When the phrase “there are plenty more fish in the sea” is employed, it’s usually to serve as a balm after a relationship goes sour. But in this case, we mean literal fish.

Image source: Bruno de Giusti/Wikimedia

Image source: Bruno de Giusti/Wikimedia

A new study from researchers with the Malaspina Expedition, managed by the Spanish National Research Council, found there could be 10 times more fish mass in the ocean than previously estimated.

According to a release about the research published in the journal Nature Communications, 1,000 million tons of fish had been estimated prior to the study. The researchers on the expedition believe the numbers could be far more due to acoustic observations they made in the mesopelagic ocean zone at depths between 200 to 1,000 meters deep. This type of fish comes up toward the upper layer in the ocean to feed and swims deeper at night.

Such a difference in estimated biomass has large implications for what researchers know about various factors in the ocean environment.

“The fact that the biomass of mesopelagic fish (and therefore also the total biomass of fishes) is at least 10 times higher than previously thought, has significant implications in the understanding of carbon fluxes in the ocean and the operation of which, so far, we considered ocean deserts,” expedition lead Xabier Irigoien, a researcher from AZTI-Tecnalia and KAUST in Saudi Arabia, said in a statement.

This fish was captured during Malaspina Expedition circumnavigation between Auckland and Honolulu. (Photo credit: Spanish National Research Council/JOAN COSTA)

This fish was captured during Malaspina Expedition circumnavigation between Auckland and Honolulu. (Photo credit: Spanish National Research Council/JOAN COSTA)

“Mesopelagic fish accelerate the flux for actively transporting organic matter from the upper layers of the water column, where most of the organic carbon coming from the flow of sedimentary particles is lost,” Irigoien added. “Their role in the biogeochemical cycles of ocean ecosystems and global ocean has to be reconsidered, as it is likely that they are breathing between 1 and 10 percent of the primary production in deep waters.”

The expedition traveled 32,000 nautical miles as it circumnavigated the globe between the latitudes 40°N and 40°S. Observations were taken during the daytime hours.

“Malaspina has provided us the unique opportunity to assess the stock of mesopelagic fish in the ocean,” researcher Carlos Duarte with the Spanish National Research Council said in a statement. “Until now we only had the data provided by trawling. It has recently been discovered that these fishes are able to detect the nets and run, which turns trawling into a biased tool when it comes to count its biomass.”

Featured image via Shutterstock.

(H/T: Science Daily via Reddit)

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