The Little Things That Count

Fisheries don’t necessarily go after the species highest in the food web first, a new study says.

Fishermen are thought to initially target top predators and then move lower in the food web, perhaps because the higher-ranking species bring in more money. But after analyzing records dating back to the 1950s, researchers couldn’t find a link between high food web position and increased revenues.

Instead, the average yearly revenue for the lowliest species was 39 percent greater than that of species high in the food web, the team reports in the Proceedings of the National Academy of Sciences. For example, shrimp and abalone tended to be sold at high prices even though they aren’t top predators.

The team did find a link between fishing patterns and the amount of effort needed to catch an organism. Species targeted in 2004 lived at depths about 35 percent greater than species fished in the 1950s, suggesting that fishermen snapped up the shallow-ranging animals first because they cost less to catch. – Roberta Kwok

Source: Sethi, S.A., Branch, T.A. & R. Watson. 2010. Global fishery development patterns are driven by profit but not trophic level. Proceedings of the National Academy of Sciences DOI: 10.1073/pnas.1003236107.

Image © negaprion,