Prey predator interactions in the face of management regulations: changes in Mediterranean small pelagics are not due to increased tuna predation
|Author(s)||Van Beveren Elisabeth1, Fromentin Jean-Marc1, Bonhommeau Sylvain2, 3, Nieblas Anne-Elise1, Metral Luisa1, Brisset Blandine1, Jusup Marko4, Bauer Robert Klaus1, Brosset Pablo2, 5, Saraux Claire1|
|Affiliation(s)||1 : IFREMER, UMR MARBEC, Inst Francais Rech Exploitat MER, Ave Jean Monnet,BP171, F-34203 Sete, France.
2 : IFREMER, UMR MARBEC, Ave Jean Monnet,BP171, F-34203 Sete, France.
3 : IFREMER Delegat Ocean Indien, Rue Jean Bertho,BP60, F-97822 Le Port, France.
4 : Hokkaido Univ, Ctr Math Social Creat, Kita Ku, N12 W7, Sapporo, Hokkaido 0600812, Japan.
5 : Univ Montpellier II, UMR MARBEC, Ave Jean Monnet,BP171, F-34203 Sete, France.
|Source||Canadian Journal Of Fisheries And Aquatic Sciences (0706-652X) (Canadian Science Publishing, Nrc Research Press), 2017-09 , Vol. 74 , N. 9 , P. 1422-1430|
|WOS© Times Cited||11|
|Abstract||Recently, the abundance of young Atlantic bluefin tuna (Thunnus thynnus) tripled in the North-western Mediterranean following effective management measures. We investigated whether its predation on sardine (Sardina pilchardus) and anchovy (Engraulis encrasicolus) could explain their concurrent size and biomass decline, which caused a fishery crisis. Combining the observed diet composition of bluefin tuna, their modelled daily energy requirements, their population size and the abundance of prey species in the area, we calculated the proportion of the prey populations that were consumed by bluefin tuna annually over 2011-2013. To assess whether tuna could alter the size structure of the three small pelagic populations (anchovy, sardine and sprat), the size distributions of the consumed prey species were compared to those of the wild populations. We estimated that the annual consumption of small pelagic fish by bluefin tuna is less than 2% of the abundance of these populations. Furthermore, size selectivity patterns were not observed. We thus concluded that tuna predation is unlikely to be the main cause of major changes in the small pelagic fish populations from this area.|