CoopeTárcoles, Costa Rica. Equator Initiative Case Study Series

The artisanal fishers of the community of Tárcoles, located in the Gulf of Nicoya on the Pacific coast of North America (Central America)-Costa Rica; faced declining fish stocks due to a combination of overharvesting by commercial shrimp boats and unsustainable local fishing practices. At the same time, development of the tourism sector along the coast threatened to restrict access to the shore and to marginalize their work. The local fishing cooperative Coope Tárcoles R.L. was founded in 1985 to confront these twin threats. At the forefront of these efforts has been the development of fishing bylaws that stress sustainable practices, enshrined in the community's 'Code of Responsible Fishing'. In partnership with CoopeSolidar R.L., the initiative launched a sustainable and community-based ecotourism venture in 2007 to provide an alternative source of income for local residents. In 2009, meanwhile, the group was successful in gaining approval of a community-managed marine area

Natural selection influences AFLP intraspecific genetic variability and introgression patterns in Atlantic eels

International audienceInvestigating patterns of genetic variation in hybridizing species provides an opportunity to understand the impact of natural selection on intraspecific genetic variability and interspecific gene exchange. The Atlantic eels Anguilla rostrata and A. anguilla each occupy a large heterogeneous habitat upon which natural selection could differentially shape genetic variation. They also produce viable hybrids only found in Iceland. However, the possible footprint of natural selection on patterns of genetic variation within species and introgressive hybridization in Icelandic eels has never been assessed. We revisited amplified fragment length polymorphism data collected previously using population genomics and admixture analyses to test if (i) genetic variation could be influenced by non-neutral mechanisms at both the intra- and interspecific levels, and if (ii) selection could shape the spatio-temporal distribution of Icelandic hybrids. We first found candidate loci for directional selection within both species. Spatial distributions of allelic frequencies displayed by some of these loci were possibly related with the geographical patterns of life-history traits in A. rostrata, and could have been shaped by natural selection associated with an environmental gradient along European coasts in A. anguilla. Second, we identified outlier loci at the interspecific level. Non-neutral introgression was strongly suggested for some of these loci. We detected a locus at which typical A. rostrata allele hardly crossed the species genetic barrier, whereas three other loci showed accelerated patterns of introgression into A. anguilla in Iceland. Moreover, the level of introgression at these three loci increased from the glass eel to the yellow eel stage, supporting the hypothesis that differential survival of admixed genotypes partly explains the spatio-temporal pattern of hybrid abundance previously documented in Iceland