Acoustic survey finds plenty more fish in the sea

An international team of marine scientists has calculated that the global biomass of fish is 30 times more than previously thought.

Researchers were previously unable to calculate the biomass of so-called mesopelagic fish, because these species only migrate to the ocean surface at night and are good at avoiding nets and fishing gear.

Researchers aboard the 2010 Malaspina Circumnavigation Expedition used acoustic surveys to compile the new estimate.

The findings published in Nature Communications, calculate that there are 3 billion tonnes of mesopelagic fish in the ocean. Their biomass may be increasing because these fish are largely untouched by fisheries, while their main predators, tuna and swordfish, are in decline.

The research, which involved 400 scientists, found the species’ extraordinary biomass must play a key role in the healthy biogeochemical cycles of the oceans.

Read more at University of Western Australia