Southeast Fisheries Science Center, National Marine Fisheries Service, Beaufort, NC, 28516, USA.
Department of Applied Ecology, Center for Marine Sciences and Technology, North Carolina State University, Morehead City, NC, 28557, USA.
Sci Rep. 2021 May 5;11(1):9580. doi: 10.1038/s41598-021-88806-3.
Most demersal fishes are difficult to observe and track due to methodological and analytical constraints. We used an acoustic positioning system to elucidate the horizontal and vertical movements of 44 red snapper (Lutjanus campechanus) off North Carolina, USA, in 2019. Mean movement rate and distance off bottom varied by individual, with larger red snapper generally moving faster and spending more time farther off the bottom than smaller individuals. We used generalized additive mixed models that accounted for temporal autocorrelation in the data to show that mean hourly red snapper movement rate was lower during the day than at night and was negatively related to bottom water temperature. Moreover, red snapper spent more time off the bottom during the day than at night, and vertical movements were mostly related to bottom upwelling events that sporadically occurred in May-July. Our results and previous observations suggest that red snapper feed primarily on benthic organisms at night, and display diel vertical migration (i.e., thermotaxis) up to warmer waters (when present) during the day to aid digestive efficiency. Movement is a central organizing feature in ecology, and the sustainable management of fish will benefit from a better understanding of the timing and causes of fish movement.
由于方法学和分析上的限制，大多数底层鱼类很难被观察和追踪。我们使用声学定位系统来阐明 2019 年在美国北卡罗来纳州的 44 条红鲷鱼（Lutjanus campechanus）的水平和垂直运动。个体之间的平均移动速度和离底距离有所不同，一般来说，体型较大的红鲷鱼移动速度较快，离底时间也较长，而体型较小的个体则移动速度较慢，离底时间也较短。我们使用广义加性混合模型来解释数据中的时间自相关，结果表明，红鲷鱼的平均每小时移动速度在白天比晚上低，与底层水温呈负相关。此外，红鲷鱼在白天离底的时间比晚上多，垂直运动主要与 5 月至 7 月间偶发的底层上升流事件有关。我们的研究结果和以往的观察结果表明，红鲷鱼主要在夜间以底栖生物为食，并在白天进行昼夜垂直洄游（即热泳），以到达更温暖的水域（如果存在），以提高消化效率。运动是生态学中的一个核心组织特征，更好地了解鱼类的运动时间和原因将有助于鱼类的可持续管理。
