KRILL BIOMASS STUDY IN ANTARTICA
The Institute of Marine Research (Norway) has been monitoring the krill biomass since 2011, covering an area of 60,000 square kilometers in Antarctic waters to estimate abundance.
The Norwegian Institute of Marine Research (IMR) has released its findings after 10 years of surveying the krill biomass in Antarctica. The science, based on data from acoustics and trawl surveys confirms the high concentration of krill in the area around the Antarctic Peninsula. The comprehensive analysis will be a cornerstone for krill management in The Commission for Conservation of Antarctic Marine Living Resources (CCAMLR)
Antarctic krill are small crustaceans which swim in the Southern Ocean. Species of krill occur in most oceans, but it is only around Antarctic that it swims in dense swarms. The species form one of the biggest biomass swarms on Earth.
IMR started its annual krill surveillance cruises in 2011, monitoring Subarea 48.2 off the South Orkney Islands. Aker BioMarine vessels have served as research platforms during the ongoing study, equipped with scientific trawls and echo sounders, covering a 60,000 square kilometer area over the 10-year-period.
“The results from the first 10 years of monitoring gives us new data which confirm that the area we operate in has consistently high densities of krill . To us, this means that the precautionary approach taken by industry and regulators is sustainable and ensures that the fishery does not drive any change in the krill population or in the Antarctic ecosystem,” says Pål Skogrand, VP Policy and Impact, Aker BioMarine.
Krill survey methods
The monitoring is a mandatory part of the Norwegian license to access the krill fishery in Antarctica’s Southern Ocean. The surveys were conducted between late January and early February each year.
Findings from the IMR survey
- Estimated mean density for the entire survey area ranged from a low of 1.4 million tons in 2017 to a high of 7.77 million tons in 2012.
- The survey results show clear annual variability in krill density but no significant trends.
- After the first 10 years monitoring, IMR Norway concludes that the krill biomass in the South Orkney waters is consistently high – among the highest concentrations in the Scotia Sea.
“The current paper sums up the results from a fruitful collaboration between scientists and the industry. Among other results, we show that the catch level in the CCAMLR sub-area 48.2 is precautionary according to the harvest control rule which is agreed by CCAMLR. Of course, the existing harvest control rule is a compromise based on historic krill catches and it has been worked a long time in CCAMLR to get a more flexible management system in place taking into account risk of the fisheries to krill-dependent predators. The basis for such a feedback management system and how it will be implemented has not been agreed upon, but regular krill monitoring is almost certainly going to play an essential role to inform such a management system”, says Georg Skaret, Researcher, Institute of Marine Research.
“We have shown that a good collaboration between scientists and the industry and the option of using industry platforms for the krill monitoring increases the opportunity of obtaining high-quality monitoring data in these remote areas where scientific monitoring is expensive and logistically challenging. The data we have collected are now available for use in further studies addressing topics relevant for the management of the krill”, Skaret continued.
Collaboration is key to a sustainable fishery
The Antarctic krill fishery is considered to be one of the most sustainable reduction fisheries today due to the precautionary harvesting limits and management. In 2022, a science paper, published in Fisheries Management and Ecology, concluded that the Antarctic krill fishery is the cleanest fishery in the world in terms of it’s extremely low bycatch rate.
“As krill is the key species in the Antarctic ecosystem regular monitoring is important, which is why we will continue to support up-to-date biomass estimations every year. It is in our industry’s best interest to ensure that krill is well managed, and so far, science indicates that CCAMLR is doing a pretty good job” says Skogrand.