FN Archimer Export Format PT Rapport TI Update of pollack abundance indices from professional fishing data (2016-2018) BT AF CAILL-MILLY, Nathalie LISSARDY, Muriel BRU, NOELLE AS 1:1;2:1;3:2; FF 1:PDG-ODE-LITTORAL-LERAR;2:PDG-ODE-LITTORAL-LERAR;3:; C1 Ifremer, LITTORAL, LERAR, 1 allée du Parc Montaury, F-64600 Anglet, France Université de Pau et des Pays de l'Adour, E2S UPPA, CNRS, LMAP, Anglet, France C2 IFREMER, FRANCE UNIV PAU & PAYS ADOUR, FRANCE SI ANGLET SE PDG-ODE-LITTORAL-LERAR UR https://archimer.ifremer.fr/doc/00631/74351/74006.pdf LA English DT Report AB The ROMELIGO project included a proposal of abundance indicators for pol-89a stock using professional fishing data. The methodolgy is based on the selection of a sample of representative vessels grouped in a cluster with the same technical characteristics, taking into account their LPUE for specifed period and area. The analysis was conducted on an historical dataset from 2005 to 2015. To be able to update it, a conditional decision tree was used to find rules to assign any new vessels to one of the predefined GNS clusters. Then, the trends of LPUE on the overall period were considered: for the past three years, the LPUEs display low levels compared to the whole series while the highest levels were observed between 2011 and 2015. No management measure likely to affect the indicators was identified by professionals. At this time no new element leads to discuss the relevance of this GNS indicator but attention should be paid to its use alone (linked to the possible various uses of the gear). PY 2020 PD MAY ID 74351 ER EF