Brown trout in Japan
In recent years, the natural breeding area of brown trout has spread rapidly in about 10 years and the survey can not be made in time.
In “Nagano” where I live, Brown trout grows naturally in the mainstream of each river
It is still rare at mountain streams where the but it is problematic as to how it will become in the future
From the viewpoint of the fishermen, the expansion of the habitat and the expansion of the habitat seem to be very intense than the research institution’s presentation.
Brown trout that can correspond to the mainstream area where existing trout does not live is an easy-to-live environment.
Brown trout also increased in my fishing ground
They grow to large size, average about 45 - 50 cm
I have caught 70 centimeters or more
It is a pleasant thing to do as an angler but it is a difficult problem
Nagano Environmental Conservation Research Institute 2054-120 Kitago, Nagano 381-0075, Japan
e-mail: kitano-satoshi@pref. nagano .jp
Ecological Impacts of Invasive Exotic Trout in Japan
“Abstract Rainbow trout (Oncorhynchus mykiss), brown trout (Salmo trutta) and brook trout (Salvelinus fontinalis) introduced to Japanese inland waters have significant impacts on native aquatic organisms such as white-spotted charr (Salvelinus leucomaenis), Dolly Varden charr (Salvelinus malma), masu salmon (Oncorhynchus masou) and Sakhalin taimen (Hucho perri), in coldwater habitats. Rainbow and brown trout have successfully established reproducing populations in Japan, and especially expanding their distribution in Hokkaido. Brook trout have shown relatively limited invasion in some spring-fed streams and ponds both in Honshu and Hokkaido. The introduced exotic trout have been implicated in reducing populations of native fishes, especially stream salmonids, through predation, competitive interaction for resources, and interspecific hybridization. Monitoring, management, including eradication, and evaluation of the effectiveness of these measures should be carried out to contain the ecological risks of trout invasion.”
