Instituto Boto Cinza Guiana dolphin distribution between 2005-2007 in Sepetiba Bay, Brazil

Original provider: Projeto Boto Cinza Dataset credits: Projeto Boto Cinza Abstract: Between August 2005 and July 2007, 376 Guiana dolphin (<i>Sotalia guianensis</i>) encounters were documented in Sepetiba Bay. For the purpose of this study all dolphin sightings were classified as groups or aggregations. Groups (N = 268, x = 20, range = 1–90) consisted of dolphins in apparent association usually engaged in the same behaviour and moving in the same direction. Aggregations (N = 108, x = 204, range = 100–450) consisted of temporal association of numerous groups gathered in an area, totalling several hundred individuals usually engaged in the same behavior but not necessarily moving in the same direction. Guiana dolphin groups and aggregations differed significantly in behavioral activity, spatial and temporal distribution and age composition. Most aggregated dolphins were engaged in foraging/feeding activities and primarily located at the interior of the bay, and also, aggregations were more likely recorded during morning hours and had more neonates and calves present when compared to groups. The plotted global positioning system (GPS) records of aggregations formed two distinct clusters of distribution within the bay, indicating potential areas where conservation strategies could be implemented.原始提供方： 灰河豚项目（Projeto Boto Cinza） 数据集署名： 灰河豚项目（Projeto Boto Cinza） 摘要： 2005年8月至2007年7月期间，研究人员在塞佩蒂巴湾（Sepetiba Bay）共计记录到376起圭亚那海豚（Guiana dolphin，学名*Sotalia guianensis*）的目击事件。本研究将所有海豚目击记录划分为群体与聚合群两类：群体（样本量268，平均个体数为20，个体数范围1~90）指存在明确社交关联、通常开展同一行为且同向移动的海豚集合；聚合群（样本量108，平均个体数为204，个体数范围100~450）则指多个临时聚集于同一区域的群体集合，总个体数可达数百，通常开展同一行为但未必同向移动。 圭亚那海豚的群体与聚合群在行为活动、时空分布以及年龄组成上均存在显著差异。绝大多数聚合群内的海豚均处于觅食/摄食活动状态，且主要分布于海湾内部；与群体相比，聚合群更易在上午时段被记录到，且其内部的新生幼豚与幼崽数量更多。基于全球定位系统（Global Positioning System，GPS）记录绘制的聚合群分布点位，在海湾内形成了两个显著的分布簇，可为针对性保护策略的制定提供潜在目标区域。