Stomach contents of long‐finned pilot whales ( Globicephala melas edwardii ) mass‐stranded on the Argentine Patagonian coast in 2009

CHALCOBSKY, AILEN; GARCÍA, NÉSTOR A.; COSCARELLA, MARIANO A.; CRESPO, ENRIQUE A.

MARINE MAMMAL SCIENCE

WILEY-BLACKWELL PUBLISHING, INC

Año: 2021 p. 1 - 13

0824-0469

Five massive strandings of pilot whales, Globicephala melas edwardii, have been recorded in the past 40 years in Patagonia. Basic ecological information on this species remain scarce, including its diet. We performed stomach content analysis on 22 females and 6 males stranded in Caleta Malaspina, in 2009, describing their feeding habits. The preys were taxonomicaly identified, and their size and weight were estimated by linear regressions. Numerical dominance (N%), frequency of occurrence (FO%), wet weight (W%) and relative importance index (IRI%) were estimated. The general and the specific overlapping indices (GO y SO) were calculated to evaluate differences in male and female resource utilization and between reproductive stages. The differences between sizes of prey consumed among the subgroup were evaluated. The main prey items were Illex argentinus (IRI%= 60.51%; N%=35.05%; PH%=81.14%) y Doryteuthis gahi (IRI%=38.97%; N%=61.06%; PH%=13.77%), both with FO%=100%. Other prey items were found (5 cephalopod and 5 fish species). Among the subgroups, complete overlapping was not found although the indices indicate a high degree of overlap. Differences of mean sizes of preys resulted statistically significant for some subgroups but such differences may not be of biological relevance. Hence, diets of all stranded dolphins were similar.