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46-506: Completed on 5 November 1975, the Vacha Dam is situated 680 metres (2,230 ft) above sea level . The dam was designed by Bulgarian hydroengineers, though their work was overseen by Russian , Japanese and Italian experts. It is a concrete gravity structure of 144.5 metres (474 ft) height, making it the tallest dam in Bulgaria together with Krichim Dam. Its pumped storage power plant has

92-734: A hydrofoil . Some have a mouth that can expand to a large size and contains no incisiform teeth; catfish generally feed through suction or gulping rather than biting and cutting prey. Some families, though, notably the Loricariidae and Astroblepidae , have a suckermouth that allows them to fasten themselves to objects in fast-moving water. Catfish also have a maxilla reduced to a support for barbels ; this means that they are unable to protrude their mouths as other fish such as carp . Catfish may have up to four pairs of barbels - nasal, maxillary (on each side of mouth), and two pairs of chin barbels, though pairs of barbels may be absent depending on

138-459: 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, but the European stock of American catfishes has not achieved the dimensions of these fish in their native waters and have only increased

184-504: A capacity of 160 MW. The potential of hydroelectric projects on the Vacha River in southern Bulgaria was recognized by the Bulgarian government at least as early as the early 1960s. The June 1962 edition of Water Power stated that the dam was "scheduled to add 436 MW to the Bulgarian system by the end of 1965." In 1964, Energy International reported that dam construction on the river

230-478: A defense, these spines may be locked into place so that they stick outwards, enabling them to inflict severe wounds. In numerous catfish species, these fin rays can be used to deliver a stinging protein if the fish is irritated; as many as half of all catfish species may be venomous in this fashion, making the Siluriformes overwhelmingly the vertebrate order with the largest number of venomous species. This venom

276-474: 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 (species that eat dead material on the bottom), and even to a tiny parasitic species commonly called

322-445: A historic mean sea level . In geodesy , it is formalized as orthometric height . The zero level varies in different countries due to different reference points and historic measurement periods. Climate change and other forces can cause sea levels and elevations to vary over time. Elevation or altitude above sea level is a standard measurement for: Elevation or altitude is generally expressed as " metres above mean sea level" in

368-495: A juvenile obaichthyid lepisosteiform , possibly a junior synonym of Obaichthys . The authors of the original study still stood by their original conclusion based on the absence of important holostean characters, and noted that it could not be a juvenile, since the bones were completely ossified. The taxonomy of catfish is quickly changing. In a 2007 and 2008 paper, Horabagrus , Phreatobius , and Conorhynchos were not classified under any current catfish families. There

414-416: A legend of a human-sized catfish called The Golden One who inhabits the depths of the dam and whose scales flicker in warm and still weather. As of 2003, there are three houseboats permanently moored in the reservoir. Above mean sea level Height above mean sea level is a measure of a location's vertical distance ( height , elevation or altitude ) in reference to a vertical datum based on

460-661: A part of cascade development on the Vacha River in southern Bulgaria. Vacha River, one of the main right tributaries of the Maritsa , is the second longest river that has its source in the Rhodopes , the Arda being the longest. It is 105 kilometres (65 mi) long and is formed by the confluence of the rivers Chairdere and Buynovska . The Vacha runs through the Rhodopes forming a deep valley where

506-826: A rate three times faster than that of the past century. In June 2005, researchers named the newest family of catfish, Lacantuniidae , only the third new family of fish distinguished in the last seventy years, the others being the coelacanth in 1938 and the megamouth shark in 1983. The new species in Lacantuniidae , Lacantunia enigmatica , was found in the Lacantun river in the Mexican state of Chiapas . The higher-level phylogeny of Siluriformes has gone through several recent changes, mainly due to molecular phylogenetic studies. While most studies, both morphological and molecular, agree that catfishes are arranged into three main lineages ,

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552-536: A result of long branch attraction , incorrectly placing Loricarioidei as the earliest-branching catfish lineage. When a data filtering method was used to reduce lineage rate heterogeneity (the potential source of bias) on their dataset, a final phylogeny was recovered which showed the Diplomystidae are the earliest-branching catfish, followed by Loricarioidei and Siluroidei as sister lineages, providing both morphological and molecular support for Diplomystidae being

598-557: Is Phreatobius cisternarum , known to live underground in phreatic habitats. Numerous species from the families Ariidae and Plotosidae , and 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

644-484: Is a monument to the members of the World War II anti-fascist Anton Ivanov Rhodope Partisan Detachment in the area. The reservoir created by the Vacha Dam stretches upstream over a length of 20 kilometres (12 mi). Physicochemical analysis of the reservoir water has been carried out during 2008 and 2009 to determine the diversity, distribution and quantitative development of phytoplankton , and to primarily evaluate

690-442: Is complex. Land mass subsidence (as occurs naturally in some regions) can give the appearance of rising sea levels . Conversely, markings on land masses that are uplifted (due to geological processes) can suggest a relative lowering of mean sea level. Catfish Extant families: Extinct family: Catfish (or catfishes ; order Siluriformes / s ɪ ˈ lj ʊər ɪ f ɔːr m iː z / or Nematognathi ) are

736-593: Is disagreement on the family status of certain groups; for example, Nelson (2006) lists Auchenoglanididae and Heteropneustidae as separate families, while the All Catfish Species Inventory (ACSI) includes them under other families. FishBase and the Integrated Taxonomic Information System lists Parakysidae as a separate family, while this group is included under Akysidae by both Nelson (2006) and ACSI. Many sources do not list

782-594: Is hemmed between the Krichin Reservoir on the upstream and the Devan HPP and is part of the Dospad-Vacha cascade development involving six dams. The construction of this highest concreted masonry dam in Bulgaria was started in the 1960s and completed in 1975. The benefits derived from the project cover power generation of 160 MW, irrigation, reservoir fisheries and drinking water supply to part of Plovdiv Province . There

828-476: Is produced by glandular cells in the epidermal tissue covering the spines. In members of the family Plotosidae and of the genus Heteropneustes , this protein is so strong it may hospitalize humans who receive a sting; in Plotosus lineatus , the stings can be lethal. The dorsal- and pectoral-fin spines are two of the most conspicuous features of siluriforms, and differ from those in other fish groups. Despite

874-570: Is usually considered to be the earliest branching catfish lineage and the sister group to the other two lineages, Loricarioidei and Siluroidei. Molecular evidence usually contrasts with this hypothesis, and shows the suborder Loricarioidei as the earliest branching catfish lineage, and sister to a clade that includes the Diplomystidae and Siluroidei; this phylogeny has been obtained in numerous studies based on genetic data. However, it has been suggested that these molecular results are errors as

920-776: The Cypriniformes (carps and minnows), Characiformes (characins and tetras), Gonorynchiformes (milkfish and beaked salmons) and Gymnotiformes (South American knifefish), a superorder characterized by the Weberian apparatus . Some place Gymnotiformes as a sub-order of Siluriformes; however, this is not as widely accepted. Currently, the Siluriformes are said to be the sister group to the Gymnotiformes, though this has been debated due to more recent molecular evidence. As of 2007 there were about thirty-six extant catfish families, and about 3,093 extant species have been described. This makes

966-766: The Late Cretaceous , including the Andinichthyidae , Vorhisia vulpes and possibly Arius . A potential fossil record is known from the earlier Coniacian - Santonian stages in Niger of West Africa , though this has been considered unreliable, and the putative earliest armored catfish known from the fossil record, Afrocascudo , lived during the Cenomanian age of the Late Cretaceous in Morocco of North Africa ( Kem Kem Group ). The describers of Afrocascudo claimed that

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1012-418: The candiru , Vandellia cirrhosa . Neither the armour-plated types nor the naked types have scales. Despite their name, not all catfish have prominent barbels or "whiskers". Members of the Siluriformes order are defined by features of the skull and swimbladder . Catfish are of considerable commercial importance; many of the larger species are farmed or fished for food. Many of the smaller species, particularly

1058-591: The metric system , or " feet above mean sea level" in United States customary and imperial units . Common abbreviations in English are: For elevations or altitudes, often just the abbreviation MSL is used, e.g., Mount Everest (8849 m MSL), or the reference to sea level is omitted completely, e.g., Mount Everest (8849 m). Altimetry is the measurement of altitude or elevation above sea level. Common techniques are: Accurate measurement of historical mean sea levels

1104-510: The Americas. They are the only ostariophysans that have entered freshwater habitats in Madagascar , Australia, and New Guinea . They are found in fresh water/ brackish water environments, though most inhabit shallow, running water. Representatives of at least eight families are hypogean (live underground) with three families that are also troglobitic (inhabiting caves). One such species

1150-538: The ariid catfish, where the young retain yolk sacs late into juvenile stages, and many pimelodids, which may have elongated barbels and fin filaments or coloration patterns. Sexual dimorphism is reported in about half of all families of catfish. The modification of the anal fin into an intromittent organ (in internal fertilizers) as well as accessory structures of the reproductive apparatus (in both internal and external fertilizers) have been described in species belonging to 11 different families. Catfish have one of

1196-464: The armor is formed solely by expanded vertebral processes that form plates. Finally, the lateral armor of doradids , Sisor , and hoplomyzontines consists of hypertrophied lateral line ossicles with dorsal and ventral lamina . All catfish other than members of the Malapteruridae ( electric catfish ), possess a strong, hollow, bony, leading spine-like ray on their dorsal and pectoral fins . As

1242-508: The catfish order the second or third most diverse vertebrate order; in fact, one out of every twenty vertebrate species is a catfish. Catfish are believed to have a Gondwanan origin primarily centered around South America, as the most basal living catfish groups are known from there. The earliest known definitive members lived in the Americas from the Campanian to Maastrichtian stages of

1288-553: The dam would not fail. In February 2012, Bulgarian Minister of Economy and Energy, Traycho Traykov started an inspection of dams in the country, amongst them Vacha and Krichim dams and the Orpheus Water Power Plant . The inspection was initiated by reports that dams in the region had been overflowing and were hazardous, and engineers in the country warned that the problem would worsen due to snow melt and cause potential flooding. The Vacha Dam Reservoir has been created as

1334-1524: The earliest branching catfish. Below is a list of family relationships by different authors. Lacantuniidae is included in the Sullivan scheme based on recent evidence that places it sister to Claroteidae . Phylogeny of living Siluriformes based on 2017 and extinct families based on Nelson, Grande & Wilson 2016. † Andinichthyidae Nematogenyidae [REDACTED] Trichomycteridae [REDACTED] Callichthyidae [REDACTED] Astroblepidae [REDACTED] Loricariidae [REDACTED] Diplomystidae † Bachmanniidae † Hypsidoridae Cetopsidae [REDACTED] Siluridae [REDACTED] Pangasiidae Mochokidae [REDACTED] Claroteidae Plotosidae Ictaluridae [REDACTED] Clariidae [REDACTED] Ailiidae Sisoridae [REDACTED] Bagridae [REDACTED] Aspredinidae Doradidae [REDACTED] Auchenipteridae [REDACTED] Heptapteridae [REDACTED] Pseudopimelodidae [REDACTED] Pimelodidae [REDACTED] Unassigned families: Extant catfish species live inland or in coastal waters of every continent except Antarctica . Catfish have inhabited all continents at one time or another. They are most diverse in tropical South America, Asia, and Africa, with one family native to North America and one family in Europe. More than half of all catfish species live in

1380-429: The ecological pressure on native European fauna . Walking catfish have also been introduced in the freshwater areas of Florida, with the voracious catfish becoming a major alien pest there. Flathead catfish , Pylodictis olivaris , is also a North American pest on Atlantic slope drainages. Pterygoplichthys species, released by aquarium fishkeepers, have also established feral populations in many warm waters around

1426-439: The former ranges throughout Europe, and the latter is restricted to Greece . Mythology and literature record wels catfish of astounding proportions yet are to be proven scientifically. The typical size of the species is about 1.2–1.6 m (3.9–5.2 ft), and fish more than 2 m (6.6 ft) are rare. However, they are known to exceed 2.5 m (8.2 ft) in length and 100 kg (220 lb) in weight. In July 2009,

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1472-487: The genus Corydoras , are important in the aquarium hobby . Many catfish are nocturnal , but others (many Auchenipteridae ) are crepuscular or diurnal (most Loricariidae or Callichthyidae , for example). Molecular evidence suggests that in spite of the great morphological diversity in the order, all catfish form a monophyletic group. Catfish belong to a superorder called the Ostariophysi , which also includes

1518-456: The genus is possible. As far as known for most catfish, features that are often characteristic of species, such as mouth and fin positions, fin shapes, and barbel lengths, show little difference between juveniles and adults. For many species, pigmentation pattern is also similar in juveniles and adults. Thus, juvenile catfish generally resemble and develop smoothly into their adult form without distinct juvenile specializations. Exceptions to this are

1564-404: The largest ranges in size within a single order of bony fish . Many catfish have a maximum length of under 12 cm (4.7 in). Some of the smallest species of the Aspredinidae and Trichomycteridae reach sexual maturity at only 1 cm (0.39 in). The wels catfish , Silurus glanis , and the much smaller related Aristotle's catfish , are the only catfish indigenous to Europe ;

1610-566: The order. In loricarioids and in the Asian genus Sisor , the armor is primarily 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 (family Amphiliidae ) and in hoplomyzontines ( Aspredinidae ),

1656-490: The presence of cyanotoxins from the point of view of reservoir water usage as a safe drinking water source. The study indicated that the level of cyanotoxin in the reservoir was within limits. Continued monitoring of the level of cyanoprokaryota and their toxins was considered essential in all reservoirs for risk assessment of the water for contamination. The Vacha reservoir has been stocked with catfish , carp and other fish species popular among fishermen. The locals tell

1702-467: The presence of a Weberian apparatus . Their well-developed Weberian apparatus and reduced gas bladder allow for improved hearing and sound production. Catfish do not have scales ; their bodies are often naked. In some species, their 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 ; some form of body armor appears in various ways within

1748-510: The presence of a derived loricariid so early on would indicate the extensive diversification of catfish, or at least loricarioids, prior to the beginning of the Late Cretaceous. As extant loricariids are only known from South America, much of this diversification must have occurred on the supercontinent of West Gondwana prior to its fragmentation into South America and Africa. Britz and colleagues suggested that Afrocascudo instead represents

1794-430: The recently revised family Anchariidae . The family Horabagridae , including Horabagrus , Pseudeutropius , and Platytropius , is not shown by some authors but presented by others as a true group. Thus, the actual number of families differs between authors. The species count is in constant flux due to taxonomic work as well as description of new species. Between 2003 and 2005, over one hundred species were named,

1840-501: The relationship among these lineages has been a contentious point in which these studies, performed for example by Rui Diogo , differ. The three main lineages in Siluriformes are the family Diplomystidae , the denticulate catfish suborder Loricarioidei (containing the Neotropical "suckermouth" catfishes), and the suborder Siluroidei, which contains the remaining families of the order. According to morphological data, Diplomystidae

1886-475: The species. Catfish barbels always occur in pairs. Many larger catfish also 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 generally small. Like other ostariophysans , they are characterized by

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1932-471: The two dams, the Krichim and Vacha, are located. The reservoir lies 40 km (25 mi) from Plovdiv , one of Bulgaria's major cities, and a potential breach in the dam walls would gravely endanger the city. In the direct vicinity of the reservoir is the town of Krichim . The Vacha Dam is 144.5 metres (474 ft) in height and has a water spread which stretches 30 kilometres (19 mi) upstream. The dam

1978-599: The widespread use of the spines for taxonomic and phylogenetic studies the fields have struggled to effectively use the information due to a lack of consistency in the nomenclature, with a general standard for the descriptive anatomy of catfish spines proposed in 2022 to try and resolve this problem. Juvenile catfish, like most fish, have relatively large heads, eyes, and posterior median fins in comparison to larger, more mature individuals. These juveniles can be readily placed in their families, particularly those with highly derived fin or body shapes; in some cases, identification of

2024-428: The world. Most catfish are bottom feeders . In general, they are negatively buoyant , which means that they usually 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 perhaps serving as

2070-433: The “Design Earthquake (DE)” and Maximum Credible Earthquake (MCE), taking due note of the interaction between the foundation soil and the structure and the non-linear behaviour of concrete. The seismic accelerations considered in the analysis were 0.32 g, 0.5 g and 1.1 g. The analysis concluded that the dam is safe under the seismic considerations except that partial damage could occur under the maximum seismic design factor but

2116-429: Was underway. It appears that development of the dam took longer than expected, eventually completed in 1975. As the dam was designed for a maximum seismic design acceleration of 0.05 g according to the regulations apparent in Bulgaria in 1964, it was considered appropriate to study the safety of the dam structure by two dimensional finite element method under revised seismic norms prescribed in 1984, namely for two levels,

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