What is the news?
As per report published in Nature Climate Change, Antarctic Krill started shifting southwards closer to poles due to warming of the ocean.
About Antarctic Krill
- The Antarctic krill is an extremely common, pelagic crustacean native to the waters surrounding Antarctica and is one of the most important prey species near the bottom of Southern Ocean food webs.
- It is a small, swimming crustacean that lives in large schools, called swarms. Sometimes reaching densities of 10,000–30,000 individual animals per cubic metre.
- Moreover , Krill feed on phytoplankton, microscopic, single-celled plants that drift near the ocean’s surface and live off carbon dioxide and the sun’s rays. Meanwhile , they in turn are the main staple in the diets of literally hundreds of different animals, from fish, to birds, to baleen whales.
- Krill is caught to make fishmeal or oil that is sold as a human health supplement.
- Diet and feeding : Antarctic krill are mainly herbivorous
- Breeding :Female Antarctic krill lay up to 10,000 eggs at a time, sometimes several times a season.
- Physical description : With their large black eyes, krill are mostly transparent, although their shells have a bright red tinge from small pigment spots. Their digestive system is usually visible and this is often a vivid green from the pigment of microscopic plants they have eaten. Adult Antarctic krill are approximately six centimetres in length and weigh over a gram.
- Population trend : stable
- Movement patterns : not migrant as per IUCN
- IUCN Status of Antarctic Krill (Euphausia Superba) – Least Concern
- Impacted by climate change and may result in a reduced habitat range
- The reproductive output and recruitment success of krill has been related to the extent, timing and duration of winter sea ice cover. The underside structure of sea ice provides a nursery ground for overwintering krill larvae and a substrate for algae which are their food. Extensive winter sea ice promotes strong spring phytoplankton bloom when retreating in spring which fuels the adults’ reproductive output for their summer spawning season
- Krill growth has also been observed to decrease above a temperature optimum of 0.5 degrees Celsius
- Even ,their early developmental stage of krill is vulnerable to increased levels of CO2.
How Climate Change impacting Antarctic Krill movement ?
- It is often predicted that species move towards the poles as the climate warms. It’s already happening with krill. Besides , the warming of climate is becoming increasingly unhealthy for krill to reproduce.
- Moreover, this movement of krill represents climate change through warming of waters.
- As per the scientists, waters in the Southwest Atlantic warmed 1 degree Celsius over the past 90 years, which is home to most krills.
- Because of this, krill are concentrating into a narrowing band towards the coast of Antarctica.
Impact of Antarctic Krill movement :
- As per the British Antarctic Survey (BAS), krill are among the most abundant creatures on Earth with an estimated total of 780 trillion, excluding larvae and eggs.
- Besides, Krills are food for whales, seals, penguins and other predators.
- Meanwhile , in this study, based on catch data from 1926-2016, also revealed that the average krill getting bigger apparently because young krill were less likely to survive. Moreover , Krills can live for about 6 years in waters around the frozen continent.
- Due to this , impact on food chain in the region such as mass shifting of krills are depleting resources for the penguins and whales. Moreover, as the krills are shifting southwards, they are also caught by industrial trawlers.
- Trawlers are large boat that uses a wide, cone-shaped net to catch fish.
- Main populations of the shrimp-like crustaceans which form vast swarms, have also moved about 440 km south in the past 90 years as per the report.
About CCAMLR :
The Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) was established by international convention in 1982 with the objective of conserving Antarctic marine life. This was in response to increasing commercial interest in Antarctic krill resources, a keystone component of the Antarctic ecosystem and a history of over-exploitation of several other marine resources in the Southern Ocean.