Читать книгу Clinical Guide to Fish Medicine - Группа авторов - Страница 70

Extant species are all within the family Salmonidae. Salmonids are important in aquaculture and fisheries. They are physostomous with small cycloid scales. They have pyloric ceca. There is obvious sexual dimorphism in mature adults, with modified jaws (kypes) seen in mature males (Figure A1.22). Many species migrate between freshwater and saltwater, although not all rely on migration, e.g. rainbow trout (Oncorhynchus mykiss) typically remain in freshwater but some populations, known as steelheads, migrate back to freshwater after spending two to three years in saltwater.