Having suffered a mini stock collapse in 2015-2016, Barents Sea capelin recovered quickly in 2016-2017. This quick recovery was most likely due to good recruitment and feeding conditions. The ban on capelin fishery was therefore lifted for 2018.
The stock of cod, one of capelin's main predators, declined slightly after a peak in 2013 due to a decrease in large and old fish. Its spatial distribution has extended to the north and northeast in recent years, where the cod put increased predation pressure on alternative prey. Large cod and haddock dominated the 2017 cumulative biomass of demersal fish, estimated at 4.2 million tonnes. For pelagic fish, the number was 3.7 million tonnes, close to the long-term mean.
The Barents Sea has experienced dramatic changes over recent decades. The year 2016 was anomalously warm, especially in the eastern area, where temperatures were around five degrees above the long-term mean. With high air and water temperature, especially in the west, 2017 could also be characterized as a warm, though generally colder than 2016.
There was record-high storm activity throughout most of 2017, but larger than normal proportion of easterly winds weakened the inflow of Atlantic water in spring and summer. The area covered by Atlantic water was slightly reduced, though plankton-rich water masses from the Atlantic still provided good feeding conditions for planktivorous fish like capelin and various juveniles. In 2017, most juveniles had high growth rates, and those of certain species were the largest observed in the time- series.
WGIBAR's job is to discuss and record such observed changes in the ecosystem of the high-latitude Barents Sea. The group's fifth meeting this year was held in the Norwegian town of Tromsø in early March and was attended by 21 scientists from both Russia (PINRO) and Norway (IMR, the Arctic University of Norway, the Norwegian Polar Institute and the Norwegian Institute for Nature Research (NINA). The experts represented a range of disciplines from oceanography and stock assessment to sea birds, marine mammals, and plankton.
Alongside changes in temperature and fish trends, the group also looked at marine litter in the sea area. After analysing data from visual observations on the surface and trawls in the pelagic and sea bottom zones, the indications were of a relatively low amount of litter, including macro plastic.
Photo: Erik Mandre, Shutterstock