Pond Boss Forums MANAGING AN EXISTING POND Evaluating and adjusting fish populations Trout, Managing Naturaly Spawning brookies

Hello pro's & part timers.

Thank you all for making this forum such an great place to gather information & hapilly waste away a boring afternoon.

My pond is about 2 acres, 10 - 12 feet maximum depth. Brook trout spawn naturally on the gravelly sections where water percolates up from the ground. From what I understand these brookies have been self sustaining for 12 years or more (we only bought the place last year). Last fall I added 250 all female 4" rainbows for variety. Aside from the brookies and the rainbows there are no other species of fish present. We do not feed the fish at all however we do have amazing insect hatches that are great fun to watch.

I only started keeping a fishing record in August last year most fish caught were 8" (9/10) the biggest I caught was 10.5" & deep chested.

My questions are:

1 - What would indicate overcrowding?

2 - How should I manage/harvest to attain bigger average sizes overall?

3 - Can a 8" brookie (in september) be the previous years spawn? I never saw anything between 4" and 7" last year. I'm thinking the fish that were 3 - 4" in the fall were born that spring . Is this right?

4 - If the previous assumptions are right, then as I only caught 3-4 fish better than 9.5" should I assume overcrowding? How would I remedy this if it's the case?

Thank you all for your thoughts and insights on this. It's really appreciated.

Chris H.

SmallFry,
First, it's been my observation that in every case where rainbows have been introduced to a self sustaining native brook trout fishery, the brookies disapear within a few years. The exotic rainbows out compete them.

1) Slow to no growth will be evidence of overcrowding. You will eventually end up with all one size (stunted) fish in the pond.

2) I hope Greg or someone chimes in here.
Maybe start a feeding program. Don't harvest the largest fish.

3) Yes. An 8" brook in Sept. of 2003 could have been from the ("previous year") spring of 2002 spawn.

4) Again I hope one of the pro's answer. However give more info. ..
What's the most common size fish caught?
How did you sample the fish population? IE: did you fish all areas of the pond? When? Am, Pm, Cool weather, Hot weather? Give the pros as much info as you can & maybe they can get a feel for your situation & give an educated guess to this question.

If you fish are deep bodied they have enough feed. Your rainbows will be more agressive than your brook trout, but they will probably die out in 3 to 4 years if you do not restock as it is doubtful they will be able to spawn successfully in the pond as the brook trout can.

Under optimum conditions brook trout can grow 1 1/2 inches per month.

You should be able to get stocking recommendations from you Ministry of Natural Resources for your pond size as not to overstock.

You could get optimum growth and larger maximum size by feeding, but you run the risk of enriching the pond and getting weed problems and other problems that go with that. If you have such a prolific insect population I would stick with staying in the guidelines for stocking densities and enjoy your pond!

Ric & Cecil,

Thanks for the replies. The rainbows shouldn't decimate the brookie population as I bought all female stock. I intend to harvest these as soon as they are big enough to catch on hook & line.

As for Size, of the 40 fish I caught & kept.

37 were 7.5 - 8.5 inches, never smaller. In this size they are not very deep chested at all. To me they have the same physical appearance as mountain stream dwelling brookies. Is this overcrowding or normal for 2 year old brookies?

3 were 9.5 inches or better at this size they are deep chested and heavy. I wouldnt have kept these but fishing with live bait doesn't always leave you the option of letting them go.

I fished in all conditions sunny through cloudy weather, hot to cold, early morning through evening. The fish always bite.... I usually fish to keep 8 Fish, under the best conditions it takes longer to put on a worm than catch a fish and the worst day I had (cold/cloudy/light rain) was 1 hour to get my 8 fish.

So any ideas how many fish I should keep per season (2 acre pond) & what sizes should be kept and what should be released to get bigger fish overall?

Thank you all for your input

You wouldn't have had to worry if you had male rainbows. It is very, very, rare for rainbows to successfully spawn in ponds. Brook trout can do it with ease while rainbow and browns cannot.

I assume you are talking of the brookies? If so, at that size they are typically not as deep as older more muture fish. If they are really skinny with large heads in proportion to their bodies that is an indicator that they are too crowded. As you know male muture brook trout in the fall will develop somewhat of a hump back (not as pronounced as a sockeye or pink salmon) and will have a taller profile so to speak. The head lengthens somewhat too.

It's hard to say just by what to tell you without actually doing an electroshocker survey etc. or age determination via scales or otoliths. Sounds like you've got plenty in the pond. I would thin them out a little and once your catch rate drops back off. Be aware it is possible out fish out brook trout. They are very easy to catch. But unless your PH and alkalinity is quite low and you pond does not produce enough food I would think you should be able to produce 12 to 14 brook trout with the right density. Be also aware that you may have larger fish that you are not aware of yet. The smaller fish are more agressive and less shy than you larger fish and may beat the larger fish to the hook. I have found trophy size brook trout a challenge at times to catch.

Brook trout can have a relatively short life span compared to other salmonids although they tend to live longer the farther north you go. Any idea what strain you have? You could add some different stock to freshin up the gene pool and a stock that is known to be fairly long lived as in the Lake Nipigon strain which is what I have.

Cecil,
When you mentioned what strain it gave me a thought. Since his brookies can spawn in his pond would it be benificial if he put in some fall spawners?

I'm not sure it would matter when the trout were put in. I don't see any advantage to putting in fall spawners unless I am missing something here.

I was thinking it would provide more forage if there were fry availiable summer & winter.
I'm thinking now that's what I'm going to do.
I'm spending ALOT trying to have a self sustaining trout pond. If I had a natural one like SmallFry I'd do as he is trying to improve it but I'd also be very careful not to upset the balance.

Cecil,

I used only female rainbows to safe guard my own pond but also to be sure the stream below the pond remains (excluding an escapee or two) brook trout only...

12 to 14 inch brookies would be nice, that's just about what I was hoping for as top sizes. I think the pond was probably overpopulated in the spring of last year, but the previous owner once he knew he had sold had something of a fishing free for all and regardless my fishing was excellent, in numbers at least. I just think my pond is likely to overcrowd because the mergansers stop (and stay) here, the ospray spends his days here, the creek is full of parr in summer and the fish always bite.

Most and this board would probably drive all the birds and predators away but I think in my case they are actually beneficial, this works out well as bird watching is also a great hobby.

I have no clue as to what strain I have... How long do Nipigon live Vs. domestic strain? Do you know of a site that documents the different strains?

I visited your site & I must say you raise some nice looking fish, I like the Browns.