Unravelling the ecological role and trophic relationships of uncommon and threatened elasmobranchs in the western Mediterranean Sea

Type Article
Date 2015-11
Language English
Author(s) Barria ClaudioORCID1, Coll MartaORCID1, 2, Navarro JoanORCID1, 3
Affiliation(s) 1 : CSIC, ICM, E-08003 Barcelona, Spain.
2 : IRD, UMR MARBEC, F-34203 Sete, France.
3 : CSIC, Dept Conservat Biol, EBD, Seville 41092, Spain.
Source Marine Ecology Progress Series (0171-8630) (Inter-research), 2015-11 , Vol. 539 , P. 225-240
DOI 10.3354/meps11494
WOS© Times Cited 40
Keyword(s) Mediterranean Sea, Rays, Sharks, Skates, Species at risk, Stable isotopes, Trophic ecology, Trophic level
Abstract Deficiencies in basic ecological information on uncommon and endangered elasmobranch fishes impair the assessment of their ecological role in marine ecosystems. In this study, we examined the feeding ecology (diet composition and trophic level) and trophic relationships of 22 elasmobranchs (2 Carcharhiniformes, 1 Hexanchiformes, 1 Lamniformes, 3 Myliobatiformes, 6 Rajiformes, 6 Squaliformes and 3 Torpediniformes) present in the western Mediterranean Sea. To obtain a comprehensive view of the feeding ecology of these species, we combined different approaches: stable isotope analyses (delta C-13 and delta N-15 values), stomach content analyses and published sources. Our results revealed differences in feeding strategies among elasmobranch groups: skates (Rajiformes) mainly consume crustaceans; sharks (Carcharhiniformes, Hexanchiformes, Squaliformes and Lamniformes) prefer mixed diets composed of cephalopods, crustaceans and fishes; electric rays (Torpediniformes) feed mostly on fishes; and the diet of stingrays (Myliobatiformes) varies between species. Sharks and electric rays show higher trophic positions than skates, and the former occupy similar positions to other apex predators. Skates are more similar to other mesopredator fishes. These new findings offer essential information on the ecological role of several elasmobranchs in the western Mediterranean Sea and provide useful data for managers for future conservation strategies.
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