Department of Biology and Centre for Coastal Studies and Aquaculture, University of New Brunswick, Saint John, Canada.
Idaho Department of Fish and Game, Coeur d' Alene, Idaho, United States of America.
PLoS One. 2021 Mar 17;16(3):e0247768. doi: 10.1371/journal.pone.0247768. eCollection 2021.
Larval shortnose sturgeon, reared at 17°C, were subjected to delayed feeding treatments of 0, 5, 10, 15, 18, and 23 days post-yolk absorption to examine effects of food deprivation on growth, survival, swimming activity, and escape capabilities. Starvation affected growth and survival but despite degree of starvation, larvae were able to resume growth and experience high survivorship following feeding. Specific growth rate based on larval dry weight for the period directly following first feeding was highest for the day 15 and 18 delayed feeding treatments. There were no differences in survival between the 0 and 5 day treatments, however survival was reduced to 71.2%, 45.4%, and 28.8% for 10, 15, and 18 day delayed feeding treatments, respectively. Shortnose sturgeon had a point-of-no-return (PNR; 55.7% initiated feeding) at ~19 days (or 42 days post-fertilization) following the full absorption of yolk. Mean percent swimming activity and swimming speeds showed an interaction between delayed feeding treatment and larval age, such that no differences were detected at 1 and 6 days post-yolk absorption, while these swimming behaviors generally increased or spiked as feeding was delayed for 10, 15, and 18 days post-yolk absorption. At 23 days post-yolk absorption, only swimming speed increased for larvae that were denied food for 18 days. While there was an interaction between delayed feeding treatments and age for proportion of larvae exhibiting an escape response, generally, larvae from all feeding treatments exhibited a positive escape response. There were also interactions between delayed feeding treatments and age post-yolk absorption for mean and maximum escape speeds, such that less aggressive escape responses were typically detected the longer larvae were denied food. Our research suggests that larval shortnose sturgeon increase physical activity during periods of starvation to find a food patch while remaining vigilant but maybe not as capable to defend against a predatory attack as fed individuals.
将孵化后 17°C 下饲养的幼龄短吻鲟进行 0、5、10、15、18 和 23 天的延迟摄食处理，以研究摄食不足对生长、存活、游泳活动和逃逸能力的影响。饥饿影响生长和存活，但尽管饥饿程度不同，幼鱼在摄食后能够恢复生长并保持高存活率。首次摄食后直接进行的幼鱼干重特定生长率在 15 天和 18 天延迟摄食处理中最高。0 天和 5 天处理之间的存活率没有差异，但 10 天、15 天和 18 天延迟摄食处理的存活率分别降低至 71.2%、45.4%和 28.8%。短吻鲟在卵黄完全吸收后约 19 天（或受精后 42 天）达到无回头点（PNR；55.7%开始摄食）。平均游泳活动百分比和游泳速度显示出延迟摄食处理和幼鱼年龄之间的相互作用，因此在卵黄吸收后 1 天和 6 天没有检测到差异，而这些游泳行为通常随着卵黄吸收后 10 天、15 天和 18 天的延迟而增加或飙升。在卵黄吸收后 23 天，只有在 18 天未摄食的幼鱼中游泳速度增加。虽然延迟摄食处理和年龄对表现出逃避反应的幼鱼比例存在相互作用，但一般来说，所有摄食处理的幼鱼都表现出积极的逃避反应。延迟摄食处理和卵黄吸收后年龄之间也存在平均和最大逃逸速度的相互作用，因此，幼鱼被剥夺食物的时间越长，通常检测到的逃避反应越不活跃。我们的研究表明，幼龄短吻鲟在饥饿期间增加身体活动以寻找食物斑块，同时保持警惕，但可能不如摄食个体有能力防御捕食者的攻击。
