Hybridization between sea turtle species occurs with particularly high frequency at two adjacent nesting areas in northeastern Brazil. To understand the outcomes of hybridization and their consequences for sea turtle conservation, we need to evaluate the extent of hybridization occurrence and possible deleterious effects in the hybrid progeny. Thus, we investigated the hypothesis of the existence of a new hybrid spot offshore of Brazil’s northeastern coast. The Abrolhos Archipelago is surrounded by the largest and richest coral reefs in the South Atlantic and is known to be a nesting site for loggerhead turtles (Carettacaretta). In this study, we performed a multidisciplinary investigation into levels of hybridization in sea turtles and their reproductive output in the Abrolhos beaches. Genetic data from mitochondrial DNA (mtDNA) and six autosomal markers showed that there are first-generation hybrid females nesting in Abrolhos, resulting from crossings between hawksbill males (Eretmochelysimbricata) and loggerhead females, and backcrossed hatchlings from both parental species. The type and extent of hybridization were characterized using genomic data obtained with the 3RAD method, which confirmed backcrossing between F1 hybrids and loggerhead turtles. The reproductive output data of Abrolhos nests suggests a disadvantage of hybrids when compared to loggerheads. For the first time, we have shown the association between hybridization and low reproductive success, which may represent a threat to sea turtle conservation.

There is a great demand to develop new acoustic techniques to efficiently map the seabed and automate the interpretation of acoustic, sedimentological, and imaging data sets, eliminating subjectivity. Here, we evaluate the potential, limitations and complementariety of distinct supervised and automatic classification techniques in the mapping of reefs by comparing these results with a reference map. The study was carried out in the Abrolhos Continental Shelf (Eastern Brazilian Continental Margin) using a multibeam echosounder and side scan sonar (SSS) dataset. Two automatic supervised techniques were applied. A reference map was derived by detailed manual interpretation carried out by three experts. The two supervised classification techniques were: benthic terrain modeler (BTM), a morphometric classification with focus on spatial analyses of the bathymetric grid derivatives, and object-based image analysis (OBIA), a segmentation applied to the backscatter data from the SSS mosaic. Both automatic techniques obtained similar values of reef coverage area, but overestimated the reef area when compared with the reference map. The agreement between BTM and OBIA results and the reference map was 69% and 67%, respectively. Disagreement was mainly due to quantity of reef (both methods over-estimated reef), while the disagreement in spatial allocation was relatively low, it indicates that both methods are reasonable representation of the spatial patterns of reef. Efficient mapping of reef in the wider area of the Abrolhos Continental Shelf will be best achieved by a further development of automatic methods tested against reference maps obained from representative areas of the seabed. By combining the results of the two automatic methods, it was possible to create an ensemble map, which achieved better agreement with the reference dataset.

No abstract

O Banco dos Abrolhos, região que abriga a cidade de Caravelas, Bahia, possui um conjunto de Unidades de Conservação (UCs) em sua porção costeiro-marinha. A presente pesquisa teve como objetivo avaliar a percepção dos pescadores da cidade de Caravelas, situado no Extremo Sul da Bahia, sobre estas Unidades, e também realizar um resgate histórico da pesca no Parque Nacional Marinho dos Abrolhos (PaRNaM-Abrolhos) antes de ser uma UC. Para realizar o estudo, utilizou-se o método de coletas de dados através de entrevistas semiestruturadas. Constatou-se que maioria dos pescadores entrevistados sabe o que é uma UC e julga importante preservá-la, já que as Unidades, especialmente, o ParNaM-Abrolhos, auxiliam na manutenção de estoques pesqueiros. O Arquipélago de Abrolhos era o ponto mais usado para realizar a captura dos pescados antes de se tornar parque, auxiliava na renda financeira da classe de pescadores da região. Foi apontado como principais motivos para a redução de peixes ao longo dos anos, a dragagem, o excesso de embarcações, a mudança de rota dos peixes e o mergulho. Considerando que a maioria da classe pesqueira declara importante a existência das Unidades, evidenciando pequenos conflitos comparado com tempos passados e, o enfoque do trabalho não consistiu em analisar a diferença desses conflitos ao longo dos anos, recomenda-se novos trabalhos que investiguem esta temática.