Pacific giant bass
| Pacific giant bass | ||||||||||||
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Pacific giant bass ( Stereolepis gigas ) |
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| Scientific name | ||||||||||||
| Stereolepis gigas | ||||||||||||
| Ayres , 1859 |
The Pacific giant perch ( Stereolepis gigas ) is a very large species of marine fish from the family of the wreck perch (Polyprionidae). It occurs on the North American Pacific coast from Humboldt Bay to the southern tip of Baja California . Reports of occurrences in northern Japanese coastal waters are possibly based on a confusion with Stereolepis doederleini , the second species of the genus Stereolepis .
features
Stereolepis gigas has a beefy, grouper- like appearance with a large mouth adapted to a predatory way of life. It can reach a maximum length of 2.5 meters and a maximum weight of over 250 kg. Young fish are bright orange in color and patterned with conspicuous large and black spots. When they reach sexual maturity , the spots disappear and the fish take on a bronze-purple hue. With advancing age, the fish become darker and darker, initially dark gray, then black with a whitish belly. The dorsal fin is placed in a pit when lying back.
For Stereolepis gigas an age of 72 to 75 years old has been demonstrated. The species can possibly be 90 or over 100 years old.
Way of life
Stereolepis gigas lives near the coast at depths of 10 to 80 meters above muddy, sandy or rocky ground and in kelp forests. Large specimens usually live below 30 meters, while small ones are usually seen at depths of 6 to 10 meters. Large specimens leave the coastal areas several times a year to hunt spawning squids in the open sea . As a larva or juvenile fish, Stereolepis gigas is eaten by numerous predators, especially fish and marine mammals. Adult specimens are only captured by larger sharks or humans.
Stereolepis gigas is one of the top predators of its ecosystem, the kelp forest , and as an ambulance hunter catches its prey by suddenly sucking in prey swimming by by suddenly opening its mouth. It feeds on invertebrates and fish. The prey animals include the crab Cancer antennarius , the Californian lobster ( Panulirus interruptus ), the Californian round stingray ( Urobatis halleri ), the torpedo perch Caulolatilus princeps , barracudas and the saw bass Paralabrax clathratus and Paralabrax nebulifer .
Stereolepis gigas is afflicted by various parasites, including endoparasitic hooked suction worms and ectoparasitic woodlice , which mainly attack the gill rakes. The wrasse Oxyjulis californica acts as a cleaner fish in Stereolepis gigas and eats parasites from the skin, from the gills and from the mouth.
Reproduction
Stereolepis gigas spawn in summer from July to September in pairs or in more or less large spawning schools. The up to 60 million eggs, which are 1.6 mm in diameter, and the larvae that hatch after 24 to 36 hours are pelagic . After about a month in the plankton, the benthic juvenile fish phase begins . Stereolepis gigas reaches sexual maturity at the age of 11 to 13 years . Males then weigh around 18 kg, females 23 to 27 kg.
Danger
Although the species has been protected in California since 1962 and its commercial fishing is prohibited, Stereolepis gigas is now critically endangered. It continues to be fished on the Pacific coast of Mexico.
literature
- William N. Eschmeyer, Earl S. Herald, Howard Hamann: A field guide to Pacific Coast Fishes of North America. From the Gulf of Alaska to Baja California (Peterson Field Guides; 28). Houghton Mifflin, Boston, Mass. 1983, ISBN 0-395-33188-9 .
Web links
- Stereolepis gigas on Fishbase.org (English)
- Helke, Z. and A. Lahr 2012. Stereolepis gigas , Animal Diversity Web. Accessed September 1, 2014.
- Stereolepis gigas in the endangered Red List species the IUCN 2004. Posted by: Cornish, A. (Grouper & Wrasse Specialist Group), 2004. Retrieved on September 1, 2014.