FN Archimer Export Format
PT Rapport
TI Report of the Seabass (Dicentrarchus labrax) Otolith and Scale Exchange Scheme 2013
BT 
AF MAHE, Kelig
   SEVIN, Karine
   MOERMAN, Martine
   HOLMES, Alison
AS 1:1;2:1;3:2;4:3;
FF 1:PDG-RBE-HMMN-RHBL;2:PDG-RBE-HMMN-RHBL;3:;4:;
C1 Ifremer, france
   Ilvo, Belgium
   Cefas, UK
C2 IFREMER, FRANCE
   ILVO, BELGIUM
   CEFAS, UK
SI BOULOGNE
SE PDG-RBE-HMMN-RHBL
UR https://archimer.ifremer.fr/doc/00185/29596/27963.pdf
LA English
DT Report
CR CGFS2012
   EVHOE 2010
   EVHOE 2011
   IBTS 2012
   IBTS 2013
BO Gwen Drez
   Thalassa
AB The ICES Planning Group on Commercial Catch, Discards and Biological Sampling (PGCCDBS) identified the need of a seabass Dicentrarchus labrax) otolith exchange to take place in 2013. It was the second exchange after that’s of 2011. The IFREMER institute coordinated this exchange. A total of 223 fish from the bay of Biscay (ICES area : VIII, N=29), the Eastern English Channel (ICES area : VIId, N=149) and the North Sea (ICES area : IV, N=45) was sampled onboard French research vessels (Gwen-Drez and Thalassa) during 3 international surveys (EVHOE, CGFS and IBTS). The length range of the fish was between 26 and 71 cm, with mean 42.3 cm. For each fish, the Sagittae otoliths and few scales were used to compare the age estimation between the both calcified pieces. Only 3 readers were participated from France (1 reader), Belgium (1 reader) and UK England (1 reader). During the first exchange in 2011, there were only 2 countries (France and UK England). Only images were used during this exchange. The analyses did not show a high mean precision of age estimate for individual fish with Coefficient of Variation (CV) of 9.4% and percent agreement to modal age of 68.6%. Among 223 fish, 84 were read with 100% agreement (37%) and thus a CV of 0%. During this exchange, 2 different calcified pieces (otolith and scale) from the same sampling were analysed. The results showed precision of age estimation from the scales (Agreement = 78.4%; CV=1.4) was better than that’s from the otoliths (Agreement = 55.7%; CV=13.4). However, the size of sampling for the otolith exercise (N=149) is twice as much as that’s of the scale exercise (N=74, Tab. 2). Moreover, 2 readers (France and Belgium) preferred to analyse otoliths and only 1 reader the otoliths of seabass.
PY 2014
ID 29596
ER

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