I thought stocked trout are sterile

[Rockyman41]

Killed some time with my daughter on Saturday at the diplomat mine trout pond. We did pretty well and my daughter ended up catching her first fish.

Anway, we kept a couple for the frying pan but when I went to clean them I had a bit of a surprise. One fish was full of eggs and the other milt. I had noticed the ones we released were leaking milt as well. I've never seen this with any other trout I've caught and I was under the impression that stocked trout were triploid and therefore sterile. I can't imagine they would be able to spawn in the mud bottomed pond.

[aulrich]

Yea they are normal fish for the most part. There is a stock lake I fish and you can see them trying to spawn on the gravel of the boat launch.

[EZM]

There are many "mechanisms" for hatcheries to produce fish that are sterile, or in some cases all the same sex.

I'm not an expert but did some reading on this a while back - here's how I understand it ....

Triploids (3N) - are pressure shocked fertilized eggs that create sterile fish to be hatched out of those eggs - it is nearly 100% effective. Some species will still produce eggs/sperm, although the eggs/sperm are not viable. This is the most common form of stocked trout where population control is required or desired.

All Female (AF) fish - are exactly that - all female. This method is most problematic as there is/are various steps in the process that don't always ensure 100% results. These fish are often smaller and weaker and don't make great stock. This method is not used commonly anymore.

All Female Triploid - AF3N - this is all female triploids. These can also produce eggs, although. Again, not viable. 1 in 1,000 fish remains a male but only 1 in 1000 of these will have a developed sperm duct.

So I guess my point is - they may have eggs/sperm - but it doesn't mean they are viable.

[the local angler]

i have also encountered this too but the thing that confuses me is not the reproduction part but why they won't stock lakes and ponds with trout that are fertile? ya i understand they need fresh running water to help the eggs and such but if trout stocked in lakes and ponds can reproduce and regenerate the population wouldn't that be a good thing? reduces the cost of stocking every year?

[Pudelpointer]

Triploid fish are more expensive to produce, therefore they are only put in select fisheries - such as delayed retention fisheries that rarely winter kill.

Most trout stocked into AB waters are not triploid. Why waste $$ putting triploid fish into lakes where people are killing 5 trout per day, every day, day after day, after day?

The main benefit to triploid trout is not population control, it is that they have a higher survival rate / longer life, and therefore attain greater size faster, as they are not physically stressed by spawning.

Successful reproduction of rainbow trout in lake environments is virtually nil. Without cold, clean, well oxygenated moving water with clean, silt free gravel, tainbow trout eggs will not survive. The only exception to the "moving water" requirement is (rarely) springs with suitable substrate.

[Rockyman41]

Well there you go, I learned something new. Thanks guys!

I was wondering why I had never noticed this before but then I realized I've never fished for trout this early in the season. I also rarely keep trout but such is the nature of bait fishing, a couple got hooked badly and I had to keep them. They ended up being pretty tasty cooked over the campfire that night.

[waterninja]

Originally Posted by Rockyman41

Killed some time with my daughter on Saturday at the diplomat mine trout pond. We did pretty well and my daughter ended up catching her first fish.

Anway, we kept a couple for the frying pan but when I went to clean them I had a bit of a surprise. One fish was full of eggs and the other milt. I had noticed the ones we released were leaking milt as well. I've never seen this with any other trout I've caught and I was under the impression that stocked trout were triploid and therefore sterile. I can't imagine they would be able to spawn in the mud bottomed pond.

Yeh, the females still produce eggs and even lay them. The males come and eat them. If you saved some of those eggs Rocky, they are absolutly the most effective bait to use in the future. All you have to do is learn how to make the little roe sacks out of the little squares of mesh that some fishing stores sell.

[EZM]

[QUOTE=Pudelpointer;3192502]

The main benefit to triploid trout is not population control, it is that they have a higher survival rate / longer life, and therefore attain greater size faster, as they are not physically stressed by spawning.

QUOTE]

Agreed on all points with one exception .... triploids are used in any watershed where there is a risk of spawning/contaminating wild rainbow or cutthroats - so the term "population control" I agree, isn't the correct term I should have used, it's more like interbreeding, contaminating etc...

There are quite a few lakes where 3N are used here in Alberta where there isn't a significant risk of contamination nor is there suitable/viable habitat for spawning but they still stock 3N's.

The methods used today aren't significantly more expensive compared to what they were even 10-15 years ago according to an article I recently read. This is great news considering a great point you made, triploids grow faster, live longer and as a result make them more attractive to put/take fisheries.

The only thing better than a 10" fat rainbow in a pan - is a 14" fat rainbow in a pan.

[the local angler]

interesting points thanks for the response.

[Bill L]

Originally Posted by waterninja

Yeh, the females still produce eggs and even lay them. The males come and eat them. If you saved some of those eggs Rocky, they are absolutly the most effective bait to use in the future. All you have to do is learn how to make the little roe sacks out of the little squares of mesh that some fishing stores sell.

I use cheap pantyhose from a dollar store to make bait sacks for power bait and cheese. This really works good for keeping your bait on the hook and can be a life saver if you take kids fishing.

[EZM]

Originally Posted by Bill L

I use cheap pantyhose from a dollar store to make bait sacks for power bait and cheese. This really works good for keeping your bait on the hook and can be a life saver if you take kids fishing.

And ..... you can save some pantyhose for the next time you decide to rob a liquor store too.