Intensive Commercialization of Endangered Sharks and Rays (Elasmobranchii) Along the Coastal Amazon as Revealed by DNA Barcode

Elasmobranchs represent a well-defined group, composed of about 1,150 species inhabiting diverse aquatic environments. Currently, several of these species have been classified as threaten due to overexploitation. Therefore, we used DNA barcode to identify traded species of sharks and stingrays in the municipality of Bragança (Amazon coastal region), a major fishery landing site in northern Brazil. We collected a total of 127 samples labeled into 24 commercial nomenclatures over 1-year period. Twenty species were discriminated and 13 of them are recognized under some threatening status. In relation to sharks, Carcharhinidae showed the highest number of species, half of them classified as endangered, followed by hammerhead sharks (Sphyrnidae), with four species also regarded as threatened with extinction. The Rhinopteridae and Dasyatidae rays were the most abundant groups, with trade records of the following threatened species: Rhinoptera brasiliensis, Rhinoptera bonasus, Hypanus berthalutzae, and Fontitrygon geijskesi. It is noteworthy that threatened species of elasmobranchs have been frequently and regularly exploited because of inefficient fishery management policies. Therefore, effective inspection practices need to be incorporated in fisheries, including the use of DNA barcode to enable a reliable method of species authentication and to assure the proper commercialization.

CAPTURE AND HANDLING STRESS IN INCIDENTALLY CAPTURED RAYS FROM SMALL-SCALE FISHING: A PHYSIOLOGICAL APPROACH

Incidental capture is the most common threat to rays worldwide, by both artisanal and industrial fishing. To better understand this threat, we evaluated the capture and handling stress in three incidentally captured benthopelagic ray species: American cownose ray (Rhinoptera bonasus), Brazilian cownose ray (Rhinoptera brasiliensis), spotted eagle ray (Aetobatus narinari), and one benthic species, the longnose stingray (Hypanus guttatus). Through analyzing secondary stress physiological variables (plasma lactate and glucose), our results revealed a similar physiological stress response in benthopelagic rays, suggesting they are resilient to capture using beach seine fishing. We also demonstrated that handling for research can increase the stress in both American cownose and spotted eagle rays, suggesting that more stringent handling protocols for research should be required. Findings from this study expands on the number of ray species for which stress to capture and handling has been evaluated, providing recommendations for appropriate research and management.

Genetic diversity assessment for the vulnerable migratory cownose ray Rhinoptera bonasus (Myliobatiformes: Rhinopteridae) from the southwestern Atlantic Ocean

ABSTRACT Rhinoptera bonasus is a bento-pelagic and highly migratory species occurring from southern United States to northern Argentina. Due to overfishing effects, R. bonasus is currently at risk, classified by the IUCN Red List as vulnerable. Considering the lack of molecular data available for R. bonasus, this study aimed to describe the genetic variability and population structure of specimens sampled from three Brazilian coast ecoregions (Amazon ecoregion, Pará; Northeastern ecoregion, Pernambuco and Southeastern ecoregion, Rio de Janeiro, São Paulo and Santa Catarina), through five polymorphic microsatellite markers. Here testing the panmixia hypothesis for Brazilian ecoregions and test natal philopathy. A total of 69 analyzed specimens revealed individual and significant genetic differentiation between the sampled locations. Φ ST (0.12), PCA, DAPC and Bayesian analyses of the genetic population structure revealed at least two distinct genetic R. bonasus groupings. IBD tests were significant, indicating a correlation between genetic and geographical distance among populations, which can be explained by reproductive philopatric behavior. Philopatric behavior associated with R. bonasus mobility may influence the differentiation values observed for all loci in the investigated samples.

UTILIZAÇÃO DE UMA ÁREA DE PROTEÇÃO AMBIENTAL POR UMA COMUNIDADE DE ELASMOBRÂNQUIOS NO ATLÂNTICO SUL OCIDENTAL

Globalmente a explotação dos peixes cartilaginosos marinhos é cada vez mais crescente principalmente em áreas costeiras. Entretanto, existem áreas no Atlântico Sul Ocidental que ainda são pouco conhecidas quanto a sua biodiversidade de elasmobrânquios. Portanto, o objetivo deste trabalho é de conhecer a comunidade de elasmobrânquios marinho-estuarinos e suas respectivas áreas de uso em uma unidade de conservação de uso sustentável (APA do Delta do Parnaíba), no nordeste do Brasil, a partir do monitoramento dos desembarques da pesca artesanal na região. A partir do monitoramento de 1184 desembarques realizados entre janeiro de 2016 e janeiro de 2017, foi possível identificar nove espécies de tubarões (Carcharhinus leucas, C. porosus, C. acronotus, C. limbatus, Galeocerdo cuvier, Sphyrna mokarran, S. lewini, Rhizoprionodon porosus e Ginglymostoma cirratum) e sete espécies de raias (Hypanus guttatus, H. americanus, H. marianae, Fontitrygon geijskesi, Gymnura micrura, Aetobatus narinari e Rhinoptera bonasus) que fazem uso de três áreas batimetricamente distintas. As espécies com as maiores frequências de ocorrência foram R. porosus (36%) e H. gutattus (61%). Os resultados demonstram que a área é utilizada por distintas espécies, dentre elas espécies consideradas em risco de extinção, como o S. mokarran.USE OF AN ENVIRONMENTAL PROTECTION AREA BY A COMMUNITY OF ELASMOBRANCHS IN THE TROPICAL SOUTHWESTERN ATLANTICABSTRACTWorldwide the exploitation of marine cartilaginous fi sh is increasing, mainly in coastal regions. However, there are areas in the Southwestern Atlantic that are still little known about their elasmobranch biodiversity. Therefore, this work aims to know the community of marine estuarine elasmobranchs and their respective areas of use in a sustainable use conservation unit (APA of the Parnaíba Delta), in the northeast of Brazil, from the monitoring of the landings of the fi shingin the region. From the monitoring of 1184 landings between January 2016 and January 2017, it was possible to identify nine species of sharks (Carcharhinus leucas, C. porosus, C. acronotus, C. limbatus, Galeocerdo cuvier, Sphyrna mokarran, S. lewini, Rhizoprionodon porosus and Ginglymostoma cirratum) and seven species of stingrays (Hypanus guttatus, H. americanus, H. marianae, Fontitrygon geijskesi, Gymnura micrura, Aetobatus narinari and Rhinoptera bonasus) which make use of three diff erent depth ranges. The most frequent species were R. porosus (36%) and H. gutattus (61%). The results demonstrate that the area is used by diff erent species, among them species considered endangered, such as S. mokarran.Keywords: Selachians; Batoids; Conservation biology.