Pond Boss Forums MANAGING AN EXISTING POND Corrective stocking What limits RES in northern climate?

In may of 2007 we added 100 3" redear sunfish to a 1.5 acre pond in northwest Iowa that contains LMB, stunted bluegill, and a few bonus SMB. I know this is slightly north or where the RES is normally found. So to have the best chance at survival I called around until I found a source that used fish from as far north as possible for their broodstock (the initial sources I contacted had RES, but were trucked in from Arkansas). The fish we ended up buying are from broodstock from Southern Iowa.

I know the stocking rate is pretty low, but since I wasn't sure they would make it and my dad didn't want to spend alot we only got 100. Also larger fish would have been nice, but since that was the largest that supplier had and the fact the pond was full of stunted bluegills (that we hoped would lower the chances of a LMB consuming the RES) we went with the 3 inchers anyway.

We hadn't caught one until last week. What was amazing though was that it was 9.25" and had a Wr of about 130. I had assumed that since RES didn't do well up North it was because of the cold. Last winter was one of the longest winters we have had in a while, with ice cover lasting much longer than normal. Which I figured would have put an end to our RES experiment or at the very least made growth very slow. But that RES certainly had a great growth rate given supposed sub-optimal conditions.

Now I find myself doubting that it is the cold. Is it possible that the RES distribution to the North is limited by something other than cold? Possibly lower recruitment/reproductive success? I know down south that the RES generally spawn at a slightly different time than the bluegills (later from what I read here). But maybe since things warm up so quickly in the north there is too much competition from LMB/Bluegills at the same time for the best nesting sites?

And it all leads me to this thought: Is it possible to maintain a RES population up north by simply stocking a few every year?

Edit: I would also like to add that we suspect many more of the RES to be thriving due to the near disappearance of the black and yellow grubs that had been a major problem (anywhere from 2 or 3 to 20 per fish) in the BG for the last 3 years. This was the reason for stocking.

very interesting ready to see what some of the pro will say.

First off, congratulations. Big Redears are truly great.

Non-pro opinion here: Remember that it's not so much the severity or length of the Winter that matters, rather what happens down in the water. Long-lasting ice cover, as long as there is sufficient O2 in the pond for the fish (from clear ice or a small lightly aerated hole) will not lower the bottom temperature below 39 degrees F (water's densest point) in a nice deep pond.

Last Winter was a real tough one for my RES due to several late season cold spells after the main iced over period had passed. I had a number of Redears die because of two cold, windy stretches when high winds blew 20-something air so fast that ice could not form, and another time when 15" of snow fell on open water. I would have loved to have had ice cover for those three weeks - I lost some large Redears including the biggest one I have ever seen.

We have ice cover for a few months and some ponds have thriving populations of redear and some don't.

I even caught a few redear icefishing last winter.

Are you absolutely sure thee were no RES in the pond prior to stocking the 3 inchers in May 2007 ? Here is why I ask. I will double check this tonight and repost.

RES do not grow (at all or not much if any)in water temps below 50 F. They don't eat much either.

In that location it means that the RES had to grow 6.25 inches and put on that weight in no more than 11 growing mths (May 07 - Sept 07 and Mar 08 - Aug 08) probably less. That would be an incredible growth rate for a year in the south not counting northern cold water or possible spawning weight loss. Our RES grow most of the year as our winter water temps at depth stay above 55 F. IMO a RES that size here would be 24 to 30 mths old or more. Your RES in my guess are 16 to 18 mths old. In cold water I would guess that a 9.25 inch 130RW RES was at least 4 years old. I need to check some stats to be sure on the #s.

@Theo: Hadn't thought about conditions where supercooling could occur. Luckily this pond is in a deep valley and gets little wind. It is usually the last pond to "ice-out" in the area by a week or so (sometimes the ice-out process is assisted by my brother and I in the jon boat when we get impatient. Its simple, run the front of the boat up on the ice with both of us in the back, then move to the front to break the ice, rinse and repeat).

@ewest: There were absolutely no RES in the pond before. My dad has owned pond since 1993 and none were ever caught. Then the pond winterkilled in 2000 (in large part by 2+ feet of snow that accumulated on the pond, due to the lack of wind to move it.) It was restocked the following year with the standard BG, CC, and LMB available through the DNR. None were caught between that stocking and may 2007 either.

The growth of that fish has me mystified as well, thats why I brought it up. I wasn't sure if they would even get that big given the conditions they would be living in. And based on urogenital pore shape/color and overall coloration it is a female. Hopefully we will catch more. Soon.

I should mention that in June one was also supposedly caught by someone that wasn't sure what it was. But we weren't there to verify it, so I cant say it wasn't actually just another bluegill. But that fish was estimated at 8-9 inches, which is why I kind of doubted that it was a RES until now.

Thanks all for the comments and keep them coming!

High quality water, when covered with ice, but not much snow can maintain oxygen throughout the water column during the winter, thus giving (as Theo said) a 39 degree refuge for the winter. Maybe even a little food to boot. We see this repeatedly in central Nebraska borrow pits where we have excellent overwintering capabilities of RES

In water bodies where redears are forced closer and closer to freezing level waters RES begin to stress, and often die when exposed for a period of time to this cooler water.

Ask Dr. Willis sometime what he saw at my farm. It was a February day, and we were seining RES out of a pond that had been ice covered for months and they were absolutely gorgeous. But when they went into a horse tank with 33 degree water, they perished right before our eyes, even as the bluegill swam about unaffected.

Colder water stress compounded by duration equals dead redears.


...by the way, I'm convinced that you made a smart move acquiring the RES from a more northern broodstock.

Absolutely and positively no question about the wisdom of getting fish that have for several generations or more been able to adapt to local conditions. There is a bunch of scientific evidence directly on point. Plus the more the species is likely to encounter a limiting factor in a location(cold water for RES or high summer temps for SMB , YP etc)the more critical local adaptation becomes.

Prior cold RES threads


http://www.pondboss.com/forums/ubbthread...=true#Post25793

http://www.pondboss.com/forums/ubbthread...ite_id=1#import

I think the growth from 3" RES to 9.25" in 11 growing months (ewest estimate) is possible. This growth averages out to slightly less than 0.5mm per day. I have seen 3"-4" yellow perch and BG grow close to or at 1 mm/day. 11 months X 30 days = 330days x 0.5mm/day = 165mmm. Assuming a few of the 3" RES were 3.5" and maybe a few were 4" this is 89-101mm. 90mm + 165mm = 255mm which is 10". If the pond had lots of soft shelled snails such as the genus Physella, the newly stocked RES could have had all the snails to eat they wanted and growth could have been optimum. Does anyone have any info on the nutrition value of snails compared to fish?

Yes, I just looked it up.

SNAIL - SHELL = FISH

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Leave it to me to say something stupid. I hadn't seen JHAP around lately so I thought I should carry the torch.

Bill I am not aware of any fish species that maintains its yoy growth rate for long. Possible - I guess anything is possible. No evidence of anything like this on RES from any northern climate or southern either.

Here are some northern averages for total length of RES I worked up based on numbers from Carlander vol II 1977 :

1 year - 4.33 in
2 year - 5.91 in
3 year - 6.88 in
4 year - 7.56 in
5 year - 9.21 in
6 year - 9.29 in
7 year - 9.84 in

The youngest I can find data to 9 inches is year 3 in Fla with a year around growing season.

ewest - I like a challenge. As you know the published literature does not contain all the information that is available, lots of gray literature and unpublished info is out there. I and others have grown YP to 6.5 and 7" from April 24 at hatch to November 01 of same year. Calculate that growth rate. Also see and calculate Bruce's growth rate of his 14 month old BG that were 7" long which includes overwintering (abt 5 mo) in well water temps. Carlander reports LMB at one year can in the high range be 254-442 mm (many of those are not far southern states OH,IL,WV,KS MO, OR); calculate those growth rates per day and consider a winter slow down. In my YP during the 2nd yr, I can see 4" of growth in 6 months (May-Sep30) or 130 days and 102 mm which converts to 0.78mm per day during the second yr.

In reality cstephen's RES are essentially 3 yrs old. 1 yr at 3-4" when he stocked them May 2007. 2 yr at May 2008 and for the 3 months Jun,Jul,Aug this summer makes them essentially 3 yrs old or at least 3 summers growth. Carlander reports a 3 yr old RES from AK to be up to 269mm or 10.5" thus I think what cstephen reports is possible; not common place, but possible and feasable.

Interestingly enough, my age-3 RES, that have no access to pellets are pushing 8.5 inches. Lots of fresh water and snails.

I think the growth is possible given really good forage. A pond with no previous snail eaters could definitely have beau coup for RES to eat.

It's basically having to grow 3" or so per warm season, and I think that's possible under such conditions.

Average growth is not what is experienced with a small number of initial stockers in a saturated forage environment. Remember the world RES record grew in (Santee-Cooper) following a snail population explosion (IIRC).

What????

Me, say something stupid???

What is COMPLETELY ironic about that statement is that last night I was reading my Pond Boss magazine that had arrived in Thursday's mail. Now I'm going to draw a mustache on the cover photo just for spite.

Blacken in a couple of teeth for me, would you?

I might have gone a little overboard with the shaved eyebrows and pink nail polish.

Oh and by the way, Bass Proshops does't take kindly to you modifying magazine covers. Guess I have to add the Rancho Cucamonga Bass Pro Shop to the list of places I can never return to again.

That looks just like my Brother-in Law!

Remind me to never let Lusk put me on the cover of the best pond management magazine in the USA. Everyone is jealous of you Bruce.

Good stuff, Jeff.

In the real version, though, I noticed Bruce has the rod AND the fishing line in his teeth. I don't know about you, but if my dentist saw me doing that, he'd be ticked. Bruce isn't setting a very good example for his patients, I'm afraid.

And just what do you expect from a part time dentist?

he flosses with clothesline

Nice come back JHAP!!!!!!! (great suggestion Theo!)