Análise da diversidade genética voltada à conservação do cavalo marinho Hippocampus patagonicus no litoral do Brasil

Abstract

Seahorses are highly endangered fish worldwide. Among the causes pointed in decline of populations is indiscriminate fishing on non-target organisms, the bycatch. More 95% of seahorses present in international trade come from this type of fishing. Considering the high impact this anthropic action on H. patatagonicus, the knowledge of genetic diversity and the population structure in regions of intense fishing activity can help to take conservation measures. Here we evaluate this information for part of the species distribution, especially with analysis of animals captured by bycatch along the coast of Rio de Janeiro, where fishing activity is intense. The genetic information has been accessed by mitochondrial data from partial sequencing of 652 bp cytochrome oxidase gene subunit I (COI) and the nuclear genome, from four primers Inter Simple Sequence Repeat (ISSR). The 30 COI sequences obtained here for the samples RJ were analyzed together with GenBank database for individuals of Rio Grande do Sul (RS) and Argentina (AR) showing increased genetic distance for the samples of RJ in relation to the other two populations. In interpopulational analysis, the RJ samples were also the ones with the highest diversity. The analysis of similarity by Neighbor-joining and the model of the number of Kimura 2 parameters and the Baps separated into groups monophyletic the populations of RJ of those of RS and RA. Molecular analysis of variance (AMOVA) also showed high population structure (Fst = 48.68), also separating the samples. The ISSR data revealed 74 loci, all polymorphic for the 60 individuals analyzed. The intrapopulation genetic distance was smaller for the individuals of the Macaé and Joatinga groups up to Ilha Grande, and higher for the samples from Ilha Rasa to Santana Island. The similarity analysis by Neighbor-joining, the model number of differences together with Evanno test and Bayesian analysis made through Structure, defined distinct genetic patterns, almost separating them into monophyletic groups. AMOVA revealed a high population structure for the species studied (Fst = 34.33). Genetic differentiation H. patagonicus along the coast of Rio de Janeiro reflects the importance of genetic studies not only in macro scale, as well as in micro-regional, reflecting the importance of this type of analysis as a way to support correct management actions aimed at conservation species that are in danger of extinction. This population structure and the high genetic diversity of RJ samples support the importance of conservation of the seahorses of this locality from an evolutionary point of view, revealing the uniqueness there genetic patrimony observed.