>When you say mature at 6" do you mean full sized or reproductively mature.
Full size. Such fish are usually also characteristically highly coloured.
>Are they reproductively mature at 6" in other streams
I think Salmo trutta does have 'sneaker' males (as do Oncorhynchus, don't
they?), that may be reproductively mature at very small sizes, but these
usually retain the potential to continue to grow when in more productive
environments
>or something in the food that promotes early maturation?
It isn't early maturation that is the case here, but a greatly reduced
growth limited by a unpredictable and variable food source.
Salmo trutta is a fascinating and highly variable species, that in the past
was split up into many different species just within the British Isles. Some
of the Irish Lochs have distinct trophically specialized reproductively
isolated populations that I should imagine actually are well on their way to
speciation.
/-----------------------------------------------------------------------------
/"Unless stated otherwise, comments made on this list do not necessarily
/ reflect the beliefs or goals of the North American Native Fishes
/ Association"
/ This is the discussion list of the North American Native Fishes Association
/ nanfa_at_aquaria.net. To subscribe, unsubscribe, or get help, send the word
/ subscribe, unsubscribe, or help in the body (not subject) of an email to
/ nanfa-request_at_aquaria.net. For a digest version, send the command to
/ nanfa-digest-request_at_aquaria.net instead.
/ For more information about NANFA, visit our web page, http://www.nanfa.org