Conservancy fairy shrimp
Encyclopedia
The conservancy fairy shrimp, Branchinecta conservatio, is a small crustacean
in the family Branchinectidae
. It ranges in size from about 1.25 centimetre (0.492125984251969 in) to 2.5 centimetre (0.984251968503937 in) long. Fairy shrimp
are aquatic species in the order Anostraca. They have delicate elongate bodies, large stalked compound eyes, no carapace
s, and eleven pairs of swimming legs. They glide gracefully upside down, swimming by beating their legs in a complex, wavelike movement that passes from front to back. Fairy shrimp feed on algae
, bacteria
, protozoa
, rotifer
s and detritus. This species is endemic to California
in the United States.
cool-water vernal pool
s which fill with water in the rainy season, then slowly dry up from their outer, more shallow edges to their deeper areas in the center. However, the shrimp are gone long before the pool finally dries up. The fairy shrimp have been spotted and collected in vernal pools from early November to early April.
Female fairy shrimp carry their eggs in a ventral brood sac. The eggs are either dropped to the pool bottom or remain in the brood sac until the mother dies and sinks. When the pool dries out, so do the eggs. They remain in the dry pool bed until rains and other environmental stimuli hatch them.
Resting fairy shrimp eggs are known as cyst
s. They are capable of withstanding heat, cold and prolonged desiccation
. When the pools refill, some, but not all, of the cysts may hatch. The cyst bank in the soil may contain cysts from several years of breeding.
Hatching can begin within the same week that a pool starts to fill. Average time to maturity is forty-nine days. In warmer pools, it can be as few as nineteen.
It is very pretty.
al regions of California
. It may still exist in unsurveyed pools within this region.
The species is currently known from several disjunct populations: the Vina Plains in Tehama County
, south of Chico
in Butte County
, the Jepson Prairie Preserve and surrounding area in Solano County
, the Sacramento National Wildlife Refuge Complex
in Glenn County
, Mapes Ranch west of Modesto
, San Luis National Wildlife Refuge
and the Haystack Mountain/Yosemite Lake area in Merced County
, and two locations on the Los Padres National Forest
in Ventura County
.
Holland (1978) estimated that between 60 and 85 percent of the habitat that once supported vernal pools had been destroyed by 1973. Since then a substantial amount of remaining habitat has been converted for human uses. The rate of loss of vernal pool habitat in the state has been estimated at two to three percent per year (Holland and Jain 1988).
The conservancy fairy shrimp has been classified as a United States Federal Endangered Species (Federal Register 59:48136; September 19, 1994).
Crustacean
Crustaceans form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. The 50,000 described species range in size from Stygotantulus stocki at , to the Japanese spider crab with a leg span...
in the family Branchinectidae
Branchinectidae
Branchinectidae is a family in the order Anostraca , containing two genera – Branchinecta and Archaebranchinecta. The majority of the species are in the genus Branchinecta, with only Archaebranchinecta pollicifera and the fossil Archaebranchinecta barstowensis in the second genus....
. It ranges in size from about 1.25 centimetre (0.492125984251969 in) to 2.5 centimetre (0.984251968503937 in) long. Fairy shrimp
Fairy shrimp
Anostraca is one of the four orders of crustaceans in the class Branchiopoda; its members are also known as fairy shrimp. They are usually long . Most species have 20 body segments, bearing 11 pairs of leaf-like phyllopodia , and the body lacks a carapace...
are aquatic species in the order Anostraca. They have delicate elongate bodies, large stalked compound eyes, no carapace
Carapace
A carapace is a dorsal section of the exoskeleton or shell in a number of animal groups, including arthropods such as crustaceans and arachnids, as well as vertebrates such as turtles and tortoises. In turtles and tortoises, the underside is called the plastron.-Crustaceans:In crustaceans, the...
s, and eleven pairs of swimming legs. They glide gracefully upside down, swimming by beating their legs in a complex, wavelike movement that passes from front to back. Fairy shrimp feed on algae
Algae
Algae are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms, such as the giant kelps that grow to 65 meters in length. They are photosynthetic like plants, and "simple" because their tissues are not organized into the many...
, bacteria
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...
, protozoa
Protozoa
Protozoa are a diverse group of single-cells eukaryotic organisms, many of which are motile. Throughout history, protozoa have been defined as single-cell protists with animal-like behavior, e.g., movement...
, rotifer
Rotifer
The rotifers make up a phylum of microscopic and near-microscopic pseudocoelomate animals. They were first described by Rev. John Harris in 1696, and other forms were described by Anton van Leeuwenhoek in 1703...
s and detritus. This species is endemic to California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
in the United States.
Ecology
Conservancy fairy shrimp inhabit rather large, moderately turbidTurbidity
Turbidity is the cloudiness or haziness of a fluid caused by individual particles that are generally invisible to the naked eye, similar to smoke in air. The measurement of turbidity is a key test of water quality....
cool-water vernal pool
Vernal pool
Vernal pools, also called vernal ponds or ephemeral pools, are temporary pools of water. They are usually devoid of fish, and thus allow the safe development of natal amphibian and insect species...
s which fill with water in the rainy season, then slowly dry up from their outer, more shallow edges to their deeper areas in the center. However, the shrimp are gone long before the pool finally dries up. The fairy shrimp have been spotted and collected in vernal pools from early November to early April.
Female fairy shrimp carry their eggs in a ventral brood sac. The eggs are either dropped to the pool bottom or remain in the brood sac until the mother dies and sinks. When the pool dries out, so do the eggs. They remain in the dry pool bed until rains and other environmental stimuli hatch them.
Resting fairy shrimp eggs are known as cyst
Cyst
A cyst is a closed sac, having a distinct membrane and division on the nearby tissue. It may contain air, fluids, or semi-solid material. A collection of pus is called an abscess, not a cyst. Once formed, a cyst could go away on its own or may have to be removed through surgery.- Locations :* Acne...
s. They are capable of withstanding heat, cold and prolonged desiccation
Desiccation
Desiccation is the state of extreme dryness, or the process of extreme drying. A desiccant is a hygroscopic substance that induces or sustains such a state in its local vicinity in a moderately sealed container.-Science:...
. When the pools refill, some, but not all, of the cysts may hatch. The cyst bank in the soil may contain cysts from several years of breeding.
Hatching can begin within the same week that a pool starts to fill. Average time to maturity is forty-nine days. In warmer pools, it can be as few as nineteen.
It is very pretty.
Distribution
The historical distribution of the conservancy fairy shrimp is not known. However, the distribution of vernal pool habitats in the areas where the species is now known to occur were once more continuous and larger in area than they are today. It is likely the conservancy fairy shrimp once occupied suitable vernal pool habitats throughout a large portion of the Central Valley and southern coastCoast
A coastline or seashore is the area where land meets the sea or ocean. A precise line that can be called a coastline cannot be determined due to the dynamic nature of tides. The term "coastal zone" can be used instead, which is a spatial zone where interaction of the sea and land processes occurs...
al regions of California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
. It may still exist in unsurveyed pools within this region.
The species is currently known from several disjunct populations: the Vina Plains in Tehama County
Tehama County, California
Tehama County is a county located in the northern part of the U.S. state of California. It is bisected by the Sacramento River. As of 2010 its population was 63,463, up from 56,039 as of 2000. The county seat is Red Bluff.-History:...
, south of Chico
Chico, California
Chico is the most populous city in Butte County, California, United States. The population was 86,187 at the 2010 census, up from 59,954 at the time of the 2000 census...
in Butte County
Butte County, California
Butte County is a county located in the Central Valley of the US state of California, north of the state capital of Sacramento. As of the 2010 census, it had a population of 220,000. The county seat is Oroville. Butte County is the "Land of Natural Wealth and Beauty."Butte County is watered by the...
, the Jepson Prairie Preserve and surrounding area in Solano County
Solano County, California
Solano County is a county located in Bay-Delta region of the U.S. state of California, about halfway between San Francisco and Sacramento and is one of the nine San Francisco Bay Area counties. The county's population was reported by the U.S. Census to be 413,344 in 2010...
, the Sacramento National Wildlife Refuge Complex
Sacramento National Wildlife Refuge Complex
The Sacramento National Wildlife Refuge Complex is part of the United States system of National Wildlife Refuges . It is located in northern California, in the valley of the Sacramento River....
in Glenn County
Glenn County, California
Glenn County is in the California Central Valley. As of 2010, it had a population of 28,122. The county seat is the city of Willows.-History:Glenn County was formed in 1891 from parts of Colusa County. It was named for Dr. Hugh J...
, Mapes Ranch west of Modesto
Modesto, California
Modesto is a city in, and is the county seat of, Stanislaus County, California. With a population of approximately 201,165 at the 2010 census, Modesto ranks as the 18th largest city in the state of California....
, San Luis National Wildlife Refuge
San Luis National Wildlife Refuge
The San Luis National Wildlife Refuge in the San Joaquin Valley of central California is one of the great remnants of a historically bountiful wintering grounds for migratory waterfowl on the Pacific Flyway...
and the Haystack Mountain/Yosemite Lake area in Merced County
Merced County, California
Merced County , is a county located in the Central Valley of the U.S. state of California, north of Fresno and southeast of San Jose. As of the 2010 census, the population was 255,793, up from 210,554 at the 2000 census. The county seat is Merced...
, and two locations on the Los Padres National Forest
Los Padres National Forest
Los Padres National Forest is a forest located in southern and central California, which includes most of the mountainous land along the California coast from Ventura to Monterey, extending inland...
in Ventura County
Ventura County, California
Ventura County is a county in the southern part of the U.S. state of California. It is located on California's Pacific coast. It is often referred to as the Gold Coast, and has a reputation of being one of the safest populated places and one of the most affluent places in the country...
.
Threats
The ephemeral wetlands that support this network of populations are remnants of what was formerly a pristine vernal pool ecosystem, which has been converted to primarily agricultural and urban uses. This highly disturbed remnant habitat is imperiled by a variety of human-caused activities, primarily urban development, water supply and flood control projects and conversion of land for agricultural use.Holland (1978) estimated that between 60 and 85 percent of the habitat that once supported vernal pools had been destroyed by 1973. Since then a substantial amount of remaining habitat has been converted for human uses. The rate of loss of vernal pool habitat in the state has been estimated at two to three percent per year (Holland and Jain 1988).
The conservancy fairy shrimp has been classified as a United States Federal Endangered Species (Federal Register 59:48136; September 19, 1994).
Additional information and references
- California Dept. of Fish & Game, California Vernal Pool Assessment, Preliminary Report
- Eriksen, C.H., and D. Belk. 1999. Fairy shrimps of California's puddles, pools, and playas, Mad River Press, Eureka, CA.
- Holland, R.F. 1978. The geographic and edaphic distribution of vernal pools in the Great Central Valley, California. California Native Plant Society, Special Publication 4:1-12.
- Holland, R. F., and S. Jain. 1988. Vernal pools. Pages 515-533 In: M.E. Barbour and J. Major, eds. Terrestrial vegetation of California, new expanded edition. California Native Plant Society, Special Publication Number 9, Sacramento, CA.
- U.S. Fish & Wildlife Service. 1994. Endangered and Threatened Wildlife and Plants; Determination of Endangered Status for the Conservancy Fairy Shrimp, Longhorn Fairy Shrimp, and the Vernal Pool Tadpole Shrimp; and Threatened Status for the Vernal Pool Fairy Shrimp. Portland, Oregon.
- U.S. Fish and Wildlife Service. 2003. Endangered and Threatened Wildlife and Plants; Final Designation of Critical Habitat for Four Vernal Pool Crustaceans and Eleven Vernal Pool Plants in California and Southern Oregon Vernal pool crustaceans and plants in California and Oregon. Portland, Oregon.
- U.S. Fish and Wildlife Service. 2005. Endangered and Threatened Wildlife and Plants; Final Designation of Critical Habitat for Four Vernal Pool Crustaceans and Eleven Vernal Pool Plants in California and Southern Oregon; Evaluation of Economic Exclusions From August 2003 Final Designation; Final Rule. Portland, Oregon.
- U.S. Fish and Wildlife Service. 2006. Endangered and Threatened Wildlife and Plants: Designation of Critical Habitat for Four Vernal Pool Crustaceans and Eleven Vernal Pool Plants; Final Rule. Portland, Oregon.
- U.S. Fish and Wildlife Service. 2005. Recovery Plan for Vernal Pool Ecosystems of California and Southern Oregon. Portland, Oregon.