Ocean warming has predictably driven some marine species to migrate polewards or to deeper water, matching rates of environmental temperature change (climate velocity) to remain at tolerable temperatures. Most species conforming to expectations are fish and other strong swimmers that can respond to temperature change by migrating as adults. On the Northwest Atlantic continental shelf, however, many benthic invertebrates’ ranges have instead shifted southwards and into shallower, warmer water. We tested whether these ‘wrong-way’ migrations could arise from warming-induced changes in the timing of spawning (phenology) and transport of drifting larvae. The results showed that larvae spawned earlier in the year encounter more downwelling-favourable winds and river discharge that drive transport onshore and southwards. Phenology and transport explained most observed range shifts, whereas climate velocity was a poor predictor. This study reveals a physical mechanism that counterintuitively pushes benthic species, including commercial shellfish, into warmer regions with higher mortality.

可以预见，海洋变暖驱使一些海洋物种向极地或向更深的水域迁移，使环境温度变化率（气候速度）保持在可接受的温度范围内。符合预期的大多数物种是鱼类和其他坚强的游泳者，它们可以通过成年移民来应对温度变化。然而，在西北大西洋的大陆架上，许多底栖无脊椎动物的范围却向南转移，进入了更浅，更温暖的水域。我们测试了这些“错误的”迁移是否可能是由变暖的产卵时间（物候学）和幼虫运输的时间变化引起的。结果表明，今年早些时候产卵的幼虫遇到了更多的向下气流，有利于风和河水排放，从而推动了陆上和南部的运输。物候和运输解释了大多数观察到的范围变化，而气候速度是一个较差的预测指标。这项研究揭示了一种反常地将底栖物种（包括商业贝类）推入死亡率更高的较温暖区域的物理机制。