Baleias e golfinhos em águas costeiras e oceânicas: uma abordagem integrada para distribuição, exposição a atividades humanas e conservação das espécies no Brasil e no mundo

Abstract

The distribution of species is of utmost importance to ensure proper protection of both species and ecosystems. Cetaceans (whales and dolphins) play crucial roles in regulating marine ecosystems, yet our understanding of the distribution of marine organisms, especially cetaceans, remains limited. This study aimed to fill this gap by using suitability modeling to assess the distribution of these species and their relationship with the environment. The present dissertation consisted of three chapters. In the first chapter, through a systematic review, the need for a well-established analytical protocol to ensure the replicability of whale analyses was highlighted. Factors such as chlorophyll concentration, depth, and distance from the coast were essential in explaining cetacean distributions, varying according to habitat type and marine zone. The second chapter addressed the exposure of cetaceans to cumulative human activities and the overlap of the most suitable areas with Marine Protected Areas (MPAs). The results showed that many MPAs do not cover oceanic areas with high exposure to cumulative human activities. Waters over the continental shelf were identified as more suitable for Bryde’s whales (Balaenoptera brydei) and bottlenose dolphins (Tursiops truncatus), especially in Southeastern Brazil, where cumulative human activities are more significant. In the third chapter, the feeding behavior of Guiana dolphins (Sotalia guianensis) was investigated, influenced by chlorophyll concentration, depth, and vessel traffic. Fishing gear represented risks, necessitating effective measures to reduce conflicts and improve the effectiveness of local MPAs. Focusing on the conservation of umbrella species like whales and dolphins can benefit other species sharing the same habitats. However, considering different spatial scales and specificities of each species is essential for effective conservation strategies. The establishment and improvement of MPAs is crucial in conserving cetacean species and reducing human impacts in general on marine biodiversity. The findings may inform decision-making by relevant parties, ensuring that collective efforts can lead to the conservation of biodiversity and ecosystem