Pennsylvania Cooperative Fish and Wildlife Research Unit, Pennsylvania State University, University Park, Pennsylvania, USA.
Department of Ecosystem Science and Management, Pennsylvania State University, University Park, Pennsylvania, USA.
J Fish Biol. 2019 Oct;95(4):1061-1071. doi: 10.1111/jfb.14099. Epub 2019 Aug 12.
Individual aggression and thermal refuge use were monitored in brook trout Salvelinus fontinalis in a controlled laboratory to determine how fish size and personality influence time spent in forage and thermal habitat patches during periods of thermal stress. On average, larger and more exploratory fish initiated more aggressive interactions and across all fish there was decreased aggression at warmer temperatures. Individual personality did not explain changes in aggression or habitat use with increased temperature; however, larger individuals initiated comparatively fewer aggressive interactions at warmer temperatures. Occupancy of forage patches generally declined as ambient stream temperatures approached critical maximum and fish increased thermal refuge use, with a steeper decline in forage patch occupancy observed in larger fish. These findings suggest that larger individuals may be more vulnerable to stream temperature rise. Importantly, even at thermally stressful temperatures, all fish periodically left the thermal refuge to forage. This indicates that the success of refugia at increasing population survival during periods of stream temperature rise may depend on the location of thermal refugia relative to forage locations within the larger habitat mosaic. These results provide insights into the potential for thermal refugia to improve population survival and can be used to inform predictions of population vulnerability to climate change.
个体攻击行为和热避难所的使用在受控实验室中监测了溪红点鲑（Salvelinus fontinalis），以确定鱼类体型和个性如何影响在热应激期间在饲料和热栖息地斑块中花费的时间。平均而言，体型较大和更具探索性的鱼类发起的攻击性互动更多，而且所有鱼类在温度升高时的攻击性都会降低。个体个性并不能解释随着温度升高，攻击性或栖息地利用的变化；然而，体型较大的个体在较温暖的温度下发起的攻击性互动相对较少。随着环境溪流温度接近临界最大值，鱼类增加了对热避难所的利用，饲料斑块的占用率通常会下降，在较大的鱼类中观察到饲料斑块占用率的下降更为陡峭。这些发现表明，较大的个体可能更容易受到溪流温度上升的影响。重要的是，即使在热应激温度下，所有鱼类都会定期离开热避难所去觅食。这表明，在溪流温度上升期间，避难所对于增加种群生存的成功可能取决于热避难所相对于较大栖息地镶嵌体中饲料位置的位置。这些结果提供了有关热避难所提高种群生存能力的潜力的见解，并可用于告知对气候变化下种群脆弱性的预测。
