Data from: No effect of elevated carbon dioxide on reproductive behaviors in the three-spined stickleback

Ocean acidification, the reduction in ocean pH resulting from
anthropogenic emissions of carbon dioxide (CO2), has been predicted to
alter the behavior of fishes. During experimental exposure to CO2
concentrations projected for the year 2100 (~1000 µatm), fish have been
reported to display disturbances in activity, learning, behavioral
lateralization, and even attraction to predator cues. Reproductive
behaviors have received far less attention, despite an intensive research
effort on ocean acidification and its ecological importance. Here, we
investigate whether elevated levels of CO2 affect reproduction in breeding
pairs of the three-spined stickleback, Gasterosteus aculeatus, a model
species in behavioral, evolutionary ecology, and environmental toxicology.
We found that males under both present day levels (400 µatm) and future
levels (1000 µatm) of CO2 developed normal sexual ornaments, pursued
normal nest building activities, exhibited similar levels of courtship
behaviors and displacement fanning, and had the same mating probability.
Moreover, fanning behavior during the paternal care period followed what
is expected for the species for males from both treatments, and there was
no effect of treatment on the numbers of offspring produced. This study is
the first to investigate the effect of elevated CO2 on the complete
breeding cycle in detail, studying an array of highly fitness-relevant
traits. Our study showing surprising resilience of fish reproduction is an
important contribution in order to realistically predict the impacts of
future ocean acidification.

海洋酸化（Ocean acidification）是指人为排放二氧化碳（carbon dioxide, CO₂）导致的海水pH值降低，此前学界已预测其会改变鱼类的行为模式。当实验中鱼类暴露于预测的2100年二氧化碳浓度（约1000微大气压）环境时，已有研究报道其会出现活动异常、学习障碍、行为侧化（behavioral lateralization）紊乱，甚至会被捕食者线索吸引。尽管当前针对海洋酸化及其生态重要性的研究已较为深入，但繁殖行为相关的探究却相对匮乏。本研究以行为学、进化生态学及环境毒理学领域的模式物种——三刺棘鱼（Gasterosteus aculeatus）的繁殖配对个体为研究对象，探究二氧化碳浓度升高是否会对其繁殖过程产生影响。研究结果显示，处于当前（400微大气压）与未来（1000微大气压）二氧化碳浓度环境下的雄性三刺棘鱼，均能发育出正常的第二性征，开展正常的筑巢行为，展现出相似水平的求偶行为与驱扇行为（displacement fanning），且交配概率无显著差异。此外，两种二氧化碳浓度处理组的雄性亲鱼，其育幼期的驱扇行为均符合该物种的典型模式，且处理组对后代产出数量无显著影响。本研究首次详细探究了二氧化碳浓度升高对鱼类完整繁殖周期的影响，涵盖了一系列与适合度（fitness）高度相关的性状。本研究揭示了鱼类繁殖具备出人意料的恢复能力，这对于精准预测未来海洋酸化的生态影响具有重要的学术贡献。