Atlantic Spanish mackerel
The Atlantic Spanish mackerel is a migratory species of mackerels that swims to the Northern Gulf of Mexico in spring, returns to south Florida in the Eastern Gulf, to Mexico in the Western Gulf in the fall. The fish exhibits a green back. Lateral line curving down from the upper end of the gill cover toward caudal peduncle; the first dorsal fin is black at the front. Posterior membranes are white with a black edge, its single row of cutting edged teeth in each jaw are large, uniform spaced and flattened from side to side. As with the King mackerel and the Cero mackerel, these teeth look similar to those of the Bluefish, Pomatomus saltatrix. Spanish mackerel occur seasonally from the Yucatán peninsula, Mexico, as far north as Cape Cod, Massachusetts, they are a shallow water species, preferring sand bottom in depths of 10 to 40 feet found as deep as 80 feet. It appears that one Atlantic and one or more Gulf groups of Spanish mackerel occur in Florida waters. With rising water temperatures, the Atlantic group migrates along the Atlantic coast of the United States from Miami Florida, beginning in late February through July reaching as far as southern Cape Cod, Massachusetts returning in fall.
An Eastern Gulf group moves northward from the Florida Keys during late winter and spring, appearing off the central West Coast of Florida about April 1. Movement terminates along the northern Texas coast. During fall, this group migrates back to its wintering grounds in the Keys; the Gulf group of Spanish mackerel spawn in batches from May to September off shore of Texas, off the Gulf shore of Florida as early as April in some years. The Atlantic group spawns starting in April off the Carolinas and from late August to late September in the northernmost part of its range. Spanish mackerel mature by age-1 at a fork length of 14 inches. Females grow to larger sizes than males. Females may live as long as 11 years, growing to 11 pounds and 33 inches FL. Males reach about age-6 and 19 inches FL. Spanish mackerel are carnivores; as with other members of the genus, food consists of small fishes with lesser quantities of shrimp and squid. Striped anchovies and clupeoids such as menhaden and thread herring, are important forage in North Carolina, Florida and Veracruz.
The percentage of anchovies consumed is higher for juveniles than for adults. Spanish mackerel are a valued fish throughout their range from North Carolina to Texas. Recreational anglers catch Spanish mackerel from boats while trolling or drifting and from boats, piers and beaches by casting spoons and jigs and live-bait fishing. Fast lure retrieves are key to catching these quick fish. Commercial methods are run-around gill netting, by trolling lures similar to those used by recreational anglers. On November 4, 1987, Woody Outlaw caught a world-record 13 pound Spanish mackerel on a blue and white Sea Witch with a strip of fastback menhaden on a 7/0 hook, held by a Shimano bait-casting reel on a Kuna rod with 30-pound test line. Spanish mackerel are managed in commercial and recreation fisheries with bag limits, size limits, commercial trip limits, with only seasonal fishing allowed; the management of mackerel has been considered a success because the population used to be in decline, but is now on the rise without overfishing occurring.
Spanish mackerel are marketed fresh or frozen as fillets as commercially caught fish are too small to sell in the form of steaks. Their raw flesh is white, they may be prepared by broiling, baking or by smoking. The Spanish mackerel is a popular sushi fish. By analogy with the Japanese Spanish mackerel, a member of the same genus, it is called sawara on sushi menus. Spanish mackerel are similar in appearance to small King Cero mackerel. All three are similar in shape and coloration, they may be distinguished as follows: The lateral line on Spanish and Cero mackerel slopes from the top edge of the gill to the tail. In contrast that of the king mackerel takes an abrupt drop at mid-body; the first dorsal on Spanish and Cero mackerel has a prominent black patch. The King mackerel has none; as all three species keep the first dorsal folded back in a body groove, this difference is not evident. Spanish mackerel have prominent yellow spots on the flanks at all sizes. In addition to such spots, Cero mackerel have one or more yellow stripes along the centerline.
Young King mackerel have similar, but smaller spots. Worldwide, there are many members of this genus quite similar to one or another of these three species. In particular, off Mexico, Atlantic Spanish mackerel may be confused with Serra Spanish mackerel which may appear in the same area. Atlantic mackerel
Plaice is a common name for a group of flatfish that comprises four species: the European, American and scale-eye plaice. Commercially, the most important plaice is the European; the principal commercial flatfish in Europe, it is widely fished recreationally, has potential as an aquaculture species, is kept as an aquarium fish. Commercially important is the American plaice; the term plaice comes from the 14th-century Anglo-French plais. This in turn comes from the late Latin platessa, meaning flatfish, which originated from the Ancient Greek platys, meaning broad; the European plaice is a right-eyed flounder belonging to the Pleuronectidae family. They are a commercially important flatfish, they range geographically from the Barents Sea to the Mediterranean. European plaice are characterised by their smooth brown skin, with distinctive red spots and bony ridge behind the eyes, they feed on polychaetes and bivalves and can be found at depths up to 200 metres. At night they move into shallow waters to feed, during the day they bury themselves in the sand.
Their maximum recorded length is 100 cm, maximum reported age 50 years. Together with sole, European plaice form a group of flatfish that are the most important flatfish in Europe. European plaice have been fished from the North Sea for hundreds of years, they are fished from beam trawlers, otter trawlers or seiners. In the Celtic Sea the plaice species is considered overfished. A smoke cooked. Like the European plaice, the American plaice is a right eyed flatfish belonging to the Pleuronectidae family. American plaice are an Atlantic species, they are found in Europe, where they are called rough dab or long rough dab. They spawn with peak activity in April and May, they are brown or reddish, are smaller than European plaice, with a rougher skin and larger scales. Their maximum recorded length is 82.6 cm, maximum reported age 30 years. They are found between depths of 90 metres and 250 metres, on sandy bottoms with temperatures between -0.5 and 2.5 °C. They feed on small invertebrates; the species is considered by the Northwest Atlantic Fisheries Organization to be overfished, with no signs of recovery.
Though they are currently endangered in Canada due to overfishing, the Canadian government believes the species is abundant. Plaice is the second-most caught flatfish in Canada, accounting for 50 percent of all flatfish caught. American plaice may be an intermediate host for the nematode parasite Otostrongylus circumlitis, a lungworm of seals affecting animals less than 1 year of age. Alaska plaice can live for up to 30 years and grow to 60 centimetres long, but most that get caught are only seven or eight years old, about 30 cm. Most commercial fisheries do not target Alaska plaice, but many are caught as bycatch by commercial trawlers trying to catch other bottom fish. Thus, many Alaska plaice get caught anyway - so much so that, for example, the 2005 total allowable catch in the Bering Sea and Aleutian Islands management area was reached before the end of May of that year; the scale-eye plaice is a flatfish of the family Pleuronectidae. It is a demersal fish, it can weigh up to 1.2 kilograms.
Its native habitat is the northern Pacific from the Sea of Okhotsk to Japan and Korea, though it is found in the Bering Sea. In North German and Danish cuisine plaice is one of the most eaten fish. Filleted and pan-fried plaice is popular hot or cold as an open sandwich topping together with remoulade sauce and lemon slices. Battered plaice can be served hot with french fries and remoulade sauce as a main dish. Breaded frozen plaice, ready to be baked or fried at home, are available in supermarkets. Fresh plaice is oven-baked. "The flesh of plaice is white and subtle-flavoured." Plaice is sometimes used in countries where the dish is popular. Plaice, along with the other major demersal fish in the North Sea such as cod and sole, is listed by the ICES as "outside safe biological limits." Moreover, they are growing less now and are older than six years, whereas they can reach forty. The World Wide Fund for Nature says that in 2006 "of the eight plaice stocks recognised by ICES, only one is considered to be harvested sustainably while three are overexploited.
Data is insufficient to assess the remaining stocks. Rijnsdorp, A. D. Changes in fecundity of female North Sea plaice between three periods since 1900. ICES Journal of Marine Science. S; the plaice being the buckland lectures. Publisher Edward Arnold Gibson, R. N. Flatfishes: Biology and Exploitation. Blackwell Publishing Clover, Charles. 2004. The End of the Line: How overfishing is changing the world and what we eat. Ebury Press, London. ISBN 0-09-189780-7 1998 Marine Fisheries Review article Bulletin announcing reaching the total allowable catch of Alaska plaice for 2005 Guide to Responsible Sourcing of Plaice - produced by Seafish https://web.archive.org/web/20071008001434/http://www.seafish.org/upload/file/fisheries_management/Plaice%20Factsheet2%20%20final.pdf Meet the Ek
Curing (food preservation)
Curing is any of various food preservation and flavoring processes of foods such as meat and vegetables, by the addition of salt with the aim of drawing moisture out of the food by the process of osmosis. Because curing increases the solute concentration in the food and hence decreases its water potential, the food becomes inhospitable for the microbe growth that causes food spoilage. Curing can be traced back to antiquity, was the primary way of preserving meat and fish until the late-19th century. Dehydration was the earliest form of food curing. Many curing processes involve smoking, cooking, or the addition of combinations of sugar, nitrite. Meat preservation in general comprises the set of all treatment processes for preserving the properties, taste and color of raw cooked, or cooked meats while keeping them edible and safe to consume. Curing has been the dominant method of meat preservation for thousands of years, although modern developments like refrigeration and synthetic preservatives have begun to complement and supplant it.
While meat-preservation processes like curing were developed in order to prevent disease and to increase food security, the advent of modern preservation methods mean that in most developed countries today curing is instead practised for its cultural value and desirable impact on the texture and taste of food. For lesser-developed countries, curing remains a key process in the production and availability of meat; some traditional cured meat are cured with salt alone. Today, potassium nitrate and sodium nitrite are the most common agents in curing meat, because they bond to the myoglobin and act as a substitute for the oxygen, thus turning myoglobin red. More recent evidence shows that these chemicals inhibit the growth of the bacteria that cause the disease botulism; the combination of table salt with nitrates or nitrites, called curing salt, is dyed pink to distinguish it from table salt. Neither table salt, nor any of the nitrites or nitrates used in curing is pink. Untreated meat decomposes if it is not preserved, at a speed that depends on several factors, including ambient humidity and the presence of pathogens.
Most meats cannot be kept at room temperature in excess of a few days without spoiling. If kept in excess of this time, meat begins to change color and exude a foul odor, indicating the decomposition of the food. Ingestion of such spoiled meat can cause serious food poisonings, like botulism. Salt-curing processes have been developed since antiquity in order to ensure food safety without relying on artificial anti-bacterial agents. While the short shelf life of fresh meat does not pose a significant problem when access to it is easy and supply is abundant, in times of scarcity and famine, or when the meat must be carried over long voyages, it spoils quickly. In such circumstances the usefulness of preserving foods containing nutritional value for transport and storage is obvious. Curing can extend the life of meat before it spoils, by making it inhospitable to the growth of spoilage microbes. A survival technique since prehistory, the preservation of meat has become, over the centuries, a topic of political and social importance worldwide.
Food curing dates back both in the form of smoked meat and salt-cured meat. Several sources describe the salting of meat in the ancient Mediterranean world. Diodore of Sicily in his Bibliotheca historica wrote that the Cosséens in the mountains of Persia salted the flesh of carnivorous animals. Strabo indicates that people at Borsippa were salting them to eat; the ancient Greeks prepared tarichos, meat and fish conserved by salt or other means. The Romans called this dish salsamentum – which term included salted fat, the sauces and spices used for its preparation. Evidence of ancient sausage production exists; the Roman gourmet Apicius speaks of a sausage-making technique involving œnogaros. Preserved meats were furthermore a part of religious traditions: resulting meat for offerings to the gods was salted before being given to priests, after which it could be picked up again by the offerer, or sold in the butcher's. A trade in salt meat occurred across ancient Europe. In Polybius's time, the Gauls exported salt pork each year to Rome in large quantities, where it was sold in different cuts: rear cuts, middle cuts and sausages.
This meat, after having been salted with the greatest care, was sometime smoked. These goods had to have been important, since they fed part of the Roman people and the armies; the Belgae were celebrated above all for the care. Their herds of sheep and pigs were so many, they could provide skins and salt meat not only for Rome, but for most of Italy; the Ceretani of Spain drew a large export income from their hams, which were so succulent, they were in no way inferior to those of Cantabria. These tarichos of pig would become sought, to the point that the ancients considered this meat the most nourishing of all and the easiest to digest. In Ethiopia, according to Pliny, in Libya according to Saint Jerome, the Acridophages salted and smoked the crickets which arrived at their settlements in the spring in great swarms and which constituted, it was said, their sole food; the smoking of meat was a traditional practice in No
Fat is one of the three main macronutrients, along with carbohydrate and protein. Fats molecules consist of carbon and hydrogen atoms, thus they are all hydrocarbon molecules. Examples include cholesterol and triglycerides; the terms "lipid", "oil" and "fat" are confused. "Lipid" is the general term, though a lipid is not a triglyceride. "Oil" refers to a lipid with short or unsaturated fatty acid chains, liquid at room temperature, while "fat" refers to lipids that are solids at room temperature – however, "fat" may be used in food science as a synonym for lipid. Fats, like other lipids, are hydrophobic, are soluble in organic solvents and insoluble in water. Fat is an important foodstuff for many forms of life, fats serve both structural and metabolic functions, they are a necessary part of the diet of most heterotrophs and are the most energy dense, thus the most efficient form of energy storage. Some fatty acids that are set free by the digestion of fats are called essential because they cannot be synthesized in the body from simpler constituents.
There are two essential fatty acids in human nutrition: linoleic acid. Other lipids needed by the body can be synthesized from other fats. Fats and other lipids are broken down in the body by enzymes called lipases produced in the pancreas. Fats and oils are categorized according to the number and bonding of the carbon atoms in the aliphatic chain. Fats that are saturated fats have no double bonds between the carbons in the chain. Unsaturated fats have one or more double bonded carbons in the chain; the nomenclature is based on the non-acid end of the chain. This end is called the n-end, thus alpha-linolenic acid is called an omega-3 fatty acid because the 3rd carbon from that end is the first double bonded carbon in the chain counting from that end. Some oils and fats are therefore called polyunsaturated fats. Unsaturated fats can be further divided into cis fats, which are the most common in nature, trans fats, which are rare in nature. Unsaturated fats can be altered by reaction with hydrogen effected by a catalyst.
This action, called hydrogenation, tends to break all the double bonds and makes a saturated fat. To make vegetable shortening liquid cis-unsaturated fats such as vegetable oils are hydrogenated to produce saturated fats, which have more desirable physical properties e.g. they melt at a desirable temperature, store well, whereas polyunsaturated oils go rancid when they react with oxygen in the air. However, trans fats are generated during hydrogenation as contaminants created by an unwanted side reaction on the catalyst during partial hydrogenation. Saturated fats can stack themselves in a packed arrangement, so they can solidify and are solid at room temperature. For example, animal fats tallow and lard are solids. Olive and linseed oils on the other hand are liquid. Fats serve both as energy sources for the body, as stores for energy in excess of what the body needs immediately; each gram of fat when burned or metabolized releases about 9 food calories. Fats are broken down in the healthy body to release their constituents and fatty acids.
Glycerol itself can be converted to glucose by the liver and so become a source of energy. There are many different kinds of fats. All fats are derivatives of fatty acids and glycerol. Most fats are glycerides triglycerides. One chain of fatty acid is bonded to each of the three -OH groups of the glycerol by the reaction of the carboxyl end of the fatty acid with the alcohol. Water is eliminated and the carbons are linked by an -O- bond through dehydration synthesis; this process is called esterification and fats are therefore esters. As a simple visual illustration, if the kinks and angles of these chains were straightened out, the molecule would have the shape of a capital letter E; the fatty acids would each be a horizontal line. Fats therefore have "ester" bonds; the properties of any specific fat molecule depend on the particular fatty acids. Fatty acids form a family of compounds that are composed of increasing numbers of carbon atoms linked into a zig-zag chain; the more carbon atoms there are in any fatty acid, the longer its chain will be.
Long chains are more susceptible to intermolecular forces of attraction, so the longer ones melt at a higher temperature. Fatty acid chains may differ by length categorized as short to long. Short-chain fatty acids are fatty acids with aliphatic tails of fewer than six carbons. Medium-chain fatty acids are fatty acids with aliphatic tails of 6–12 carbons, which can form medium-chain triglycerides. Long-chain fatty acids are fatty acids with aliphatic tails of 13 to 21 carbons. Long chain fatty acids are fatty acids with aliphatic tails of 22 or more carbons. Any of these aliphatic fatty acid chains may be glycerated and the resultant fats may have tails of different lengths from short triformin to long, e.g. cerotic acid, or hexacosanoic acid, a 26-carbon long-chain saturated fatty acid. Long chain fats are exemplified by tallow. Most fats found in foo
Okhotsk atka mackerel
The Okhotsk atka mackerel known as hokke in Japan known as the Arabesque greenling, is a mackerel-like species in the family Hexagrammidae. The primary population of the fish is found off the Sea of Okhotsk. According to legend, it was discovered by Nichiji. Pleurogrammus azonus is considered synonymous with the Atka mackerel, P. monopterygius. However, it is a separate species; this fish was documented as Stellistius katsukii but the older name Pleurogrammus azonus takes precedence. The Okhotsk atka mackerel is an important fish in Japanese cuisine. Known as hokke in Japanese, the fish can be fresh, dried, or frozen, can be served raw, grilled or fried. Froese and Pauly, eds.. "Pleurogrammus azonus" in FishBase. March 2012 version. Nelson, J. S. 1994. Fishes of the World. Wiley, New York. Shinohara, G. and K. Amaoka, 1994. Stellistius katsukii Jordan & Tanaka, 1927, a junior synonym of Pleurogrammus azonus Jordan & Metz, 1913. Jap. J. Ichthyol. 40:487-490
Methylmercury is an organometallic cation with the formula +. It is the major source of organic mercury for all humans, it is a bioaccumulative environmental toxicant. "Methylmercury" is a shorthand for "methylmercury cation", is more "methylmercury cation" or "methylmercury cation". It is composed of a methyl group bonded to a mercury ion; as a positively charged ion it combines with anions such as chloride and nitrate. It has high affinity for sulfur-containing anions the thiol groups on the amino acid cysteine and hence in proteins containing cysteine, forming a covalent bond. More than one cysteine moiety may coordinate with methylmercury, methylmercury may migrate to other metal-binding sites in proteins. Methylmercury is formed from inorganic mercury by the action of microbes that live in aquatic systems including lakes, wetlands, sediments and the open ocean. Natural sources of mercury to the atmosphere include volcanoes, forest fires, volatization from the ocean and weathering of mercury-bearing rocks.
In the past, methylmercury was produced directly and indirectly as part of several industrial processes such as the manufacture of acetaldehyde. There are few anthropogenic sources of methylmercury pollution in the United States other than as an indirect consequence of the burning of wastes containing inorganic mercury and from the burning of fossil fuels coal. Although inorganic mercury is only a trace constituent of such fuels, their large scale combustion in utility and commercial/industrial boilers in the United States alone results in release of some 80.2 tons of elemental mercury to the atmosphere each year, out of total anthropogenic mercury emissions in the United States of 158 tons /year. Flooding of soils associated with reservoir creation has been linked to increased methylmercury concentrations in reservoir water and fish. Methylmercury production in inland and marine ecosystems has been attributed to anaerobic bacteria in the sediment. However, peaks in methylmercury in ocean water column and strong associations between methylmercury and organic matter remineralization suggest water column production of methylmercury during carbon remineralization.
Direct measurements of methylmercury production using stable mercury isotopes were made in oxic waters, but the microbes involved are still unknown. Acute methylmercury poisoning occurred at Grassy Narrows in Ontario, Canada as a result of mercury released from the mercury-cell Chloralkali process, which uses liquid mercury as an electrode in a process that entails electrolytic decomposition of brine, followed by mercury methylation in the aquatic environment. An acute methylmercury poisoning tragedy occurred in Minamata, Japan following release of methylmercury into Minamata Bay and its tributaries. In the Ontario case, inorganic mercury discharged into the environment was methylated in the environment; because methylmercury is formed in aquatic systems and because it is not eliminated from organisms it is biomagnified in aquatic food chains from bacteria, to plankton, through macroinvertebrates, to herbivorous fish and to piscivorous fish. At each step in the food chain, the concentration of methylmercury in the organism increases.
The concentration of methylmercury in the top level aquatic predators can reach a level a million times higher than the level in the water. This is because methylmercury has a half-life of about 72 days in aquatic organisms resulting in its bioaccumulation within these food chains. Organisms, including humans, fish-eating birds, fish-eating mammals such as otters and whales that consume fish from the top of the aquatic food chain receive the methylmercury that has accumulated through this process. Fish and other aquatic species are the main source of human methylmercury exposure; the concentration of mercury in any given fish depends on the species of fish, the age and size of the fish and the type of water body in which it is found. In general, fish-eating fish such as shark, marlin, larger species of tuna, largemouth bass, northern pike, have higher levels of methylmercury than herbivorous fish or smaller fish such as tilapia and herring. Within a given species of fish and larger fish have higher levels of methylmercury than smaller fish.
Fish that develop in water bodies that are more acidic tend to have higher levels of methylmercury. Ingested methylmercury is and absorbed by the gastrointestinal tract, it is found complexed with free cysteine and with proteins and peptides containing that amino acid. The methylmercuric-cysteinyl complex is recognized as and/or by amino acids transporting proteins in the body as methionine, another essential amino acid; because of this mimicry, it is transported throughout the body including across the blood–brain barrier and across the placenta, where it is absorbed by the developing fetus. For this reason as well as its strong binding to proteins, methylmercury is not eliminated. Methylmercury has a half-life in human blood of about 50 days. Several studies indicate that methylmercury is linked to subtle developmental deficits in children exposed in-utero such as loss of IQ points, decreased performance in tests of language skills, memory function and attention deficits. Methylmercury exposure in adults has been linked to increased risk of cardiovascular disease including heart attack.
Catfish are a diverse group of ray-finned fish. Named for their prominent barbels, which resemble a cat's whiskers, catfish range in size and behavior from the three largest species alive, the Mekong giant catfish from Southeast Asia, the wels catfish of Eurasia and the piraíba of South America, to detritivores, to a tiny parasitic species called the candiru, Vandellia cirrhosa. There are armour-plated types and there are naked types, neither having scales. Despite their name, not all catfish have prominent barbels. Members of the Siluriformes order are defined by features of the swimbladder. Catfish are of considerable commercial importance. Many of the smaller species the genus Corydoras, are important in the aquarium hobby. Many catfish are nocturnal. Extant catfish species live in coastal waters of every continent except Antarctica. Catfish have inhabited all continents at another. Catfish are most diverse in tropical South America and Africa with one family native to North America and one family in Europe.
More than half of all catfish species live in the Americas. They are the only ostariophysans that have entered freshwater habitats in Madagascar and New Guinea, they are found in freshwater environments. Representatives of at least eight families are hypogean with three families that are troglobitic. One such species is Phreatobius cisternarum, known to live underground in phreatic habitats. Numerous species from the families Ariidae and Plotosidae, a few species from among the Aspredinidae and Bagridae, are found in salt water. In the Southern United States, catfish species may be known by a variety of slang names, such as "mud cat", "polliwogs", or "chuckleheads"; these nicknames are not standardized, so one area may call a bullhead catfish by the nickname "chucklehead", while in another state or region, that nickname refers to the blue catfish. Representatives of the genus Ictalurus have been introduced into European waters in the hope of obtaining a sporting and food resource. However, the European stock of American catfishes has not achieved the dimensions of these fish in their native waters, have only increased the ecological pressure on native European fauna.
Walking catfish have been introduced in the freshwaters of Florida, with the voracious catfish becoming a major alien pest there. Flathead catfish, Pylodictis olivaris, is a North American pest on Atlantic slope drainages. Pterygoplichthys species, released by aquarium fishkeepers, have established feral populations in many warm waters around the world. Most catfish are bottom feeders. In general, they are negatively buoyant, which means that they will sink rather than float due to a reduced gas bladder and a heavy, bony head. Catfish have a variety of body shapes, though most have a cylindrical body with a flattened ventrum to allow for benthic feeding. A flattened head allows for digging through the substrate as well as serving as a hydrofoil; some contains no incisiform teeth. However, some families, notably Loricariidae and Astroblepidae, have a suckermouth that allows them to fasten themselves to objects in fast-moving water. Catfish have a maxilla reduced to a support for barbels. Catfish may have up to four pairs of barbels: nasal and two pairs of chin barbels though pairs of barbels may be absent depending on the species.
Catfish barbels always come as pairs. Many larger catfish have chemoreceptors across their entire bodies, which means they "taste" anything they touch and "smell" any chemicals in the water. "In catfish, gustation plays a primary role in the orientation and location of food". Because their barbels and chemoreception are more important in detecting food, the eyes on catfish are small. Like other ostariophysans, they are characterized by the presence of a Weberian apparatus, their well-developed Weberian apparatus and reduced gas bladder allow for improved hearing as well as sound production. Catfish do not have scales. In some species, the mucus-covered skin is used in cutaneous respiration, where the fish breathes through its skin. In some catfish, the skin is covered in bony plates called scutes. In loricarioids and in the Asian genus Sisor, the armor is made up of one or more rows of free dermal plates. Similar plates are found in large specimens of Lithodoras; these plates may be supported by vertebral processes, as in scoloplacids and in Sisor, but the processes never fuse to the plates or form any external armor.
By contrast, in the subfamily Doumeinae and in hoplomyzontines, the armor is formed by expanded vertebral processes that form plates. The lateral armor of doradids and hoplomyzontines consists of hypertrophied lateral line ossicles with dorsal and ventral lamina. All catfish, except members of Malapteruridae, possess a strong, bony leading spine-like ray on their dorsal and pectoral fins; as a defense, these spines may be locked into place so that they stick outwards, which can inflict severe wounds. In several species catfish can use these f