Adult Rainbow Trout sampling

[tsfarling]

As most of you know, we are well underway with out juvenile trout sampling in the LMF. One thing that is different this year is we started collecting adults from the river. Some of you may have been witness to this and some maybe not. We are collecting adults from where we have sampled juvenile trout only so this means in Evening Hole. So far, 15 adults have been sampled from EH. We get strange looks when carrying a bucket of 5 rainbow trout out of EH. If you see us, most likely we have our backpack shocking units on us at the time but sometimes we cannot get 5 with the backpack unit so we have to fish for a couple more. All part of the job! Ha! We haven't taken any significant trophy fish from EH. We have seen them, plenty of them, but haven't sampled any. We needed a couple of them but I put them back. Most of the fish we have gotten from EH have been between 10-14" in length. Anyways, if you see us out there, say hello!

Significant adult rainbow trout diet items from what we have found so far:

Crayfish
Caddisflies
Mayflies
Isopods

One had no food in its stomach. It was the smallest fish and had coloring and fin damage consistent with a stocked fish so it probably hadn't adjusted to the system yet.

[mirvc17]

Tyler,

I thought most/all? of the stocked rainbows would be of the triploid type and sterile. Did the LMF not use sterile trout somewhere along the way? I thought the purpose of using triploids was they grow faster in the same amount of time because they don't spend the energy trying to reproduce and makes them more ideal for put and take fisheries.

[Fenwick]

Thanks for the report Tyler. I'd love to see more about what you and your team do there. Always interesting to me. I see there are some welcome updates on the foundation website: lmfrfoundation.org/latest-news-and-updates/

I dunno if you publish your research reports on another website or just submit data to the university but I'd sure love to follow along with everything. The hatchery website makes no mention (not that it has to) about triploid sterile rainbow stock. Where do all the baby fingerling paar marked rainbows come from if not from stockers that reproduce in the LMF?

[Smallfry]

Thanks for the update! The work you do sure is interesting.

[golferjeff]

Neither the Missouri hatchery nor the old Nebraska one stocked triploids. All are capable of reproduction if they live long enough. Triploids are costlier to raise and are extensively used by private stocking groups. Donaldson triploids are very popular in Utah and Nevada. Most of the rainbow fry currently swimming around are from spawned fish (maybe all).

[jonbo]

Hey Grant, thanks as always for the link to the LMF report, and Jeff, thanks for the info clearing up the "triploid question".

[mirvc17]

Interesting... in New Mexico, the wildlife department only stocks female triploids because they are concerned about possible hybridization with native species. The Seven Springs hatchery only produces Rio Grand cutthroat.

[tsfarling]

Definitely not sterile fish. They don't have to worry about any of these guys hybridizing with anything in that water obviously. The Rio Grand cutties are needing protection and rainbows overrun their habitat and interbreed.