title: Isotopic niches of fin whales from the Mediterranean Sea and the Celtic Sea (North Atlantic).
abstract: The fin whale (Balaenoptera physalus) is the most abundant and widespread mysticete species in the Mediterranean Sea, found mostly in deep, offshore waters of the western and central portion of the region. In the Mediterranean, this species is known to feed mainly on krill, in contrast to its Atlantic counterpart, which displays a more diversified diet. The International Whaling Commission recognizes several managements units in the Atlantic and the Mediterranean Sea and the connectivity between these populations is still being debated. Questions remain about inter-individual feeding strategies and trophic ecology. The goal of this study was to compare isotopic niches of fin whales from the Mediterranean Sea and the Celtic Sea (North Atlantic). δ13C and δ15N values were analysed in 136 skin biopsies from free-ranging Mediterranean fin whales sampled in 2010 and 2011 during campaigns at sea. δ13C and δ15N values ranged from -20.4 to -17.1‰ and from 5.9 to 8.9‰, respectively. These values are in good agreement with those estimated previously from baleen plates from Mediterranean and North Atlantic fin whales. The narrow isotopic niche width of the Mediterranean fin whale (Standard Ellipses area SEAc) compared to the North Atlantic fin whale raises many concerns in the context of global changes and long-term consequences. One could indeed expect that species displaying narrow niches would be more susceptible to ecosystem fragmentation and other anthropogenic impacts.
authors.affiliation: Laboratory of Oceanology-MARE, University of Liege, Belgium. Electronic address: Krishna.das@ulg.ac.be.
authors.forename: Krishna
authors.initials: K
authors.lastname: Das
authors.affiliation: Laboratory of Oceanology-MARE, University of Liege, Belgium.
authors.forename: Ophélie
authors.initials: O
authors.lastname: Holleville
authors.affiliation: Marine and Freshwater Research Centre, Galway-Mayo Institute of Technology, Galway, Ireland; Irish Whale and Dolphin Group, Merchant's Quay, Kilrush, Co. Clare, Ireland.
authors.forename: Conor
authors.initials: C
authors.lastname: Ryan
authors.affiliation: Marine and Freshwater Research Centre, Galway-Mayo Institute of Technology, Galway, Ireland; Irish Whale and Dolphin Group, Merchant's Quay, Kilrush, Co. Clare, Ireland.
authors.forename: Simon
authors.initials: S
authors.lastname: Berrow
authors.affiliation: Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover, Foundation, Werftstraße 6, D-25761 Büsum, Germany.
authors.forename: Anita
authors.initials: A
authors.lastname: Gilles
authors.affiliation: WWF-France, 6 Rue des Fabres, 13001 Marseille, France.
authors.forename: Denis
authors.initials: D
authors.lastname: Ody
authors.affiliation: Laboratory of Oceanology-MARE, University of Liege, Belgium.
authors.forename: Loïc N
authors.initials: LN
authors.lastname: Michel
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000378:metabolism*; D002247:Carbon Isotopes; D017753:Ecosystem; D019550:Environmental Medicine; D004784:Environmental Monitoring; D050617:Fin Whale / Q000502:physiology*; D008522:Mediterranean Sea; D009587:Nitrogen Isotopes
chemical_list: D015415:Biomarkers; D002247:Carbon Isotopes; D009587:Nitrogen Isotopes
keywords: Balaenoptera physalus; Baleen whales; Conservation; SIBER model; Stable isotopes