Otolith shape variation provides a marker of stock origin for north Atlantic bluefin tuna (Thunnus thynnus)
|Author(s)||Brophy Deirdre1, Haynes Paula1, Arrizabalaga Haritz2, Fraile Igaratza2, Fromentin Jean-Marc3, Garibaldi Fulvio4, Katavic Ivan5, Tinti Fausto6, Karakulak F. Saadet7, Macias David8, Busawon Dheeraj9, Hanke Alex9, Kimoto Ai10, Sakai Osamu10, Deguara Simeon11, Abid Nouredinne12, Santos Miguel Neves13|
|Affiliation(s)||1 : Galway Mayo Inst Technol, Marine & Freshwater Res Ctr, Dublin Rd, Galway H91 T8NW, Ireland.
2 : AZTI Tecnalia, Div Marine Res, Portualdea Z-G, E-20110 Pasaia, Gipuzkoa, Spain.
3 : Univ Montpellier, IFREMER, Marine Biodivers Exploitat & Conservat, UMR,MARBEC,IRD,CNRS, Ave Jean Monnet,BP 171, F-34203 Sete, France.
4 : Univ Genoa, Dept Earth Environm & Life Sci, Corso Europa 26, I-16132 Genoa, Italy.
5 : Inst Oceanog & Fisheries, Setaliste 1,Mestrovica 63, HR-21000 Split, Croatia.
6 : Univ Bologna, Dept Biol Geol & Environm Sci, Sch Sci, Via Selmi 3, I-40126 Bologna, Italy.
7 : Istanbul Univ, Fac Fisheries, Ordu St 200, TR-34470 Istanbul, Turkey.
8 : Spanish Inst Oceanog, Pesquero Pesquero S-N, E-29640 Malaga, Spain.
9 : Fisheries & Oceans Canada, Peches & Oceans Canada, St Andrews Biol Stn, 531 Brandy Cove Rd, St Andrews, NB E5B 2L9, Canada.
10 : Natl Res Inst Far Seas Fisheries, 5-7-1 Orido, Shimizu, Shizuoka 4248633, Japan.
11 : Federat Maltese Aquaculture Producers FMAP, St Christopher St,54 VLT 1462, Valletta, Malta.
12 : Inst Natl Rech Halieut INRH, Reg Ctr Tangier, BP 5268, Dradeb, Tangier, Morocco.
13 : IPMA Portuguese Inst Ocean & Atmosphere, Ave 5 Outubro S-N, P-8700305 Olhao, Portugal.
|Meeting||5th ICES International Science Otolith Symposium (IOS), Mallorca, SPAIN, OCT 20-24, 2014|
|Source||Marine And Freshwater Research (1323-1650) (Csiro Publishing), 2016 , Vol. 67 , N. 7 , P. 1023-1036|
|WOS© Times Cited||4|
|Note||Special issue : Fish Otoliths as Indicators in Ecosystem Based Management|
|Keyword(s)||elliptical Fourier analysis, population structure, stock mixture analysis|
|Abstract||Two stocks of bluefin tuna (Thunnus thynnus) inhabit the north Atlantic; the western and eastern stocks spawn in the Gulf of Mexico and the Mediterranean Sea respectively. Trans-Atlantic movements occur outside spawning time whereas natal homing maintains stock structure. Commercial fisheries may exploit a mixed assemblage of both stocks. The incorporation of mixing rates into stock assessment is precluded by uncertainties surrounding stock discrimination. Otolith shape descriptors were used to characterise western and eastern stocks of Atlantic bluefin tuna in the present study and to estimate stock composition in catches of unknown origin. Otolith shape varied with length and between locations and years. Within a restricted size range (200-297-cm fork length (FL)) the two stocks were distinguished with an accuracy of 83%. Bayesian stock mixture analysis indicated that samples from the east Atlantic and Mediterranean were predominantly of eastern origin. The proportion assigned to the eastern stock showed slight spatial variation; however, overlapping 95% credible intervals indicated no significant difference (200-297 cm FL: central Atlantic, 73-100%; Straits of Gibraltar, 73-100%; Morocco, 50-99%; Portugal 64-100%). Otolith shape could be used in combination with other population markers to improve the accuracy of mixing rate estimates for Atlantic bluefin tuna.|