Greetings, fellas!
Thought I might enter this discussion for a moment. Part of the way I make a living is growing huge bass for clients. It's not an easy thing to do, or many people would do it.
Walt and Eric addressed research studies, so I'll be more colloquial and let you know some real world stories of situations that have happened with my lake management business.
There are some consistencies though.
Here's my first statement. Every trophy bass lake I manage, that grows good numbers of double-digit bass, has gizzard shad. Every one.
Second, if we don't have threadfins, we stock them.
Third, each of these lakes has giant bluegll and none have seen an overall decrease in bluegill sizes. But, I do see an increase in numbers of mid-sized bluegill, especially 3-4 inchers.
Here's what happens.
I start a lake with bluegill, redear sunfish and fathead minnows to establish a food chain. Then, after enough time to establish these fish, I stock bass at 50 per surface acre. I think the best way to stock bass is to stock small fingerlings and mix the gene pool. Personally, I like to stock half Floridas and half natives, but I will go 1/3 Florida, 1/3 Natives and 1/3 F1 crosses.
I allow this fishery to develop. Oftentimes, we'll feed the bluegill with Aquamax to expedite the process of establishing several size classes of bluegill.
As bass grow, we monitor their growth rates, either by hook and line or electrofishing or both. I usually won't electrofish until the third year, however, to leave the fish alone.
Job One is to get bass to 16.5 inches long as soon as possible. That's a hard job, especially since these critters start reproducing at 9-10" long, sometimes at the beginning of their second year.
In the second year, we stock threadfins...when they are available and as long as the lake has a good chance for the fish to survive most winters. In Texas and parts of the south, threadfins will live 4 of 5 winters. Draw an east-west line through Oklahoma City and south of that line threadfins will live 2-3 out of 5 winters, depending how far south of that line the lake is.
Once we can consistently quantify that at least 25% (by head count) of the bass we collect via electrofishing are 16.5 inches long or larger, I'll stock gizzard shad.
Keep in mind, my mission has not been to grow huge bluegill with these lakes. The mission has been to grow huge bass.
My thinking has been that once a bass grows to 16.5 inches in length, its feeding habits change dramatically. Up to that point, these bass depend primarily on small fish, especially young of the year bluegill and similar size creatures. But, a 16.5 inch bass' mouth can reach around a 9-10" bass. That's what they begin to feed on. Enter gizzard shad. These growing bass now have the chance to quickly grow to 18, 19, 20 inches in length. The larger they become, the larger the meals they eat, less often.
While I won't dispute that shad compete with bluegill for food, I will offer that this does not have a negative impact on bluegill. I'll tell you quite the contrary. As the bass population increases in biomass and the size classes are fairly distributed, so are the bluegill size classes, although I also see an increase in 3-4" bluegill numbers. This "balanced" system is pretty much dictated by the dynamics of the predator base. In well managed trophy bass lakes, there are different size ranges of bass feeding in different niches of the food chain and they effectively control numbers of bluegill. The consequences...every time...is that we always grow some huge bluegill, often pushing two pounds. Big bass eat big bluegill, helping thin their numbers, resulting in fewer large bluegill which grow exceptionally fast and quite large.
What I see with shad, both species, is that their populations ebb and flow, feast or famine. During late summer, early fall, we'll see tens of thousands of shad but by winter, their numbers have diminished. Bluegill ebb and flow more often and their numbers rise and fall more consistently that the shad.
I electrofished a lake this week...a 30 acre lake I have helped off and on for 25 years. At first, this lake was overloaded with overcrowded bass and very little food. Through a harvest program, taking bass, and stocking bluegill adults, the lake reversed. Over time, the club worked hard to manage the dynamics of the fishery and here's what I saw Tuesday.
Keep in mind their mission is to have a balanced fish and they don't care too much about growing many giant bass.
We observed 5 size classes of gizzard shad (no one will own up to stocking them) and the majority were this year's hatch, fish about 3-4 inches long. We collected 5 size classes of bass (125 fish) and Wr's were right at 100, some a little higher, but not much. We collected 6 size classes of bluegill, 3 of those classes from this year, with several bluegill at least 10 inches long. We also collected 3 size classes of redear sunfish and 3 size classes of black crappie. By far, the largest biomass was gizzard shad. At the same time, there is very little structure/cover for those species of fish which need it.
Bottom line, we saw good numbers of bluegill larger than 7" and quite a few true trophies.
The majority of the bass were well beyond 16 inches, but we did see this year's class (which we normally don't, when the bass are overcrowded) as well as plenty of last year's bass hatch. This lake is neither fertilized nor fed any supplemental feed.
Another lake, 120 acres east of Athens, Texas, was electrofished two weeks ago. If we saw one school of young of the year threadfins, we saw 250, rippling the mirror-flat water just before dark. Each school had 750-2,000 fish in it. That's lots of baby threadfins. When we cranked up the electrofishing boat, we saw tens of thousands of these creatures, along with several schools of gizzard shad, too. Bass are thriving, but so are the bluegill. We collected several bluegill in the 1 3/4 pound size range and observed hundreds smaller fish.
So, my experiences suggest that while shad may compete with bluegill for food, the other dynamics of the fishery overcome that competition in healthy ways.
I do believe, however, that this lake has so many huge bluegill in part due to the fact we supplementally feed them Aquamax pellets for the purpose of increasing their sizes and numbers. This client DOES want to grow some huge bass, which we are doing. One other note about this lake...in the past we have stocked tilapia, but this year chose not to simply because there were so many shad going into the growing season and the bluegill were numerous, too. So far, it looks like a good decision.
I could cite more stories, all similar, but I gotta go make a living.
But, I thought it proper to share my perspective.
