Stranding Events of <i>Kogia</i> Whales along the Brazilian Coast

<div><p>The genus <i>Kogia</i>, which comprises only two extant species, <i>Kogia sima</i> and <i>Kogia breviceps</i>, represents one of the least known groups of cetaceans in the global ocean. In some coastal regions, however, stranding events of these species have been relatively common over the last decades. Stranding provides the opportunity to investigate the biology of these cetaceans and to explore the epidemiological aspects associated with the mortality of the organisms found on the beach. A number of disturbances (including pelagic fisheries, chemical pollution, boat strikes, and noise pollution) have been confirmed to pose a particular threat to the <i>Kogia</i> species. However, no study has yet investigated potential relationships between environmental conditions and stranding events. Here we analyse how a collection of environmental, physical, and biological variables, such as wind, sea surface temperature (SST), water depth, and chlorophyll-a, correlate to <i>Kogia</i> stranding events along the Brazilian coast. The results of our statistical analyses suggest that <i>K</i>. <i>sima</i> is more likely found in warm tropical waters, which provide an explanation for the high frequency of stranding in northeastern Brazilian coast. In contrast, <i>K</i>. <i>breviceps</i> appears to have a preference for temperate and productive waters. Wind speed results to be also an important factor for predicting <i>Kogia</i> strandings in Brazilian coast. Additionally, literature information in combination with our own data and analyses of stomach contents confirms that oceanic cephalopods constitute the primary nutritional source of both <i>Kogia</i> species. By using the available information as a qualitative proxy for habitat preference and feeding ecology, our study provides a novel and comprehensive assessment of <i>Kogia</i> stranding data in relation to environmental conditions along the Brazilian coast.</p>