Toothed whales in the northwestern Mediterranean: Insight into their feeding ecology using chemical tracers

peer reviewed Risso’s dolphins, pilot whales and sperm whales rarely strand in the northwestern Mediterranean. Thus, their feeding ecology, through the analysis of stomach contents, is poorly known. The aim of this study was to gain further insight into the segregation/superposition of the diet and...

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Bibliographic Details
Published in:Marine Pollution Bulletin
Main Authors: Praca, Emilie, Laran, Sophie, Lepoint, Gilles, Thomé, Jean-Pierre, Quetglas, Antoni, Belcari, Paola, Sartor, Paolo, Dhermain, Frank, Ody, Denis, Tapie, Nathalie, Budzinski, Hélène, Das, Krishna
Format: Article in Journal/Newspaper
Language:English
Published: Elsevier 2011
Subjects:
Chemical tracers
Stable isotopes
Organochlorines
Sperm whale
Pilot whale
Risso's dolphin
Mediterranean Sea
marine mammals
pollutants
pollution
Life sciences
Environmental sciences & ecology
Aquatic sciences & oceanology
Sciences du vivant
Sciences de l’environnement & écologie
Sciences aquatiques & océanologie
toothed whales
Online Access:https://orbi.uliege.be/handle/2268/87934
https://orbi.uliege.be/bitstream/2268/87934/1/2011%20MPB%20Praca.pdf
https://doi.org/10.1016/j.marpolbul.2011.02.024
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Summary:peer reviewed Risso’s dolphins, pilot whales and sperm whales rarely strand in the northwestern Mediterranean. Thus, their feeding ecology, through the analysis of stomach contents, is poorly known. The aim of this study was to gain further insight into the segregation/superposition of the diet and habitat of Risso’s dolphins, pilot whales and sperm whales using chemical tracers, namely, stable isotopes (d13C, d15N) and orga- nochlorines. Significantly different d15N values were obtained in Risso’s dolphins (11.7 ± 0.7‰), sperm whales (10.8 ± 0.3‰) and pilot whales (9.8 ± 0.3‰), revealing different trophic levels. These differences are presumably due to various proportions of Histioteuthidae cephalopods in each toothed whale’s diet. Similar d13C contents between species indicated long-term habitat superposition or corroborated impor- tant seasonal migrations. Lower congener 180 concentrations (8.20 vs. 21.73 lg.g????1 lw) and higher tDDT/ tPCB ratios (0.93 vs. 0.42) were observed in sperm whales compared with Risso’s dolphins and may indi- cate wider migrations for the former. Therefore, competition between these species seems to depend on different trophic levels and migration patterns.

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