| Abstract: | Self-feeding device is extensively used in aquaculture farms, but for salmonids the individual feeding behavior has seldom been continuously observed. In this article, the individual self-feeding behavior of 10 rainbow trout was continuously monitored with a PIT tag record for 50 days with three replicates. The?sh fell into three categories according to their feeding behavior, i.e. high triggering ?sh(trigger behavior more than 25% of the group, HT), low triggering ?sh(1%–25%, LT) and zero triggering ?sh(less than1%). The results showed that in a group of 10 individual 1–2 HT ?sh accounted for most of the self-feeding behavior(78.19%–89.14%), which was far more than they could consume. The trigger frequency of the?sh was signi?cantly correlated with the initial body weight( P <0.01), however, no signi?cant dif ference in growth rate among the HT, LT, and ZT ?sh was observed( P >0.05). Cosinor analysis showed that the two HT ?sh in the same group had similar acrophase. Though some of the HT ?sh could be active for 50 d, there were also HT ?sh decreased triggering behavior around 40 d and the high trigger status was then replaced by other ?sh, which was ?rst discovered in salimonds. Interestingly, the growth of the group was not af fected by the alternation triggering ?sh. These results provide evidence that in the self-feeding system the HT ?sh didn't gain much advantage by their frequent self-feeding behavior, and high trigger status of the HT ?sh is not only an individual character but also driven by the demand of the group. In the self-feeding system, the critical individual should be closely monitored. |
