Impacts Of Increased Sea Surface Temperatures On The California Halibut, Paralichthys Californicus (Technical Report)

The California halibut (Paralichthys californicus) has a valuable commercial and recreational fishery in California. Increasing ocean temperatures resulting from climate change could have significant implications on the geographic range and ecology of this species, impacting fisheries and fisheries management approaches. In this study, a quantitative compilation of values from 11 climate models were used to project increases in sea surface temperature (SST) in the near future (2021-2050). Future projections in this report follow the business as usual (BAU) climate scenario, using predicted temperature increases if there is no reduction in greenhouse gas (GHG) emissions from current levels. Results show increases in warming along the southern extent of the species range, exceeding the temperature threshold in which California halibut eggs arrest cell development (24 oC). These results could have future recruitment implications. Even if adult fish are able to tolerate these increased temperatures, they may not be reproductively successful, which could result in a decline in fish along the southern trailing edge of the species range. Warmer temperatures are also projected along the coast of California. Future annual average temperatures range between 20-22oC within California Department of Fish and Wildlife’s Southern stock, which is outside of the preferred egg temperature threshold, potentially impacting recruitment in this area as well. Fisheries management agencies should consider likely impacts from climate change and create management plans that are climate- ready and adaptive.