Got 3 of these today in a "Z" trap just checking things out..
Can someone give some insight as to growth rates of new hatch??

Hmmm...what size, Kenny?

Smallest of the 3 at 2-3/16", largest 3-1/16"..
There is no other possible explanation, I've hand-sorted every fish that's been put here.

For new crop 2019 yellow perch very good growth is 1 mm/day. Exceptional unheard of YP growth would be 2mm/day. Exceptional growth of trout fry can be 3.9mm/day. However in early spring in KS the water temperature would be 50-60F thus YP growth would be expected to be less than optimal at best 0.8 to 1.0mm/day which equates to Mar 26 hatch + 30 days on April 28 = 1.1" size. I think somehow this is a perch from the 2018 year class.
I commonly see YP this small in the spring from the previous year's hatch. Note a very few exceptional growing individuals from that year class could be 8.5" as 8 months (240days) growing season (50F+) calculates to 0.89mm/day.

I'm perplexed..
July 21, 2018 I stocked 26 YP from 91-113mm
9 YP from 122-154mm,
The only other YP stocking besides the giants I put in (13 now)was the 161 fish I pulled from tank to bucket, measuring a couple in every net to get an average, which was just over the 8" mark at 204mm. The smallest fish I could find in that 161 was 134mm.
The smallest fish here in the trap was 56mm, a LOT smaller than anything I stocked, even the 2 bigger ones were 77mm, still smaller than anything I put in.
Had to be some stealthy suckers to get by me..
I guess that's how it happens but I feel I've been trained to do better than that. It's not acceptable to me to be that careless but I have no other explanation..??..

Is it possible you had a an early spawn in Feb 2019 that you missed seeing?

Just a non-scientific observation: Added YP and just 12 LCS to pond and worried none had survived. Currently have young of both species washing out drain pipe.

I had ice until almost the 20th of March.. I have no idea what happened under the ice but only seen 2 ribbons in late March.

I am convinced Bill Cody expertly manages ponds with a micrometer and a 0.01 Grain accurate scale.

For your 3 small perch; 56mm/30days = 1.8mm/day and 77mm/30days = 2.5mm/day. Ice off Mar 20. If eggs were laid under the ice in 39F water (laid on March 15-20 temperature water it will take close to 12-14 days to hatch that puts it at March 27-30. When eggs hatch at around 46F, it takes at least 2-3 days for them to begin swimming. Small perch were captured April 27th - 27days. IMO it is not feasable for them to grow 2.5+mm/day in early spring temperatures to grow to 77mm by April 27. Maybe you have a super strain of yellow perch; if so fishery science should hear about it.

I guess what may answer my question is see how many I can trap.
I am human and no doubt could have missed a few tiny ones but if I catch many more I may have other questions.

Maybe you have a super strain of yellow perch; if so fishery science should hear about it.

All joking aside, this would explain some other things although I seriously doubt that's the case..

This is pic of original stock size in July, last summer..
Just to compare.


And yesterday's..

That picture of the stocker perch shows it had a full belly; maybe fat, maybe it just ate a small fish, or it had eggs. Eggs in July for YP is the least likely of the three choices. However if the perch were raised in cold water plus the fact that year one perch are usually late to spawn, it is possible, not likely, that a few of the stocker perch had a late spawn last year. If I would see that same stocker perch in prespawn, I would definitely consider it a gravid female. Never say never.

Thanks for sharing the info on expected growth rates, extremely helpful as a std to gauge by.
Appreciate your help greatly!

I can't wait to find out how this ends up - Kenny can you take some photos showing us the urogenital opening of some of these mystery fish? I don't know if we'll be able to verify gender, but females should have a crescent shape, males a round, pore shape. This may allow us some more data to hypothesize.

I've got 6 in the aquarium now.. when I get them a tad bigger to pull otoliths I will get some pics at that point.

YP at 4"-5" will be extremely hard for any of us to determine male or female with any certainty.

If I'm extracting Otolith, I should be able to do Ovary check..I "think".

My guess is late hatch last year. Even trained FS experts make mistakes in stocking. In addition newly stocked fish in an unfull pond try to reproduce to fill it up with their kind.

Right there with you ewest. Late fall hatch. I have had young perch hold onto their eggs and you would think they would absorb them back but may lay them late fall.

If I was a betting man I would be betting a late fall hatch.

Cheers Don.

You may both be right. Another 7-10 days these guys in aquarium will be big enough to extract otolith and we'll know for sure.

I've never heard of a fall YP spawn [Cody has never discussed it to my knowledge], if that's the case, this could be a significant scientific discovery.

I'll remain the outcast and stick with they came from an early 2019 spawn (maybe even under the ice).

When these unknown age yellow perch are being grown in the aquarium what are your feeding them? Any idea what their growth rate is as you are holding them>

I used my fine mesh and caught loads of 3/8"-3/4" FHM. I put about 50 a night in, only a few left by morning.
I have only 1 I fin clipped for re-measurement-and haven't disturbed them yet but they are very obviously growing.
I'm quite impressed with their aggressive feeding habits-this is a first for me to observe YP. They seem similar to SMB in their stalking nature.
As for growth, I'm only speculating here but I've tried to gage the fin clipped fish and it was 69mm and it sure looks to be close to 3.5" (87-88mm)in 11 days?? 1.6mm/day but that's a guess-4-5mm would change that back to a more common 1 to 1.2 per day per Cody growth rate. They aren't having to work for food very hard either-maybe skewed there as well.

Keep it up Kenny you have my full attention.
Cody Note - Yes good work and reporting. Thanks for the updates.

Ok, netted the fin clipped perch tonight.
107mm
69 to 107 in 17 days figures out to 2.235mm per day.
Not very scientific in the aquarium surrounded by 100's of FHM, but the numbers are what they are. Question I have is "can this be duplicated in the wild"..
I may have my answer to that in maybe 10 days. I'd like to get it about 5" to get it to a size it's reasonable to find the otoliths..
EDIT: I left an important part of this out.. I have kept my water temp at 71 degs from the night I put all 6 in, so THAT growth rate of 2.235 is below what I believe to be optimum growing temp, please correct me if wrong here.

Fin clipped perch pulled, measured 143mm (close to 5-5/8")
Growth of Perch in aquarium calculated out to 1.94mm/day which considering being in aquarium with 100's of FHM I don't believe this to be anything "super-natural" and I'm not sure it could ever be duplicated in the wild. I have been trying to purposely trap and catch small perch from the pond and I have actually caught well over 100 now-most are in the 4.5" range, some slightly smaller and larger.
I managed to get both otoliths pulled in 1 piece without breaking and with the size (never attempted a walleye this small)I'm a bit surprised I found both. I did this a couple of days ago and generally we dry them for 4-6 days then drop them in epoxy cups which I will be doing Saturday and after a few days they will be sawed in half and sent for verification.
In my fishing/trapping efforts the last 12-14 days, I've found several unexpected surprises that prove to me #1, "It can happen to anyone", and #2, sometimes there "is" no answer..
First surprise was a 4-1/2" GSF...go figure.
Second surprise was a 13-1/2" BCP. Not sure if 1 or 2 applies to any of this.
I have been slightly disappointed in the fact that fishing with high-end, finesse methods that I have not caught a SMB on FHM, GSH or Worms. I've caught several of the elusive RES, some beautiful males and females, and about every size of Perch I had hoped to see this early (within 1 yr of stocking).
I should have an answer on perch age within a couple of weeks, I'll report here.

Snipe,

Very interesting thread! How accurate is otolith aging?

Realistically, they claim 24hrs one way or the other. We get them back in approx. days since hatch. So far since using this method on the same lake we pull eggs from, I don't believe we've ever had anything outside of 30-35 days estimation. That's figuring an average spawn date of March 24 peak, so nothing more than 30 days before of after that date in many years.
In this case, I'll be looking to hear back on an annular ring, if present, so we know if they were late year hatch after stocking or early this year. If they come back with a hatch date more than 30 days earlier than I stocked then good chance I had some small fry in that I did not see.

Got a phone call today regarding otoliths..
First of all, annular ring is present.
2 techs each with an otolith, one says approx. 255 days, the other says 252 days.
Calculates out to around October 1st.
I was hoping to see no annular ring but maybe it's even stranger to have a fall hatch. I have NO experience with YP and I have NO data available that says this has ever happened with walleye but we aren't (I have never) pulling otolith from WAE in a pond.
One thing about using otolith that is nice is you have 2, and 2 sides of each to verify so you can't change it to be what it's not.
I hope someone has an understanding of this as the bio's I work with are almost in disbelief and 2 of them frequent this site and have asked if someone has an explanation, their ears are open.

Dude....what the? Calling Dr. Perca!

I notified the Doc, TJ, We'll see what he has to say.
And.. If DJ and LL are watching, pay attention!

A few seasons ago I noted RES spawning in October around my dock - until then I'd never heard reports of RES multiple, or late season, spawning.

Perch species are early Spring spawners, I've never read anything to dispute this. This evidence suggests otherwise...I'm intrigued!

I can understand the possibility of 1-2 females having the urge to fill a gap. Something has to trigger that. It also has to simultaneously trigger the males to the same condition.
In WAE, I've seen at least 2 instances where an unbalanced population causes a misfire on a successful spawn. With WAE, the males are the trigger for the female. If males numbers are not sufficiently high enough the females just move off and reabsorb eggs.
I guess where I'm going with this is one has to trigger the other.. what's the mechanism in play here? Is it a function of the male vs. the female???

I have learned to never say never when dealing with natural things. Late or early spawns can probably happen; it is unusual, non-normal but strange things do happen. We caught a large female YP last week with eggs. This fish was likely reabsorbing the eggs. Very late or very early development of eggs and spawn in YP is possible because it is known to happen in other species. Never say Never. There are still lots of things to be learned about the extreme complexity of Mother Nature.