Tim,
This may be one of those questions that can only be answered by "it depends". For your pond, there is a probably a goldilocks standing weight and population of BG that will produce the most appropriate (in an average year) quantity of YOY. It is just .... what is that number and how many would you have to remove (or possibly add) to reach that number? Anticipating growth, the weight each Fall would presumably be reduced (or possibly increased) to a level below that target weight. How much? Who knows?
Anyways,
this paper consolidates a number of research findings and you may be interested in reading it. Though the synopsis is intended to influence the management of Wisconsin BG, the source references cover a wide geographic area. Anyways, if after reading it thoroughly you find any inspiration, please let us know. A few quips from the paper are below:
Population size structure influences maturation and reproductive behavior of male bluegills. In Illinois ponds, Aday et al. (2002) found that peak spawning activity in a population of stunted bluegills (all nesting males < 6.3 inches) occurred three to four weeks later than in two populations of non-stunted bluegills (all nesting males ≥ 7.1 inches).
Populations with higher standing stocks of bluegill may produce lower-density cohorts of offspring. In 38 Midwestern bass-bluegill ponds ranging between 0.5 and 6.0 acres in area, Novinger and Legler (1978) reported that bluegill populations with standing stocks of 100-150 pounds/acre produced the maximum densities of offspring by fall. In ponds with lower and higher standing stocks, densities of age-0 bluegills recovered in fall rotenone samples were considerably lower.
Schneider (1999) documented low spawning activity in a lightly exploited and dense population of large adult bluegills in Blueberry Pond, Michigan – a relatively shallow, clear, weedy, 20-acre private lake with an extremely high density of large bluegill (204 per acre ≥ 8 inches). He observed very little spawning activity and very low recruitment despite finding that Blueberry Pond bluegills of variable size and condition exhibited normal reproductive potential after being transferred into experimental ponds at low density (8-31 adults per pond, drained after four months to count all age-0 bluegills).
Schneider (1999) estimated that only 2% of the adult bluegills even attempted to spawn in Blueberry Pond. Because these fish demonstrated the capacity to spawn at expected levels when removed from their high-density environment, Schneider discussed the possibility that social inhibition may have repressed bluegill reproduction in Blueberry Pond.
There are a variety of examples of walleye (Sander vitreus) demonstrating effectiveness in controlling bluegill recruitment through predation. When walleye assumed dominance in the fish community of 293-acre Escanaba Lake, Wisconsin during the late 1940s and early 1950s, angler catch rates for panfish were extremely low (Kempinger and Carline 1977). As estimated density of age-2-and-older walleyes declined from ~35/acre in the late 1950s to ~15/acre in the early 1960s, angler catch rates for panfish, including bluegills, increased to low but detectable levels of 0.04-0.06/hour. When walleye density rebounded to levels above 25/acre and northern pike (Esox lucius) became well established in the mid to late 1960s, angler catch rates for all panfish species crashed to pre-1955 levels. These co-occurring phenomena suggest that Escanaba Lake predators (particularly walleyes) exerted strong control over panfish recruitment. Kempinger and Carline (1977) believed that a small number of adult panfish were able to produce large numbers of juveniles to sustain high densities of predators in Escanaba Lake, but very few survived to adulthood.
So about as clear as mud, right? Each pond is different but it isn't a cinch that removing some BG will harm the production of food for your LMB. There is potential to increase the production of YOY by doing so. But that isn't a cinch either.
