A study identifies reasons for disparities between regional fish catch and ocean productivity and explores their implications under climate change. Photosynthesis drives marine food webs. However, the differences among fish catch from different marine ecosystems far exceed the differences among regional values in algal production. To identify factors that explain contemporary catch patterns, Charles Stock and colleagues modeled catch patterns using a synthesis of global fishing effort, global fish catch data including small-scale fisheries, and plankton food web estimates derived from a prototype high-resolution global earth system simulation. Large catch differences between heavily fished regions could be explained by an energy-based model that incorporated regional differences in food web structure and energy transfer efficiency, and integrated both benthic and pelagic sources of energy. Algal production did not explain catch patterns by itself. A climate change projection relying on the energy-based model estimated more than 50% shifts in fish catch in some regions by the end of the 21st century under high emissions scenarios. According to the authors, failing to account for the effect of regional variation in food web structure and energy transfer efficiencies could result in incorrect estimates of future catch trends and hinder adaptation to climate change. - Read at PNAS.org
Article #16-10238: “Reconciling fisheries catch and ocean productivity,” by C. A. Stock et al.