Scientists from the Ecosystems and Oceanography Division of the Pacific Islands Fisheries Science Center in collaboration with Scientists from the University of British Columbia and NOAA’s Geophysical Fluid Dynamics Laboratory recently published a paper in the journal Climatic Change looking at Climate-induced primary productivity change and fishing impacts on the Central North Pacific ecosystem and Hawaii-based pelagic longline fishery.
This study combined an updated Ecopath with Ecosim (EwE) model for the Central North Pacific with output from a coupled NOAA Geophysical Fluid Dynamics Laboratory climate and biogeochemical model to investigate the likely ecosystem impacts of fishing and climate-induced primary productivity changes. Four model simulations were conducted based on 2 fishing effort and climate scenarios from 2010 to 2100.
The model results showed that small and large phytoplankton biomass decreased by 10 % and 20 % respectively, resulting in a 10 % decline in the total biomass of all higher trophic level groups combined. Study results also showed that climate impacts affected the Hawaii longline fishery, with a 25–29 % reduction in modeled target species yield. These climate impacts on the ecosystem and the fishery were partially mitigated by a drop in fishing effort, where scenarios with a 50 % reduction in fishing effort partially restored longline target species yield to current levels, and decreased longline non- target species yield. These model results suggested that a further reduction in fishery landings mortality over time than the 2010 level may be necessary to mitigate climate impacts and help sustain yields of commercially preferred fish species targeted by the Hawaii longline fishery through the 21st century.
The full paper can be read here