Papers by Brian Blackwell
Journal of Freshwater Ecology, Jun 1, 1995
ABSTRACT We examined the zooplankton community and physicochemical parameters of the lower Trinit... more ABSTRACT We examined the zooplankton community and physicochemical parameters of the lower Trinity River, Texas during March 1992-March 1993, and evaluated the suitability of each for survival of paddlefish Polyodon spathula. Samples were collected every 2–4 weeks from mid-river channel and backwater stations at each of four sites. Eight paddlefish stomachs were analyzed, and eighteen paddlefish were aged and their relative weight values were determined. Physicochemical parameters generally were suitable for ...
Journal of Freshwater Ecology, Dec 1, 1996
ABSTRACT We evaluated the ability of low-density triploid grass carp (Ctenopharyngodon idella) st... more ABSTRACT We evaluated the ability of low-density triploid grass carp (Ctenopharyngodon idella) stockings to provide partial control of submersed vegetation (maintain 10–40% coverage) in four small impoundments. Triploid grass carp were stocked during May 1991 at densities ranging from 4.0 to 7.5 per surface ha; additional triploid grass carp (5.0 per surface ha) were added to one impoundment during June 1992. Submersed vegetation was monitored initially and during July 1991–1994. Grass carp stockings of 4.0 per surface ha ...
North American Journal of Fisheries Management, 2022
We used a long‐term data set (2000–2016) of larval, age‐0 (juvenile), and age‐2 Yellow PerchPerca... more We used a long‐term data set (2000–2016) of larval, age‐0 (juvenile), and age‐2 Yellow PerchPerca flavescenscatches from nine glacial lakes in eastern South Dakota to track multiple cohorts through time to determine whether year‐class strength (measured as gill‐net CPUE of age‐2 fish) could be indexed at the larval or juvenile stage. We observed a strong relationship between larval and juvenile abundance (r = 0.78), but neither were related to abundance of the same cohort at age 2. Furthermore, categorical analyses suggested that some of the strongest age‐2 year‐classes corresponded with the lowest larval and juvenile catches and vice versa. Our assessment suggests that Yellow Perch year‐class strength in eastern South Dakota glacial lakes may not be fixed until some point after the juvenile (i.e., fall age 0) stage and correspondingly that values for larval and juvenile CPUE are of limited utility as early indices of year‐class strength for Yellow Perch. Before using abundance esti...
Journal of Fish and Wildlife Management, 2018
Potential recruitment of age-0 Walleye Sander vitreus to adults is often indexed by the relative ... more Potential recruitment of age-0 Walleye Sander vitreus to adults is often indexed by the relative abundance of age-0 individuals during their first summer or fall. However, relationships between age-0 and adult Walleye abundance are often weak or nonsignificant in many waters. Overwinter mortality during the first year of life has been hypothesized as an important limitation to Walleye recruitment in lakes, but limited evidence of such mortality exists, likely due to difficulties in sampling age-1 Walleye during spring. The objectives of this study were to: 1) compare results from nighttime electrofishing to index relative abundance of age-1 Walleyes with relative abundance indices of minifyke nets in four eastern South Dakota lakes; 2) determine whether size-selective mortality was occurring in those four lakes; and 3) if size-selective mortality was occurring in these lakes, determine whether that mortality was attributed to body condition. We sampled four natural lakes in eastern ...
Reviews in Fish Biology and Fisheries, 2016
North American black bullhead, Ameiurus melas, which were introduced to Europe in the nineteenth ... more North American black bullhead, Ameiurus melas, which were introduced to Europe in the nineteenth and twentieth centuries, have received relatively little study. With focus on growth and reproduction, this extensive review, which includes new European data, aims to inform the risk analysis process concerning this non-native species in Europe. Surprisingly, the new data for Europe were more comprehensive than for native populations, with data available mainly from Oklahoma, and North and South Dakota (USA). In terms of relative growth, juvenile A. melas were found to have a relatively uniform body shape regardless of the population's origin, whereas adults developed different phenotypes depending upon location. Overall growth trajectory was significantly faster for native than for non-native populations. Growth index values decreased significantly with increasing latitude in non-native but not native populations-the latter decreasing weakly with increasing altitude in the populations located at latitudes \40°. Mean general condition (slope 'b'), mean sex ratio and mean egg diameter did not differ significantly between
North American Journal of Fisheries Management, 2017
The American Fisheries Society (AFS) has recommended standard gears and methods for collecting No... more The American Fisheries Society (AFS) has recommended standard gears and methods for collecting North American freshwater fish data, but selectivity of these gears, including gill nets, is poorly described for most species. We calculated contact selectivity for species commonly collected with AFS standard gill nets in lakes and reservoirs of North America, including Black Bullhead Ameiurus melas, Channel Catfish Ictalurus punctatus, Walleye Sander vitreus, and Yellow Perch Perca flavescens. The normal selectivity curve provided the best fit to empirical catch data for all species. Inclusion of a tangle factor improved model fit for Black Bullhead, Channel Catfish, and Walleye, indicating that tangling is an important means of capture for these species. Channel Catfish were more susceptible to tangling than the closely related Black Bullhead, likely because larger Channel Catfish are more vulnerable to tangling by spines in the smallest meshes, whereas Black Bullhead in the same meshe...
North American Journal of Fisheries Management, 2016
We performed a field experiment in five eastern South Dakota lakes to investigate fish escapement... more We performed a field experiment in five eastern South Dakota lakes to investigate fish escapement differences between modified fyke nets with two common throat configurations (restricted and unrestricted). Nets with restricted and unrestricted throats were deployed in pairs for 24 h on similar habitat. Captured fish were measured for TL and were given day‐specific marks. The paired nets were redeployed, and marked fish were randomly assigned to be stocked into the restricted or unrestricted net for 24 h; stocking densities (stratified into low, medium, and high) were species specific. Marked fish that were retained after 24 h were used to quantify escapement, whereas newly captured fish were used to estimate differences in mean CPUE and size structure. Mean CPUE of Black Bullheads Ameiurus melas, Black Crappies Pomoxis nigromaculatus, and Bluegills Lepomis macrochirus approximately doubled when restricted nets were used. Mean TL of Black Crappies was 31 mm greater (95% confidence in...
Paired gear comparisons were performed between North American Standard (Standard) and South Dakot... more Paired gear comparisons were performed between North American Standard (Standard) and South Dakota Game, Fish and Parks (SDGFP) gill nets on four mainstem impoundments of the Missouri River (Oahe, Sharpe, Francis Case, Lewis and Clark) during July-September 2013 to facilitate a statewide transition to Standard sampling gears. Differences in catch per unit effort (CPUE), size structure, mesh efficiencies, and diversity were quantified and conversions for relative abundance between Standard and SDGFP gears were developed using regression analyses. Monofilament Standard gill nets were 24.4 meters long and produced higher Catch Per Unit Effort (CPUE) of Freshwater Drum while 106.7 meter multifilament SDGFP gill nets yielded higher CPUE for Channel Catfish, Sauger, and Walleye. Standard gill nets selected for larger Channel Catfish, Freshwater Drum and Walleye but SDGFP gill nets selected for larger Smallmouth Bass. Mesh efficiencies of Standard nets were significantly higher than those ...
Paired gear comparisons were performed between North American Standard (Standard) and South Dakot... more Paired gear comparisons were performed between North American Standard (Standard) and South Dakota Game, Fish and Parks (SDGFP) gears for both gill nets and fyke nets in 13 Eastern South Dakota lakes during June-August of 2013 to facilitate a statewide transition to Standard sampling gears. Differences in catch per unit effort (CPUE), size structure, and diversity were quantified and conversions for relative abundance between Standard and SDGFP gears were developed using regression analyses. Longer SDGFP gill nets yielded higher CPUE for all species except White Bass. Standard gill nets selected for larger bullhead, Northern Pike, Walleye, and Yellow Perch. Black Crappie and Bluegill were sampled in greater numbers by Standard fyke nets while bullhead, Walleye, and Yellow Perch CPUE was higher for SDGFP fyke nets. Standard fyke nets selected for larger Black Crappie, Bluegill, Northern Pike, and Smallmouth Bass while SDGFP fyke nets selected for larger bullhead and Yellow Perch. No ...
We evaluated the extent of spatial synchrony in recruitment and estimated factors related to year... more We evaluated the extent of spatial synchrony in recruitment and estimated factors related to year-class strength in yellow perch populations among 37 eastern South Dakota glacial lakes sampled with gill nets in 2009, 2010, and 2011. Distance between lakes ranged from 1.7 km to 134.5 km. The extent of spatial synchrony among lakes was assessed using cross-correlation analysis of cohort catch per effort data. Correlation coefficients for the 136 bivariate correlations included in correlative analyses ranged from -0.47 to 0.99 (mean = 0.71), with 79% of correlations greater than 0.50, 64% of correlations greater than 0.70, and 37% of correlations greater than 0.90, suggesting synchronous population fluctuations. The extent of synchrony was not related to distance between lakes, at least not within the spatial scale included in this study. Year-class strength was assessed relative to combinations of climatic and hydrological variables using an information-theoretic approach. The winter ...
North American Journal of Fisheries Management, 2015
We estimated the influence of predation by Smallmouth Bass Micropterus dolomieu on recruitment of... more We estimated the influence of predation by Smallmouth Bass Micropterus dolomieu on recruitment of age‐0 Yellow Perch Perca flavescens in two northeastern South Dakota glacial lakes. We estimated a likely range in consumption of age‐0 Yellow Perch using Smallmouth Bass diet information from two time periods when age‐0 Yellow Perch constituted high (2008) and low (2012 and 2013) proportions of Smallmouth Bass diets, and bass population size estimates as inputs in a bioenergetics model. The proportion of age‐0 Yellow Perch consumed by the Smallmouth Bass populations was determined by comparing estimates of consumption with estimates of age‐0 perch production. During 2008, age‐0 Yellow Perch constituted between 0% and 42% of Smallmouth Bass diets by weight, whereas during 2012 and 2013, age‐0 perch constituted between 0% and 20% of bass diets by weight. Across both lakes and time periods, production of age‐0 Yellow Perch ranged from 0.32 to 1.78 kg·ha−1·week−1. Estimates of Smallmouth B...
Supplemental and maintenance stockings are important tools for the management of Walleye Sander v... more Supplemental and maintenance stockings are important tools for the management of Walleye Sander vitreus in South Dakota. However, survival of stocked Walleyes is often unpredictable. Thus, the objectives of this study were to examine Walleye recruitment relative to fry stockings in eastern South Dakota glacial lakes and estimate the influences of extrinsic factors on recruitment variability. Using Walleye fry stocking data and corresponding age-2 Walleye relative abundance data from 22 natural lakes over a 17-year period, we developed Ricker stock-recruitment models. Variation in stock-recruitment relationships was examined by parameterizing traditional stock-recruitment models with extrinsic variables including winter severity index (WSI), the change in fall to spring water level, and adult Yellow Perch Perca flavescens relative abundance. Using Akaike’s information criterion (AICc), stocking rate was the most-supported model in predicting age-2 Walleye recruits. Others models prov...
North American Journal of Fisheries Management, 2007
We collected annual gill-net samples of yellow perch Perca flavescens in six South Dakota lakes o... more We collected annual gill-net samples of yellow perch Perca flavescens in six South Dakota lakes over 4-5 years. We also simulated the effects of reductions in daily creel limits for yellow perch (i.e., from 25 fish/angler to 5, 10, or 15 fish/angler) and use of minimum total length limits (229 and 254 mm). Population indices varied widely among lakes and
North American Journal of Fisheries Management, 2005
We evaluated harvest patterns, exploitation, size selectivity, and angler catch preferences assoc... more We evaluated harvest patterns, exploitation, size selectivity, and angler catch preferences associated with winter fisheries for yellow perch Perca flavescens (i.e., ice fishing) on South Dakota lakes. Seasonal trends in the percentage of anglers targeting yellow perch and in yellow perch harvest were apparent in creel surveys on seven lakes; trends varied among lakes. Exploitation of yellow perch was estimated on two lakes through tag‐return studies. Nonreporting rates estimated from surrogate postcards varied between angler groups (19–52%). On East 81 Slough, where the relative stock density (RSD) of yellow perch of 254 mm or longer (RSD‐254) was low (RSD‐254 = 10), exploitation was only 7% during the winter of 2000–2001; much of the total annual mortality (48%) in the population was attributed to natural causes (40%). Conversely, the estimated exploitation rate on Pelican Lake, where size structure was dominated by larger fish (RSD‐254 = 92), was 61% from December to June. Angler...
Journal of Freshwater Ecology, 1996
ABSTRACT We evaluated the ability of low-density triploid grass carp (Ctenopharyngodon idella) st... more ABSTRACT We evaluated the ability of low-density triploid grass carp (Ctenopharyngodon idella) stockings to provide partial control of submersed vegetation (maintain 10–40% coverage) in four small impoundments. Triploid grass carp were stocked during May 1991 at densities ranging from 4.0 to 7.5 per surface ha; additional triploid grass carp (5.0 per surface ha) were added to one impoundment during June 1992. Submersed vegetation was monitored initially and during July 1991–1994. Grass carp stockings of 4.0 per surface ha ...
Journal of Freshwater Ecology, 2011
South Dakota (SD) represents the northwestern edge of gizzard shad's (Dor... more South Dakota (SD) represents the northwestern edge of gizzard shad's (Dorosoma cepedianum) native range. However, with recent climate warming the gizzard shad is experiencing a natural range expansion northward. Little knowledge exists regarding temperatures that are required for overwinter survival, and less is known regarding population dynamics of gizzard shad in these populations. The objectives of this research were to
Journal of Applied Ichthyology, 2011
The expansion of smallmouth bass Micropterus dolomieu throughout North America has created substa... more The expansion of smallmouth bass Micropterus dolomieu throughout North America has created substantial changes in some food webs and created novel interactions with native predators in many systems through competition and predation, causing declines in native predator populations. In this study, we examined potential interactions between smallmouth bass (introduced) and walleye Sander vitreus (a native predator) in two Missouri River reservoirs and four natural lakes in South Dakota, USA, using historical standardized sampling data, which indexed four fitness-related factors (relative abundance, size structure, condition, and growth) of both species. Of the 24 total relationships tested among all water bodies, three (13%) were determined to be significant (size structure in Pickerel Lake: P = 0.06; condition in Lake Kampeska: P = 0.06, and growth at Brant Lake: P = 0.02). Of these three, two relationships were negative as would be expected if negative interactions exist between these two species (size structure in Pickerel Lake: r =)0.61; condition in Lake Kampeska: r =)0.61); the remaining relationship was positive (growth at Brant Lake: r = 0.75). Further, no water body consistently demonstrated significant negative interactions in all relationships tested. The results of our study did not support the concept that introduced smallmouth bass interfere with walleye populations in South Dakota waters. Rather, it is more likely that other environmental factors influence the observed variability in walleye demographics and dynamics observed in this study. At this time, we believe that both fisheries will continue to co-exist. However, continuous monitoring of both species is warranted as changing environmental conditions in the future could allow these interspecific relationships to shift toward the dominance of smallmouth bass over walleye.
Fisheries Research, 2014
ABSTRACT Fisheries managers often stock prey fish to increase abundance and growth of predatory s... more ABSTRACT Fisheries managers often stock prey fish to increase abundance and growth of predatory sport fishes. One species commonly used in the U.S. Midwest is gizzard shad Dorosoma cepedianum; gizzard shad have been used to increase growth and condition of walleye Sander vitreus in many Midwestern systems. Additionally, with warming climates and stocking, gizzard shad are experiencing a natural range expansion. While this expansion may be beneficial for top predators like walleye, mixed results exist on the effects of gizzard shad on other recreationally important fishes in these systems. Our objectives were to determine if annual growth, relative abundance, and condition of yellow perch, Perca flavescens and walleye populations changed following the introduction of gizzard shad. Adult, pre-spawn gizzard shad were introduced in 2008 and 2009 at densities higher than those which resulted in self-sustaining populations in other South Dakota reservoirs. Yellow perch and walleye population dynamics were estimated during 2007 (pre-shad), 2008–2009 (shad present) and 2010 (post-shad) in two glacial lakes stocked with adult gizzard shad and a reference lake (not stocked with shad). Our results suggest that at the densities documented in this study and in the time frame assessed, gizzard shad did not negatively impact yellow perch as total length at age was similar, condition remained high and zooplankton resources were likely not limiting. Walleye did consume gizzard shad when available and shad appeared to have a neutral or positive effect on walleye growth, relative abundance and condition in these systems during this study. The addition of shad may be a viable option to improve walleye populations without negatively impacting sympatric yellow perch populations under the conditions tested in this study. However, the introduction of a non-indigenous species should be done with caution, especially a potential competitor like gizzard shad.
Journal of Freshwater Ecology, 1995
ABSTRACT We examined the zooplankton community and physicochemical parameters of the lower Trinit... more ABSTRACT We examined the zooplankton community and physicochemical parameters of the lower Trinity River, Texas during March 1992-March 1993, and evaluated the suitability of each for survival of paddlefish Polyodon spathula. Samples were collected every 2–4 weeks from mid-river channel and backwater stations at each of four sites. Eight paddlefish stomachs were analyzed, and eighteen paddlefish were aged and their relative weight values were determined. Physicochemical parameters generally were suitable for ...
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Papers by Brian Blackwell