Center for Marine Biodiversity and Conservation

Climate change impacts are projected to shift the distribution and abundance of global fisheries, affecting revenues and livelihoods worldwide (Barange et al., 2018; Lam et al., 2016). The creation of climate-resilient fisheries requires knowledge of how culturally and economically valuable species will be impacted by rising sea surface temperatures, ocean deoxygenation, and climatic variability. Two Western Pacific fisheries, the Pacific bluefin tuna (PBF; Thunnus orientalis) and Japanese anchovy (JA; Engraulis japonicus), may be particularly vulnerable to the impacts of climate change due to overfishing, sub-tropical spawning grounds, and declining prey availability (FAO, 2020; ISC, 2020). Chasing catch may become the new reality for commercial fleets around the world as PBF and JA inhabit new waters away from historic fishing grounds. In order to promote sustainable management of major global fisheries, policymakers must have the best tools and information available for how climate change will affect fisheries distribution and abundance through the 21st century.

This study is aimed at improving the scientific basis for creating fisheries that are resilient to climate change by using climate change projections, species-specific life history traits, and ecological information to project potential fish stock distribution in response to changing coastal and oceanic conditions. Current projections focus on the use of suitable thermal habitat as a proxy for future species distribution and abundance (Morley et al., 2018). The aim of this study is to improve on these projections by evaluating the potential effects of changes in ocean mixing, nutrients, and other factors in addition to temperature as well as by incorporating information on how the target species (PBF and JA) are likely to respond to these changes using life history characteristics. 

Based on a decision tree provided by the Environmental Defense Fund, climate change is expected to impact every life stage of PBF and JA and centered around changes in sea surface temperature, ocean deoxygenation, and climatic variability. Future abundance of both species’ hinges on the survival of larval stages, recruitment success, and conservation measures to prevent the depletion of young age classes. Northward shifts in distribution are anticipated for both species into the next century, raising concerns about future international management. The entrance of new players into the PBF and JA fisheries may require international agreements based on the shift in distribution of each stock. International cooperation and adaptive management measures must be adopted by fisheries management entities to maintain productive fisheries that continue to generate social and economic benefits associated with PBF and JA.