Specialists from the Australian Scientific and Applied Research Association (CSIRO) found that fluctuations in the krill population — small marine planktonic crustaceans — are due to a changing global climate and are directly related to an increase in the number of whales in the southern hemisphere. The report, dedicated to his discovery, scientists have published in the scientific journal Global Change Biology.
“The results obtained by our group underline the importance of preserving and increasing krill populations, which is directly related to the restoration of the number of whales in the waters of our oceans. Small crustaceans are one of the main sources of food for huge marine mammals, so the obvious idea was to link possible climate changes affecting the population krill, with an increase in its population, as well as a change in the number of whales, “explains CSIRO senior researcher Viv Tallok, who led the study.
According to Tullock, this is the first case in science when researchers were able to directly link the effects of climate change to fluctuations in the amount of krill and its subsequent impact on the whale population. “Whales, especially blue and southern smooth whales, as well as fin whales, are threatened because they lack food in the Atlantic and Indian oceans. And the numbers of krill are falling as these crustaceans become too hot and they leave these places: over the past 90 years, the majority of their populations have migrated an average of 440 km from their usual habitats, “says Tallock.
A computer model created by CSIRO staff for assessing risks to ecosystems was used to predict growth variations in the krill population. According to Eva Plagani, a CSIRO researcher, the study showed how environmental change, in particular, rising ocean temperatures could affect the increase in the numbers of krill and whales. “Our modeling takes into account such complex factors, the natural growth rate of the whale population, the relationship between species development and water temperature, and the dependence of species on the fishery,” explains Plagani.
According to scientists, climate change, especially strongly pronounced in high latitudes, including in Antarctic waters, can lead to a significant reduction in the whale population and even local extinction of some of their species by the year 2100.
Krill is the collective name for small marine planktonic crustaceans of commercial sizes (from 1 to 6.5 cm), forming clusters in the surface water layers of temperate and high latitudes of the oceans of both hemispheres.