Flounders are a group of flatfish species. They are demersal fish, found at the bottom of oceans around the world; some species will also enter estuaries.
A flatfish is a member of the ray-finned demersal fish order Pleuronectiformes, also called the Heterosomata, sometimes classified as a suborder of Perciformes. In many species, both eyes lie on one side of the head, one or the other migrating through or around the head during development. Some species face their left sides upward, some face their right sides upward, and others face either side upward.
Halibut is the common name for three flatfish in the genera Hippoglossus and Reinhardtius from the family of right-eye flounders and, in some regions, and less commonly, other species of large flatfish.
The yellowbelly flounder is a flatfish of the genus Rhombosolea, found around New Zealand. A different species from the genus Rhombosolea is found in Australia and also goes by the name yellow-belly flounder. The Māori people have commonly fished for R. leporina, and many other species of flatfish, throughout New Zealand's coastal waters for hundreds of years. The Māori name for this species is pātiki tōtara.
The Atlantic halibut is a flatfish of the family Pleuronectidae. They are demersal fish living on or near sand, gravel or clay bottoms at depths of between 50 and 2,000 m. The halibut is among the largest teleost (bony) fish in the world, and is a threatened species owing to a slow rate of growth and overfishing. Halibut are strong swimmers and are able to migrate long distances. Halibut size is not age-specific, but rather tends to follow a cycle related to halibut abundance.
The Greenland halibut or Greenland turbot belongs to the family Pleuronectidae, and is the only species of the genus Reinhardtius. It is a predatory fish that mostly ranges at depths between 500 and 1,000 m (1,600–3,300 ft), and is found in the cold northern Atlantic, northern Pacific, and Arctic Oceans.
The European flounder is a flatfish of European coastal waters from the White Sea in the north to the Mediterranean and the Black Sea in the south. It has been introduced into the United States and Canada accidentally through transport in ballast water. It is caught and used for human consumption.
A bottom feeder is an aquatic animal that feeds on or near the bottom of a body of water. Biologists often use the terms benthos—particularly for invertebrates such as shellfish, crabs, crayfish, sea anemones, starfish, snails, bristleworms and sea cucumbers—and benthivore or benthivorous, for fish and invertebrates that feed on material from the bottom. However the term benthos includes all aquatic life that lives on or near the bottom, which means it also includes non-animals, such as plants and algae. Biologists also use specific terms that refer to bottom feeding fish, such as demersal fish, groundfish, benthic fish and benthopelagic fish. Examples of bottom feeding fish species groups are flatfish, eels, cod, haddock, bass, grouper, carp, bream (snapper) and some species of catfish, sharks.
South Korea is a major center of aquaculture production, and the world's third largest producer of farmed algae as of 2020.
Kudoa is a genus of Myxozoa and the only genus recognized within the monotypic family Kudoidae. There are approximately 100 species of Kudoa all of which parasitize on marine and estuarine fish. Kudoa are most commonly known and studied for the negative effects the genus has on commercial fishing and aquaculture industries.
Tenacibaculum is a Gram-negative and motile bacterial genus from the family of Flavobacteriaceae.
Philasterida is an order of ciliates in the subclass Scuticociliatia.
Thalassotalea is an aerobic and chemo-organo-heterotrophic genus of bacteria from the family Colwelliaceae which occur in the ocean and in sea ice.
Thalassotalea ganghwensis is a Gram-negative, aerobic and halophilic bacterium from the genus of Thalassotalea which has been isolated from tidal flat sediments in Korea.
Miamiensis avidus is a species of unicellular marine eukaryote that is a parasite of many different types of fish. It is one of several organisms known to cause the fish disease scuticociliatosis and is considered an economically significant pathogen of farmed fish. M. avidus is believed to be the cause of a 2017 die-off of fish and sharks in the San Francisco Bay.
Philasterides dicentrarchi is a marine protozoan ciliate that was first identified in 1995 after being isolated from infected European sea bass reared in France. The species was also identified as the causative agent of outbreaks of scuticociliatosis that occurred between summer 1999 and spring 2000 in turbot cultivated in the Atlantic Ocean. Infections caused by P. dicentrarchi have since been observed in turbot reared in both open flow and recirculating production systems. In addition, the ciliate has also been reported to cause infections in other flatfishes, such as the olive flounder in Korea and the fine flounder in Peru, as well as in seadragons, seahorses, and several species of sharks in other parts of the world.
Scuticociliatosis is a severe and often fatal parasitic infection of several groups of marine organisms. Species known to be susceptible include a broad range of teleosts, seahorses, sharks, and some crustaceans. The disease can be caused by any one of about 20 distinct species of unicellular eukaryotes known as scuticociliates, which are free-living marine microorganisms that are opportunistic or facultative parasites. Scuticociliatosis has been described in the wild, in captive animals in aquariums, and in aquaculture. It is best studied in fish species that are commonly farmed, in which typical effects of infection include skin ulceration, hemorrhage, and necrosis, with post-mortem examination identifying ciliates in the skin, gills, blood, and internal organs including the brain.
Enteromyxum leei is a species of myxozoan, histozoic parasite that infects the intestinal tract and sometimes associated organs, like gall bladder and liver, of several teleostean fish species. Myxozoans are microscopic metazoans, with an obligate parasitic life-style. The parasite stages of this species live in the paracelullar space between fish enterocytes. It is the causative agent of enteromyxosis, or emaciative disease, also known as "razor blade syndrome" in sparid fish. E. leei has a wide host and geographical range within marine fish, and even freshwater fish have been infected experimentally. E. leei initially emerged in the Mediterranean in the late 1980s and it is believed to have been unintentionally introduced into the Red Sea. Its pathogenicity and economic impact depend on the host species. In the gilt-head seabream, it is manifested as a chronic disease that provokes anorexia, delayed growth with weight loss, cachexia, reduced marketability and increased mortality. In other species, it has no clinical signs. In sharpsnout seabream, infection results in very high mortality rates, which have pushed fish farmers to abandon the culture of this fish species.
Hysterothylacium is a genus of parasitic roundworms in the family Raphidascarididae. As of 2020 it consists of over 70 species and is considered one of the largest of the ascaridoid genera parasitising fish.
Philasteridae is a family of ciliates in the order Philasterida.
