The fate of bycatch species released back into the water is crucial to estimate population status and consequent decisions to implement adequate management measurements for elasmobranchs. The shortnose guitarfish, Zapteryx brevirostris, is an endemic species of the Southwest Atlantic. It is currently listed as 'Vulnerable' both in the International Union for Conservation of Nature and Brazilian red lists. Although this species displays high tolerance to capture and transportation by fishers from the capture site to the fish market, a significant reduction in survival rates is observed during the reproductive period. Thus, the aim of the present study was to examine post-capture and post-commercial transportation consequences in pregnant females obtained as bycatch from artisanal fisheries in Southern Brazil. Results showed high abortion rates and reduced maternal survival after abortion, with all abortions occurring within 28 h of monitoring in laboratory. Stress plasma markers were also evaluated, to determine the physiological consequences of capture-induced parturition to pregnant females. Results showed alteration in all markers measured (plasma urea, pH, lactate, phosphorus, and potassium) with values for dead pregnant females being different from non-pregnant females and those which survived capture and subsequent abortions. The mortality caused by fisheries bycatch may prove difficult to manage, with immediate release and specific handling protocols for pregnant females implemented through environmental education environmental education and fishermen training programs, potential options to maintain adequate maternal survival and recruitment for this species.

No abstract

No abstract

Congenital deformities are relatively common in rays and sharks. The present study aimed to describe a case of bicephaly in an R. lalandii embryo. Through radiographic images and evaluation of the external and internal condition of the embryo in comparison with a young of the year with no deformities of the same species, it was possible to characterize the abnormality observed. Such data are important to determine the frequency and types of anomalies observed in elasmobranchs, thusallowing greater knowledge about developmental abnormalities in the group and their possible causes. RESUMODeformidades congênitas são relativamente comuns em raias e tubarões. O presente estudo teve como objetivo descrever um caso de bicefalia em um embrião de R. lalandii. Através de imagens radiográficas e avaliação da condição externa e interna do embrião em comparação com um jovem do ano sem deformidades da mesma espécie, foi possível caracterizar a anormalidadeobservada. Tais dados são importantes para determinar a frequência e tipos de anomalias observadas em elasmobrânquios, permitindo assim o maior conhecimento sobre as anormalidades de desenvolvimento no grupo e suas possíveis causas.Palavras-chave: Malformação; Tubarão; Espécie endêmica; Morfologia.

The assessment of physiological responses to capture provides useful information for elasmobranch conservation. In particular, understanding these impacts in species caught as bycatch that are released after capture can predict their "post-release" fate and aid in management plans. Although well studied in several species, capture-stress is nonetheless frequently assessed without considering putative variability between sexes. Given the high mortality of pregnant Zapteryx brevirostris females reported in the literature, the present study aimed at determining greatest vulnerability period for males. Our results demonstrate that, when caught during the reproductive period, males display higher mortality (68%) than when caught outside the reproductive period (zero mortality). Seven out of 11 markers (i.e. sodium, chloride, potassium, lactate, phosphorus, triglycerides and condition factor) differed significantly following capture-induced stress between males caught during the reproductive period and those caught outside this period. Results demonstrate the need for specific protocols during the reproductive period, also considering the influence of sex on physiological responses to stress for effective management.