Department of Biology, College of Science and Engineering, Western Washington University, Bellingham, WA, United States of America.
Department of Environmental Sciences, College of the Environment, Western Washington University, Bellingham, WA, United States of America.
PLoS One. 2022 Jun 27;17(6):e0270491. doi: 10.1371/journal.pone.0270491. eCollection 2022.
Surf smelt (Hypomesus pretiosus) are ecologically critical forage fish in the North Pacific ecosystem. As obligate beach spawners, surf smelt embryos are exposed to wide-ranging marine and terrestrial environmental conditions. Despite this fact, very few studies have assessed surf smelt tolerance to climate stressors. The purpose of this study was to examine the interactive effects of climate co-stressors ocean warming and acidification on the energy demands of embryonic and larval surf smelt. Surf smelt embryos and larvae were collected from spawning beaches and placed into treatment basins under three temperature treatments (13°C, 15°C, and 18°C) and two pCO2 treatments (i.e. ocean acidification) of approximately 900 and 1900 μatm. Increased temperature significantly decreased yolk size in surf smelt embryos and larvae. Embryo yolk sacs in high temperature treatments were on average 7.3% smaller than embryo yolk sacs from ambient temperature water. Larval yolk and oil globules mirrored this trend. Larval yolk sacs in the high temperature treatment were 45.8% smaller and oil globules 31.9% smaller compared to larvae in ambient temperature. There was also a significant positive effect of acidification on embryo yolk size, indicating embryos used less maternally-provisioned energy under acidification scenarios. There was no significant effect of either temperature or acidification on embryo heartrates. These results indicate that near-future climate change scenarios may impact the energy demands of developing surf smelt, leading to potential effects on surf smelt fitness and contributing to variability in adult recruitment.
海鳟（Hypomesus pretiosus）是北太平洋生态系统中具有重要生态意义的摄食鱼类。作为海滩产卵的专性生物，海鳟的胚胎会暴露在广泛的海洋和陆地环境条件下。尽管如此，很少有研究评估过海鳟对气候胁迫因素的耐受能力。本研究旨在探讨海洋变暖和酸化这两种气候胁迫因素对海鳟胚胎和幼鱼能量需求的交互影响。从产卵海滩收集海鳟胚胎和幼鱼，并将其放入处理盆中，置于三种温度处理（13°C、15°C 和 18°C）和两种 pCO2 处理（即海洋酸化）下，pCO2 分别约为 900 和 1900 μatm。温度升高显著降低了海鳟胚胎和幼鱼的卵黄大小。高温处理下的胚胎卵黄囊平均比常温下水体中的胚胎卵黄囊小 7.3%。幼鱼的卵黄和油球也呈现出同样的趋势。高温处理下的幼鱼卵黄囊比常温下的幼鱼小 45.8%，油球小 31.9%。酸化对胚胎卵黄大小也有显著的正效应，表明在酸化情景下，胚胎会利用更少的母体提供的能量。温度或酸化对胚胎心率均没有显著影响。这些结果表明，未来的气候变化情景可能会影响正在发育的海鳟的能量需求，从而对海鳟的适应性产生潜在影响，并导致成年鱼数量的变化。
