Biomass of Mesopelagic Fish 10 Times Higher Than Originally Thought
According to research completed by the Malaspina Expedition, and analyzed by oceanographer, Xabier Irigoien from AZTI-Tecnalia and KAUST, the biomass of Mesopelagic fish could be ten times higher than it was originally thought.
The expedition, led by Carlos Duarte from the University of Australia Ocean Institute traveled around 36,000 miles taking readings of depths between 200 and 1,000 meters.
Mesopelagic fish are those who thrive in the “twilight zone,” such as lantern fish and cyclothonids. Research has shown that these fish can avoid being caught in trawling nets. Until the expedition’s results, the only method of counting the population of Mesopelagic fish has been via trawling nets.
“Malaspina has provided us the unique opportunity to assess the stock of mesopelagic fish in the ocean. 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.” States Carlos Duarte.
Previous estimates on the biomass of Mesopelagic fish were around one billion tons, with this new research, estimates are around 10 billion.
The study also revealed that throughout the night, these Mesopelagic fish rise to the upper layers in order to feed, returning to the lower layer during the day to avoid predators. This habit means that carbon in the form of feces is transported approximately half of a mile under the water which is further than previously thought.
“Their role [mesopelagic fish] in the biogeochemical cycles of ocean ecosystems and global ocean has to be reconsidered, as it is likely that they are breathing between one percent and 10 percent of the primary production [of carbon] in deep waters,” states Xabier Irigoien.
Biomass of Mesopelagic fish 10 times higher than originally thought.