Robert M. Neumann

Seasonal Variations in Concentrations of Mercury in Axial Muscle Tissue of Largemouth Bass

Abstract Largemouth bass Micropterus salmoides were collected from Lake Lillinonah and Pickerel Lake, Connecticut, during three sampling periods in 1996: spring (May 14–15); summer (Jul 22–30); and fall (Oct 10–17). Total mercury concentrations ranged from 0.106 to 2.293 μg/g in Lake Lillinonah and from 0.456 to 1.762 μg/g in Pickerel Lake. In both lakes, there was a significant positive relationship between total mercury concentration and length and age during each season. Mean mercury concentrations adjusted for length were significantly different among seasons in Pickerel Lake (P = 0.0002) and Lake Lillinonah (P = 0.0006) and were 26–43% higher during spring than summer and fall in both lakes. Mean mercury concentrations adjusted for age were significantly different among seasons in Lake Lillinonah (P = 0.02) but not in Pickerel Lake (P = 0.06). In Lake Lillinonah, mean mercury concentrations adjusted for age were significantly higher during spring than during fall (P < 0.017). These results suggest th...

Bioaccumulation and Biomagnification of Mercury in Two Warmwater Fish Communities

ABSTRACT Total mercury concentrations were determined in two Connecticut lakes for six fish species representing a range of trophic levels—largemouth bass (Micropterus salmoides), chain pickerel (Esox niger), black crappie (Pomoxis nigromaculatus), bluegill (Lepomis macrochirus), smallmouth bass (M. dolomieu), and yellow perch (Perca flavescens). Total mercury concentrations in all fishes increased with length and age. Slopes of log10 mercury concentration-age regressions, which were used to compare bioaccumulation rates, were different among species in both lakes. In both lakes, no difference in bioaccumulation rate was found between top-level predators. Top-level predators and intermediate trophic level species (black crappie and yellow perch) accumulated mercury at a faster rate than bluegills. Intermediate trophic level species had bioaccumulation rates comparable to top-level predators over the range of ages sampled. Differences in mercury concentrations between a top-level predator (largemouth bass)...

Factors Related to Mortality of Black Bass Caught during Small Club Tournaments in Connecticut

Abstract Factors related to the initial and delayed mortality of largemouth bass Micropterus salmoides and smallmouth bass M. dolomieu were determined at small club tournaments held at two Connecticut lakes during April–October of 2001–2002. Organizational characteristics of tournaments, environmental conditions, and initial mortality data were collected from 58 tournaments at Mansfield Hollow Reservoir and 41 tournaments at Gardner Lake. Delayed mortality at 72 h was also determined for 29 tournaments at Mansfield Hollow Reservoir and 25 tournaments at Gardner Lake. In total, 3,290 largemouth bass and 1,035 smallmouth bass were observed for initial mortality; 1,784 largemouth bass and 647 smallmouth bass were observed for 72-h delayed mortality. Initial and delayed mortality rates were 2.2% and 1.0% for largemouth bass and 4.8% and 2.8% for smallmouth bass. Logistic regression indicated that initial mortality was significantly greater (P < 0.0001) for smallmouth bass than for largemouth bass, and that in...

Impacts of Small Club Tournaments on Black Bass Populations in Connecticut and the Effects of Regulation Exemptions

Abstract Annual tournament-associated mortality of largemouth bass Micropterus salmoides and smallmouth bass M. dolomieu (≥30 cm) was quantified at Mansfield Hollow Reservoir and Gardner Lake, Connecticut, during 2001 and 2002 to determine the effects of tournaments on black bass populations. Nontournament and tournament anglers followed a 30-cm minimum length limit during both years. Tournament anglers—but not nontournament anglers—were exempt from new, more restrictive regulations (a 30–41-cm protected slot length limit at Mansfield Hollow Reservoir; a 41-cm minimum length limit at Gardner Lake) imposed in 2002. Annual tournament-associated mortality of largemouth bass was 2.4–8.4% of total annual mortality, 1.0–3.2% of the population size, and 2.0–20.8% of annual fishing mortality. For smallmouth bass, tournament-associated mortality was approximately 7% of total annual mortality, 4% of the population size, and 29–52% of annual fishing mortality. Based on the levels of total annual mortality, annual fi...

Relationships between Concentrations of Mercury in Largemouth Bass and Physical and Chemical Characteristics of Connecticut Lakes

Abstract Concentrations of total mercury were determined for axial muscle tissue of 438 largemouth bass Micropterus salmoides from 46 lakes representing five regions in Connecticut to determine relationships between mercury concentrations and lake characteristics and to assess regional differences in mercury concentrations. Expected concentrations of mercury (EHg) predicted for a length of 356 mm for each population ranged from 0.103 to 0.795 μg/g wet weight. Principal components analysis revealed that, in general, two types of lakes were represented in the data set and were grouped based on hydrologic characteristics. Type-II lakes (artificial impoundments) had a significantly lower mean retention time than type-I lakes (natural drainage lakes) and a significantly larger mean watershed area, watershed area : surface area ratio, watershed area: lake volume ratio, and shoreline development index. Mean EHg was approximately 20% higher in type-II lakes (0.514 μ/g wet weight) than in type-I lakes (0.410 μg/g ...

Comparison of snorkeling and electrofishing for estimating abundance and size structure of brook trout and brown trout in two southern New England streams

Abstract Abundance and size structure of brook trout Salvelinus fontinalis and brown trout Salmo trutta determined by snorkeling were compared with estimates determined by electrofishing depletion in 30 habitat units of two Connecticut streams. Snorkel counts were significantly correlated ( P

Seasonal and Size-Related Food Habits of Largemouth Bass in Two Connecticut Lakes

Abstract Stomach contents of 425 largemouth bass were identified and quantified using the Relative Importance (RI) index over three seasons (spring, summer, and fall) from Lake Lillinonah and Pickerel Lake, Connecticut. In Lake Lillinonah during spring, aquatic insects had the highest RI, followed by crayfish and fish (primarily white perch). During summer and fall, the RI of aquatic insects decreased, the RI of crayfish remained consistent, and the RI of fish approximately doubled. Fish (primarily bluegill) was the most important diet item of largemouth bass from Pickerel Lake during all seasons. Aquatic insects were the second most important diet item during spring and summer. In Lake Lillinonah and Pickerel Lake, the RI of aquatic insects decreased and the RI of fish increased with increasing fish length; aquatic insects were most important in largemouth bass less than 300 mm. In contrast to Lake Lillinonah where the RI of crayfish and fish were of equal importance in largemouth bass ≥ 380 mm, largemou...

Range and Movement of Resident Holdover and Hatchery Brown Trout Tagged with Radio Transmitters in the Farmington River, Connecticut

Abstract The 5.8-km West Branch Farmington River Trout Management Area (TMA) is one of Connecticuts premier catch-and-release fisheries for brown trout Salmo trutta. However, little is known about the behavior of brown trout in this system and to what extent brown trout emigrate from the TMA. The objectives of this study were to determine the movement, range, and emigration of resident holdover and newly stocked brown trout tagged with radio transmitters in the TMA. Transmitters were implanted into 22 first-year (mean total length = 314 mm) and 25 second-year (mean total length = 432 mm) holdover brown trout. Twenty catchable-size (mean total length = 290 mm) brown trout were also implanted with transmitters and released into the TMA. The mean range (distance between the extreme upstream and downstream locations) was greater for second-year holdover brown trout than for first-year holdover brown trout, and it was greater in fall than in winter. The movement (distance moved between successive locations) o...

Distribution, Habitat Use, Growth, and Condition of a Native and an Introduced Catfish Species in the Hudson River Estuary

ABSTRACT White catfish (Ameiurus catus) is native to the Hudson River and is now coexisting with the recently established channel catfish (Ictalurus punctatus). These species were sampled from four freshwater reaches and four habitat types of the Hudson River estuary to assess whether the two species overlapped in their habitat use, and whether any impact on the native species was evident. Catfishes were sampled in 1998 and 1999 using baited hoop nets (N = 708 net nights). Catch-per-unit-effort (CPUE, number offish per net night; total catch = 368) of white catfish was significantly different among reaches and habitat types; CPUE was greatest in the upstream reach, and in offshore shoal habitat. Channel catfish (total catch = 344) were more abundant in offshore shoal habitats in upriver reaches, but were more abundant in nearshore and tributary mouth habitats in downstream reaches. Individuals of both species were largest upstream. Individual condition (as relative weight, Wr) varied with reach in white catfish, and was low in a downstream reach; in contrast, Wr did not vary among reaches in channel catfish. White catfish grew slowly compared to channel catfish. Relative to populations in other water bodies in North America, Hudson River fishes of both species grew slowly in their first year, but otherwise grew at expected rates. Channel catfish are becoming more abundant in the Hudson River, as white catfish appear to decline. Channel catfish establishment may be facilitated by greater flexibility in habitat use.

Relative Weight as a Body Condition Index for Chain Pickerel

ABSTRACT Weight-length data from 115 chain pickerel Esox niger populations from 13 states and one Canadian province were used to develop a standard weight (Ws) equation that would allow calculation of relative weight (Wr) values. We developed the 75th-percentile Ws equation using the regression-line-percentile (RLP) method. The proposed Ws equation is log10 Ws(g) = −5.824 + 3.243 log10total length (TL; mm). The English equivalent of this equation is log10 Ws(lb) = −3.293 + 3.243 log10TL(in). The equation is useful for 150 mm and longer chain pickerel. We found no evidence of consistent trends of increasing or decreasing Wr values calculated with the proposed RLP Ws equation. We recommend the use of the proposed RLP Ws equation for assessment of chain pickerel body condition. The proposed Ws equation should serve as a basis for further evaluation of Wr as an index to growth and other physiological trends for chain pickerel.