The swimming kinematics of larval Atlantic cod, Gadus morhua L., are resilient to elevated seawater pCO2@en

Kinematics of swimming behavior of larval Atlantic cod, aged 12 and 27 days post-hatch (dph) and cultured under three pCO2 conditions (control-370, medium-1800, and high-4200 µatm) from March to May 2010, were extracted from swim path recordings obtained using silhouette video photography. The swim paths were analyzed for swim duration, distance and speed, stop duration, and horizontal and vertical turn angles to determine whether elevated seawater pCO2-at beyond near-future ocean acidification levels-affects the swimming kinematics of Atlantic cod larvae. There were no significant differences in most of the variables tested: the swimming kinematics of Atlantic cod larvae at 12 and 27 dph were highly resilient to extremely elevated pCO2 levels. Nonetheless, cod larvae cultured at the highest pCO2 concentration displayed vertical turn angles that were more restricted (median turn angle, 15°) than larvae in the control (19°) and medium (19°) treatments at 12 dph (but not at 27 dph). Significant reduction in the stop duration of cod larvae from the high treatment (median stop duration, 0.28 s) was also observed compared to the larvae from the control group (0.32 s) at 27 dph (but not at 12 dph). The functional and ecological significance of these subtle differences are unclear and, therefore, require further investigation in order to determine whether they are ecologically relevant or spurious.本数据集提取自2010年3月至5月的实验记录：研究人员通过剪影视频摄影法（silhouette video photography）获取了12日龄和27日龄的大西洋鳕幼鱼（larval Atlantic cod，孵化后天数days post-hatch，简称dph）的游泳路径，这些幼鱼在三种二氧化碳分压（pCO2）条件下培养，分别为对照组（370 µatm）、中等浓度组（1800 µatm）与高浓度组（4200 µatm），后续从游泳路径记录中提取了其游泳行为的运动学（swim kinematics）数据。研究人员对上述游泳路径展开分析，测量了游泳时长、游泳距离与速度、停留时长、水平及垂直转向角度等参数，以探究超过近未来海洋酸化（ocean acidification）阈值的海水二氧化碳分压升高是否会对大西洋鳕幼鱼的游泳运动学特征产生影响。绝大多数被测变量未出现显著差异：12日龄和27日龄的大西洋鳕幼鱼的游泳运动学特征对极端升高的二氧化碳分压具有极强的耐受性。不过，高浓度组培养的幼鱼在12日龄时的垂直转向角度（中位转向角为15°）较对照组（19°）与中等浓度组（19°）更为受限，但这一差异在27日龄幼鱼中并未出现；此外，在27日龄幼鱼中，高浓度组个体的停留时长（中位停留时长为0.28秒）较对照组（0.32秒）出现显著缩短，但这一差异在12日龄幼鱼中未被观测到。上述细微差异的功能与生态学意义尚不明确，因此需要开展进一步研究，以判断其是否具有生态学相关性，亦或是随机误差导致的假阳性结果。