Healthy Planet Marine Studies Initiative

Bloom of the Jellyfish

Huge spikes in jellyfish numbers cause mayhem for fishermen.

Photo: Volvox

HUGE SPIKES IN JELLYFISH NUMBERS cause mayhem for fishermen, clogging their nets and wasting their effort. These “blooms” may stem from changing climate and ocean conditions, as well as overfishing of forage fish (sardines, anchovies, herring and the like). These tiny fish normally keep jellies in check by competing for the same food. When jellyfish populations explode, they divert protein across the food web in the way a “roundabout” diverts cars to multiple routes, say OSU researcher James Ruzicka and postdoctoral scholar Kelly Robinson. Forage fish, on the other hand, move protein up the web more efficiently, creating an “energy expressway.” Jellies, they argue, should be part of fisheries management strategies.