Mapping Global Fisheries Patterns and Their Consequences

Despite increasing reports of fisheries collapses world wide, investigations of the effects of fishing on the global marine environment have been constrained by the paucity of fisheries landings data on suitable spatial scales. Working to overcome this, we have developed new databases and approaches that demonstrate basin-scale reductions in biomass and landings due to intensifying fishing effort, and equally disturbing, reductions in the size and trophic level of species landed. Starting with international, regional, and national datasets acquired from many sources, we have collated global datasets and mapped fisheries landings from 1950 to the present to a system of 30-min spatial cells. To facilitate this, we have also developed databases describing the global distribution of all fished species, as well as the fishing patterns/access rights of all fishing nations. Our methods effectively “reverse engineer” landing records to approximate the original catch patterns. The process includes disaggregation of records bundled as ‘miscellaneous fishes’ and the “de-flagging” of reflagged fishing vessels. Our results have revealed rich evidence of dramatic change, which includes declines in catch, reductions in fish length, and a general reduction in the tropic level of landings. The analyses have also uncovered major problems in ‘official’ datasets, including significant over-reporting that has masked decades of decline. As we proceed, we remain committed to making our data available through our Web pages at www.seaaroundus.org.