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Publication
Abundance dynamics of a new, endemic batoid from Brazil: The Lutz’s stingray, Hypanus berthalutzae
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Advisor(s)
Abstract(s)
The Lutz’s stingray, Hypanus berthalutzae, is a recently identified, endemic dasyatid species which occurs in shallow habitats exclusively along most of the Brazilian coast. It is frequently caught as bycatch in different fisheries throughout the range of its distribution, but information on population trends and the impacts of fishing is still scarce. Therefore, this study aimed to describe the structure and dynamics in H. berthalutzae relative abundance off Recife, Northeast Brazil, in order to provide baseline data for species management. H. berthalutzae were caught and sampled in a fisheries-independent, standardized longline and drumline survey which used > 500,000 hooks during ∼11 years. H. berthalutzae catch composition (N = 86) was characterized by a striking predominance of females, with a female:male ratio of 16:1. Most of these individuals measured were considered to be mature. H. berthalutzae catch rates were largely reduced after hooks previously operating directly on the seafloor were suspended in the middle of the water column. Such an effect was included in a zero-inflated generalized additive model developed to assess spatiotemporal and environmental
modulators of H. berthalutzae abundance, for which both month and lunar phase proved to be statistically significant predictors. A higher abundance of H. berthalutzae was observed in the rainy season, from March to July (χ2= 19.22; p < 0.001), as well as during full moon periods (Z = 2.38; p = 0.017). The effects of other candidate predictors such as sampling site or year were either nonexistent or superimposed by other more deterministic factors. The results achieved in this fully standardized survey depict the dynamics in adult H. berthalutzae which might be expected to occur in coastal habitats off northeastern Brazil, thus providing a solid contribution to improve the management of
local artisanal fisheries towards the recovery and sustainability of H. berthalutzae populations across their range.
Description
Acknowledgments : The authors are thankful to the crew of R.V. Sinuelo and R.V. Pedrinho and to all interns from the Laboratório de Tecnologia Pesqueira at the Universidade Federal Rural de Pernambuco (LATEP/UFRPE) for assisting with field work. This work was funded by the State Government of Pernambuco, Brazil. IBN sincerely thanks FACEPE - Fundação de Amparo a Ciência e Tecnologia do Estado de Pernambuco for her PhD and postdoctoral fellowship. Funding to YN through an International Macquarie University Research Training Program scholarship is deeply acknowledged. ASA acknowledges funding provided by CAPES –
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES BJT-1049/2013) and by FCT – Fundação para a Ciência e
Tecnologia (UID/MAR/04292/2013).
Keywords
CPUE Dasyatidae Elasmobranch Fisheries-independent Longline ZIGAM
Citation
Ilka Branco-Nunes, Yuri Niella, Fábio Hissa Vieira Hazin, Emmanuelly Creio, Paulo Guilherme Vasconcelos de Oliveira, André Sucena Afonso, Abundance dynamics of a new, endemic batoid from Brazil: The Lutz’s stingray, Hypanus berthalutzae, Regional Studies in Marine Science, Volume 48, 2021, 102059, ISSN 2352-4855, https://doi.org/10.1016/j.rsma.2021.102059
Publisher
Elsevier