Occurrence, residency patterns and habitat use of the bottlenose dolphin, Tursiops truncatus truncatus, on two Marine Protected Areas in Southeastern Brazil.

Rodrigo H Tardin,Guilherme Maricato,Maria Alice S Alves,Sheila M Simão,Israel S Maciel,Tatiana F Maria

doi:10.1590/0001-3765202020180843

Abstract

The common bottlenose dolphin, Tursiops truncatus, is widely distributed. However, information about its ecology and behavior in Brazilian waters is scarce especially about the 'offshore' ecotype, an Evolutionarily Significant Unit in the Southwest Atlantic. We report for the first time the occurrence, behavior and habitat use of bottlenose dolphins Tursiops truncatus truncatus, in two Marine Protected Areas (MPA) in Cabo Frio coast, Brazil. There were fifteen sightings of different groups throughout the year. An overall of 429 individuals were photo-identified. 90.7% dolphins did not present a degree of residence, 1.4% dolphins were considered with high residency to the area, 5.8% medium and 2.1% low. Our habitat use map indicated dolphins were more common off ~10km from Cabo Frio municipality and between depths around 20-70m. Bottlenose dolphins on Cabo Frio coast were more frequently observed performing travelling, followed by foraging and socio-sexual behavior. Group sizes varied from three to 120 individuals. Larger groups were observed when travelling and foraging. Despite the existence of two local Marine Protected Areas, the fast human development in Cabo Frio may threaten this important area for bottlenose dolphins in terms of food resources and shelter from predators.

Highlights

The knowledge concerning a species habitat preference is a central question in ecology
Since the ecology of the T. truncatus truncatus is poorly understood along Brazilian coast, we provide baseline ecological information about their occurrence, group size, composition, behavior, residence patterns and habitat use in Cabo Frio, Rio de Janeiro, Brazil
Our study presents the first information about aspects on the ecology and behavior of T. truncatus truncatus on an upwelling area covered by two Marine Protected Areas (MPA), in Cabo Frio coast, Southeastern Brazil

Summary

Introduction

The knowledge concerning a species habitat preference is a central question in ecology. A species may choose a habitat based on the availability and quality of food sources and possible mates The comprehension of these relationships in highly mobile marine species, such as cetaceans, is a challenging task. Investigating important ecological patterns such as occurrence and habitat use, in general, demand a large amount of funding and time which constrains our knowledge about these species ecology, especially on regional scale. On developing countries, such as Brazil, most research effort is concentrated on the Guiana dolphin, Sotalia guianensis, a coastal

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