(02-04-2023, 02:26 AM)filletedalive Wrote: What information do we have on identifying the sex of male vs female perch? Would identifying spawning females and releasing them be in our best interest long term, or would make perch survival be more beneficial?
There are no distinguishing physical characteristics to make it easy to differentiate between male or female perch. During most of the year...until pregnant females get greatly swollen abdomens...all we can do is guess that the largest fish we catch are females. Smaller fish can be either males or young females.
Selective angler harvest is almost never an issue with perch. Their population is influenced a lot more by water levels (spawning conditions) and natural predation than by anglers keeping a few females. Wherever perch exist they become a part of the food chain. Their young (up to 2-3") are a diet mainstay for not only all other predators in the ecosystem...but for adult perch as well. And until they grow larger than 4 or 5 inches they feed bass, walleyes, catfish, pike and other species. But perch are prolific spawners (under ideal conditions) and they are generally able to maintain good populations even with natural predation and angler harvest.
However, at least here in Utah, we have seen occasional crashes in the perch populations. Some are the result of low water and poor spawning conditions in reservoirs. Other drops in perch numbers have been due to sudden dieoffs throughout the lake...due to disease or parasites. And once there is a big decline the whole lake suffers until the perch are able to rebuild their numbers...if they ever do. Yuba Reservoir, Starvation Reservoir and Jordanelle reservoirs have all seen decimations of perch numbers due to low water or dieoffs. And Deer Creek reservoir has never been the same after the introduction of smallmouths into the food chain. All of these used to be full of perch...and produced lots of "teen-inchers".
Willard has been an interesting phenomenon. Perch were never planted in Willard. But, like smallmouths...and even a few tiger muskies...they found their way down from Pineview and gradually established a population in Willard. Perch were seldom caught in Willard until about 2010. Then a few would show up each fall for anglers fishing for crappies...but almost none were caught during the warmer months. Beginning about 2018, anglers fishing Willard after late September began catching more perch...and some bigguns. Since very few Willardites bothered to fish Willard except during the crappie run, the walleye run or during the striper boils, there was not much attention given to perch. But when a few serious perch jerkers began making good hauls of porky perch in the late fall, more and more guys delayed winterizing their boats and began fishing the perch right up until iceup.
With the decline in wiper numbers the young perch had a better chance of survival during the lean months with no baby shad for the wipers to feed on. During that shadless time all the predators in the lake have to subsist on whatever they can find...crawdads, log perch, spottail shiners and the young of bluegills, crappies, perch and even catfish. But when the predator population declines, so does predation on the young of other species...like perch. So today, we have a pretty big population of perch. And those that survive past the edible sizes grow fast...and big. During part of the year they have to make a living on abundant midge larvae. But as soon as the shad start hatching the perch start glutting on those...and feed on them heavily until they get too big in the late fall.
However, there is one phenomenon in Willard that keeps the perch big and healthy. That is that the shad have an extended spawn...from sometime in April through late May or early June. The first shad to hatch reach 5" by iceup. The last to hatch are only about 2" when water temps drop below about 55 degrees in late September. Those late hatchlings have not developed enough to live on anything but zooplankton and when the zooplankton decrease in the cold water, millions of baby shad die off. Their carcasses are gobbled up by terns and gulls on the surface. The ones that die and sink to the bottom are eagerly slurped up by catfish and perch. And each year the perch form large schools both for feeding on shad and to prepare for the late winter spawn. All the big perch caught by anglers in the late fall are usually swollen...not only with ripening eggs but with shadlets too. Good nutrition that produces big fat perch that are great eating.