• Energy Research

Includes BOATSv2 with slight modifications matching the analysis in the Manuscript "Small fish biomass limits the catch potential in the High Seas". It also includes forcing used for the analysis and data and masks necessary for the study and comparison of simulations. Simulations can be run by launching the script MC_run.m .

AbstractClimate change is expected to profoundly affect key food production sectors, including fisheries and agriculture. However, the potential impacts of climate change on these sectors are rarely considered jointly, especially below national scales, which can mask substantial variability in how communities will be affected. Here, we combine socioeconomic surveys of 3,008 households and intersectoral multi-model simulation outputs to conduct a sub-national analysis of the potential impacts of climate change on fisheries and agriculture in 72 coastal communities across five Indo-Pacific countries (Indonesia, Madagascar, Papua New Guinea, Philippines, and Tanzania). Our study reveals three key findings: First, overall potential losses to fisheries are higher than potential losses to agriculture. Second, while most locations (> 2/3) will experience potential losses to both fisheries and agriculture simultaneously, climate change mitigation could reduce the proportion of places facing that double burden. Third, potential impacts are more likely in communities with lower socioeconomic status.

AbstractThe High Seas, lying beyond the boundaries of nations' Exclusive Economic Zones, cover most of the ocean surface and host half of marine primary production. Yet, a tiny fraction of global wild fish catch comes from the High Seas, despite intensifying industrial fishing efforts. The paradoxically small fish catch could reflect economic barriers to exploiting the High Seas ‐ such as the difficulty and cost of fishing in remote ocean parts ‐ or ecological features resulting in a small biomass of commercial fish (10g–100 kg) relative to primary production. We use the coupled biological‐economic model BOATS to estimate contributing factors, comparing observed catches with simulations where: (a) fishing cost depends on distance from shore and seafloor depth; (b) catchability depends on seafloor depth or vertical habitat extent; (c) regions with micronutrient limitation have reduced biomass production; (d) the trophic transfer of energy from primary production to demersal food webs depends on water depth; and (e) High Seas biomass migrates to coastal regions. The dominant factor is ecological: commercial fish communities receive much primary production in shallow waters but less in deep waters, limiting exploitable biomass in High Seas. Other factors play a secondary role, with migrations having a potentially large but uncertain role, while economic factors have smaller effects. We estimate the High Seas hosted 25 of a global 2.8 0.7 Gt biomass in the early 20th century, changing to 47% of a global 1.5 0.4 Gt of commercial fish biomass during the early 21st century. Our results stress the limited potential of High Seas to provide food through wild capture fisheries.