| Oyster crab | |
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| Z. ostreus on Crassostrea virginica | |
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| Species: | Z. ostreus |
| Binomial name | |
| Zaops ostreus | |
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The oyster crab (Zaops ostreus) is a small, whitish or translucent crab in the family Pinnotheridae.
Oyster crabs are small in size, typically measuring around 1 to 2 centimeters in width. They have a flattened body shape with a round carapace (shell) and relatively short legs. Their coloration can vary but often includes shades of brown, gray, or green, helping them blend in with their surroundings. Male oyster crabs are often smaller than females.
Oyster crabs primarily inhabit oyster beds, which are found in coastal waters. These beds serve as vital ecosystems for many species of Zaops. [4] The structure of oyster beds provides a complex habitat that offers food, shelter, and breeding grounds for a diverse range of organisms, including the oyster crab. Estuaries and coastal bays provide ideal conditions for oysters to thrive, which in turn supports the populations of oyster crabs. These environments are particularly significant for oyster crabs because they often have brackish water - a mixture of fresh and saltwater. The variability of salinity, temperature, and nutrient availability in these areas can influence the distribution and health of oyster populations and consequently the oyster crabs that depend on it. [5] In regions where mangroves are present, oyster populations can establish on the roots and trunks of mangrove trees, creating a unique habitat that oyster crabs may also inhabit. These swamps offer a different ecological niche with shelter from predators and a rich source of food material. In some areas, artificial reefs created for oyster restoration and to enhance fisheries can also become habitats for oyster crabs. [4] These man-made structures can support oyster colonies, which in turn provide potential habitats for the crabs.
It is less than half an inch across, and lives inside the gills of an oyster or a clam. [6] It uses the oyster for protection and lives on the food that the oyster gets for itself. It is found in oysters in the North Atlantic Ocean. [6]
Many animals are predators of oyster crabs, including humans.
Oyster crabs can be found as parasites on various hosts such as bivalves (oysters, mussels, clams, scallops, and cockles), which are located using chemical detection. The host type depends on the life stage of the individual; larvae typically feed on plankton while adults tend to parasitize oysters. Specifically, oysters are used as housing and protection, as well as a food source. The oyster crab first invades its bivalve host during its first crab stage (after larval stage) before it develops into the hard-shell stage. Then, the oyster crab attaches to and scrapes food off of the oyster’s gills, which are used to filter food particles and various microorganisms (dinoflagellates and diatoms) out of the water. This oyster does not benefit in the process, its gills being constantly pierced and abraded until its ability to filter out food is hindered. An oyster may also bring in small crustaceans that it does not feed on, but are a part of the oyster crab’s diet. Once an oyster crab has reached its hard-shell stage, it will stay in its oyster if it is a female, or will leave its host as a male in search of females who have remained immotile. This is the only completely free-swimming stage of the oyster crab. Once copulation has taken place, males typically die while females live long enough to lay eggs. [7] [8]
As the growth rate of the host increases, so does the growth rate of the oyster crab, regardless of its current stage of development in its life cycle. [7] [8]
Oyster crabs are found in coastal, neritic regions waters all over the world. Off of every coast in the Pacific, Atlantic, Southern, and Indian oceans, it is likely that oyster crabs will be observed. [9] These observations of oyster crabs in these coastal areas are closely related to oyster bays. [10] [11] The reason for these correlations is the oyster crabs make habitats out of the oyster bays, and many organisms, including oyster crabs, inhabit oyster bays as well. [11] [12]
Oyster crabs inhabit a wide range of invertebrate bivalves for nutrition and shelter. Habitat preferences are dependent on oyster crab sex. Male oyster crabs are considered to be free-living, leaving their host after the hard shell stage in search for a female oyster crab. Female oyster crabs find a suitable host where it will thrive until reaching sexual maturity and lay eggs inside the host. Both male and female oyster crabs parasitize a bivalve as a first stage larva. Oyster crabs have been found within the gills of the mantle cavity or within the water conduction system of mollucs. A bivalve can house one or a few oyster crabs but infestations do not rise above more than one female oyster crab. Their habitat regions include intertidal saltwater and marine aquatic biomes along the atlantic and pacific oceans.
Zaops ostreus is found along the eastern seaboards of North America and South America, from Massachusetts to Brazil, including the Gulf of Mexico and the Caribbean Sea. [5] They are also distributed along the Atlantic coast of North America, ranging from Nova Scotia in Canada to Florida in the United States.
Oyster crabs become sexually mature when they reach the hard stage. Males do not mature beyond this, but females will typically undergo four more stages, losing their swimming legs and growing a wider abdomen to become ovigerous (egg-bearing). [13] Once females have fully matured, they become sedentary, never leaving their host.
Eventually, mature males will leave their bivalves in search of a female, locating them using their pheromones. [13] Males are usually smaller and flatter, allowing them to slip into the bivalve harboring the female. The males exhibit polygyny mating. They mate with more than one female in different host bivalves. Oyster crabs are known to have precopulatory courtship rituals, consisting of tactile and olfactory cues. [14] Eggs carried by the female's pleopods are fertilized through indirect sperm transfer. [14] They can carry 7,957 to 9,456 eggs, holding them for up to 5 weeks. [15] Oyster crab females begin producing one batch of eggs the first year and after the second or third year, they can increase to two batches. [15] Once the eggs have developed into free-swimming zoeae, they will leave the mother's oyster in search of their own. [16]
Oyster is the common name for a number of different families of salt-water bivalve molluscs that live in marine or brackish habitats. In some species, the valves are highly calcified, and many are somewhat irregular in shape. Many, but not all oysters, are in the superfamily Ostreoidea.
The New Zealand pea crab, is a species of small, parasitic crab that lives most commonly inside New Zealand green-lipped mussels. Adult females are about the size and shape of a pea, while adult males are smaller and flatter. Adult New Zealand pea crabs are completely reliant on their host mussel for shelter and food, which it steals from the mussel's gills. The New Zealand pea crab is found throughout New Zealand and can infect up to 70% of natural populations. These crabs are of concern to green-lipped mussel aquaculture because they reduce the size and growth of mussels, although infected mussels can be harvested and consumed.
Isopoda is an order of crustaceans. Members of this group are called Isopods and include both terrestrial and aquatic species such as woodlice. All have rigid, segmented exoskeletons, two pairs of antennae, seven pairs of jointed limbs on the thorax, and five pairs of branching appendages on the abdomen that are used in respiration. Females brood their young in a pouch under their thorax.
Rhizocephala are derived barnacles that are parasitic castrators. Their hosts are mostly decapod crustaceans, but include Peracarida, mantis shrimps and thoracican barnacles. Their habitats range from the deep ocean to freshwater. Together with their sister groups Thoracica and Acrothoracica, they make up the subclass Cirripedia. Their body plan is uniquely reduced in an extreme adaptation to their parasitic lifestyle, and makes their relationship to other barnacles unrecognisable in the adult form. The name Rhizocephala derives from the Ancient Greek roots ῥίζα and κεφαλή, describing the adult female, which mostly consists of a network of thread-like extensions penetrating the body of the host.
The American oystercatcher, occasionally called the American pied oystercatcher, is a member of family Haematopodidae. Originally called the "sea pie", it was renamed in 1731 when naturalist Mark Catesby observed the bird eating oysters. The current population of American oystercatchers is estimated to be 43,000. There are estimated to be 1,500 breeding pairs along the Atlantic and Gulf Coasts of the US. The bird is marked by its black and white body and a long, thick orange beak.
Cancer pagurus, commonly known as the edible crab or brown crab, is a species of crab found in the North Sea, North Atlantic Ocean, and perhaps the Mediterranean Sea. It is a robust crab of a reddish-brown colour, having an oval carapace with a characteristic "pie crust" edge and black tips to the claws. A mature adult may have a carapace width up to 25 centimetres and weigh up to 3 kilograms. C. pagurus is a nocturnal predator, targeting a range of molluscs and crustaceans. It is the subject of the largest crab fishery in Western Europe, centred on the coasts of the British Isles, with more than 60,000 tonnes caught annually.
The family Argulidae, whose members are commonly known as carp lice or fish lice, are parasitic crustaceans in the class Ichthyostraca. It is the only family in the monotypic subclass Branchiura and the order Arguloida, although a second family, Dipteropeltidae, has been proposed. Although they are thought to be primitive forms, they have no fossil record.
Cymothoa exigua, or the tongue-eating louse, is a parasitic isopod of the family Cymothoidae. It enters fish through the gills. The female attaches to the tongue, while the male attaches to the gill arches beneath and behind the female. Females are 8–29 mm (0.3–1.1 in) long and 4–14 mm (0.16–0.55 in) wide. Males are about 7.5–15 mm (0.3–0.6 in) long and 3–7 mm (0.12–0.28 in) wide. The parasite severs the blood vessels in the fish's tongue, causing the tongue to fall off. It then attaches itself to the remaining stub of tongue and the parasite itself effectively serves as the fish's new "tongue".
Oyster farming is an aquaculture practice in which oysters are bred and raised mainly for their pearls, shells and inner organ tissue, which is eaten. Oyster farming was practiced by the ancient Romans as early as the 1st century BC on the Italian peninsula and later in Britain for export to Rome. The French oyster industry has relied on aquacultured oysters since the late 18th century.
Pinnotheridae is a family of tiny soft-bodied crabs that live commensally in the mantles of certain bivalve molluscs and the occasional large gastropod mollusc species in genera such as Strombus and Haliotis. Tunicotheres moseri is commensal with a tunicate. The earliest fossils attributable to the Pinnotheridae date from the Danian.
The pea crab, Pinnotheres pisum, is a small crab in the family Pinnotheridae that lives as a parasite in oysters, clams, mussels, and other species of bivalves.
Pinnixa faba, known as the pea crab, mantle pea crab or large pea crab, is a pea crab which lives harmlessly within a large edible clam. This species is a symbiont of Tresus capax and Tresus nuttallii in its mature stage.
Neotrypaea californiensis, the Bay ghost shrimp, is a species of ghost shrimp that lives on the Pacific coast of North America. It is a pale animal which grows to a length of 11.5 cm (4.5 in). One claw is bigger than the other, especially in males, and the enlarged claw is thought to have a function in mating. N. californiensis is a deposit feeder that lives in extensive burrow systems, and is responsible for high rates of bioturbation. It adversely affects oyster farms, and its numbers are controlled in some places by the application of pesticides. It carries out an important role in the ecosystem, and is used by fishermen as bait.
Petrolisthes armatus, the green porcelain crab, is a species of small porcelain crab in the family Porcellanidae. It is believed to be native to Brazil but has spread to other parts of the world. Populations in the south eastern part of the United States have increased dramatically and the species is considered to be an invasive species.
Nuttallia obscurata, the purple mahogany clam, dark mahogany clam, varnish clam or savory clam, is a species of saltwater clam, a marine bivalve mollusk in the family Psammobiidae. It was first described to science by Lovell Augustus Reeve, a British conchologist, in 1857.
Loxothylacus panopaei is a species of barnacle in the family Sacculinidae. It is native to the Gulf of Mexico and the Caribbean Sea. It is a parasitic castrator of small mud crabs in the family Panopeidae, mostly in the Gulf of Mexico, the Caribbean Sea and the eastern Atlantic Ocean.
Sacculina carcini, the crab hacker barnacle, is a species of parasitic barnacle in the family Sacculinidae, in particular a parasitic castrator, of crabs. The crab that most often is used as a host is the green crab, the natural range of which is the coasts of Europe and North Africa. It can be found attached to the crab's abdomen and affects consumption rates by humans.
Armases cinereum, also known as the squareback marsh crab or wharf crab, is a species of crab in the family Sesarmidae. The wharf crab is a small crab that is dark brown to muddy in color, which allows it to blend in with its usual surroundings. It is found on the Atlantic southeastern coast, down into the Gulf of Mexico. It is an omnivore and is prevalent in marshy coastal environments along the Southwestern Atlantic.
Tunicotheres is a monotypic genus of crabs in the family Pinnotheridae, and Tunicotheres moseri is the only species in the genus. This crab lives commensally in the atrial chamber of a small ascidian. It is found in the tropical western Atlantic Ocean, the Caribbean Sea and the Gulf of Mexico.
Calyptraeotheres garthi is a species of pea crab in the family Pinnotheridae. It is found in the southwestern Atlantic Ocean and is a parasitic castrator of the slipper limpet Crepidula cachimilla.
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Williams, Ernest H., and Lucy Bunkley-Williams. “Life cycle and life history strategies of parasitic crustacea.” Parasitic Crustacea, 2019, pp. 179–266, https://doi.org/10.1007/978-3-030-17385-2_5.
Hanke, Marc H., et al. “Oyster utilization and host variation of the oyster pea crab (Zaops Ostreum).” Journal of Shellfish Research, vol. 34, no. 2, Aug. 2015, pp. 281–287, https://doi.org/10.2983/035.034.0209.