Swim bladder measurements of Cyclothone species from the BATHYPELAGIC cruise to the Northeast Atlantic Ocean

This dataset contains the values of swim bladder length, height, width, angle, volume, equivalent spherical radius and aspect ratio in Cyclothone spp. measured during the Bathypelagic cruise (from 24th May to 23rd June 2018). Samples were obtained with MOCNESS-1 m² (with a 0.2 mm mesh size) zooplankton net during day and night hauls carried out from the surface to 1800 m depth. MOCNESS samples were preserved in 5% buffered formalin. Standard length (SL, ±0.01 mm) and swim bladder (Sw, ±0.001 mm) on each specimen were measured at the land-based laboratory. A stereo microscope fitted with an ocular micrometer was used to obtain the swim bladder length height, width, and swim bladder angle (θ). The longitudinal axis was set as the reference line for the angle (θ =0) with positive values over the reference line. Swim bladder volumes were approximated using the formula for a prolate spheroid, the equivalent spherical radius was estimated following the equation of Strasberg (1953) and the aspect ratio was calculated as the ratio of the height to the longitudinal semi-axis.本数据集收录了2018年5月24日至6月23日深远洋航次（Bathypelagic cruise）中测得的圆罩鱼属（Cyclothone spp.）个体的鱼鳔（swim bladder）长度、高度、宽度、角度、体积、等效球半径及纵横比数据。样本采用MOCNESS-1平方米浮游生物网（网孔尺寸0.2 mm），通过从表层至1800 m水深的昼夜拖网采集获得。采集得到的MOCNESS样本经5%缓冲福尔马林溶液固定保存。所有样本均在陆上实验室完成测量，记录每尾标本的标准体长（SL，精度±0.01 mm）与鱼鳔（Sw，精度±0.001 mm）相关参数。采用搭载目镜测微尺的体视显微镜测量鱼鳔的长度、高度、宽度及鳔角（θ），以鱼体纵轴作为鳔角测量的基准线（θ=0），基准线上方的角度取值为正。鱼鳔体积采用长椭球体公式近似计算，等效球半径根据Strasberg（1953）提出的公式估算，纵横比则以鱼鳔高度与纵半轴的比值计算得出。