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Pool-and-weir fish ladder at Bonneville Dam on the Columbia River Drone video of a fish way in Estonia, on the river Jägala FERC fish ladder safety sign. A fish ladder, also known as a fishway, fish pass, fish steps, or fish cannon, is a structure on or around artificial and natural barriers (such as dams, locks and waterfalls) to facilitate diadromous fishes' natural migration as well as ...
Fishes are a paraphyletic group and for this reason, the class Pisces seen in older reference works is no longer used in formal taxonomy.Traditional classification divides fish into three extant classes (Agnatha, Chondrichthyes, and Osteichthyes), and with extinct forms sometimes classified within those groups, sometimes as their own classes: [1]
Populations of large predatory fish in the global oceans were estimated to be about 10% of their pre-industrial levels by 2003, [1] and they are most at risk of extinction; there was a disproportionate level of large predatory fish extinctions during the Cretaceous–Paleogene extinction event 66 million years ago. [2]
The cobia (Rachycentron canadum) (/ ˈ k oʊ b i ə /, KOH-bee-ə) is a species of marine carangiform ray-finned fish, the only extant representative of the genus Rachycentron and the family Rachycentridae. Its other common names include black kingfish, black salmon, ling, lemonfish, crabeater, prodigal son, codfish, and black bonito.
Lutjanidae or snappers are a family of perciform fish, mainly marine, but with some members inhabiting estuaries, feeding in fresh water. The family includes about 113 species. Some are important food fish. One of the best known is the red snapper. Snappers inhabit tropical and subtropical regions of all oceans.
Gars have been referred to as primitive fish or living fossils because they have retained some morphological characteristics of their earliest ancestors, such as a spiral valve intestine, and a highly vascularized swim bladder lung that supplements gill respiration for breathing both air and water.
The Asian arowana (Scleropages formosus) comprises several phenotypic varieties of freshwater fish distributed geographically across Southeast Asia. [3] While most consider the different varieties to belong to a single species, [4] [5] [6] [3] [7] work by Pouyaud et al. (2003) [8] differentiates these varieties into multiple species.
Cavefish or cave fish is a generic term for fresh and brackish water fish adapted to life in caves and other underground habitats. Related terms are subterranean fish, troglomorphic fish, troglobitic fish, stygobitic fish, phreatic fish, and hypogean fish.