Bluegill Recruitment, Growth, Population Size Structure, and Associated Factors in Minnesota Lakes

Abstract

To better understand the differences among populations of bluegill Lepomis macrochirus, we analyzed the relationships between bluegill recruitment, growth, population size structure, and associated factors from approximately 2,600 Minnesota lakes. Potential explanatory variables for our models included bluegill year‐class strength, growth, population size structure, the relative abundance and mean weight of predator species, physical and chemical characteristics of lakes, summer air temperature, and season. Bluegill year‐class strength, growth, and population size structure were more strongly related to each other than to predator and lake characteristics, temperature, or season. Growth of age‐6 bluegills was positively associated with population size structure and inversely related to year‐class strength, suggesting density‐dependent growth effects for adult bluegills. Growth of age‐3 bluegills was inversely related to Secchi depth, so early growth and productivity may be linked. Bluegill population size structure was positively associated with length at age 5, as expected from the analysis of growth, and was inversely associated with mean year‐class strength. Bluegill year‐class strength was negatively associated with population size structure, length at ages 4 and 5, and lake area. Although predator variables were not included in one‐ or two‐variable regression models, bluegill growth was positively related to the relative abundance of yellow perch Perca flavescens, walleye Sander vitreus (formerly Stizostedion vitreum), black bullhead Ameiurus melas, and brown bullhead A. nebulosus and negatively related to that of largemouth bass Micropterus salmoides and yellow bullhead A. natalis. The results suggest that management strategies for improving bluegill growth and population size structure should focus on bluegill recruitment and growth rather than on external environmental factors.

Size and Age at Maturity of Bluegill (Lepomis macrochirus) in Southeastern South Dakota Impoundments

“…Previous research has suggested that bluegill growth can be density-dependent (Novinger and Legler 1978, Osenberg et al 1988, Breck 1993, Tomcko and Pierce 2005. Given minimal differences observed in age and size at maturity coupled with large differences in size structure, total attainable size, and growth rates following maturation between lake types, we believe that density-dependent relationships (Novinger and Legler 1978) and competition for food resources (Hoxmeier et al 2009) may be the primary factors affecting maximum attainable total length and size structure in our four studv impoundments.…”

“…Our first hypothesis was that juvenile male bluegill in populations dominated by large (3 150 mm total length) male bluegill (hereafter referred to as high size structure populations) would exhibit delayed maturation and be larger at maturation than bluegill in low size structure populations (i.e., those dominated by individuals 5 150 mm) due to social inhibition of maturation (e.g., Drake et al 1997, Jennings et al 1997, Aday et al 2006. Our second hypothesis was that population abundance would influence size structure in a density-dependent manner, with highabundance populations exhibiting lower size structure and low-abundance populations exhibiting higher size structure (e.g., Novinger andLegler 1978, Tomcko andPierce 2005). Gaining knowledge on size and age at maturity in these systems will provide biologists with pertinent information for the management of this popular sportfish.…”

“…The most commonly cited causes for inadequate bluegili size structure include overharvest (Coble 1988, Drake et al 1997, Jacobson 2005, the influence of male social interactions (Drake et al 1997, Jennings et aI. 1997, Aday et al 2006, deficiency of an ample predator assemblage (Novinger and Legler 1978, Guy and Willis 1990, Tomcko and Pierce 2005, and resource availability (Swingle 1951, Gerking 1962, Aday et al 2006. Age and size at maturity can influence bluegill size structure and tend to be variable across geographic locations (Gross 1991, Drake et al 1997, Jennings et al 1997, Aday et al 2003and 2006 is available pertaining to the age and size at maturation of bluegill in southeastern South Dakota impoundments.…”

Growth and Survival of Largemouth Bass following Supplemental Feeding of Bluegills in Small Impoundments

“…A high density of age-0 Bluegills in a single control pond increased the control mean value, but differences among treatments were not statistically significant (Table 2). Because a complex set of interacting environmental factors contributes to larval fish recruitment (Houde 1987;Cargnelli and Gross 1996;Tomcko and Pierce 2005), there may have been limitations (e.g., densitydependent competition) that prevented the greater number of Bluegill larvae produced in the feeding treatments from translating into greater numbers of age-0 individuals. Furthermore, the increased numbers of Bluegill larvae in the feeding treatments might not have had sufficient time to grow and mature into age-0 Bluegills by the time harvest occurred; a longer period before harvest would have provided more prey items for the adult and age-0 Largemouth Bass.…”

Trophic scaling of Percichthys trucha (Percichthyidae) in monospecific and multispecific lakes in western Patagonia

“…Our results revealed much higher fish population density in monospecific lakes and stunted body sizes compared to those inhabiting multispecific lakes. This "overcrowding" condition (density-dependent) may lead to the observed small body size (Tomcko and Pierce, 2005) and caused these populations to function as stunted-like population. Stunted population are those in which the average size of adults is substantially smaller than that of conspecifics in similar populations (Aday, 2008) and have some distinguishing ecological features as: slower growth rate, convergence of ageclasses towards a similar size at earlier ages, a shorter life-span and an earlier age at maturity (Aday and Graeb, 2012).…”