Do you love big bluegill?
Why Everything You Know About Bluegill Management is Wrong
BY MATT MILLER
OCTOBER 15, 2015
Bluegills are prone to overpopulation. This is accepted knowledge among many anglers.
If you don’t catch and keep a lot of bluegills out of a pond, you’ll often hear a fisherman say, the bluegills will overrun the place. You’ll soon have a pond full of runty, stunted fish.
This is why the bag limits for bluegills are typically very liberal – it is not unusual to be able to keep 25 fish a day. It’s the angler’s duty to catch and eat as many as possible – keep the herd in check, if you will.
It sounds good, but current research suggests it’s wrong.
In fact, research conducted by Andrew Rypel, research biologist with the Wisconsin Department of Natural Resources, suggests the opposite: that liberal harvest limits on bluegills actually decreases the size of fish.
“Fish Here Aren’t As Big As They Used to Be”
Bluegills are often the first fish many anglers encounter (including me). They are common in farm and urban ponds. They’re the fish kids catch with a Mickey Mouse rod, a bobber and worms.
In the spring, many anglers target them on their spawning beds, where the biggest males are often easy to catch (see yesterday’s blog for the full details on this spectacle).
Bluegills are also popular because they’re tasty. Anglers call them and similar-sized species – crappies, perch, other sunfish – panfish. They’re the perfect size to fit in a frying pan.
Rypel and his colleagues in Wisconsin noticed something over the years: Anglers reported decreasing size of bluegills and other panfish. Of course, conventional angling wisdom would suggest the solution to this would be to harvest even more bluegills. After all, decreasing size is a sign of overpopulation.
Research tells a different story.
Rypel analyzed size trends going back to the 1940’s, and found that bluegills (and other panfish species) steadily declined in size over a 70-year period.
Researcher Andre Rypel (right) first encountered bluegills as many of us do: as a young kid, fishing.
“The regulations are relatively liberal,” he says. “I thought one possibility might be that we were fishing them too hard. As we looked at the data, we found that evidence of bluegills becoming stunted because they were overpopulated was not as common as previously thought.”
Fishing pressure, particularly on spawning beds where bluegills are most vulnerable, can be intense. And that pressure may be decreasing the size of fish.
In response to the trend, the Wisconsin DNR reduced the bag limit to 10 fish on 10 lakes as a test. Researchers, including Rypel, analyzed fish size before and after the regulation.
They found that fish size increased on average a half-inch on maximum size and .8 inch on mean size.
That may not sound like much, but consider that a typical bluegill is six or seven inches, and a really large one is ten inches.
Rypel published the findings in the North American Journal of Fisheries Management.
A New Experiment in Bluegill Management
The next phase of the project is to implement new management strategies on 100 Wisconsin lakes. One third will have a reduced limit of 10, one third will have a reduced limit of 5, and one third will have a reduced bag limit only during the spawning season.
The management regimes will run for ten years. “We’re going to find out what different regulations can do for panfish size,” says Rypel.
The good news is that bluegill size rebounds when fishing pressure decreases. A study by Rypel in collaboration with researchers at the University of Wisconsin-Milwaukee, School of Freshwater Sciences found that the reduction in size was not likely due to a shift in genetics, as has been shown to be the case in some other prominent studies on fishing pressure.
Anglers have, in general, been reluctant to embrace size limit reductions. Rypel points out that the limit reductions may actually result in more meat harvested. That may seem counterintuitive, but it’s true. “As bluegills get bigger in length, they get exponentially bigger in weight,” he says. “So if you catch a few larger bluegills, you often get more meat than if you caught a bunch of smaller ones.”
There is still a lot biologists don’t know about bluegills. New research will likely call for more changes in fishing regulation, but Rypel acknowledges that science is only one part of fisheries regulation.
“Regulations are a blunt instrument,” he says. “They cannot account for all aspects of fisheries management. If they get too complicated, they become much more difficult to enforce. We want regulations that are easy to understand and easy to enforce. There are trade-offs. In this case, reducing the bag limit could help the resource tremendously while still meeting the expectations of anglers.”
And while the bluegill may seem an unlikely symbol for global fisheries management, what Rypel says applies to large commercial fisheries as surely as it does the local farm pond. Regulations are only ever partly about science, and they can never fully account for the complexity of a fishery.
The key for resource managers is to use sound science to create regulations that work best – for fish and for people.
“Bluegills have the opportunity to get bigger with a relatively minor shift in fishing regulations,” says Rypel. “Our research is providing the evidence that it benefits anglers, too. The findings seem counter-intuitive to many anglers, who have long believed that smaller bluegills was a sign of overpopulation. But perhaps our long-term studies can convince them that lower bag limits can mean better fishing, and bigger panfish fillets for the fish fry.”
TAGS: Field Notes, Fish, Fisheries, Nature + People, NaturePop, Weird Nature
Matt Miller is director of science communications for The Nature Conservancy and editor of the Cool Green Science blog. A lifelong naturalist and outdoor enthusiast, he has covered stories on science and nature around the globe. Matt has worked for the Conservancy for the past 14 years, previously serving as director of communications for the Idaho program. More from Matt
Jim, you say "As has been pointed out, not all waters are ideal, or even marginal, for producing quality sized bluegill." I presume there is information somewhere that discusses this and I would really like to check it out. I am baffled by the idea that a lake the size of Ray Roberts can be so productive for quality sized crappie and not sunfishes. I have family members, and their friends here who have fished this large lake for a number of years and they have been very successful at catching large numbers of quality crappie and sandies. However, they do just look at me when I mention fishing for bluegill like I'm completely nuts. So it's seems obvious from my encounters so far that bluegill fishing is not that common. That would lead me to believe that under-fishing for bluegill could be a factor, but I don't see how that's possible in a body of water as large as Ray Roberts. It's a mystery to me, so could you please help me understand what marginal effects might be causing this. I moved 1600 miles to live by a lake which I had hoped would be a haven for bluegills, and to look elsewhere would be a tragedy, much less nearly impossible at my age and condition!
Duane I say solve the puzzle! Assume the big fish are there … you just have to find them! Maybe you can relate what has happened to me and my experiences on this one lake I fish close to my residence.
The lake is heavily overfished, scoured clean of weeds all open water season, heavily used by residents recreational boating and jet skiing and it has an efficient public launch. Ask the locals their B.Gill population is stunted with many sub-eaters. The locals fish the lake like their jobs, eat all the 7-8 “ slot fish and state the big fish are the 8” plus fish but rarely seen.
The DNR suggested this lake for me to learn to fly fish because of the population of gills for action but would be small in the 4-6” range. I caught a many, many gills that day just about all in that range except one that really stood out. It would easily have broken the 10” mark if it had a complete tail. It was a gill of such size and proportion that I never experienced in my whole lifetime of fishing.
From that point on I knew a community of large gills existed in that lake but where? The locals heavily pounded the shorelines with the red and whites and took many fish. If I was to tap into this hidden community of big fish I needed to fish differently and smarter. I looked deeper with slip floats, vertical jigging and drop shotting. Experience fishing the first deep break revealed many of the same common slot fish. I had to go deeper. This was July and a thermocline forms on this lake at the 17’ mark… I drop shotted the flats just above the 17’ contour… Voila!! Success!!! Many 9-10” fish were tagged using the thermocline break.
The thermocline break became a building block to form a pattern of fishing to include ice fishing locations and spawning areas for fishing in the following seasons. In 2017 Earl and I now own the 100% 10 year history of the Pumpkinseed Master Angler fish and 50% of the B.Gill Master Angler fish in just a few months!!.
I say crack the code of the lake by digging in researching and getting experience in on the lake. Get a mapping sonar create your own map know your fishing grounds like the back of your hand. Fish the dirtiest water in the area vertical jig the edges… etc, etc.
It’s sounds like you could have a fun journey ahead of you.
Fun journey ahead indeed Slip Sinker. I agree there should and may well be large bluegills in Ray Roberts lake. However, the more commonly sought after white bass and crappie, using the vertical jigging method in deeper waters has yielded no mention of any large gills. I have read or heard somewhere that larger bluegills may school beneath crappie in deeper water, and they will take the larger lures especially when tipped with live baits. But again, no mention of any occasional big bluegill being caught with minnow tipped jigs or spoons. I will continue making inquires and hopefully be engaged by September with my own searcch.
here is another article that explains what some of you guys have been discussing. very good article.
on KY lake where i fish, it is vast with 2,000 miles of bay studded shoreline, we do have big bluegills and shellcrackers but not everybody catches those sizes. the smaller fish are taken care of by LMB, which on the last trap net study yielded 45 pounds per acre. thats a lot of bluegill culling bass. the sheer size of the lake makes a lot of places for fish to hide. the TARP entries show 170 bluegill at 10” or larger and 250 entries for shellcracker at 11” and larger. what is interesting is that both species largest entry is right at 14.5”. that kind of tells me that bluegill in this lake are doing as well as shellcracker, which have a 20 per person limit. there is no limit on bluegill.
there are a couple of things that worry me though, such as guides and other fisherman keeping 500 fish an outing (Garry Mason is about the only guide that i know of that imposed a limit on his boat), and the silver carp problem. folks here have always been taught that if you release the females then the bluegills will be a renewable resource, ive always had my doubts about that line of thinking. last year i read a fishing report of one of the guides, that was boasting about catching those high number of bluegills the year before, having trouble finding the bigger bluegill that year.
the same holds true on KY lake as it does on Slip Sinker’s lake, even without a noticeable thermocline on KY lake. the bigger fish spawn first and early and when they are done they head for the hard bottom and shell beds on humps off the old river channel, similar to ledge fishing for bass. hopefully, this post spawn ritual will ensure many years of good bluegill fishing on Ky lake.
Very good article Tracy… thanks for sharing… a lot of parallel thinking nowadays when it comes to B.Gill management. I particularly like this paragraph from the article…
The likely key to why reduced harvest resulted in larger bluegills was not that they survived to live longer and grow larger, but because they didn’t begin reproducing until they reached a larger size. Sexually mature fish channel a lot of energy into developing gonads and building and guarding nests, which leaves less energy for body (somatic) growth. By delaying sexual maturity until reaching a larger size, the fish can grow faster because energy is not shunted to reproduction. Jacobson found that average length at maturity of male bluegill increased from 6 inches before the 10-fish regulation to 6½ to 7 inches four years after the regulation was implemented. During the same time period, average length at maturity stayed at 6 inches in the reference lakes with 30-fish limits.
Read more: http://www.in-fisherman.com/panfish/bluegill/managing-bluegills/#ixzz56yVzHfn2
So here’s where I think it get’s dicey… to the point that many of us BBG’ers might disagree with one another particularly members North and South…but to me it makes sense considering the years of aquarium experience breeding tropical fish, mainly cichlids…. Cichlids spawn and act very closely to the native Lepomis.
raising the temp in the aquarium speeds up the growth and life cycle of the fish. Spawning, hatching and raising the cichlids I would then cull out the smaller specimens and would keep the larger, beautiful and more robust specimens for my own stock. In just a couple years effort I would a nice lineage of fish.
Now in southern states pertaining to B.Gill growth rate to attain 10 inches might be achieved in just a few short years while in northern tier states it takes 8-10 years to reach a trophy size of 10”… like in my neighborhood. Here is where the damage is really noticed at a quicker pace… take out the big bulls and it takes a few years to replace and genetically steps down the quality sized future fish. I’m even excluding the little satellite male B.Gills situation in the theorem which makes it significantly worse.
So given the success us aquarists used through the years to produce better quality fish by culling the smaller specimens… wouldn’t it work on any body of water on any species North or South? As time and experience go on it only makes more sense to me. Slot limits and lower limits work!
the smaller fish are taken care of by LMB, which on the last trap net study yielded 45 pounds per acre. thats a lot of bluegill culling bass.
Wow, 14.5 inch RES and B.Gills … that’s incredible! With that nice LMB population really helps.
there are a couple of things that worry me though, such as guides and other fisherman keeping 500 fish an outing (Garry Mason is about the only guide that i know of that imposed a limit on his boat), and the silver carp problem
It is concerning about the carp population… a BOW only supports so many fish per acre no matter what species and they take up a lot of room.
I've seen some nice vids from your neighborhood actually showing how they coral and net the carp in huge quantities. They are an ongoing problem but with better harvesting techniques they might be just kept under control. There is an actual market for them where they are prepared into fish cakes… interesting none the less.
thanks for an interesting read
Entertaining as well as informative video on conservative b.gill harvesting.