ARTHOPODS
(Krill)
Vocabulary
krill:shrimp-like planktonic crustaceans; major source of food for e.g. baleen whales.
Swimmerets: One of the paired abdominal appendages of certain aquatic crustaceans, such as shrimp, lobsters, and isopods, that function primarily for carrying the eggs in females and are usually adapted for swimming. Also called pleopod.
Herbivore: An animal that feeds on plants.
Invertebrate: animal species that do not develop a vertebral column.
Bentheuphausia ampblyops: found living in deeper waters (below 3,000 feet).
Swimmerets: One of the paired abdominal appendages of certain aquatic crustaceans, such as shrimp, lobsters, and isopods, that function primarily for carrying the eggs in females and are usually adapted for swimming. Also called pleopod.
Herbivore: An animal that feeds on plants.
Invertebrate: animal species that do not develop a vertebral column.
Bentheuphausia ampblyops: found living in deeper waters (below 3,000 feet).
Classification
Krill belong to the large arthropod subphylum, the Crustacean. The most familiar and largest group of crustaceans, the class Malacostraca, includes thesuperorder Eucarida comprising the three orders, Euphausiacea (krill), Decapoda (shrimp, lobsters, crabs), and the planktonic Amphionides. The order Euphasiacea comprises two families. The more abundant Euphausiidae contains ten different genera with a total of 85 species. Of these, the genus Euphausia is the largest, with 31 species. The lesser known family, the Bentheuphausiidae, has only one species, Bentheuphausia amblyops, a bathypelagic krill living in deep waters below 3,300 ft.
Morphology
Krill are crustaceans and as such they have a chitinous exoskeleton made up of three segments: the cephalic (head), thorax, and the abdomen. In krill, the first two segments are fused into one segment, the cephalothorax. This outer shell of krill is transparent in most species.
Most krill are about 1 to 2 centimeters long as adults, but a few species grow to sizes of the order of 6 to 15 centimeters. The largest krill species is the mesopelagicThysanopoda spinicauda (Brinton 1953). Krill can be easily distinguished from other crustaceans, such as true shrimps, by their externally visible gills.
As with other crustaceans, krill have compound eyes and two antennae. Krill eyes are intricate; some species can adapt to different lighting conditions through the use of screening pigments (Gaten 2006).
Krill have several pairs of thoracic legs called pereiopods or thoracopods (so named because they are attached to the thorax; their number varies among genera and species). These thoracic legs include the feeding legs and the grooming legs. Additionally, all species have five swimming legs called pleopods or "swimmerets," very similar to those of the common freshwater lobster.
Most krill are about 1 to 2 centimeters long as adults, but a few species grow to sizes of the order of 6 to 15 centimeters. The largest krill species is the mesopelagicThysanopoda spinicauda (Brinton 1953). Krill can be easily distinguished from other crustaceans, such as true shrimps, by their externally visible gills.
As with other crustaceans, krill have compound eyes and two antennae. Krill eyes are intricate; some species can adapt to different lighting conditions through the use of screening pigments (Gaten 2006).
Krill have several pairs of thoracic legs called pereiopods or thoracopods (so named because they are attached to the thorax; their number varies among genera and species). These thoracic legs include the feeding legs and the grooming legs. Additionally, all species have five swimming legs called pleopods or "swimmerets," very similar to those of the common freshwater lobster.
Biology
Female krill can lay 1000 eggs at one time. This helps increase the population. Also they travel in schools of over 5000 to make it difficult to be eaten.
Distribution Map
Importance
(Ecological,Economical)
What are Krill?
Krill are tiny, pink, semi-transparent crustaceans with large black eyes and are usually around only two inches in length. Amazingly, their digestive systems are usually visible and are often seen as a bright green color due to the phytoplankton, tiny single-celled plants, and algae that they eat. They can survive up to two hundred days without food, and typically, they can live between five and ten years. There are eighty-five known species of Krill. The Antarctica Krill are the largest, with the densest populations living in the waters around Antarctica where the oceans contain few contaminants and are far more untouched than in other areas of the world. Krill gather in swarms so dense and widespread during certain periods of the year that they turn the surface of the ocean a pink-red color and can be seen from space.4 This is wonderful defense mechanism for them; if a predator were to come along, the predator would have a difficult and confusing time picking out any single Krill for themselves. 4 But Krill also tend to spend their days in the deep depths of the oceans hiding from predators, surfacing at night to feed.1 The worldwide population of Krill has been estimated to outweigh the human population of the world. 2
How important are Krill?
Most of the animals of the Antarctic – seals, whales, and squid – depend on Krill! They are also a major part of the diets of a variety of marine animals including fish, birds, and whales.
The Decline of Krill
Like many other sea dwelling creatures, the number of Krill is decreasing drastically. Certain studies have shown their numbers to have decreased by eighty percent since the 1970's. Some believe that the decline in Krill is one of the reasons some penguin species are also declining in number. 10 Scientists also worry that the decline in Krill will make it difficult for Baleen whales to repopulate to the numbers they were once at.2
There are many reasons for the Krill’s decline. The rising sea temperatures, a result of the greenhouse effect, compromises Krill’s their major food source, phytoplankton. As sea temperatures rise, the pattern by which the phytoplankton blooms is altered. Additionally, the loss of ice due to rising sea temperatures also means the loss of ice-algae (food source).1 Rising sea temperatures put Krill and animals that feed off of them at risk.
Also, the thinning of the ozone layer increases the amount of ultraviolent light that reaches the Antarctic and serves as another threat to the Krill’s survival.
Protecting Krill
Today, 400,000 tons of Krill are caught annually. Krill oil is marketed as a dietary supplement because it contains high amounts of Omega-3 fatty acids. It is also used to treat high cholesterol. However, even if alternatives are found and utilized for Krill oil, over half of the Krill caught are actually used for fish meal or animal feed.
Thankfully, Krill are protected under a fishing treaty that was enacted in 1981. The Convention on the Conservation of Antarctic Marine Living Resources sets limits on the number of Krill that can be caught, taking into consideration the needs of the ecosystem.7 The treaty also protects the Antarctic ecosystem from expanding fisheries and helps in the recovery of great whales and over fished species.
The Antarctic Krill Conservation Project also works to protect the Krill population. It is comprised by a network of organizations that work together to promote Krill conservation and the conservation of the Antarctic marine ecosystem. They do this by adopting the following principles:
(1) Utilizing “a highly precautionary, effective and integrated ecosystem-based package for Antarctic krill management that ensures that functional relationships in the Antarctic ecosystem are maintained, and that krill abundance and availability for predators is not compromised, taking full account of climate change and other relevant environmental factors”;
(2) Preventing “the expansion of the fishery until these measures have been approved”;
(3) And by “formally recognize[ING], through appropriate commitments and actions not limited to CCAMLR or the Antarctic Treaty System, that the Antarctic's unique character as the last great wilderness, as home to exceptional concentrations of biodiversity including penguins, whales, and albatrosses, and its critical role in global environmental processes, requires special conservation actions, including but not limited to protected and closed areas.” 9
1 http://animals.nationalgeographic.com/animals/invertebrates/krill/
2 http://www.coolantarctica.com/Antarctica%20fact%20file/wildlife/krill.htm
3 http://www.krillfacts.org/krill-facts.html
4 http://www.krillfacts.org/1-krill-facts-center.html
5 http://www.antarctica.gov.au/about-antarctica/fact-files/animals/krill
6 http://www.doc.ic.ac.uk/~kpt/terraquest/va/ecology/ecology.html
7 http://www.antarctica.gov.au/about-antarctica/fact-files/animals/krill
8 http://www.coolantarctica.com/Antarctica%20fact%20file/wildlife/krill.htm
9 http://www.krillcount.org/solutions.htm
Krill are tiny, pink, semi-transparent crustaceans with large black eyes and are usually around only two inches in length. Amazingly, their digestive systems are usually visible and are often seen as a bright green color due to the phytoplankton, tiny single-celled plants, and algae that they eat. They can survive up to two hundred days without food, and typically, they can live between five and ten years. There are eighty-five known species of Krill. The Antarctica Krill are the largest, with the densest populations living in the waters around Antarctica where the oceans contain few contaminants and are far more untouched than in other areas of the world. Krill gather in swarms so dense and widespread during certain periods of the year that they turn the surface of the ocean a pink-red color and can be seen from space.4 This is wonderful defense mechanism for them; if a predator were to come along, the predator would have a difficult and confusing time picking out any single Krill for themselves. 4 But Krill also tend to spend their days in the deep depths of the oceans hiding from predators, surfacing at night to feed.1 The worldwide population of Krill has been estimated to outweigh the human population of the world. 2
How important are Krill?
Most of the animals of the Antarctic – seals, whales, and squid – depend on Krill! They are also a major part of the diets of a variety of marine animals including fish, birds, and whales.
The Decline of Krill
Like many other sea dwelling creatures, the number of Krill is decreasing drastically. Certain studies have shown their numbers to have decreased by eighty percent since the 1970's. Some believe that the decline in Krill is one of the reasons some penguin species are also declining in number. 10 Scientists also worry that the decline in Krill will make it difficult for Baleen whales to repopulate to the numbers they were once at.2
There are many reasons for the Krill’s decline. The rising sea temperatures, a result of the greenhouse effect, compromises Krill’s their major food source, phytoplankton. As sea temperatures rise, the pattern by which the phytoplankton blooms is altered. Additionally, the loss of ice due to rising sea temperatures also means the loss of ice-algae (food source).1 Rising sea temperatures put Krill and animals that feed off of them at risk.
Also, the thinning of the ozone layer increases the amount of ultraviolent light that reaches the Antarctic and serves as another threat to the Krill’s survival.
Protecting Krill
Today, 400,000 tons of Krill are caught annually. Krill oil is marketed as a dietary supplement because it contains high amounts of Omega-3 fatty acids. It is also used to treat high cholesterol. However, even if alternatives are found and utilized for Krill oil, over half of the Krill caught are actually used for fish meal or animal feed.
Thankfully, Krill are protected under a fishing treaty that was enacted in 1981. The Convention on the Conservation of Antarctic Marine Living Resources sets limits on the number of Krill that can be caught, taking into consideration the needs of the ecosystem.7 The treaty also protects the Antarctic ecosystem from expanding fisheries and helps in the recovery of great whales and over fished species.
The Antarctic Krill Conservation Project also works to protect the Krill population. It is comprised by a network of organizations that work together to promote Krill conservation and the conservation of the Antarctic marine ecosystem. They do this by adopting the following principles:
(1) Utilizing “a highly precautionary, effective and integrated ecosystem-based package for Antarctic krill management that ensures that functional relationships in the Antarctic ecosystem are maintained, and that krill abundance and availability for predators is not compromised, taking full account of climate change and other relevant environmental factors”;
(2) Preventing “the expansion of the fishery until these measures have been approved”;
(3) And by “formally recognize[ING], through appropriate commitments and actions not limited to CCAMLR or the Antarctic Treaty System, that the Antarctic's unique character as the last great wilderness, as home to exceptional concentrations of biodiversity including penguins, whales, and albatrosses, and its critical role in global environmental processes, requires special conservation actions, including but not limited to protected and closed areas.” 9
1 http://animals.nationalgeographic.com/animals/invertebrates/krill/
2 http://www.coolantarctica.com/Antarctica%20fact%20file/wildlife/krill.htm
3 http://www.krillfacts.org/krill-facts.html
4 http://www.krillfacts.org/1-krill-facts-center.html
5 http://www.antarctica.gov.au/about-antarctica/fact-files/animals/krill
6 http://www.doc.ic.ac.uk/~kpt/terraquest/va/ecology/ecology.html
7 http://www.antarctica.gov.au/about-antarctica/fact-files/animals/krill
8 http://www.coolantarctica.com/Antarctica%20fact%20file/wildlife/krill.htm
9 http://www.krillcount.org/solutions.htm
KRILL OIL Controversy
Interesting facts on Krill
-Krill is a transparent shrimp-like creature.
-It is extremely important for many animals in the seas especially squid, whales, and many fish.
-Krill contain vitamin A which is mostly stored in their eyes.
-No other marine animal produces such large amounts of vitamin A.
-The blue whale is the largest animal and depends solely on krill for its nourishment; over 2 million krill weighing 1 ton have been found in the stomach of a whale.
-There are 85 species of krill.
-Of the 85 species, 48 occur in a three oceans; 11 occur in two oceans and 26 are restricted to one ocean.
-Most krill lay eggs in the surface of the sea; the eggs tend to sink; every so often the krill develop in very deep waters and have to swim upward to the surface where tiny plants called phytoplankton are, on which they feed.
-It is extremely important for many animals in the seas especially squid, whales, and many fish.
-Krill contain vitamin A which is mostly stored in their eyes.
-No other marine animal produces such large amounts of vitamin A.
-The blue whale is the largest animal and depends solely on krill for its nourishment; over 2 million krill weighing 1 ton have been found in the stomach of a whale.
-There are 85 species of krill.
-Of the 85 species, 48 occur in a three oceans; 11 occur in two oceans and 26 are restricted to one ocean.
-Most krill lay eggs in the surface of the sea; the eggs tend to sink; every so often the krill develop in very deep waters and have to swim upward to the surface where tiny plants called phytoplankton are, on which they feed.