Fourth Annual Grant Winners 2003-2004

Edward O. Keith, Ph.D., Oceanographic Center
Lemnuel V. Aragones, Ph.D., Rosenstiel School of Marine and Atmospheric Sciences, University of Miami

Dean Richard Dodge – Oceanographic Center

Title: An Examination of the Home Range of Selected Small Cetaccans in the Southern Tanaon Strait, Central Philippines

Abstract:

Over the past decade the status of knowledge of marine mammals in the Philippine archipelago has increased dramatically, expanding from an initial list of 12 known species to a current list of 25 confirmed species and two unconfirmed species. However, much remains to be learned about the life history of small cetaceans in the Philippines. We propose to conduct a short-term radiotelemetry study of the home range and movement patterns of small cetaceans, primarily spotted dolphins (Stenella attenuata) and spinner dolphins (Stenella longirostris), in the Tañon strait. The Tañon strait is a localized branch of the Cebu strait, which is heavily utilized by cetaceans. This area has also been the site of heavy industrialization and terrestrial and aquatic habitat modification and/or destruction. We propose to attach radiotelemetry transponders to selected animals in the southern portion of the Tañon strait, and to follow them using global positioning systems (GPS) data for up to two weeks. These tracking data will be entered into a geographical information system (GIS), and home range size will be estimated using computer software incorporating three different methods; minimal convex polygons, bivariate normal ellipses, and nonparametric estimates based on grids. We will also conduct interviews with local fishermen, and other interested parties to determine how these movement patterns and distributions may have changed in the recent past. We also plan to develop educational materials to inform the local populace of the benefits arising from the protection of cetaceans. Our study will not only contribute to the understanding of the basic biology of these species, but will also provide information needed to determine if anthropogenic activity is having a negative impact on them. Additionally this study will contribute to the knowledge base of those charged with the appropriate management and conservation of cetaceans in this area.