Isolation and characterization of microsatellite loci from three widespread tropical sea cucumbers of the genus Holothuria (Echinodermata, Holothuroidea), and cross-amplification among them.

Holothuria (Microthele) fuscogilva (Cherbonnier, 1980), Holothuria sp. type "Pentard" and Holothuria (Microthele) nobilis (Selenka, 1867) are three tropical sea cucumber taxa that are heavily fished worldwide for the beche-de-mer trade market. In order to investigate the population genetic structure, diversity and connectivity of these taxa, 16, 19 and 25 microsatellite loci were isolated from H. fuscogilva, Holothuria sp. type "Pentard" and H. nobilis DNA libraries, respectively. These loci were tested on 94, 60 and eight individuals of the respective species, collected from the Seychelles. The number of alleles per locus ranged from 2 to 30. The observed heterozygosity ranged from 0.245 to 0.890 for H. fuscogilva and from 0.200 to 0.950 for Holothuria sp. type "Pentard", while the expected heterozygosity ranged from 0.231 to 0.952 and from 0.504 to 0.951, respectively. Several loci were at Hardy-Weinberg equilibrium and linkage disequilibrium was detected in only three pairs of loci. Cross-amplification was also tested and almost all loci (49 over 60) were polymorphic for at least two of the three studied taxa, showing high transferability among them. These loci represent useful tools for assessing genetic diversity and population structure of these three taxa in fishery areas, and therefore providing relevant knowledge for resource management.

Isolation and characterization of 42 microsatellite loci from the prickly redfish Thelenota ananas (Echinodermata, Stichopodidae).

The prickly redfish Thelenota ananas (Jaeger, 1833) is a widely distributed tropical sea cucumber. Populations of this species have been increasingly harvested throughout its distribution area in the Indo-Pacific region, which led to significant overexploitation issues. In order to investigate the genetic structure, diversity and connectivity of its populations, 42 microsatellite loci were isolated from a T. ananas microsatellite-enriched DNA library. These loci were characterized on 24 individuals collected from the Seychelles. The number of alleles per locus ranged from 3 to 22. The observed heterozygosity ranged from 0.083 to 0.952, while the expected heterozygosity ranged from 0.162 to 0.974. No linkage disequilibrium was detected among all loci and 20 loci (48%) were at Hardy-Weinberg equilibrium. These 42 loci represent useful tools for assessing genetic diversity, structure and gene flow among T. ananas populations, providing relevant knowledge for the management and conservation of those major commercial resources.

The dynamics of institutional innovation: Crafting co-management in small-scale fisheries through action research.

This paper investigates the dynamics of institutional development and co-management performance in small-scale fisheries. The study covers different contexts and spatial and temporal scales, for nine case studies in the South Pacific. In these cases, new co-management institutions were intentionally set up from 2008 to 2016 through fishery policy intervention to address over-exploitation problems of sea cucumber resources. This was carried out in a process of adaptive experimentation, based on a collaborative and problem-solving approach to governance, and a context-based vision of sustainability issues. In order to quantitatively and empirically assess change in governance within and between cases, a multidimensional analytical framework of governance performance is developed. A set of governance performance criteria is defined and the criteria are scored using data from an institutional diagnosis of the cases, throughout the research period. Ten out of eleven criteria were positively impacted by the co-management interventions. Three institutional development trajectories can be identified for the fishery co-management building process, involving a range of gradual and abrupt changes. Consolidation of the institutional changes achieved by the interventions is required to successfully develop the resilience of the fishing systems to multiple stresses. This empirical study provides a methodology for systematically assessing institutional dynamics in fisheries, and in particular the crafting and sustaining of co-management regimes in small-scale fisheries. The approach could potentially be applied to other complex social-ecological systems.

HIARA study protocol: impacts of artificial coral reef development on fisheries, human livelihoods and health in southwestern Madagascar.

The Health Impacts of Artificial Reef Advancement (HIARA; in the Malagasy language, "together") study cohort was set up in December 2022 to assess the economic and nutritional importance of seafood for the coastal Malagasy population living along the Bay of Ranobe in southwestern Madagascar. Over the course of the research, which will continue until at least 2026, the primary question we seek to answer is whether the creation of artificial coral reefs can rehabilitate fish biomass, increase fish catch, and positively influence fisher livelihoods, community nutrition, and mental health. Through prospective, longitudinal monitoring of the ecological and social systems of Bay of Ranobe, we aim to understand the influence of seasonal and long-term shifts in marine ecological resources and their benefits to human livelihoods and health. Fourteen communities (12 coastal and two inland) were enrolled into the study including 450 households across both the coastal (n = 360 households) and inland (n = 90 households) ecosystems. In the ecological component, we quantify the extent and health of coral reef ecosystems and collect data on the diversity and abundance of fisheries resources. In the social component, we collect data on the diets, resource acquisition strategies, fisheries and agricultural practices, and other social, demographic and economic indicators, repeated every 3 months. At these visits, clinical measures are collected including anthropometric measures, blood pressure, and mental health diagnostic screening. By analyzing changes in fish catch and consumption arising from varying distances to artificial reef construction and associated impacts on fish biomass, our cohort study could provide valuable insights into the public health impacts of artificial coral reef construction on local populations. Specifically, we aim to assess the impact of changes in fish catch (caused by artificial reefs) on various health outcomes, such as stunting, underweight, wasting, nutrient intake, hypertension, anxiety, and depression.

Tectus (Trochus) niloticus search for suitable habitats can cause equivocal benefits of protection in village-based marine reserves.

In the Pacific, the protection of coral reef resources is often achieved through the implementation of village-based marine reserves (VBMRs). While substantial fisheries benefits are often reported, results of quantitative approaches are controversial for benthic macroinvertebrates, whose life history traits may cause low congruence with protective measures implemented at non-ecologically relevant scales. This study investigated the structural and behavioral responses of the exploited topshell Tectus niloticus within a very small (0.2 km2) VBMR in Vanuatu, south Pacific. The results of underwater surveys and a nine-month tagging experiment emphasized contrasted, scale-dependent responses. At the reserve scale, our results failed to demonstrate any positive effect of protection after three years of closure. In contrast, abundance, density and biomass increased more than ten-fold in the southern part of the reserve, along with significantly larger (25%) individual sizes. The dispersal of tagged specimens was also consistently lower after 2, 4 and 9 months in the latter zone. Analyses of 17 substratum variables revealed a marked small-scale patchiness delineating contrasted benthic microhabitats, the distribution of which closely matched that of trochus. We advocate that i) VBMRs have inherently unequal ecological potentials for protecting and managing highly habitat-dependent species such as trochus; ii) 'success' or 'failure' is to a certain extent pre-determined by the trajectory of species-specific microhabitats, which may outreach protection effects. This has strong implications in the Pacific where the location and size of reserves primarily depends upon marine tenure, and communities have little flexibility in setting reserve boundaries.

Modulation of habitat-based conservation plans by fishery opportunity costs: a New Caledonia case study using fine-scale catch data.

Numerous threats impact coral reefs and conservation actions are urgently needed. Fast production of marine habitat maps promotes the use of habitat-only conservation plans, where a given percentage of the area of each habitat is set as conservation objectives. However, marine reserves can impact access to fishing grounds and generate opportunity costs for fishers that need to be minimized. In New Caledonia (Southwest Pacific), we used fine-scale fishery catch maps to define nineteen opportunity costs layers (expressed as biomass catch loss) considering i) total catches, ii) target fish families, iii) local marine tenure, and iv) gear type. The expected lower impacts on fishery catch when using the different cost constraints were ranked according to effectiveness in decreasing the costs generated by the habitat-only scenarios. The exercise was done for two habitat maps with different thematic richness. In most cases, habitat conservation objectives remained achievable, but effectiveness varied widely between scenarios and between habitat maps. The results provide practical guidelines for coral reef conservation and management. Habitat-only scenarios can be used to initiate conservation projects with stakeholders but the costs induced by such scenarios can be lowered by up to 50-60% when detailed exhaustive fishery data are used. When using partial data, the gain would be only in the 15-25% range. The best compromises are achieved when using local data.

Does herbivorous fish protection really improve coral reef resilience? A case study from new caledonia (South Pacific).

Parts of coral reefs from New Caledonia (South Pacific) were registered at the UNESCO World Heritage list in 2008. Management strategies aiming at preserving the exceptional ecological value of these reefs in the context of climate change are currently being considered. This study evaluates the appropriateness of an exclusive fishing ban of herbivorous fish as a strategy to enhance coral reef resilience to hurricanes and bleaching in the UNESCO-registered areas of New Caledonia. A two-phase approach was developed: 1) coral, macroalgal, and herbivorous fish communities were examined in four biotopes from 14 reefs submitted to different fishing pressures in New Caledonia, and 2) results from these analyses were challenged in the context of a global synthesis of the relationship between herbivorous fish protection, coral recovery and relative macroalgal development after hurricanes and bleaching. Analyses of New Caledonia data indicated that 1) current fishing pressure only slightly affected herbivorous fish communities in the country, and 2) coral and macroalgal covers remained unrelated, and macroalgal cover was not related to the biomass, density or diversity of macroalgae feeders, whatever the biotope or level of fishing pressure considered. At a global scale, we found no relationship between reef protection status, coral recovery and relative macroalgal development after major climatic events. These results suggest that an exclusive protection of herbivorous fish in New Caledonia is unlikely to improve coral reef resilience to large-scale climatic disturbances, especially in the lightly fished UNESCO-registered areas. More efforts towards the survey and regulation of major chronic stress factors such as mining are rather recommended. In the most heavily fished areas of the country, carnivorous fish and large targeted herbivores may however be monitored as part of a precautionary approach.