Distribution of West Indian Manatees ('Trichechus manatus') in Puerto Rico

摘要

The paper reports results of ten aerial surveys and sightings reported through a sighting network conducted in 1988-89 to assess the occurrence and distribution of West Indian manatees in Puerto Rico. The shoreline and offshore islands were divided into 11 segments as defined by researchers who conducted similar surveys in 1976-79 (Powell et al. 1981) and 1984-85 (Rathbun et al. 1985). Findings from the study are generally consistent with earlier studies. Most manatees were seen along the southern and eastern shorelines of the island. Segments 3 and 6, which contained two important manatee habitats, Roosevelt Roads Naval Station and Jobos Bay, had the highest mean count of manatee sightings per flight (7.9 and 3.6, respectively). About 14% of the manatees seen during aerial surveys were calves. Nearly 63% of observed calves were seen in segment 3 suggesting this is a particularly important nursing area. Reports from the sighting network were consistent with results of aerial surveys. However, the sighting network provided some new information: manatees were reported in segment 10 and at distances up to 8 kilometers from shore.