/ The most pressing problem in the effective management of the West Indian manatee (Trichechus manatus) in Puerto Rico is mortality due to human activities. We assessed 90 cases of manatee strandings in Puerto Rico based on historical data and a coordinated carcass salvage effort from 1990 through 1995. We determined patterns of mortality, including type of event, condition of carcasses, spatial and temporal distribution, gender, size/age class, and the cause of death. The spatial distribution of stranding events was not uniform, with the north, northeast, and south coasts having the highest numbers. Six clusters representing the highest incidence included the areas of Fajardo and Ceiba, Bahía de Jobos, Toa Baja, Guayanilla, Cabo Rojo, and Rio Grande to Luquillo. The number of reported cases has increased at an average rate of 9.6%/yr since 1990. The seasonality of stranding events showed a bimodal pattern, from February through April and in August and September. Most identified causes of death were due to human interaction, especially captures and watercraft collisions. Natural causes usually involved dependent calves. From 1990 through 1995, most deaths were attributed to watercraft collisions. A reduction in anthropogenic mortality of this endangered species can be accomplished only through education and a proactive management and conservation plan that includes law enforcement, mortality assessment, scientific research, rescue and rehabilitation, and inter- and intraagency cooperation.

Seven species of helminths and six species of arthropods are reported from 23 of 40 brown pelicans, Pelecanus occidentalis, collected from various localities in Puerto Rico. Helminth parasites include three nematodes (Contracaecum multipapillatu m, Contracaecum mexicanum, and Eustrongylides sp.), three trematodes (Galactosomum darbyi, Mesostephanus appendiculatoide s, and Ribeiroia ondatrae), and one cestode (Tetrabothrium sulae). Arthropod parasites include Colpocephalum occidentalis, Neottialges apunctatus, Ornithodoros capensis, Phalacrodectus pelecani, Phalacrodectus punctatissimus, and Phalacrodectus sp. The presence of R. ondatrae in the brown pelican is a new species host record, and P. pelecani, P. punctatissimu s and N. apunctatus are new subspecies host records. C. multipapillatum, C. mexicanum, G. darbyi and M. appendiculatoide s are new locality records for Puerto Rico, and N. apunctatus, P. pelecani, P. punctatissimus and T. sulae are new locality records for the Caribbean. Necrosis produced by C. multipapillatu m, C. mexicanum, and R. ondatrae may have contributed to the emaciation and death of the brown pelicans examined in the present study.

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An assessment of cetacean strandings was conducted in waters off Puerto Rico and the United States and British Virgin Islands to identify, document and analyse factors associated with reported mortality events. Nineteen species of cetaceans were reported stranded. The total number of events recorded between 1867 and 1995 was 129, comprising over 159 individuals. The bottlenose dolphin (Tursiops truncatus) was the species most commonly found stranded, followed by Cuvier's beaked whale (Ziphius cavirostris), sperm whale (Physeter macrocephalus), Atlantic spotted dolphin (Stenellafrontalis) and short-finned pilot whale (Globicephala macrorhynchus). An increase in the number of strandings is evident over the past 20 years, averaging 63.l% per year. Between 1990 and 1995, the average number of cases per year increased from 2.1 to 8.2. The seasonal pattern of strandings was not found to be uniform, with a high number of strandings occurring in the winter and spring. The monthly temporal distribution showed an overall bimodal pattern, with the highest number of cases reported for February, May and September. The spatial distribution was not even, and differed between countries, within countries, and between taxonomic groups and species. Aside from undetermined causes of mortality, the ratio of natural causes in relation to human-related causes was of 1.2:1. Between 1990 and 1995, a reduction of the percentage of undetermined cause of deaths resulted from the establishment of a cooperative effort in studying mortality in an organised and systematic manner. The most common natural cause of death category was dependent calf. The most common human-related cause categories observed were entanglement and accidental captures, followed by animals being shot or speared. Evaluation and recommendations to improve the research conducted are formulated, including guidelines for the development of a strategic plan to obtain baseline data on the biology and life history of cetaceans to be applied to their conservation and management.