Blue catfish
| Blue catfish | ||||||||||||
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Blue catfish ( Ictalurus furcatus ) |
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| Scientific name | ||||||||||||
| Ictalurus furcatus | ||||||||||||
| ( Valenciennes , 1840) |
The blue catfish ( Ictalurus furcatus ) is one of the largest fish species from the family of catfish (Ictaluridae) in North America . The scientific name is derived from the Greek words ἰχθύς ( ichthýs ) ("fish") and αἴλουρος ( ailouros ) ("cat") as well as the Latin furcatus ("forked": caudal fin). The species is fished commercially and by sport anglers and is also drawn in aquaculture .
features
The blue catfish reaches a length of up to 135 centimeters and an average weight of 10 to 20 kilograms. The confirmed maximum weight is 65 kilograms, there is a report from the 19th century on a captured animal weighing over 170 kilograms. The body is moderately strong, elongated with a rounded head. The back of younger animals is pale gray-blue to olive in color, the flanks are silver-gray. Only the population in the Rio Grande has dark spots on the back and sides. The belly is grayish white. Adult animals have a steeply sloping back profile, a blue-black back color and a silvery-blue belly. The fins are light except for the clearly forked caudal fin , which has a dark edge. The mouth is below, the barbels on the lower jaw are white.
The dorsal fin has six soft rays, the anal fin 30 to 36, the pectoral fins 8 to 10 and the pelvic fins eight. The swim bladder has a front and two side chambers. The dental ligament on the intermaxillary bone is not pulled back sideways.
From the very similar channel catfish ( Ictalurus punctatus ), the blue catfish is distinguished by the most missing patches and the higher number of soft rays of the anal fin.
nutrition
In general, the main diet of these predatory fish consists of small invertebrates and fish. Occasionally, frogs , shrimps and crustaceans are also eaten. Some populations feed primarily on fish, especially small minnows . In contrast, coastal populations prefer the anchovy anchoa mitchilli . Other populations eat larvae of dragonflies , mudflies , mosquitoes and mayflies . There are three known nutritional stages during development. As long as the blue catfish are smaller than 10 centimeters, they will eat zooplankton , especially copepods . When they are between 10 and 24 centimeters tall, they eat invertebrates (crabs, mussels , snails ), bottom-dwelling fish and other organic material. From a height of 24 centimeters, the fish begin to eat larger fish and larger invertebrates. In addition, from this point on, the fish also start looking for food at night. They are particularly active in the period between midnight and sunrise.
Habitat and Distribution
Blue catfish are freshwater fish which are mainly found in large rivers but also in tributaries where they can be found in deeper river areas. But they also occur in ponds , lakes and large reservoirs . In summer they swim upstream to get to cooler areas. In winter, when looking for warmer areas, swim downstream. The fish generally live in running water and also in rapids. The water temperature is between 10 and 22 ° C. The preferred pH is between 6.6 and 8.4. The animals also tolerate brackish water , but not as well as the white catfish . The bottom of the water in which you stay can be sandy, rocky and gravelly. The fish avoid muddy bottoms. The animals are native to the estuaries of various rivers in the Gulf of Mexico , the Ohio River , the Platte River and the Missouri River . In Texas , the fish are common almost everywhere except in the northwestern part of the state. The Colorado River , the Nueces River and the Brazos River should be mentioned here in particular . The fish are also widespread in the Mississippi River and its tributaries. The fish can also be found in Guatemala , Minnesota , in the Rappahannock River and in Mexico through artificial distribution . The fish used to be found in the Iowa River and Keokuk , but this is now prevented by dams. The species occurs in subtropical North America in the Mississippi, Missouri and Ohio, as well as along the Gulf Coast in Mexico and in northern Guatemala.
Reproduction
The fish are usually sexually mature with a size of about 60 centimeters. They spawn from April to June, for which reason they immigrate to calm waters. The spawn is deposited in nests and guarded against predators until the young hatch. Adult females can lay up to 200,000 eggs, sometimes more. The population doubling time is estimated at 4.5 to 14 years.
Individual evidence
- ↑ The generic name Rafinesques (1820) seems astonishingly mutilated for this “original genius” author and was improved by Cope to “Ichthyaelurus” (such emendations are now invalid).
- ↑ Blue Catfish ( Ictalurus furcatus ). In: Texas Parks and Wildlife. (English).
- ↑ Blue Catfish-Ictalurus furcatus. ( Memento of the original from June 23, 2010 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. In: Iowa Fish Atlas. (English).
Web links
- Blue catfish on Fishbase.org (English)
- Blue Catfish ( Ictalurus furcatus ). In: Texas Parks and Wildlife. (English)
- Blue catfish. In: Florida Museum of Natural History. (English)
- Blue catfish Ictalurus furcatus . In: Texas State Department of Biology. (English)
- Ictalurus furcatus inthe IUCN 2013 Red List of Threatened Species . Listed by: NatureServe, 2012. Retrieved January 10, 2014.