They live in the gills of the fish for up to a year, before dropping off and burrowing into the river-bed. They live in deep, glacial lakes in Scotland often feeding on Arctic charr.įreshwater forms of brown trout that migrate from lakes into rivers or streams to spawn and known as ‘potamodromous’.įreshwater pearl mussels are dependent on trout (and charr and salmon) for part of their lifecycle. The very large trout of the River Laxa Myvatynssveit in Iceland can reach weights of over 10lb on a diet of tiny black flies.īrown trout can reach the ripe old age of 20 years.īrown trout eggs need a constant supply of cold, clean and well oxygenated waterįerox trout are a genetically distinct piscivorous form of Salmo trutta. However not all large trout are piscivorous. Oncorhynchus became isolated in the North Pacific and Salmo in the North Atlantic.Ī typical female brown trout produces about 2,000 eggs per kilogram (900 eggs per pound) of body weight at spawning.īrown trout can become more piscivorous (fIsh-eating) as they get larger. They have the same ancestors but divided into two groups around 15-20 million years ago.

Rainbow trout Oncorhynchus mykiss and brown trout Salmo trutta are in the same family (the Salmonidae) but are different species in different genera.

Rainbow and brown trout do not interbreed in the wild although ‘brownbows’ have been produced on fish farms.

For example, large New Zealand trout feed on the periodic plagues of mice. their choice of spawning locations and timing or adaptations to exploit different niches within the food chain. This happens because they have different life strategies e.g. Genetically different trout are capable of spawning together and producing viable offspring but many populations have remained distinct for thousands of years.

WTT Policy on Enforcement Undertakings in Englandīrown trout have between 38 and 42 pairs of chromosomes.

River Ecclesbourne, Snake Lane Fish Pass.River Trent at Stoke-on-Trent: SUNRISE project.Map of Advisory Visits and Trout in the Town Projects.

Interesting facts about the brook trout