Steven M. Sammons

Movement and Habitat Differentiation among Adult Shoal Bass, Largemouth Bass, and Spotted Bass in the Upper Flint River, Georgia

Abstract The Shoal Bass Micropterus cataractae is a fluvial specialist endemic to the Apalachicola River drainage in Alabama, Florida, and Georgia that has experienced declines throughout much of its range. The Flint River, Georgia, represents the largest remaining intact ecosystem for Shoal Bass in their native range. Spotted Bass M. punctulatus have recently been introduced into this system, causing concern about the potential negative impacts the species may have on the native populations of Shoal Bass and Largemouth Bass M. salmoides. To assess the symmetry and strength of competition and gain the greatest perspective on the interrelationships among these sympatric, congeneric species, we compared the movement patterns and habitat use of all three species of black bass present in this system. Fifteen Shoal Bass, 10 Largemouth Bass, and 6 Spotted Bass were implanted with radio transmitters in the Flint River and tracked for a period of 1 year (2008). Daily and hourly movements did not vary among specie...

Variation in Growth and Survival of Bluegills and Redbreast Sunfish in Georgia Rivers

Abstract Growth and survival of bluegills Lepomis macrochirus and redbreast sunfish L. auritus (N = 5,664) were examined in 13 river sections located in the southern half of Georgia. Bluegills tended to grow faster than redbreast sunfish within rivers where the two species were collected together. Annual survival of redbreast sunfish (range = 18–52%; mean = 38%) was greater than that of bluegills (range = 21–34%; mean = 29%). For both species, growth of males was generally greater than females, though annual survival did not differ significantly between sexes for either species. Growth of redbreast sunfish and bluegills appeared to increase along a northwest to southeast gradient across the state of Georgia. Growth variation of these sunfishes was likely mediated by prey availability, habitat, and physicochemical variables within each river section.

Effects of river flows on growth of redbreast sunfish Lepomis auritus (Centrarchidae) in Georgia rivers.

Effects of river discharge on growth of redbreast sunfish Lepomis auritus were investigated in nine rivers in Georgia, U.S.A. Fish were aged and annular total length increments (L(Tinc)) estimated from measurements from sectioned sagittal otoliths using the generalized regression model that held for the effects of decreasing L(Tinc) from annual age (X): L(Tinc)=b(o)-b(1)(X) +/-b(i)(D), where b(o), b(1) and b(i) were the regression coefficients for the intercept and slopes and D, discharge, was either a single or multiple measurements of annular or seasonal flow volume or variation in flow volume. For eight of nine rivers, higher or greater variation in flows from April to June was associated with greater L. auritus growth; in the last river, higher flows from January to March were associated with greater fish growth. Across all rivers, L. auritus growth increments were 22, 45 and 36% greater in a wet year v. a dry year at ages 1, 2 and 3 years, respectively. Based on the results of this study, increasing water withdrawals by an additional 30% in five Georgia rivers would reduce the predicted number of L. auritus recruiting to 203 mm (angler preferred size) by 19-62%.

Diets of Juvenile and Sub-Adult Size Classes of Three Micropterus spp. in the Flint River, Georgia: Potential for Trophic Competition

Abstract Concerns over the recent introduction of Micropterus punctulatus (Spotted Bass) on native M. salmoides (Largemouth Bass) and M. cataractae (Shoal Bass) prompted a one-year investigation into the food habits of these three congeneric species to determine diet overlap and potential for trophic competition in the Flint River, GA. Diet analyses among species were conducted for two size classes offish: juvenile (<200 mm total length) and subadult (200–300 mm TL). Because Spotted Bass had become established in the Flint River only a few years prior to this study, few fish >300 mm were collected; thus, diet overlap was not compared among species for larger fish. Juvenile and subadult Largemouth Bass diets were dominated by fish in all seasons, mainly sunfishes (e.g., Lepomis auritus, L. macrochirus). In contrast, Shoal Bass diets were generally dominated by insects and crayfish in the juvenile and subadult size classes, respectively. Juvenile Spotted Bass diets were variable and dominated by fish and insects depending on season. Overall, diets of introduced Spotted Bass appeared to occupy an intermediate position between Shoal Bass and Largemouth Bass. Significant diet overlap between Shoal Bass and Spotted Bass occurred in 50% of the samples, but only in 29% of the samples between Spotted Bass and Largemouth Bass and never between the two native Bass species. Thus, concerns about the trophic effects of Spotted Bass on Shoal Bass appear to be legitimate.

Polychlorinated biphenyls in adult black bass and yellow perch were not associated with their reproductive success in the upper Hudson River, New York, USA

Although production and use of polychlorinated biphenyls (PCBs) ceased nearly 35 yr ago, questions still remain concerning the potential chronic effects these compounds may have on wild fish, including their reproductive success. In the upper Hudson River, New York, USA, fish were exposed to PCBs primarily from 2 manufacturing plants located approximately 320 km upstream of New York City, New York, from the 1940s to 1977. The authors collected yellow perch (Perca flavescens), smallmouth bass (Micropterus dolomieu), and largemouth bass (M. salmoides) using electrofishing, measured PCBs in these adults, and estimated abundance and size of their offspring at age 1 yr (age-1 fish). Fish were collected annually from 2004 to 2009 from 1 control site upstream of the PCB discharge sites and from 2 sites downstream from where PCBs were released. These sites (pools) are separated by a series of dams, locks, and canals. Muscle tissue wet weight PCB and lipid-based PCB concentrations in adults in the 2 PCB exposure pools averaged approximately 1 to 3 µg/g and 100 to 500 µg/g, respectively. Age-1 abundances were not related to adult PCB concentrations but were inversely related to river flow. Size of age-1 fish was slightly greater at the PCB-exposure sites. Levels of PCBs in yellow perch, largemouth bass, and smallmouth bass in the upper Hudson River did not impair or reduce recruitment or reproductive success.

Catch and Exploitation of Shoal Bass in the Flint River, Georgia, USA: Implications for Harvest Restrictions

AbstractShoal Bass Micropterus cataractae are endemic to the Apalachicola River basin (Alabama, Florida, and Georgia) and support popular fisheries, yet little is known about the population dynamics or angler harvest of this species. To estimate the annual exploitation rate (u), 376 Shoal Bass were tagged at 16 sites over a 208-km stretch of the Flint River, Georgia, during 2008–2011. Mean annual u varied from 0.22 to 0.26, but because of the high movement rates of tagged fish, it was not possible to calculate true u for specific sites along the Flint River. The catch rate of tagged, sedentary Shoal Bass was relatively similar between areas that were accessible by motorboat (0.38) and those accessible only by canoe or kayak (0.32); however, u was 2.5 times higher in the motorboat-accessible areas (0.22) than in motorboat-inaccessible areas (0.09). The effects of three length limits (the current minimum length limit [MLL] of 305 mm TL; an MLL of 381 mm TL; and a protected slot limit of 356–432 mm TL) on th...

Impacts of Endothall Applications on Largemouth Bass Spawning Behavior and Reproductive Success

Abstract Aquatic herbicides are commonly used to control excessive and nuisance levels of submersed aquatic vegetation (SAV). At times, these applications tend to be more effective at the onset of fish spawning in spring; however, they can cause conflicts between anglers and lake management personnel assigned to control excessive SAV. We evaluated the direct application of an aquatic herbicide (Aquathol K [dipotassium salt of endothall]) on the nest behavior and fidelity of largemouth bass Micropterus salmoides and measured the subsequent reproductive success of these fish. Endothall was applied to achieve a shoreline concentration of 5 mg/L of water volume in 0.1-ha ponds (3 mg/L whole-pond concentration). It was applied directly on nests in three ponds in March 2005, 2006, and 2007 when largemouth bass initiated spawning; spawning activity was monitored over 14–15 d. Using similar techniques, we applied water to another three ponds where largemouth bass were nesting. For all 3 years, endothall did not a...