As global oceans continue to warm and deoxygenate, it is expected that marine ectotherms will reduce in body size resulting from the interactive effects of temperature and dissolved oxygen availability. A temperature-size response describes how wild populations of ectothermic species grow faster and reach a smaller size within warmer temperatures. While temperature-size responses are well observed in marine ectotherms, the mechanisms underpinning such a reduction in body size remain debated. Here, we analyse the relative influence of temperature, dissolved oxygen concentration, and geographic location (which encompasses multiple latent variables), on the maximum body length of four fish, one crustacean, and one squid species, which inhabit shallow to deep sea (1000 m) New Zealand waters across a temperature gradient of 1.5 to 18 °C. We found that all study species displayed a temperature-size response, with the strongest response exhibited by the largest species, hoki (Macruronus novaezelandiae). We also found that temperature was more important than dissolved oxygen concentration in determining maximum body length, as dissolved oxygen levels were at or near saturation in the study area. Our results suggest that larger-bodied species may experience the strongest temperature-size responses, and support expectations from the gill-oxygen limitation theory (GOLT) and the oxygen and capacity limited thermal tolerance (OCLTT) concept that increases in oxygen demand may be size- and temperature-dependent, thus driving a reduction in maximum body length of marine ectotherms with warming.

随着全球海洋继续变暖和脱氧，预计由于温度和溶解氧可用性的相互作用，海洋变温动物的体型将减小。温度大小响应描述了变温物种的野生种群如何在温暖的温度下更快地生长并达到更小的尺寸。虽然在海洋变温动物中可以很好地观察到温度大小的反应，但支持这种体型减小的机制仍然存在争议。在这里，我们分析了温度、溶解氧浓度和地理位置（包括多个潜在变量）对栖息于浅海至深海的四种鱼类、一种甲壳类动物和一种鱿鱼的最大体长的相对影响（1000 m) 新西兰水域的温度梯度为 1.5 至 18 °C。长角新星藻）。我们还发现，在确定最大体长方面，温度比溶解氧浓度更重要，因为研究区域的溶解氧水平处于或接近饱和状态。我们的研究结果表明，体型较大的物种可能会经历最强的温度响应，并支持来自鳃氧限制理论 (GOLT) 和氧和容量限制热耐受性 (OCLTT) 概念的预期，即需氧量增加可能是体型- 和温度相关，因此随着变暖导致海洋变温动物的最大体长减少。