FN Archimer Export Format PT J TI Individual fish rhythm directs group feeding: a case study with sea bass juveniles (Dicentrarchus labrax) under self-demand feeding conditions BT AF MILLOT, Sandie BEGOUT, Marie-Laure AS 1:1;2:1; FF 1:;2:PDG-DOP-DCN-HGS-LRHLR; C1 IFREMER, LRHLR, F-17137 Lhoumeau, France. C2 IFREMER, FRANCE SI LA ROCHELLE SE PDG-DOP-DCN-HGS-LRHLR IN WOS Ifremer jusqu'en 2018 IF 1.227 TC 25 UR https://archimer.ifremer.fr/doc/2009/publication-6874.pdf LA English DT Article DE ;Dicentrarchus labrax;Self feeder;Social interactions;Feed demand leader;Feeding rhythms AB The long term influence of individual biological rhythms on group feed demand behaviour was investigated in European sea bass (Dicentrarchus labrax) held under controlled environmental conditions with an on-demand feeding system. The experiment was realized over 219 days with 190 fish distributed on 4 tanks. Sea bass had a mean body mass comprised between 139 g to 183 g. The number of feed demand acts by each individual was calculated daily, and the population could thus be partitioned into three categories (high-, low-and zero-triggering fish). The duration of the period that an individual held high-triggering status could vary, but was 63 +/- 16 days on average. The transition period between two highest-triggering fish in one tank was on average 4 +/- 4 days. The group feeding rhythm followed the same pattern of feed demand rhythm as the highest-triggering individual fish. When the highest-triggering fish was nocturnal, the totality of feed demand in the group was realized during the night with one peak at 22:00, corresponding to dusk under experimental conditions. When the highest-triggering fish was diurnal, the majority of feed demand in the group was realized during the light period with one peak at 06:00, corresponding to dawn, and/or another at 12:00. This study therefore highlights that sea bass group feeding behaviour is not the sum of individual feed demand behaviours, but is directed by the rhythm and behaviour of a few high-triggering fish. The regular changes of high-triggering fish in the group proved that it was not the identity of these particular fish that was most important for the group, but their role as a feed demand leader. PY 2009 PD JUN SO Aquatic Living Resources SN 0990-7440 PU EDP Sciences VL 22 IS 3 UT 000271030300011 BP 363 EP 370 DI 10.1051/alr/2009048 ID 6874 ER EF