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Is there spatial segregation between reproductive groups of southern right whales along the coastline of southern Brazil? |
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| Authors: | Eduardo P Renault-Braga Karina R Groch Paulo C Simões-Lopes |
| Institution: | 1. Instituto Australis de Pesquisa e Monitoramento Ambiental, Imbituba, Santa Catarina, Brazil;2. Instituto Australis de Pesquisa e Monitoramento Ambiental, Imbituba, Santa Catarina, Brazil
Contribution: Conceptualization, Data curation, Formal analysis, Funding acquisition, Investigation, Methodology, Resources, Validation, Writing - original draft, Writing - review & editing;3. Laboratório de Mamíferos Aquáticos, Departamento de Ecologia e Zoologia, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, Santa Catarina, Brazil Programa de Pós-Graduação em Zoologia, Campus Centro Politécnico, Setor de Ciências Biológicas, Departamento de Zoologia, Curitiba, Paraná, Brazil Contribution: Formal analysis, Investigation, Methodology, Supervision, Validation, Visualization, Writing - original draft, Writing - review & editing |
| Abstract: | Santa Catarina State, in southern Brazil, is an important breeding ground for the southern right whale and it is possible to record mother-calf pairs and unaccompanied adults that migrate to this coast to either give birth, mate, or socialize. From the geographical position of the sightings, spatial segregation was evaluated between mother-calf pairs and unaccompanied whales. Using GAM, we analyzed 15 years of aerial survey data from 2003 to 2018. The study area (780 km2) was divided into 500 × 500 m grid cells. Whale count per grid cell was modeled using a set of explanatory variables. The explanatory variables of latitude, coast distance, seabed, and maximum SST were selected for both classes. However, coast type was also selected for unaccompanied whales, while coast linearity and bathymetric slope were additionally selected for mother-calf pairs. The response curves fitted by models indicated a certain degree of spatial segregation, by which mother-calf pairs remained closer to the coast, where the curve peak is reached at 500 m from the coast, compared to unaccompanied whales where the curve peaked near 1,000 m from the coast. Also, unaccompanied whales more frequently appeared in the southern boundaries of the study area, at latitudes south from 28.4°S. |
| Keywords: | Brazil breeding ground Eubalaena australis generalized additive models habitat modeling southern right whale spatial segregation zero inflated model |