Examining current best-practices for the use of wild post-larvae capture, culture, and release for fisheries enhancement

Demand for marine fisheries is rising despite global impacts on the productive capacity of wild fish stocks due to overfishing, habitat loss, and global warming. Fisheries enhancement programs—aimed at augmenting stocks by releasing juveniles into the wild—are expected to play an increasingly important auxiliary role in addressing capture-based fishery limitations into the future. However, concerns exist over the impacts and efficacy of aquaculture-based enhancement (ABE), releasing captive-bred fish into wild populations. An alternative but understudied approach for fisheries enhancement is wild post-larvae capture, culture, and release (PCCR). Here, we provide an overview of the PCCR process, from initial planning to measuring success, providing an overview of its implementation in a viable finfish fishery, the white seabream Diplodus sargus in the Mediterranean. We discuss management application of PCCR-based enhancement and its limitations, highlighting existing knowledge gaps and future research required to realize the full potential of this alternative approach. Notwithstanding some limitations–including limited uptake for full evaluation, some species restrictions, density-dependent mortality, and the remaining open challenge for stock enhancement generally of tracking released fish through to reproduction–PCCR offers potential as a credible auxiliary management tool for fisheries restoration

Influence of a video sequence dedicated to back pain on the beliefs of the general population

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Observation of juvenile dusky groupers (Epinephelus marginatus) in artificial habitats of North-Western Mediterranean harbors

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Common structural requirements for heptahelical domain function in class A and class C G protein-coupled receptors.

International audienceG protein-coupled receptors (GPCRs) are key players in cell communication. Several classes of such receptors have been identified. Although all GPCRs possess a heptahelical domain directly activating G proteins, important structural and sequence differences within receptors from different classes suggested distinct activation mechanisms. Here we show that highly conserved charged residues likely involved in an interaction network between transmembrane domains (TM) 3 and 6 at the cytoplasmic side of class C GPCRs are critical for activation of the gamma-aminobutyric acid type B receptor. Indeed, the loss of function resulting from the mutation of the conserved lysine residue into aspartate or glutamate in the TM3 of gamma-aminobutyric acid type B(2) can be partly rescued by mutating the conserved acidic residue of TM6 into either lysine or arginine. In addition, mutation of the conserved lysine into an acidic residue leads to a nonfunctional receptor that displays a high agonist affinity. This is reminiscent of a similar ionic network that constitutes a lock stabilizing the inactive state of many class A rhodopsin-like GPCRs. These data reveal that despite their original structure, class C GPCRs share with class A receptors at least some common structural feature controlling G protein activation

Spatio-temporal patterns of larval fish settlement in the northwestern Mediterranean Sea

International audienceMost coastal fish species spend their early life stages in the pelagic environment, before settling in coastal habitats. The variability in the arrival of larvae to coastal habitats provide information on the species' biology and recruitment potential. To explore the dynamics of larval fish supply to coastal habitats in the NW Mediterranean Sea, 13 sites were monitored using light-traps, from July 2012 to December 2015. Most variation in Catches Per Unit Effort (CPUE) among topographic basins and species were statistically significant for high (quantile 75%) and very high (quantile 90%) catches only. At year scale, CPUE displayed strong seasonality, and three main species assemblages were detected in late spring-early summer, summer and late autumn-early winter. At month scale, CPUE were higher around the new moon for all quantiles and temporally autocorrelated at a lag of about 28 days. Larval supply also varied spatially with site-specific associations, and with riverine influence. All together, these results confirm that the previously described patterns of larval supply observed in tropical and subtropical environments (e.g., the high variability at all spatial and temporal scales and the strong influence of the moon) also apply to Mediterranean fish assemblages. The larval supply in the NW Mediterranean Sea comes out as a solid candidate for monitoring the state of the marine ecosystems, highlighting the need to continue such time series

Benchmarking fish biodiversity of seaports with eDNA and nearby marine reserves

\ₑprint: https://onlinelibrary.wiley.com/doi/pdf/10.1111/conl.13001International audienceCoastal areas offer a diversity of habitats providing refugia and nursery for fish, promoting their biodiversity and associated contributions to people. Yet, natural coastlines are replaced by artificial infrastructures such as seaports and the influence of this artificialization on fish biodiversity remains poorly known. Here, we assessed fish biodiversity indicators using environmental DNA metabarcoding inside seaports and adjacent natural habitats including no-take marine reserves. We found that species assemblages within seaports were primarily influenced by their area and habitat. We detected a similar species richness in seaports and reserves during lockdown, but seaports host more threatened species than natural habitats. Yet, species turnover between seaports was lower than between natural areas, reflecting biotic homogenization. Seaport managers should consider that complexifying artificial infrastructures could increase habitat diversity and coastal fish biodiversity. Our study illustrates that eDNA-based indicators can be integrated in management and policy applications toward greener marine artificial infrastructures

Observation of juvenile dusky groupers (Epinephelus marginatus) in artificial habitats of North-Western Mediterranean harbors

International audienc

Immersion Time Determines Performance of Artificial Habitats in Commercial Harbours by Changing Biodiversity of Colonising Invertebrate Assemblages

In highly modified coastal environments, such as commercial harbours, the installation of artificial habitats has garnered support as a means of enhancing local biological recruitment and connectivity. The success of these measures depends largely on the patterns of species colonisation. Using post-installation monitoring data, we compared the composition of assemblages of invertebrates colonising artificial habitats that were immersed for different periods (~6 vs. ~18 months) in three commercial harbours along the French Mediterranean coast. The artificial habitats were colonised by taxonomically diverse invertebrate assemblages of ecological and economic importance, including molluscs, crustaceans, and echinoids. Composition differed significantly with the immersion time of the artificial habitats, with total abundance, species richness, and evenness being significantly higher after ~18 than after ~6 months of immersion, indicating that long periods are necessary to enrich these new habitats with economically and ecologically important species. These results can inform restoration protocols and emphasise the value of post-installation monitoring programs

New approach in the Mediterranean Sea on the understanding of the distribution and population dynamics of fishes’ post-larvae around Corsican coasts

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Atlas des Post-Larves de poissons de Méditerranée Occidentale

International audienceGuide d'identification des post-larves de poissons de la Méditerrané