title: Toothed whales in the northwestern Mediterranean: insight into their feeding ecology using chemical tracers.
abstract: 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 (δ(13)C, δ(15)N) and organochlorines. Significantly different δ(15)N 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 δ(13)C contents between species indicated long-term habitat superposition or corroborated important seasonal migrations. Lower congener 180 concentrations (8.20 vs. 21.73 μg.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 indicate wider migrations for the former. Therefore, competition between these species seems to depend on different trophic levels and migration patterns.
authors: MARE Centre, Laboratory for Oceanology, University of Liège, allée de la Chimie 17, 4000 Liège, Belgium. emilie.praca@gmail.com
authors: Emilie
authors: E
authors: Praca
authors: Sophie
authors: S
authors: Laran
authors: Gilles
authors: G
authors: Lepoint
authors: Jean-Pierre
authors: JP
authors: Thomé
authors: Antoni
authors: A
authors: Quetglas
authors: Paola
authors: P
authors: Belcari
authors: Paolo
authors: P
authors: Sartor
authors: Frank
authors: F
authors: Dhermain
authors: Denis
authors: D
authors: Ody
authors: Nathalie
authors: N
authors: Tapie
authors: Hélène
authors: H
authors: Budzinski
authors: Krishna
authors: K
authors: Das
mesh_terms: D000818:Animals; D002250:Carbon Radioisotopes / Q000032:analysis; D003634:DDT / Q000032:analysis; D004032:Diet; D004289:Dolphins; D004784:Environmental Monitoring / Q000379:methods; D005260:Female; D020387:Food Chain; D005766:Gastrointestinal Contents / Q000737:chemistry*; D006843:Hydrocarbons, Chlorinated / Q000032:analysis*; D008297:Male; D008522:Mediterranean Sea; D009590:Nitrogen Radioisotopes / Q000032:analysis; D011078:Polychlorinated Biphenyls / Q000032:analysis; D050661:Sperm Whale; D014874:Water Pollutants, Chemical / Q000032:analysis*; D050686:Whales, Pilot
chemical_list: D002250:Carbon Radioisotopes; D006843:Hydrocarbons, Chlorinated; D009590:Nitrogen Radioisotopes; D014874:Water Pollutants, Chemical; D003634:DDT; D011078:Polychlorinated Biphenyls