Fishing Forum

I was watching an older episode of Hooked on Utah. They caught a fat rainbow trout and made a comment about it spawning soon.  I was under the impression that rainbows in utah were sterile. How true is that?

(03-03-2020, 10:22 PM)steelhawk Wrote: [ -> ]I was watching an older episode of Hooked on Utah. They caught a fat rainbow trout and made a comment about it spawning soon.  I was under the impression that rainbows in utah were sterile. How true is that?

Most of the rainbows planted by DWR are sterile "triploids".   But they do develop eggs and milt and go through the spawn routine.  However, the eggs are not fertile.

(03-03-2020, 10:22 PM)steelhawk Wrote: [ -> ]I was watching an older episode of Hooked on Utah. They caught a fat rainbow trout and made a comment about it spawning soon.  I was under the impression that rainbows in utah were sterile. How true is that?

Yes...they think they are spawning, but are shooting blanks, lol! There are different straines thought that "spawn" at different times...some go in the winter, some in the spring.

Triploid trout are created by heat-shocking the fertilized eggs.  This results in fish that contain 3 sets of chromosomes.  Half of the fish will be XXY (triploid males) and half will be XXX (triploid females).  Both should be sterile or infertile.

Male triploids may still develop functional gonad tissue and may participate in spawning behavior even though they are sterile.
Females do not develop gonads (or, develop "string" like gonads) and do not exhibit spawning behaviour.

The northern part of the state stocks almost exclusively sterile triploids; however, other portions of the state stock fertile rainbows that have not gone through the heat shocking process. So, trout like at Otter Creek reservoir are fertile; however, very rarely are these spawns successful because of a lack of good spawning habitat.