Data from: Temperature-associated habitat selection in a cold-water marine fish

Habitat selection is a complex process, which involves behavioural decisions guided by the multiple needs and constraints faced by individuals. Climate-induced changes in environmental conditions may alter those trade-offs and resulting habitat use patterns. In this study we investigated the effect of sea temperature on habitat selection and habitat use of acoustically tagged Atlantic cod (Gadus morhua) at the Norwegian Skagerrak coast. Significant relationships between ocean temperature and habitat selection and use were found. Under favourable sea temperature thresholds (< 16°C), cod selected vegetated habitats, such as eelgrass and macroalgae beds, available in shallow areas. Selection for those habitats was especially high at night, when cod tended to ascend to shallower areas, presumably to feed. Selection and use of those habitats decreased significantly as temperature rose. Under increased sea surface temperature conditions, cod were absent from vegetated shallow habitats, both during the day and night, and selected instead non-vegetated rocky bottoms and sand habitats, available in deeper, colder areas. This study shows the dynamic nature of habitat selection and strongly suggests that cod in this region have to trade off food availability against favourable temperature conditions. Future increases in ocean temperature are expected to further influence the spatial behaviour of marine fish, potentially affecting individual fitness and population dynamics.栖息地选择是一个复杂的过程，涉及个体基于自身多重需求与约束所做出的行为决策。气候驱动的环境条件变化可能会改变这些权衡关系，进而改变栖息地利用模式。本研究以挪威斯卡格拉克海岸搭载声学标记的大西洋鳕鱼（Gadus morhua）为研究对象，探究了海水温度对其栖息地选择与利用的影响。研究发现海水温度与栖息地选择及利用模式之间存在显著关联。当海水温度处于适宜阈值（<16℃）时，鳕鱼会选择浅水区的植被生境，如鳗草床与大型藻床。这类栖息地的选择偏好于夜间尤为显著：此时鳕鱼会向浅水区上浮，推测是为了觅食。随着水温升高，鳕鱼对这类栖息地的选择与利用程度显著降低。当海水表面温度升高时，鳕鱼无论昼夜都会避开浅水区的植被生境，转而选择更深、水温更低区域的无植被岩质底与沙质生境。本研究揭示了栖息地选择的动态特性，并明确指出该区域的鳕鱼需要在食物可获得性与适宜温度条件之间进行权衡。未来海洋温度的升高预计将进一步影响海洋鱼类的空间行为，进而可能对个体适合度与种群动态产生影响。