Climate change is causing shifts in biogeography of marine species, towards higher latitude, deeper waters, or following local temperature gradients. Such species distribution changes are affecting global fisheries through increasing the dominance of warmer-water preferred species as ocean temperature increases. Previous modeling analyses projected that climate-induced changes in seafood availability would affect the entire seafood chain. However, observed climate impacts on seafood retailers and consumers have rarely been demonstrated. Seafood restaurants usually rely on the supply of locally caught species, and thus the impacts of changing catches on the food they serve, and consequently on their diners, may be reflected in their menus. In this study, 362 restaurant menus from Vancouver, British Columbia, Canada, were collated and analyzed over four different time periods (1880–1960, 1961–1980, 1981–1996, and 2019–2021). Moreover, 148 present-day menus from two other cities north (Anchorage, AK, USA) and south (Los Angeles, CA, USA) of Vancouver were also collected. An index, herein called Mean Temperature of Restaurant Seafood (MTRS), was calculated from the average temperature preference of the species of seafood identified in the menus for each time period or location. Overall, the MTRS of menus from Vancouver increased from 10.7 ± 0.7 °C to 13.8 ± 1.0 °C (95% confidence intervals) between 1888–1960 and 2019–2021. Present-day MTRS was among the highest in Los Angeles (16.5 ± 1.7 °C) and lowest in Anchorage (9.6 ± 1.0 °C). The temporal and spatial variations in MTRS are significantly related to observed patterns of average sea surface temperature and the Mean Temperature of the Catch. This suggests that restaurant menus may be used as a complementary information source regarding changes in marine ecosystems and fisheries and the seafood sector’s responses to these changes. This study also highlights the value of using unconventional information sources and their applications in the detection of climate impacts on oceans and their dependent human communities.

气候变化正在导致海洋物种的生物地理学向更高纬度、更深水域或随着当地温度梯度发生变化。随着海洋温度的升高，这种物种分布变化正在通过增加温暖水域首选物种的优势来影响全球渔业。先前的建模分析预测，气候引起的海产品供应变化将影响整个海产品链。然而，观察到的气候对海鲜零售商和消费者的影响很少得到证明。海鲜餐厅通常依赖于当地捕获的物种的供应，因此改变捕捞量对其所服务的食物以及因此对他们的食客的影响可能会反映在他们的菜单中。在这项研究中，来自加拿大不列颠哥伦比亚省温哥华的 362 家餐厅菜单，在四个不同的时间段（1880-1960、1961-1980、1981-1996 和 2019-2021）进行了整理和分析。此外，还收集了来自温哥华北部（美国阿拉斯加州安克雷奇）和南部（美国加利福尼亚州洛杉矶）的另外两个城市的 148 份现代菜单。此处称为餐厅海鲜平均温度 (MTRS) 的指数是根据每个时间段或位置的菜单中确定的海鲜种类的平均温度偏好计算得出的。总体而言，温哥华菜单的 MTRS 在 1888-1960 年和 2019-2021 年间从 10.7 ± 0.7 °C 增加到 13.8 ± 1.0 °C（95% 置信区间）。目前的 MTRS 在洛杉矶是最高的 (16.5 ± 1.7 °C)，在安克雷奇 (9.6 ± 1.0 °C) 是最低的。MTRS 的时空变化与观测到的平均海面温度和渔获物平均温度的模式显着相关。这表明餐厅菜单可以用作关于海洋生态系统和渔业变化以及海产品部门对这些变化的反应的补充信息来源。这项研究还强调了使用非常规信息源及其在检测气候对海洋及其依赖的人类社区影响方面的应用的价值。