I have been tinkering around with my small, over populated perch pond in the back forty. Long story short it has a self sustaining population of perch but I believe they are terribly stunted. They don't have the characteristic "goggle eyes" look of being old fish with no growth but I never seem to catch any keepers when I fish there. I have been searching for info on how to age them by their scales and haven't found anything of use using google. I have a plenty powerful enough microscope and clean slides, I have looked at a few scales and seen rings and such, but absent any explanation of how to interpret them it is greek to me. Does anyone have any info on the proper procedure for aging YP via scales??
Joe - You should be able to with a fair amount of accuracy determine the age of your perch using scales. As the link mentioned, collect a few scales from just behind the pectoral fin and just above the lateral line. YOu do not need to press the scale in plastic like Chris mentioned. It will help if you first clean the scale in some soapy water &/or maybe a little chlorox solution to remove any slime layer so the scale is clean. HOwever a dried scale will often curl and make it very difficult to examine, so you want to look at it damp or mount in on a glass slide under a cover slip. You should be able to use clear corn Syrup as a mounting medium. I usually soak them in a weak solution of rose bengal stain to help highlight the scale rings. You don't need real high manification for the aging process; 25X-50X maybe 100X is usually adequate (depending on size of scale). For each year the fish has lived (each winter season) you should be able to see crowding of the rings on the scale similar to the example scale shown in the link above.
COMMENTARY
I'm not sure that you really need to age your fish to solve your problem of not having larger YP. If your pond has had YP for 4 yrs and no 8"-9" perch, then there is a problem. YP with good or normal growth should be 3"-4" at age 1, 2yr = 4.5"-7", 3yr = 6"-9", 4yr = 7"-11". Even at fairly slow growth (my experience) you should have after 4 yrs YP that are 8"-9". If you in PA do not have perch this size there is a problem.
If your perch are not getting any size to them one or a combination of things could be hapenning.
1. large sized predators could be cropping or eating all or most all the perch once they reach a certain size.
2. More likely problem is the perch population in your pond is hitting a food limiting road block when they hit a certain size and not enough of the right size of food items are available for them to continue growing past a certain size. This same thing often happens with LM bass.
3. The other feature, that is closely related to No 2 or essentially the same thing, is too many perch over eating the food source and not enough food is available for them to keep growing thus stunting or very slow growth occurs beyond a certain size.
SOLUTIONS
To try and improve this problem you could try one of two things or use some sort of combination thereof.
1. Remove a fairly large number of perch thus reducing the number of "hogs feeding at the trough" as Lusk puts it. More food will then be available for remaining perch. Initially this may take a relatvely strong reduction in numbers of YP. For this to work effectively another panfish can not quickly fill the vacancy of reduced YP density. AND the natural in-pond food base has to be able to recover/reproduce fast enough to adequately feed the remaining fish/perch so growth resumes.
2. Remove some perch and enhance or add stock to increase the food chain or food availability. YP removal can in smaller ponds (less than 2ac) be mostly manual - trapping, angling, seining, although this could require a fair amount of effort depending of size of pond and numbers of overabundant YP.
3. Add an appropriate size of predator to help reduce perch numbers. Predators will also eat some of the newly stocked forage. Ideally for best control of the fishery, one should use a non-reproducing predator so they do not become too abudant and themselves become overpopulated and eventually eat all the small fish including perch. As the predator grows they will likely eat larger perch/forage which is sort of counter productive to your assumed goal of more larger perch.
4. Since I regularly raise fish in cages, I would handle the problem a little differently. I would manually remove the thin bodied or smaller, most abundant YP. Then begin a plan of annually stocking pellet fed perch. At the same time each May, I would remove (angling with worms) some 4"-6" YP, cage them and train them to eat fish food. My experience is that a fish that will bite a worm under a bobber will be an easy fish to pellet train. Pellet feed caged YP all summer, then in late fall or the next summer release them into the pond. If you can hold them overwinter, and again pellet feed them the next spring for a about month or so, a larger percentage of those caged fish will stay "on pellets". The imprinting is stonger. If you do this annually, gradually you will develop a large number of pellet eating YP and their growth will not be limited by food shortages in the pond. (For information about building small fish cages and growing fish including YP in cages see my articles in three back issues of Pond Boss magazine 2007, Mar-Apr, May-Jun, Jul-Aug).
The other option is to each year buy some larger sized pellet trained YP. If the pond has a population of pellet eating perch then a FEW non-pellet eating perch, especially the youngsters, will convert or learn to eat pellets. Your perch population with larger individuals will then gradually improve.
Thanks for the information Chris and Bill. The longer version of the story is that the half a tennis court sized pond was dug and stocked without a forage base, before I knew one needed that, it was stunted after one spawn, literally. I now have a new pond and have a good forage base started, I wanted to determine how stunted these fish were based on their age and have considered relocating them to my new pond next summer and feed training as you suggested. My only concern is I don't want to try and feed train 4 year old fish that may be nearly as grown as they will ever get. I have caught tons of little fish and I want to determine if they are YOY, if they are they could be feed trained in a cage once relocated to my other pond. This would allow me to salvage at least some of them before draining and renovating this pond. It may not be worth the effort but the fish are free, so that is a plus.
Joe - If you decide to feed train some perch in a cage. I suggest you read some of our past posts about feed training fish. Generally the smaller the perch are the easier they will take to food. When you first add pellets for them, try softening them as per past info here or in my May/Jun 2008 Pond Boss mag article pg 48 - The Softer Side of Feeding Fish. Flavoring the soft pellets, as per the article, increases the percentage of those that will train to feed.
I remember that softening bit Bill, I have caught 3 inchers 4 incher and fish nearly 6 inches long, my main goal is to get a number of the 3 inchers for feed training provided they aren't 2 year olds. I still plan to buy feed trained fish and have them in a cage side by side to these fish and monitor progress of both, it will be a cage match so to speak, but this will be after my dock is built int he spring.
Bill, that was a very good article. Those kind of tidbits in the mag. can make a big difference in managing a pond. I had been softening GFC to feed my fatheads (which was also your advice) for some time but could never get the moisture right. I had forgotten (big supprise) about the adding flavoring though .. gonna have to read it again.
I have some cheap fish food I am feeding my FH minnows, it smells like fish, how else would you flavor fish food that smells like fish??
JoG - If you think cheap fish food smells like fish, then you should take a wiff of high protein Aquamax carnivore or similar fish food. But do it sitting down, the real fishy smell will probably cause you to get light headed or even faint.
Ric - I usually put some good how-to-do-it details embeded in my articles. D.Davidson says it makes them boring.LOL.
You will be interested in one of my upcoming articles of fairly easily making good quality minnow feed from GFC or other cheap forms of fish pellets. Look for it in PBoss mag this winter.
I have been toying with the idea of using some fine netting to make a minnow feeder that would use pellet food. I see the problem of feeding minnows as most of the food that sinks settles out before they can eat it, the floating food float to shore, I was thinking of a plastic water battle for a bouy and a mesh bag hanging below if full of soaked feed, this way it would float around the pond and the minnows could peck at it until it was gone, then I could add more.
Yesterday I took a recent varmint kill and harvested maggots off of it and fed them, it looked like shark week onthe discovery channel, except with FH minnows being the sharks....lame I know, but they are the only fish I have in the new pond so far.
With a rot basket, Roadkill is the gift that keeps on giving.
And it costs just pennies a day.
I'm planning to build a nice one to feed the "other side" of the pond. I'll hand feed the side next to the house.