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Many species of salmon are anadromous and can migrate long distances up rivers to spawn Allowing fish and other migratory animals to travel the rivers can help maintain healthy fish populations. Fish migration is mass relocation by fish from one area or body of water to another. Many types of fish migrate on a regular basis, on time scales ...
Highly migratory species – a term which has its origins in the United Nations Convention on the Law of the Sea. It refers to fish species which undertake ocean migrations and also have wide geographic distributions. It usually denotes tuna and tuna-like species, shark, marlins and swordfish. See also transboundary stocks and straddling stocks.
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]
Fish stocks are subpopulations of a particular species of fish, for which intrinsic parameters (growth, recruitment, mortality and fishing mortality) are traditionally regarded as the significant factors determining the stock's population dynamics, while extrinsic factors (immigration and emigration) are traditionally ignored. Stocks fished ...
Now in its fifth edition (2016), the work is a comprehensive overview of the diversity and classification of the 30,000-plus fish species known to science. The book begins with a general overview of ichthyology , although it is not self-contained.
The classification of the Indo-Pacific blue marlin (M. mazara) and the Atlantic blue marlin (M. nigricans) as separate species is under debate. [1] Genetic data suggest, although the two groups are isolated from each other, that they are both the same species, with the only genetic exchange occurring when Indo-Pacific blue marlin migrate to and ...
A few hundred species migrate long distances, in some cases of thousands of kilometres. About 120 species of fish, including several species of salmon, migrate between saltwater and freshwater (they are 'diadromous'). [23] [24] Forage fish such as herring and capelin migrate around substantial parts of the North Atlantic ocean.
During the migration, the fish endure low water temperature of 8.0–9.5 °C (46.4–49.1 °F) due to the steady influx of snow-melt water. This low temperature induces the fish to migrate to side streams where the ground water temperature is around 17.5–21.5 °C (63.5–70.7 °F) to spawn. In other river, Ravi River, this species spawn in May.