Anthropogenic induced climate change is predicted to increase the thermal variability in coastal waters, which can have strong physiological effects on individuals and populations of marine ectotherms. The magnitude and direction of these thermal effects varies depending on species, life stage, biogeography, habitat and season. This study aimed to compare the thermal tolerance of a range of juvenile fish and adult macro-invertebrates from intertidal and estuarine habitats in a warm-temperate, thermally variable region on the south-east coast of South Africa. Seasonal variability in thermal tolerance was compared between species, taxonomic groups, biogeographical distribution and habitat affinity and related to existing and projected water temperature data to gauge the local vulnerability of each species. Critical thermal maximum (CT_max), critical thermal minimum (CT_min), thermal breadths and scopes, and the thermal safety margins of each species were quantified. The greatest differences in thermal tolerance patterns were based on taxonomy, with macro-invertebrates having broader thermal tolerance compared to fish, with the exception of the Cape sea urchin, in both summer and winter. Relatively narrow lower breadths in tolerance and safety margin values for transient juvenile sub-tropical and temperate fish species from the intertidal rocky low-shore habitat were observed in both summer and winter. This indicates that these fish species and the Cape sea urchin may be more vulnerable to projected increases in cold temperature (upwelling in summer) than warm temperature variability in this warm-temperate region if they are unable to seek thermal habitat refuge.

据预测，人为诱发的气候变化会增加沿海水域的热变异性，这会对海洋外热个体和种群产生强烈的生理影响。这些热效应的大小和方向取决于物种，生命阶段，生物地理，栖息地和季节。这项研究旨在比较南非东南沿海一个温带，热变区中潮间带和河口栖息地的一系列幼鱼和成年大型无脊椎动物的耐热性。比较了物种，分类学组别，生物地理分布和栖息地亲和力之间的热耐受性的季节性变化，并与现有和预计的水温数据相关，以衡量每种物种的局部脆弱性。临界热最大值（CT_最大值），临界热最小值（CT_最小值），热广度和范围以及每种物种的热安全裕度进行了量化。在耐热性模式上的最大差异是基于分类学的，在夏季和冬季，大型无脊椎动物比鱼类具有更宽的耐热性，但海角海胆除外。在夏季和冬季，观察到潮间带岩石低岸生境的过渡性亚热带和温带鱼类的耐受性和安全裕度值的宽度相对较窄。这表明，如果这些鱼类和海角海胆无法寻找庇护所，他们可能比这一温带地区的温升温度变化更容易受到预计的寒冷温度（夏季上升）的影响。