Sammendrag
A new system for gentle transfer of fish (Whooshh Fish Transfer System, WFTS) has been evaluated at the AquaGen Atlantic salmon broodstock premises. Transfer of broodstock between tanks was carried out by WFTS and the traditional hand-carry method which includes a MS-222 anaesthesia step. Transfer of fish by WFTS was carried out by using sedated (AQUI-S) and not sedated fish. The state of the fish were evaluated in terms of stress, behaviour, welfare, possible post-transfer delayed mortalities or other irregularities for up to one week after transfer. Generally, only modest stress reactions were determined and these were mainly related to fish handling operations before transfer, particularly when not sedated fish were loaded into the WFTS. The WFTS transfer itself did not impose an additional stress load. The hand-carry method was equally good, although the method is more labour-intensive. The use of the WFTS seems to eliminate the need for the MS-222 step. No mortalities or other irregularities were observed throughout the experimental period. We were not able to identify particular issues where fish welfare was clearly compromised. For safer and less cumbersome feeding of fish into the WFTS, it is recommended that the fish are sedated before transfer.
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