Population-scale habitat use by school sharks Galeorhinus galeus (Triakidae) in the Southwest Atlantic: insights from temporally explicit niche modelling and habitat associations

DE WYSIECKI, AGUSTÍN M.; ALEJO J. IRIGOYEN; CORTES FEDERICO; NELSON BOVCON; MILESSI ANDRES CONRADO; HOZBOR NATALIA M; COLLER MARINA NIDIA; JAUREGUIZAR, ANDRÉS J.

Marine Ecology Progress Series

Inter-Research

Año: 2022 vol. 697 p. 81 - 95

Population-scale information on the spatial ecology of threatened mobile sharks isrequired to design more effective management measures. Using an exhaustive collection of presence-only records and relevant predictors, we applied temporally explicit environmental nichemodelling to study habitat use by a school shark Galeorhinus galeus population in the SouthwestAtlantic. As a complementary tool, we developed randomized habitat association curves to assessboth the representation of data with biological information and possible intra-population variationin habitat use. Seasonal niche models supported a core area of distribution between southernBrazil and southern Argentina. Marginal seasonal variation in suitability at the northern andsouthern extremes of its distribution supported the hypothesis that the G. galeus populationbehaves to some degree as a niche shifter on an annual cycle. Habitat associations revealedregional bias in the collection of records with biological information, and suggested a complexintra-population segregation pattern between sexes and between maturity stages during the coldhalf of the year. Overall, results supported large-scale partial migrations (i.e. some individualsmigrate while others remain resident) of the G. galeus population. This study demonstrates thesignificance of future regional efforts that focus on producing more and better databases to deriverelevant information at a low cost for the management of threatened sharks and their relatives