THE ULTIMATE ANGLING BUCKET LIST

James Dawber, Sutton Springs Rainbow Both species are regularly bred as triploid fish, which
as I will explain in due course, is important on a couple
of fronts in having both a quality comprehensive rainbow trout fishery, and for the brown trout in
maintaining genetic integrity when stocked hatchery reared fish are put into certain rivers.
The intensive aspect of rainbow trout breeding and rearing which has facilitated today's still-water trout
scene boom, actually originated in Denmark, and was introduced to Britain some time during the 1950's.
The big problem back then was that when these fish were later reared for release into angling waters
rather than going straight to the table, at breeding time, they would darken up and look grotty, which
put a lot of people off.
This actually was a double problem, because two slightly different strains of rainbow trout were brought
to the UK from America - the Kamloops, and the Shasta, both of which unfortunately coloured up at
different times of the year.
This was eventually sorted out by manipulating their normally diploid eggs. These contain two sets of
chromosomes, one of which is eventually ejected but can be 'persuaded' to stay put by gentle heat and
pressure treatment, so that when the sperm, which itself contains one set of chromosomes, enters the
egg to fertilize it, instead of it developing with the usual two sets, it ends up with all three, producing
fish that are unable to reproduce, resulting in the clean, healthy, even faster growing sexless triploid
trout used almost exclusively today.
It has to be said that rainbow trout are to no small extent the bimbo's of the freshwater scene. Attractive,
stupid, and often way too easy to catch. Certainly they have become more attractive since the wider use
of triploids eliminated the need for anglers to see those sad dark looking early season diploid fish going
through their annual pre-programmed ritual of trying to breed.
356