Brian G. Blackwell

Seasonal Harvest, Exploitation, Size Selectivity, and Catch Preferences Associated with Winter Yellow Perch Anglers on South Dakota Lakes

Abstract 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. Anglers on East 81 S...

Yellow Perch in South Dakota: Population Variability and Predicted Effects of Creel Limit Reductions and Minimum Length Limits

Abstract 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 among years within lakes to the extent that indices from any individual year were largely uninformative. Creel surveys indicated that few anglers typically achieved a daily creel limit of 25 yellow perch. Except in Waubay Lake, lowering the creel limit from 25 to 5 fish/angler would be necessary to achieve harvest reductions of 25% or more within most of the fisheries we examined. Minimum length limits were projected to improve size and age structure, but harvest reductions often exceeded 50% and yield declined or only slightly increased (by ≤13%). Yellow perch in these lakes had achieved much of their full growth potential by the time they reach...

Influence of a Saugeye (Sauger × Walleye) Introduction Program on the Black Crappie Population in Richmond Lake, South Dakota

Abstract Saugeyes, a purposeful hybrid between walleye Stizostedion vitreum and sauger S. canadense, were introduced into 336-ha Richmond Lake, South Dakota, with a management objective of improving the size structure of the population of black crappies Pomoxis nigromaculatus. The objectives of this study were to determine (1) the influence of stocking size on the relative survival of saugeyes, (2) changes in the black crappie population that were potentially associated with the saugeye introduction, and (3) the incidence of black crappies in the diet of saugeyes. Saugeyes were stocked at a total length of 3–4 cm in 1992 and 1993; survival was low. Larger, 14–25-cm saugeyes were stocked annually from 1994 to 1998, and survival was significantly greater. The larger fingerlings were able to survive and establish a population in the face of predation by and competition with black crappies. Black crappie growth rates increased significantly after the saugeye population was established. Before the saugeye intr...

Timing of Yellow Perch Otolith Annulus Formation and Relationship between Fish and Otolith Lengths

Abstract We estimated the timing of annulus formation and the relationship between otolith radius length (whole view) and total length (TL) in yellow perch Perca flavescens from South Dakota lakes. Marginal increment analysis indicated that a single opaque band is formed during the summer months and that the timing of annulus formation varies with fish age. The lowest marginal increment measurements (i.e., those suggesting that annulus formation was recently completed) were most likely to occur in July, but at Waubay Lake the lowest increment for some cohorts was observed in August. Fish of age 4 or less were more likely to complete annulus formation during June. Personnel responsible for aging otoliths need to be aware of the differential timing of annulus formation. Significant relationships were observed between yellow perch TL and otolith radius length for 49 populations. Nearly all (98%) of the regression intercepts were negative. Back-calculated TLs were estimated from otolith annulus measurements u...

Physicochemical and Biological Influences on Black Bullhead Populations in Eastern South Dakota Glacial Lakes

ABSTRACT Lake and fish survey data (1991–1992) were compiled for 23 eastern South Dakota natural lakes to provide a basis for preliminary investigation of black bullhead (Ameiurus melas) populations. Survey data contained numerous physical and chemical variables describing lake environments and relative abundance and sue structure of the primary fish species present. Analyses indicated that abundance of black bullheads increased with decreasing lake size (area, depth and volume), increasing nutrients (e.g., total and dissolved phosphorus), and decreasing transparency. Overall, models of biotic variables indicated that black bullhead abundance was negatively associated with abundance of bigmouth buffalo (Ictiobus cyprinellus) and walleyes (Stizostedion vitreum), but positively associated with northern pike (Esox lucius) and common carp (Cyprinus carpio) abundance. Black bullhead sue structure was inversely related to the abundance of common carp, northern pike and yellow perch (Perca flavescens). Black bul...

Low-Density Triploid Grass Carp Stockings for Submersed Vegetation Control in Small Impoundments

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 failed to provide the desired submersed vegetation control through 1994. A stocking of 7.5 triploid grass carp per surface ha eliminated all submersed vegetation [southern naiad (Najas guadalupensis)] from one impoundment. A significant reduction in southern naiad and coontail (Ceratophyllum demersum) was apparent in 1993 following the supplemental stocking of triploid grass carp. However submersed vegetation coverage and biomass appeared to be increasing in 1994. Because elimination and...

Seasonal sampling dynamics of smallmouth bass (Micropterus dolomieu) in northeastern South Dakota

Numerous studies on smallmouth bass (Micropterus dolomieu) have focused on movements, diets, and capture rates among habitat types, but we are aware of no study that has documented capture rates and size structure by month to aid in assessment and management of this fish. The objective of this study was to determine monthly sampling dynamics and population size structure of smallmouth bass in four northeastern South Dakota glacial lakes. Smallmouth bass were collected monthly (May–September) from Enemy Swim Lake and Roy Lake in 2007 and Clear Lake and Pickerel Lake in 2008 using modified-fyke nets and night electrofishing in rocky habitats. Monthly mean catch-per-unit-effort (CPUE) values for smallmouth bass collected with fyke nets were variable but generally low (0.2–4.7 fish/net night) across months and lakes. Monthly mean CPUE values for smallmouth bass collected by electrofishing were variable in all four lakes (99.7–771.8 fish/h); however, in Clear Lake and Enemy Swim Lake CPUE significantly increased from May through September, primarily due to age-0 bass becoming vulnerable to electrofishing. For all lakes except Clear Lake, there were no significant differences in monthly mean CPUE values of 180 mm and longer smallmouth bass. Length distributions varied by month, but in general May and June samples contained a higher proportion of larger individuals than later sampling months. Overall mean relative weight (Wr) values were greater than 80, but relative weight varied among lakes and months. Our results suggest that spring (May to June) sampling of smallmouth bass using night electrofishing in rocky habitats will result in the broadest length range of captured bass.

Occurrence of Rudd (Scardinius erythrophthalmus) and Dynamics of Three Populations in South Dakota

ABSTRACT The rudd (Scardinius erythrophthalmus) was first identified in South Dakota waters during the early 1990s. Since its introduction, there has been a paucity of information concerning its presence. The objectives of this research were to summarize rudd collections in South Dakota, to describe the population dynamics of three established populations, and to assess possible effects on native fish communities. Rudd have been collected from waters in nine South Dakota counties and one Missouri River reservoir. Lake Alice, Newell Lake, and Sheridan Lake currently have self-sustaining rudd populations. Rudd relative abundance has stabilized in these three lakes. Population samples were dominated by individuals >200 mm total Length. Recruitment has been consistent with several year classes present in each lake and natural mortality tends to be low. Rudd growth rates in Lake Alice and Newell Lake were extremely fast. It currently does not appear that the fish communities have been adversely affected by the presence of rudd.

Suitability of Food Resources and Physicochemical Parameters in the Lower Trinity River, Texas for Paddlefish

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 paddlefish survival. Zooplankton densities were low (overall mean 30.1 organisms/L) but similar to other river systems supporting paddlefish. The zooplankton community was dominated by rotifers; cladocerans and copepods were not abundant. Paddlefish stomach analysis indicated rotifers were being consumed by paddlefish. Paddlefish growth appeared to be rapid despite seemingly low food densities.

Postharvest Length Changes of Angler-Caught Walleyes

Abstract Information concerning postharvest changes in fish length is important in the enforcement of length-based regulations. We evaluated whether the total length of walleye Stizostedion vitreum changed following angler harvest and being frozen. Walleyes were collected by angling during open-water periods at various water temperatures and during ice cover. To simulate angler practices, postharvest walleyes were placed in a cooler containing ice or in a live well. Postharvest, open-water-collected walleyes were measured at 1-h intervals through 10 h, at 20 h, and after 30 d of frozen storage. Walleyes collected during ice fishing were measured through 36 h, at 44 h, and after 30 d of frozen storage. All collected walleyes were frozen for 30 d because it is often the time period that fish are held before being introduced as evidence in court. Postharvest walleyes held in a cooler tended to lose length, the greatest decrease occurring from those collected at the coldest water temperatures. A two-way analy...