driven by high market value, compounded by accessibility and familiarity (well known) in the marketplace. Extinction risk in marine animals often relates closely to body size and small geographical range but our study shows a clear exception. Conservation must not lose sight of common species, especially those of high value. Greater human population density and poorer economies in the geographical ranges of endangered species illustrate that anthropogenic variables can also predict extinction risks in marine animals. Local-level regulatory measures must prevent opportunistic exploitation of high-value species. Trade agreements, for example CITES, may aid conservation but will depend on international technical support to low-income tropical countries. The high proportion of data deficient species also stresses a need for research on the ecology and population demographics of unglamorous invertebrates

Highly localised distribution patterns of juvenile sea cucumber Australostichopus mollis

Information on the environmental characteristics of the juvenile habitat of many deposit-feeding sea cucumber species is limited, despite most fished species exhibiting rapid localised depletion.\ud The current study combined large and small scale surveying techniques within a New Zealand harbour to identify areas with high densities of juvenile Australostichopus mollis, a commercially valuable aspidochirote holothurian. Data from detailed surveys were used to relate densities of\ud juveniles and adults with measures of physical habitat characteristics including depth, sediment facies type, grain size range, as well as measures of chlorophyll-a, phaeopigment, carbon and nitrogen content of surface sediment. Results revealed a highly localised distribution of juvenile A. mollis focused on one site associated with an area of high adult density. Sites of high juvenile\ud A. mollis density were characterised by sediment qualities favouring epibenthic detritivorous deposit feeding, including high nitrogen content, high phaeopigment:chlorophyll-a ratio and small grain size. The high-density juvenile site had facies that were further characterised by the presence of large shell fragments (10 cm length) of the horse mussel (Atrina zelandica), which\ud may provide a unique settlement microhabitat for early juveniles. Unlike some other sea cucumber species, juvenile A. mollis shows no distinct spatial separation from adult sea cucumbers, no association with dense macroalgae and no clear preference for shallower depths than adults. Overall, the results illustrate the highly localised pattern of recruitment of this species to a widely distributed adult population, which may help to explain the lack of previous observations of juveniles in this species. These results indicate the importance of identifying and protecting what appear to be very specific juvenile habitats in deposit-feeding sea cucumbers to ensure continuing recruitment to exploited populations

Renewal ecology: conservation for the Anthropocene

The global scale and rapidity of environmental change is challenging ecologists to reimagine their theoretical principles and management practices. Increasingly, historical ecological conditions are inadequate targets for restoration ecology, geographically circumscribed nature reserves are incapable of protecting all biodiversity, and the precautionary principle applied to management interventions no longer ensures avoidance of ecological harm. In addition, human responses to global environmental changes, such as migration, building of protective infrastructures, and land use change, are having their own negative environmental impacts.We use examples from wildlands, urban, and degraded environments, as well as marine and freshwater ecosystems, to show that human adaptation responses to rapid ecological change can be explicitly designed to benefit biodiversity. This approach, which we call “renewal ecology,” is based on acceptance that environmental change will have transformative effects on coupled human and natural systems and recognizes the need to harmonize biodiversity with human infrastructure, for the benefit of both

Renewal ecology: conservation for the Anthropocene

The global scale and rapidity of environmental change is challenging ecologists to reimagine their theoretical principles and management practices. Increasingly, historical ecological conditions are inadequate targets for restoration ecology, geographically circumscribed nature reserves are incapable of protecting all biodiversity, and the precautionary principle applied to management interventions no longer ensures avoidance of ecological harm. In addition, human responses to global environmental changes, such as migration, building of protective infrastructures, and land use change, are having their own negative environmental impacts. We use examples from wildlands, urban, and degraded environments, as well as marine and freshwater ecosystems, to show that human adaptation responses to rapid ecological change can be explicitly designed to benefit biodiversity. This approach, which we call renewal ecology, is based on acceptance that environmental change will have transformative effects on coupled human and natural systems and recognizes the need to harmonize biodiversity with human infrastructure, for the benefit of both