光照条件下南极磷虾的行为观察

2010—2011年随中国大型拖网加工船“安兴海”轮在南极南奥克尼群岛附近进行南极磷虾拖网作业,将作业过程中采集到的鲜活南极磷虾立刻转移至实验水箱,进行暂养并观察其行为。实验样本为45尾,体长为37~50 mm,整个实验持续时间为13 d,水面光照为220 lx,水温恒定在0 ℃。通过观察发现:(1) 南极磷虾进入实验水箱后体色迅速变为透明;(2) 在静水环境中,南极磷虾多数时间位置相对固定,集中于角落,沿箱壁进行角落间游动,较少穿过水箱中央,穿过水箱中央时有加速游动的现象;动水环境中能够顶流游动并形成集群,0.5 m/s时顶流游动,流速超过1 m/s时,集群消失;水流对南极磷虾的集群有极显著影响;(3) 南极磷虾进入水箱后第6天开始蜕壳,第6~9天均发现虾壳,实验对象平均体长增长5~8 mm。

Observation on behaviours of Antarctic krill(Euphausia superba)in lighting condition

In 2010—2011,active Antarctic krills(Euphausia superba)which survived and were collected immediately in the capture by a pelagic trawl with the factory trawler "Anxinghai" near South Orkney Island and were transferred to a test tank and their behaviors were observed.45 Antarctic krills were observed during the experiment,and the body length were 37-55 mm,the light intensity of water surface in test tank was kept at 220 lx,and the temperature of the water in test tank was constant at 0 ℃.The whole experiment lasted for 13 days.There are three results obtained from the experiment:(1) Body color of Antarctic krill changes rapidly after being put into test tank under lighting;(2) In static condition,Antarctic krill almost keeps in the same position in corners.When they moved,they could swim from one corner to a neighbor corner along the wall of the tank,and a few times to swim with a higher speed across the center of the test tank;In hydrodynamic conditions,they can swim against the current and aggregate to a schooling at a velocity about 0.5 m/s,schooling vanished while current is greater than 1 m/s;(3) Antarctic krill molted during the experiments,and the average body length increased about 5-8 mm.