Environmental DNA illuminates the dark diversity of sharks

In the era of “Anthropocene defaunation,” large species are often no longer detected in habitats where they formerly occurred. However, it is unclear whether this apparent missing, or “dark,” diversity of megafauna results from local species extirpations or from failure to detect elusive remaining individuals. We find that despite two orders of magnitude less sampling effort, environmental DNA (eDNA) detects 44% more shark species than traditional underwater visual censuses and baited videos across the New Caledonian archipelago (south-western Pacific). Furthermore, eDNA analysis reveals the presence of previously unobserved shark species in human-impacted areas. Overall, our results highlight a greater prevalence of sharks than described by traditional survey methods in both impacted and wilderness areas. This indicates an urgent need for large-scale eDNA assessments to improve monitoring of threatened and elusive megafauna. Finally, our findings emphasize the need for conservation efforts specifically geared toward the protection of elusive, residual populations

Drivers of reef shark abundance and biomass in the Solomon Islands

Remote island nations face a number of challenges in addressing concerns about shark population status, including access to rigorously collected data and resources to manage fisheries. At present, very little data are available on shark populations in the Solomon Islands and scientific surveys to document shark and ray diversity and distribution have not been completed. We aimed to provide a baseline of the relative abundance and diversity of reef sharks and rays and assess the major drivers of reef shark abundance/biomass in the Western Province of the Solomon Islands using stereo baited remote underwater video. On average reef sharks were more abundant than in surrounding countries such as Fiji and Indonesia, yet below that of remote islands without historical fishing pressure, suggesting populations are relatively healthy but not pristine. We also assessed the influence of location, habitat type/complexity, depth and prey biomass on reef shark abundance and biomass. Location was the most important factor driving reef shark abundance and biomass with two times the abundance and a 43% greater biomass of reef sharks in the more remote locations, suggesting fishing may be impacting sharks in some areas. Our results give a much needed baseline and suggest that reef shark populations are still relatively unexploited, providing an opportunity for improved management of sharks and rays in the Solomon Islands

Proposition d'évolution pour la formation "personne compétente"

Plus de dix ans après la mise en place de la réglementation française actuelle concernant la personne compétente en radioprotection, l'INSTN (Institut National des Sciences et techniques Nucléaires) a estimé opportun d'établir un état des lieux en termes d'adaptation de la formation initiale de la personne compétente vis-à-vis de la diversité de la demande et des besoins exprimés dans l'industrie, la recherche et le monde de la santé. Dans le cadre de ce bilan, un questionnaire a été adressé, début 1997, à des personnes formées par l'intermédiaires des organismes de formations agréés. Cette action a précédé un congrès consacré à la personne compétente conduit en présence de nombreux acteurs et notamment des représentants du ministère de l'Emploi et de la solidarité. Deux actes majeurs de réflexion sont apparus : d'une part le statut de la personne compétente et sa capacité d'agir et d'autre part sa formation. Concernant de deuxième axe, trois points forts ont été identifiés : i) le souhait d'introduire plus de pratique dans la formation actuelle (70 % des réponses) ; ii) une demande très forte (75 % des réponses) pour un recyclage périodique ; iii) le souhait d'une formation adaptée au niveau de risque

A histological study of the gametogenic cycle of the freshwater mussel Dreissena polymorpha (Pallas, 1771) in Lough Derg, Ireland

Journal of Molluscan Studies694365-373JMST