Antarctic krill fishery has lowest bycatch of trawl fisheries globally

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A recent study1 measured the amount of bycatch from Antarctic krill fishery. According to the study, total catch of Antarctic krill doubled between 2010 and 2020 from 200,000 tons to 450,000 tons. Total annual bycatch averaged 6.3 tons by continuous pumping trawlers and 19.2 tons by conventional trawlers during the same ten year period. According to the researchers bycatch from the Antarctic krill fishery was lower than other trawl fisheries globally.

One of the reasons for this may be that trawlers target krill “when aggregated in swarms large enough to maintain optimal factory productivity that seemingly contain few other species,” the researchers write.

“Overfishing is a big problem across the world’s fisheries,” says Pål Einar Skogrand, vice president of policy and impact for Aker BioMarine (Oslo, Norway). “However, this new data is very positive and demonstrates how krill fisheries can operate sustainably by ensuring a healthy population of target as well as non-target species in its fishing area. The krill fishery’s low exploitation rate of the biomass, in conjunction with these new findings on the low bycatch, proves that the krill fishery operates well within ecosystem boundaries and is becoming a real model fishery on a global level.”

Aker, for its part, utilizes a patented technology called Eco Harvesting that ensures efficient and safe harvesting by keeping the trawl submerged for long periods of time rather than hauling up to ten times per day like traditional trawlers. Hauling is high risk for bycatch of non-target species and entanglement with birds, specifically when the trawl is exposed. Less hauling minimizes this risk, says Aker. The firm’s system is also fitted with a mammal exclusion device that is monitored by acoustic sensors to ensure mammals do not enter the trawl.

“At Aker BioMarine, our Eco-Harvesting technology helps us harvest krill in a sustainable and environmentally friendly way,” says Frank Grebstad, senior vice president of vessel operations at Aker BioMarine. “The mammal exclusion device within our Eco-harvesting technology has most definitely played a role in the low bycatch numbers as it helps reduce the risk of by-catch. Our operating model on fishing ground allows us to fish the high-density krill aggregations, this is key to our strong bycatch record. If we were to chase the lower density krill swarms in Antarctica there would certainly be more bycatch of other species in the mix and the krill fishery would not be such a clean fishery.”

Reference

1. Krafft BA, Lowther A, and Krag LA, Bycatch in the Antarctic krill (Euphausia superba) trawl fishery, Fish Manag Ecol. 2022 DOI: 10.1111/fme.12607