Bottlenose dolphins at the southern extreme of the south-western Atlantic: local population decline?

MARIANO A. COSCARELLA; SILVANA L. DANS; MARIANA DEGRATI; GRISELDA V. GARAFFO; ENRIQUE A. CRESPO

JOURNAL OF THE MARINE BIOLOGICAL ASSOCIATION OF THE UNITED KINGDOM

CAMBRIDGE UNIV PRESS

Año: 2012 vol. 92 p. 1843 - 1849

0025-3154

The bottlenose dolphin is one of the best known cetacean species. Reports on behavior, population dynamics and population structure are easily found in the literature (for a review see Herman 1980; Leatherwood and Reeves 1990; Mann et al. 2000; Shane et al. 1986). However, bottlenose dolphins can exhibit extremely variable distribution patterns, from entirely resident and confined populations, to nomadic and migratory populations (Wilson et al 1997). For example, in the western Mid Atlantic, some of the distribution patterns emerging from ship surveys indicate a possible combination of year-round resident groups, groups with relatively small home-ranges but with different summer and winter areas and possible migratory groups with larger ranges (Hohn 1997). It is also expected that populations inhabiting more seasonal habitats, like more temperate areas located at higher latitudes, exhibit migratory behavior (Shane et al 1986). As a consequence of this variability, what is known about one population cannot be easily transposed to another, and short term trends cannot be easily interpreted as long-term population changes.