Krill remains one of largest underexploited marine resources in the world.
Krills are a group of various zooplankton that generally look like small shrimps. Krill and other zooplankton (free-floating organisms that don’t photosynthesize their own energy) float in the water column and represent a link in the food chain between primary producers (like phytoplankton) and larger animals ranging in size from herring to whales.
One of the largest populations of krill in the world, Antarctic krill, is in the southern ocean. It is here that it plays a role as a keystone species as the main species through which nutrients and energy are transferred to higher trophic levels. The harvesting of this krill is under strict
regulations to ensure there is enough of this krill for higher trophic level organisms, including penguins, whales, and fishes. Its biomass has been difficult to estimate, but the current estimate is near 400 million tonnes. Even with a generous precautionary limit for the ecosystem function, this could be a huge source for the world’s fishmeal and oil needs. However, the habitat of this krill is the sea ice, which is becoming less stable and krill may lose a substantial part of their habitat over the next 100 years.
The major argument for catching more krill as an input into feeds is that its demand as a direct human food is very limited. There have been some previous examples of it being processed into human food in Japan, but this was fairly limited in scope. In contrast, the former USSR in the 1980s, and now Norway currently have large krill fisheries (>100,000 tonnes annually) for the production of fishmeal. Krill are targeted by pelagic and bottom trawl fisheries that use a very fine mesh net. The organisms are so small that this is the only functional way to catch these organisms.
The impediment to these fisheries growth has been a factor of cost so far. Krill meal and oil are too expensive to use as the major constituent of feeds and thus must be supplemental for certain nutritional properties. However, as fish that can be used as food are re-directed more towards this purpose, the cost paid for these fish will rise. Eventually, krill will become a more cost effective feed ingredient, and we’ll be feeding more of our fish with krill. As this increasingly becomes the case, we’ll need to watch the development of these changing ecosystems to ensure we continue to fish with the whole ecosystem in mind.