Calabrese Sara, Jonassen Thor Magne, Steigum Endre, Åsnes Helga Øen, Imsland Albert Kjartan Dagbjartarson, Saude Carolina Serra, Wergeland Truls, Höglund Erik
Norwegian Institute for Water Research, Bergen, Norway.
Akvaplan-niva AS, Tromsø, Norway.
Front Vet Sci. 2024 Jan 15;11:1347062. doi: 10.3389/fvets.2024.1347062. eCollection 2024.
Ballan wrasse () are commonly used as cleaner fish in salmon farms as a biological treatment to mitigate sea lice infestation. Improved welfare for cleaner fish both during production of these fish and when in sea-cages with salmon is crucial for the industry's development. A common operational procedure in ballan wrasse production is transporting juveniles from one land-based farm to another for further on-growing. Episodes of increased mortality have been reported after such transportations. In this study, the relationship between transport stress and post-transport mortality at the on-growing facility was examined. It was also investigated if light sedation with AQUI-S can mitigate stress during transport. Stress was quantified by measuring cortisol release rate to the tank water during transport. This was investigated in 10 commercial live carrier truck transports (6 without AQUI-S sedation and 4 with sedation during loading and transport). The total time of transport varied between 12 and 21 h. In general, mortality was significantly higher (1.0 ± 0.6% day) the first five days post-transport compared to 15-20 days post transport (0.5% day). There was also a strong relationship between fish weight at transport and post-transport mortality, where higher mean weight at transport reduced mortality. In contrast to what was expected, AQUI-S treatment during transport procedures increased cortisol excretion rate, suggesting a stimulating effect of AQUI-S on the stress axis in ballan wrasse. Considering these results, the value of using AQUI-S to reduce stress during transport of juvenile ballan wrasse might be questioned. However, there was no relationship between cortisol release rate during transport and post-transport mortality. Furthermore, this study emphasizes that water cortisol measurements can be used as a none-invasive tool for monitoring stress and can be integrated into the welfare evaluation during commercial fish transports.
球纹隆头鱼通常被用作鲑鱼养殖场的清洁鱼，作为一种生物处理方法来减轻海虱侵扰。在这些鱼的生产过程中以及与鲑鱼一起置于海水网箱中时，提高清洁鱼的福利对该行业的发展至关重要。球纹隆头鱼生产中的一个常见操作程序是将幼鱼从一个陆地养殖场转移到另一个养殖场进行进一步养殖。据报道，此类运输后出现了死亡率增加的情况。在本研究中，考察了运输应激与幼鱼在养殖设施中运输后死亡率之间的关系。还研究了使用AQUI-S轻度镇静是否可以减轻运输过程中的应激。通过测量运输过程中鱼释放到养殖池水中的皮质醇速率来量化应激。在10次商业活鱼运输卡车运输中对此进行了研究（6次未使用AQUI-S镇静，4次在装载和运输过程中使用了镇静）。运输总时间在12至21小时之间。一般来说，运输后前五天的死亡率（1.0±0.6%/天）显著高于运输后15至20天（0.5%/天）。运输时鱼的体重与运输后死亡率之间也存在很强的关系，运输时平均体重越高，死亡率越低。与预期相反，运输过程中使用AQUI-S处理会增加皮质醇排泄率，这表明AQUI-S对球纹隆头鱼的应激轴有刺激作用。考虑到这些结果，在运输幼年球纹隆头鱼时使用AQUI-S减轻应激的价值可能会受到质疑。然而，运输过程中的皮质醇释放率与运输后死亡率之间没有关系。此外，本研究强调，水体皮质醇测量可作为一种非侵入性工具用于监测应激，并可纳入商业鱼类运输过程中的福利评估。
