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'Brine shrimp' are species of aquatic
crustaceans of the genus '''Artemia''', the only genus in the
family 'Artemiidae' of the order Anostraca (fairy shrimp, not closely related to
true shrimp). Brine Shrimp have existed since the Triassic period of the Earth's existence, and have evolved little since. They are found worldwide in saltwater, though not in oceans. ''Artemia'' is a well known genus as one variety, sometimes identified as a new species, ''Artemia nyos'', or otherwise as simply a cultivated subspecies of ''Artemia salina'', is sold as novelty gifts, most commonly under the marketing name
Sea-Monkeys.
''Artemia'' were first discovered in
Lymington,
England, in 1755. There are mixed views on whether all brine shrimp are part of one species or whether the varieties that have been identified are properly classified as separate species .
Brine shrimp eggs are metabolically inactive and can remain in total stasis for several years while in dry oxygen-free conditions, even at temperatures below freezing. This characteristic is called ''
cryptobiosis'' meaning "hidden life" (also called ''
diapause''). Once placed in water, the
cyst-like
eggs hatch within a few hours, and will grow to a mature length of around one
cm on average. Brine shrimp have a
biological life cycle of one year. This short life span, and other characteristics such as their ability to remain dormant for long periods, have made them invaluable in scientific research, including
space experiments.
Brine shrimp can tolerate varying levels of
salinity, and a common biology experiment in school is to investigate the effect of salinity levels on the growth of these creatures. They have a rudimentary nervous/spinal system, which leads researchers to believe that they may be used in experiments without concern for animal ethics.
The nutritional properties of newly hatched brine shrimp make them particularly suitable to be sold as
aquarium food as they are high in
lipids and
unsaturated fatty acids (but low in
calcium). These nutritional benefits are likely to be one reason that brine shrimp are found only in highly salinated waters, with reasonable temperatures, as these areas are uninhabitable for potential predators.
The
nauplii, or larvae, of brine shrimp are less than 0.5mm when they first hatch. They eat micro-algae, but will also eat yeast, wheat flour, soybean powder, or egg yolk
[1].
''Artemia monica'', the variety commonly known as Mono Lake brine shrimp, are found only in
Mono Lake,
Mono County, California. In
1987, Dr. Dennis D. Murphy from
Stanford University petitioned the
United States Fish and Wildlife Service to add ''Artemia monica'' to the endangered species list under the
Endangered Species Act 1973. Despite there being trillions of these creatures in Mono Lake, it was felt that rising levels of
salinity and
sodium hydroxide concentration of the lake would endanger them because of the increase in
pH. However, the US Fish and Wildlife Service reported in the ''
Federal Register'' on
7 September 1995 that this brine shrimp did not warrant listing after the threat to the lake was removed following a revised policy by the California State Water Resources Control Board
[2].
References
1. ''Artemia'' (brine shrimp) FAQ 1.1
2. Endangered and Threatened Wildlife and Plants; 12-Month Finding for a Petition to List the Mono Lake Brine Shrimp as Endangered, United States Fish and Wildlife Service, , , Federal Register, 1995
★
"Genus ''Artemia''", ''The Taxonomicon & Systema Naturae 2000'' (listings of taxonomy and scientific classification)
★
"''Artemia franciscana''" ''Invertebrate Anatomy Online''
★
"Brine Shrimp and Ecology of Great Salt Lake", United States Geological Survey