Fisheries and Marine Institute, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador, Canada.
Marine and Freshwater Research Institute, Hafnarfjörður, Iceland.
PeerJ. 2023 Jan 25;11:e14746. doi: 10.7717/peerj.14746. eCollection 2023.
In this study, we used escape location underneath the trawl to understand groundfish herding behaviour at the trawl mouth. Three collecting bags (port, center, starboard) were mounted under the trawl and behind the footgear to collect escapees. The escape-at-length of species that escaped into the center bag were compared to the two wing bags to infer fish response behaviour, herding behaviour, and swimming capacity at the trawl mouth. For roundfish, smaller-sized individuals escaped more in the center for both Atlantic cod () and haddock (), <20 and 11 cm, respectively, indicating that larger-sized fish were to a greater extent seeking to escape under the trawl at the wings, small fish being herded to the center and likely overrun due to reduced swimming capacity. For flatfish and monkfish (), results varied. European plaice (), American plaice (), and monkfish were caught most often in the wings, though not significantly for American plaice. Catches of dab () between 18 and 27 cm were significantly higher in the center, with no difference for smaller and larger individuals. The differences between fish escape location likely result from a combination of varying herding behaviour, size, and swimming capacity. Here, we were able to show how these size-dependent behaviours relate to fish response behaviour, escape behaviour, size, and likely swimming capacity.
在这项研究中，我们使用拖网下方的逃逸位置来了解拖网口处底层鱼类的放牧行为。在拖网和脚蹼后面安装了三个收集袋（左舷、中央、右舷）来收集逃逸的鱼类。将逃入中央袋的物种的逃逸长度与两个翼袋进行比较，以推断鱼类在拖网口的反应行为、放牧行为和游泳能力。对于圆口鱼类，大西洋鳕鱼（）和黑线鳕（）的较小个体在中央逃逸的比例更高，分别为<20 和 11 厘米，这表明较大的个体更倾向于在拖网的两翼下寻求逃逸，而小鱼则被赶到中央，由于游泳能力降低，可能会被淹没。对于比目鱼和鲉鱼（），结果则有所不同。欧鲽（）、美洲拟庸鲽（）和鲉鱼最常被捕捞到两翼，而美洲拟庸鲽则不显著。18 到 27 厘米的庸鲽的捕获量在中央显著更高，而对于较小和较大的个体则没有差异。鱼类逃逸位置的差异可能是由于放牧行为、体型和游泳能力的变化综合作用的结果。在这里，我们能够展示这些与体型相关的行为如何与鱼类的反应行为、逃逸行为、体型和可能的游泳能力相关。
