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It varies greatly by location. North to south, cold climate vs warmer climate. Longer or shorter growing season.
Here are the numbers from the biologists for Lake Cascade in Idaho. This data is several years old- it seems like these high rates were a temporary thing when perch were reintroduced.
Waxthumb - I just saw your post on the main forum. Not sure if you may have been referring to my post from a number of years ago, but I compiled some data from the biologists reports in the PA Fish Commission website that provided some data on ages and lengths of different species of fish. I think I have referenced this post in subsequent posts as well. I'm a numbers guy so I found the information absolutely fascinating. You can read my original post from 2015 here: https://www.iceshanty.com/ice_fishing/index.php?topic=303405.msg3187957#msg3187957As others on this thread commented, these numbers are specific to PA but I suspect you may see similar statistics in other states since the information was compiled over many samplings from many different PA waterways. The lakes themselves could also see different growth rates because of variations in habitats but again, I think the numbers are reasonably reliable even thought they are specific to PA.
That's a great illustration of the variation of length at age. Look at the 7 year olds. They range from about 225 to 350 mm , or 8.85 to 13.75 inches That's a MASSIVE length range for perch all aged the sameAlso, look at the 315-ish mm line. A fish at that length, according to this data from Cascade, could be anywhere from 5 or 6 to 15 years old!!
This past link was one where a guy ages a fish. It was in a video that was posted.https://www.iceshanty.com/ice_fishing/index.php?topic=377975.msg4090473#msg4090473
Thanks for sharing badger. In this case, it appears the state replaced one problem with another. In your post you said “They removed as many non-game predators as possible...” This is a mistake. Large predators are a very important part of any ecosystem. They limit population growth in prey species and keep the ecosystem in balance. In this case, it appears there were no large predators to stop the over abundance of perch. The perch then became a virtual apex predator in that body of water. For a few years, the population surges and the perch get bigger but eventually, there’s not enough forage to go around so the big perch cannibalize the smaller ones at an unnatural rate. This means many big perch currently but also very few smaller perch in future years. Eventually the big perch die and the overall population crashes. Eventually, the population could rebound somewhat but if the previous generations of perch over-foraged the lake’s natural prey species, there may not be enough food to go around which will lead to a large population of old, stunted perch.The easiest way to deal with this problem is to reintroduce large predators like bass, catfish, pickerel, pike, walleye, etc. These fish will eat the smaller perch which will reduce the population but it will also ensure a healthy population balance of the perch where there will be sustainable numbers of fish in different size and age ranges. This will eventually lead to a stable population.