Deep‐sea lobster shifts in distribution and population connectivity under future climate change

Abstract

New Zealand scampi ( Metanephrops challengeri ) is an economically important deep‐sea lobster species found between 140 and 640 m on New Zealand’s continental shelf and slopes. Adult scampi are sedentary and population connectivity is mediated by larval dispersion. In this study we use high‐resolution regional marine climate down‐scalings to examine how climate change will impact connectivity and population distribution in medium and high‐emissions future climate scenarios. We find that single generation larval connectivity is dominated by three ‘blocks’ of high connectivity centred on the Campbell Plateau, Chatham Rise and the west coast of the North Island. Connectivity within these ‘blocks’ remains robust under future climate but inter‐block connectivity weakens. The effect of ocean warming was assessed by examining how frequently seafloor temperature exceeded 13°C, a temperature known to cause a rapid decline in scampi health. We find that the Northland and Bay of Plenty fisheries will experience thermal stress by mid‐century followed by the Chatham Rise fishery late‐century. The Campbell Plateau fisheries experience little ocean warming but may be vulnerable to shifts in fishing effort as the northern fisheries become less viable. These results showcase climate change impacts on an important deep‐sea species and how modelling can benefit fisheries and conservation management.

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