Not-So-Plenty O’Fish: Skewed Catch Data May Threaten Global Fish Populations

0

Since the mid-’90s, the Food and Agriculture Organization has been reporting a decline in the quantity of ocean fish caught around the world. But a new series of catch reconstructions by Nature.com indicates that we may have grossly underestimated the real values involved—and the impact they have on the health of the ocean and the planet.

The problem with the traditional data sets is twofold: first, the total number of fish actually caught and processed was much higher than recorded by the FAO. Secondly, the subsequent declines appear to be much steeper than originally reported. Taken together, these two factors reflect a grim reality: the oceans have lost many more fish than previously believed, and current populations may be far less sustainable than assumed due to the smaller number of remaining fish to catch.


Catch Reconstruction Data 1950-2010 (Nature.com)

Catch Reconstruction Data, 1950-2010 (via Nature.com)

Some Very Fishy Numbers

The difference in the original FAO estimates and the Nature reconstructions lies largely in how fishing is approached on an industrial scale in the modern world, the actual amount of fish considered “landed” (i.e., caught and processed), and allowances made for discards, quotas, and changes in fishing areas to allow populations to rebuild. As described in the abstract of the study, researchers found:

Fisheries data assembled by the Food and Agriculture Organization (FAO) suggest that global marine fisheries catches increased to 86 million tonnes in 1996, then slightly declined. Here, using a decade-long multinational ‘catch reconstruction’ project covering the Exclusive Economic Zones of the world’s maritime countries and the High Seas from 1950 to 2010, and accounting for all fisheries, we identify catch trajectories differing considerably from the national data submitted to the FAO. We suggest that catch actually peaked at 130 million tonnes, and has been declining much more strongly since.

This decline in reconstructed catches reflects declines in industrial catches and to a smaller extent declining discards, despite industrial fishing having expanded from industrialized countries to the waters of developing countries. The differing trajectories documented here suggest a need for improved monitoring of all fisheries, including often neglected small-scale fisheries, and illegal and other problematic fisheries, as well as discarded bycatch.

While calculating total populations with 100% accuracy may not yet be possible, reconstructing these catches and more carefully analyzing the raw data is essential to developing a responsible approach to aquaculture and global resource management. This is especially important in the wake of a 2016 projection by the Ellen MacArthur Foundation indicating plastic waste in the ocean will outweigh the world’s ocean-dwelling fish by 2050.

About Author

A published author and longtime blogger, Claire Monserrat Jackson is a lifelong writer with a passion for the environment, social justice, and the arts. When not behind the keyboard, she can usually be found wandering through a museum, gaming with friends, or exploring nature and startling the wildlife of her native Ohio.