Pond Boss Forums MANAGING AN EXISTING POND Evaluating and adjusting fish populations Anyone else lose a few yellow perch when the water gets warm?

I have all female yellow perch in my warmwater pond with largemouths, smallmouths, and bluegills.

When we get a heat wave I always lose one or maybe two of these perch. I pulled one out of the water today that was about 12 1/4 inches measure by a tape measure and weighed 15 ounces.

Anyone else that has yellow perch (not the perch you southerners refer to that are actually bluegills LOL) lose a few in warm weather?

I realize they are a "coolwater fish" and probably get stressed by warm temps. Water temps right now are in the upper 70's on the surface and about 3 degrees cooler on the bottom (I pump 1.5 cfms to mix the water column.) I also caught and released a couple a few days ago and maybe this was one of them that was stressed by a combination of fighting the hook in warm water and the warm water.

It has been close to 90 degrees here for almost 3 weeks and I haven't lost any. I have more yellow perch in my pond than anything else because I had a bad winterkill on the warmer water species. We had very deep frost last winter. Close to 6ft in places. I went fishing last weekend and caught and released a few perch and I haven't seen any floaters. I originally stocked it last spring with 500 perch in a 2/3 acre pond 10-15 feet deep. I would think it would be better to not fish them in hot temps. I only fished mine to see if anything survived the winter. If I caught a big one in the heat of summer it would have been released into the frying pan.

It has been close to 90 degrees here for almost 3 weeks and I haven't lost any. I have more yellow perch in my pond than anything else because I had a bad winterkill on the warmer water species. We had very deep frost last winter. Close to 6ft in places. I went fishing last weekend and caught and released a few perch and I haven't seen any floaters. I originally stocked it last spring with 500 perch in a 2/3 acre pond 10-15 feet deep. I would think it would be better to not fish them in hot temps. I only fished mine to see if anything survived the winter. If I caught a big one in the heat of summer it would have been released into the frying pan.

Brian,

Thanks for your reply. Do you think size may have something to do with it? What size are your fish. Mine are all at least 11 1/2 inches and females.

Mine have only been in there since spring of 2002. They are around 6" or so. It takes a few years to get the perch nice and big. They are not fast growers. I do not know if the big ones stress easier or not.

Good morning, Cecil. I have one additional thought for you. I suspect your perch are pretty fast-growing if they are so large?? In our fast-growing populations, we often get about 11-12 inches in four years or so. These are great populations for fishing, but at least in our area, these fish tend to be pretty short-lived. We rarely see a yellow perch over age 6 in such populations, and most never get beyond 4 or 5. Only in our high density, slowing growing populations do we ever see 8 or 9 year old fish.

What I'm suggesting is that your fast-growing perch may have some pretty darn high natural mortality rates. If temps get a little warm, that may be a common time to lose a few fish to natural mortality (old age). We always say: live (or grow) fast, and die young for yellow perch. It has really affected how we can manage the perch in our public waters. We don't want to be too restrictive on regulations if they have high natural mortality, and we'll lose them anyway. Some of the southern readers probably have heard of similar situations with crappies in southern reservoirs.

Just food for thought!

Dave

Dave,

Thanks for your reply. What you say makes sense and I have read it about the growth/fast die/ young cocept in other material. Especially growth rates for northern vs southern lattitudes.

I'm still hoping most will make it one or two more years. These fish were originally raised in an RAS (Recirculating Aquaculture System), and I believe they were 3 year olds when I got them at about 9 inches in Spring 2003. They are pellet trained and grew about 2 1/2 to 3 inches that first summer. I have lost a total of about 8 our of about 95 since I got them. Three or four were probably due to hauling stress soon after I planted.

As I said, when I get one of my other two ponds in, I hope to keep the perch pond cooler with overflow from the trout pond. I will be able to regulate the water temp by how much overflow I allow to flow in with a gate valve.

I can't help thinking the fast growth/early death may be true of my largemouth bass that I pellet feed. They seem to peak out at 4 plus pounds in 4 years but I don't see any mortalilty to speak of. I sure wish other fish species would grow as fast as my trout. One and one half inches per month for trout!

Actually, Cecil, it sounds like you are doing pretty good. I think most people would expect at least 30% annual natural mortality (i.e., no angler harvest, just natural deaths) rate for yellow perch under the best of circumstances. Thus, only losing 8 so far sounds like nothing too unusual, especially when you toss in a little stress.

Dave

Dave,

Thanks. I was thinking the same.

Cecil - Your y. perch will not die from temperature when the water temps are still anywhere in the 70's. Something else is causing stress/death.

Bill,

Maybe it was the catch and release. Maybe the hook was too deep or something?

You can lose perch due to warm water but the temperature has to be in the mid 80's all the way down to where the DO is real low.

Bill,

Actually the surface temp never got above 79 even though air temps were much higher. Water temps to the bottom were within 3 degrees. I have not lost any perch that I know of for several weeks.

Cecil, how are you measuring your bottom temps. I am looking for something for my pond. I would love it if there was something with a sensor I could just leave on the bottom and run wire to a display. Does anyone know where I could look for something like this?

Brian,
There are remote bulb sensors though one long enough would be costy. The problem though would be keeping it clean. Even the slightest film on it would insulate & give false readings.
Ric

Brian,, You can get a indoor/outdoor thermometer with digital readout at most any hardware store- ACO, ACE, True Value, or home center for less than $15. Most only have a 10 foot remote sensor. Tie a sinker to the wire just above the bulb and mark off 1 foot spacings on the wire so you can take temps at various depths. I was going to splice in additional wire to lengthen the probe but couldn't find out what affect it would have on the reading from the added resistance.
Good Luck.

Dan

Where could I look to study up on this? Any suppliers you know of.

Avoid all that hastle of extending cable by buying an "Airguide" Fisherman's Temp Sensor. This is sold at most boat dealers. Tmp sensor has a 23 foot long cable/cord. AAA battery. $19.95.

Cecil - Since your deeper water was in the 70's your handling/hooking stress killed that fish.

Bill,

You mean deeper waters should have been cooler for perch?

Cecil - In your first post you said that the surface was upper 70's which I asume was around 77 to 79 F. Bottom was 3 deg cooler 74 to 76. these are ideal temps for growing perch. Water needs to be mid to hi 80's on top at least before any temperature stress occurs in perch. Deeper water than the upper 5 to 8 ft will be somewhat cooler (as you noted earlier). Coolness of botttom water will be based on aerator run times and diffuser model and configuration. If DO is adequate near bottom perch should be okay in the slightly cooler bottom water even though the top is 85 to 88F. Since you only lost one or two fish and not more were dying it was very likely that the hooking stress killed those one or two fish. The dead fish were probably very close to the size you caught, correct?

Bill,

Right on. I think it was a fish I previously hooked and released. It may have been hooked in the roof of the mouth close to the brain or something.