Current address: Florida Marine Research Institute, Florida Fish and Wildlife Conservation Commission, 100 Eighth Avenue SE, St. Petersburg, Florida 33701, U. S. A.
STATUS AND ECOLOGY OF SOTALIA FLUVIATILIS IN THE CAYOS MISKITO RESERVE, NICARAGUA
Article first published online: 26 AUG 2006
Marine Mammal Science
Volume 17, Issue 3, pages 445–472, July 2001
How to Cite
Edwards, H. H. and Schnell, G. D. (2001), STATUS AND ECOLOGY OF SOTALIA FLUVIATILIS IN THE CAYOS MISKITO RESERVE, NICARAGUA. Marine Mammal Science, 17: 445–472. doi: 10.1111/j.1748-7692.2001.tb00998.x
- Issue published online: 26 AUG 2006
- Article first published online: 26 AUG 2006
- Received: 8 June 1999 Accepted: 2 November 2000
- Sotalia fluviatilis;
- Cayos Miskito Reserve;
- South American dolphin;
- habitat use
In March through May of 1996–1998, we conducted research in the Cayos Miskito Reserve, Nicaragua, to assess the status, ecology, and distribution of Sotalia fluviatilis, a dolphin known from southern Brazil to Honduras. Aerial and boat surveys of lagoons, inlets, and coastal areas were conducted and observational information collected on Sotalia activity, behavior, and other factors relating to its ecology. During boat surveys 183 groups (536 individuals) were sighted (for areas with Sotalia, mean overall density = 0.604 individuals/km2, coastal areas = 0.647/km2, inlets = 0.578/km2, and lagoons = 0.486/km2). Overall, based on all sightings, mean group size was 3.01 (SD = 1.79, range 1–15) and varied among years (x̄= 4.20 in 1996, 2.58 in 1997, and 3.39 in 1998), but not for different months. We estimate that 49 Sotalia inhabited the portions of the Reserve we studied. Sightings of Sotalia groups were non-random (nearest-neighbor analysis); clumping of sightings indicates that some areas were preferred. In both Pahara inlet and Wauhta lagoon, sightings were more frequent after 1200 than in the morning. In coastal areas Sotalia were sighted most often within 100 m of shore (54.0%), less often from 101 to 200 m (39.1%), and infrequently from 201 to 300 m (6.8%). Seldom were animals observed in more than 5 m of water, and usually it was considerably shallower (i. e., <2 m). Feeding was the predominant of five recorded activities (i. e., traveling, feeding, socializing, resting, and other), based on time of group sighting (70.3%) and during instantaneous sampling (56.3%). Resource distribution appears to be an important factor influencing Sotalia distribution in the Reserve.