Crappie Fisheries Research Articles

Influence of Gizzard Shad on Black Crappie populations in prairie impoundments of Western South Dakota

AbstractGizzard Shad Dorosoma cepedianum have been introduced into Western South Dakota reservoirs and shown to improve the growth and size structure of sportfish, particularly Walleye Sander vitreus. Black Crappies Pomoxis nigromaculatus are a popular sportfish in these reservoirs, but influences Gizzard Shad have on these populations have not been well documented. We used 10 years of annual sampling data to evaluate changes in Black Crappie population characteristics (i.e. recruitment, growth, size structure and condition) in four Western South Dakota reservoirs after Gizzard Shad were introduced. We also compared Black Crappie population characteristics after shad introductions to populations in three reservoirs never having shad. We found Black Crappie populations in Western South Dakota reservoirs are characterized by variable recruitment, generally experiencing some level of recruitment failure. Reservoirs with Gizzard Shad showed greater mean length‐at‐age and higher proportional size distributions (PSD and PSD‐P) for Black Crappie after the shad introductions and higher values than observed in reservoirs never having shad. We found no meaningful differences in abundance, and mean condition of Black Crappie populations whether Gizzard Shad were present or not. The addition of Gizzard Shad did not appear to negatively affect Black Crappie populations but rather improved crappie size structure. Our results indicate that introductions of Gizzard Shad are a viable management option for producing quality Black Crappie fisheries in Western South Dakota reservoirs.

Long‐Term Standardized Sampling as a Tool for Evaluating Management Actions: BACI Analysis to Reevaluate Predatory Control of Stunted Crappie with Saugeye

Field evaluations of management manipulations are rarely conducted, in part because they are difficult to design and require large sampling effort. However, many commonly used management approaches have <50% success rate, indicating the need for more research. Herein, we provide a case study illustrating how historic standard sampling data from Oklahoma were used to design robust before–after control–impact study designs to evaluate the effectiveness of stocking saugeye Sander vitreus × S. canadensis as a predatory control for stunted White Crappie Pomoxis annularis populations. Comparing six manipulated lakes with six reference lakes (no saugeye stockings), we found that proportional size distribution, proportional size distribution of preferred‐size fish, and mean length at ages 1 and 2 of White Crappie all improved after stockings, but still fell short of statewide median values. Further, similar improvements in these metrics also occurred in reference lakes, suggesting they were likely caused by regional patterns (flood/drought or temperature effects) rather than management intervention. Thus, we conclude saugeye stockings are not likely to routinely improve stunted White Crappie fisheries. We encourage managers who have historic data to use these data to robustly evaluate management interventions (as illustrated in this study), because our field needs additional information regarding when management interventions will be most effective, versus when they may not have the desired outcome. These historic data sets have considerable utility in providing this type of information. Our case study illustrates the importance of replication and reference lakes to avoid erroneous conclusions in such evaluations.

The Effect of Harvest Regulations on White Crappie Fisheries in Kansas Impoundments

AbstractCrappie Pomoxis spp. (White Crappie P. annularis and Black Crappie P. nigromaculatus) support important harvest‐oriented fisheries throughout the United States. However, effects of harvest regulations vary among crappie populations and fisheries managers have little guidance for selecting the most appropriate regulatory scenario given the diversity of crappie populations throughout their distribution. In an effort to guide successful implementation of White Crappie harvest regulations, we evaluated the influence of daily creel limits and minimum length limits (MLLs) on White Crappie fisheries from a diverse suite of Kansas impoundments. White Crappie populations were sampled from 39 impoundments in 2019 and 2020, and a subsample was sacrificed for age and growth estimation. Creel data from 22 impoundments were used to estimate percent reduction in harvest when daily creel limits ranged from liberal (50 fish/d) to more restrictive (5 fish/d). Equilibrium yield models were used to evaluate the effects of various MLL regulations (203, 254, and 305 mm) on yield, the number of White Crappie harvested, and the number reaching memorable length (300 mm). Our results suggest that daily creel limits would need to be less than 10 crappie/d to reduce harvest by more than 25%. In general, the 254‐mm MLL was the most effective harvest regulation for improving yield when the growth rate was above average, conditional natural mortality was low, and exploitation was at least moderate—factors commonly associated with populations in large impoundments in this study. In populations characterized by slow growth, liberal daily creel limits (50 fish/d) may be best suited to maximize yield. Overall, our results provide a framework for fisheries managers to make informed decisions regarding implementation of harvest regulations for crappie in impoundments throughout the Central Plains region.

Standard Assessments Reveal Context‐Dependent Responses of Crappie Populations to a Length‐Based Regulation in Ohio Reservoirs

AbstractFisheries managers implement minimum length limits (MLLs) to improve the size structure of populations of crappie Pomoxis spp. throughout Midwestern and southeastern U.S. reservoirs. The success of these regulations has been mixed, with several implementations resulting in undesirable outcomes, including slow growth and stunting of crappies, and ultimately regulation removal. Consequently, it is unclear whether and where MLLs should be used to improve crappie size structure. Beginning in 2003, Ohio instituted a statewide standard sampling protocol to monitor reservoir crappie populations, and between 2003 and 2010 a 229‐mm MLL was implemented at over 40 reservoirs throughout the state. Using these spatially and temporally extensive crappie population data, we sought to (1) test for the response of crappie population adult abundance, growth, and size structure to the MLL, (2) test whether reservoir surface area and/or productivity mediated this response, and (3) model fisheries outcomes at different reservoir sizes and productivities to predict where application of a MLL would be most appropriate. Using linear mixed‐effects models and an information theoretic approach, we found that crappie population abundances generally increased, whereas growth decreased in small, unproductive reservoirs but increased in large, productive reservoirs. Overall, the MLL failed to produce increases in size structure, except in large reservoirs. Yield‐per‐recruit models predicted a decrease in angler yield in response to a 229‐mm MLL in small reservoirs, whereas in large, productive reservoirs this regulation was predicted to increase angler yield. Consequently, the MLL could improve crappie fisheries in reservoirs larger than 1,000 ha with high productivity (total phosphorus concentrations > 50 μg/L) but could be counterproductive in small, unproductive reservoirs. Finally, our approach highlights the benefits of standard sampling as we were able to integrate data across years and reservoirs to make comparisons on a statewide scale.

Consistently High Trophic Overlap between Invasive White Perch and Native Black Crappies in Southeastern Reservoirs

AbstractThe detrimental impacts of invasive species often occur through deleterious trophic interactions (e.g., competition) with native species. However, the potential for competitive interactions between species may vary among systems, among seasons, or throughout the species’ ontogeny, requiring a thorough examination of trophic niches to determine whether overlap exists and to elucidate the likelihood of competition. The Black Crappie Pomoxis nigromaculatus is a popular game fish species across the United States, but recent invasions of White Perch Morone americana, which exploit a similar trophic niche, into southern reservoirs represent a major concern for the continued sustainability of Black Crappie fisheries. We examined the trophic niches of these species throughout their ontogeny in two North Carolina reservoirs during 2009 and 2010 using a combination of diet content and stable isotope analyses. Extensive and significant similarities in diet composition and isotopic niche overlap existed between Black Crappies and White Perch throughout their ontogeny and across seasons in both systems. Overlap was particularly high between smaller (<200‐mm), invertivorous Black Crappies and all sizes of White Perch. This overlap suggests that if invertebrate resources become limited, competition during the juvenile stage could reduce growth rates and survival of young Black Crappies. By evaluating variation in the trophic niches of each species among seasons, body sizes, and reservoirs, we conclude that the potential for competitive interactions between White Perch and Black Crappie is high in southern reservoirs. Management options to either reduce White Perch abundance or prevent their spread to novel habitats may be necessary to sustain native and supplemented Black Crappie populations that are potentially vulnerable to White Perch invasions.

Trolling May Intensify Exploitation in Crappie Fisheries

In some parts of the USA, anglers targeting crappies Pomoxis spp. are transitioning from mostly stationary angling with a single pole around submerged structures to using multiple poles while drifting with the wind or under power. This shift in fishing methods could result in a change in catch efficiency, possibly increasing exploitation rates to levels that would be of concern to managers. We studied the catch statistics of anglers fishing while trolling with multiple poles (trollers) and those fishing with single poles (polers) in Mississippi reservoirs. Specifically, we tested whether (1) various catch statistics differed between trollers and polers, (2) catch rates of trollers were related to the number of poles fished, and (3) trollers could raise exploitation rates to potentially unsustainable levels. Results showed that participation in the crappie fisheries was about equally split between polers and trollers. In spring, 90% of crappie anglers were polers; in summer, 85% of crappie anglers were trollers. The size of harvested crappies was similar for the two angler groups, but the catch per hour was almost three times higher for trollers than for polers. Catch rates by trollers were directly correlated to the number of poles fished, although the relationship flattened as the number of poles increased. The average harvest rate for one troller fishing with three poles was similar to the harvest rate obtained by one poler. Simulations predicted that at the existing mix of about 50% polers and 50% trollers and with no restrictions on the number of poles used by trollers, exploitation of crappies is about 1.3 times higher than that in a polers-only fishery; under a scenario in which 100% of crappie anglers were trollers, exploitation was forecasted to increase to about 1.7 times the polers-only rate. The efficiency of trolling for crappies should be of concern to fishery managers because crappie fisheries are mostly consumptive and may increase exploitation rates to unsustainable levels. Received August 24, 2011; accepted January 11, 2012

Comparisons of Sex‐Specific Growth and Weight–Length Relationships in Minnesota Black Crappie Populations

AbstractWe examined differences in sex‐specific growth and weight–length relationships for five Minnesota populations of black crappies Pomoxis nigromaculatus. Male black crappies typically grew slightly faster than females, but observed differences in mean total lengths (TLs) at age were always 15 mm or less and were typically less than 10 mm. We detected few differences in log10(weight)–log10(TL) regressions between sexes, and predicted weights at 200 and 250 mm differed between sexes by less than 10 g. Our results indicate that biologists are justified in pooling sexes when estimating population metrics such as growth and condition because the minor differences in growth and weight–length relationships we observed would be unlikely to affect management decisions. Furthermore, while our evaluation did not specifically examine angler harvest selectivity, the small differences in growth and weight–length relationships observed between sexes seemed unlikely to promote sex‐selective angler harvest within the lakes we examined. However, it remains possible that male growth advantages of more than 10 mm may promote selective removal of male fish in black crappie fisheries regulated by minimum length limits, where anglers may use the minimum length limit as a target when selecting fish for harvest and are more likely to measure individual fish.

Predictive Evaluation of Size Restrictions as Management Strategies for Tennessee Reservoir Crappie Fisheries

Abstract We evaluated the potential effect of minimum size restrictions on crappies Pomoxis spp. in 12 large Tennessee reservoirs. A Beverton–Holt equilibrium yield model was used to predict and compare the response of these fisheries to three minimum size restrictions: 178 mm (i.e., pragmatically, no size limit), 229 mm, and the current statewide limit of 254 mm. The responses of crappie fisheries to size limits differed among reservoirs and varied with rates of conditional natural mortality (CM). Based on model results, crappie fisheries fell into one of three response categories: (1) In some reservoirs (N = 5), 254-mm and 229-mm limits would benefit the fishery in terms of yield if CM were low (30%); the associated declines in the number of crappies harvested would be significant but modest when compared with those in other reservoirs. (2) In other reservoirs (N = 6), little difference in yield existed among size restrictions at low to intermediate rates of CM (30–40%). In these reservoirs, a 229-mm li...

A Socioeconomic and Biological Evaluation of Current and Hypothetical Crappie Regulations in Sardis Lake, Mississippi: An Integrated Approach

Abstract We conducted a socioeconomic survey and review of existing biological data in an integrated evaluation of current and hypothetical fishery regulations on crappies Pomoxis spp. in Sardis Lake, Mississippi. The objectives of this study were to (1) assess angler acceptance of current and hypothetical harvest restrictions, (2) determine the recreational value of the crappie fishery to its participants, (3) estimate possible changes in recreational value based on angler responses to hypothetical regulations, and (4) integrate the results of the socioeconomic surveys with existing biological information. Using the travel cost method, we estimated mean expenditures at US$29.48 and average consumer surplus per angler per trip at $8.88. We estimated 75,601 crappie angler trips in 1995, yielding an annual consumer surplus for the Sardis Lake crappie fishery of $671,000 and a gross willingness to pay (GWP) of $2.9 million. Hypothetical changes in creel limits would have greater effects on the crappie fisher...

Rescinding a 254-mm Minimum Length Limit on White Crappies at Ft. Supply Reservoir, Oklahoma: The Influence of Variable Recruitment, Compensatory Mortality, and Angler Dissatisfaction

A 254-mm minimum length limit on crappies Pomoxis spp. was implemented on January 1, 1990, in Ft. Supply Reservoir, Oklahoma, to improve population size and age structure and angler catch rates but was rescinded 6 years later because of angler complaints. Before the regulation, the population was characterized by fast-growing and short-lived white crappies P. annularis; the spring fishery was supported by age-2 fish. Size structure fluctuated widely before the length limit was implemented, ranging from 1% to 40%, but stabilized after the length limit, exceeding 20% in 5 of the next 6 years. Age structure (percent age 3 and older) never exceeded 10% before the length limit, was greater than 10% the first 4 years after the length limit was imposed, and then declined to less than 10% in 1994–1995. Before the length limit, estimated conditional natural mortality was 45% and exploitation was 40%. Survival from age 1 to age 2 averaged 27% before the length limit and did not change substantially following its implementation. Abundance of quality-size (200–249 mm) and preferred-size (>250 mm) white crappies increased after the length limit was imposed. Angler catch rates increased following the regulation, but harvest rates were unchanged and harvest by number and yield declined. A Beverton–Holt equilibrium yield model, fitted using the pre-length-limit data, accurately predicted a reduction in yield. It was apparent from this study that typical fish population metrics are insufficient for managing a crappie fishery. Angler effort declined dramatically after the length limit was imposed, and vocal anglers registered their displeasure with their inability to harvest crappies. Reservoir-specific or lake-specific human dimensions data are also needed to properly assess angler desires before regulations are imposed. Managers should be flexible with regulations and be responsive to changing angler and fishery needs.

Use of Length Limits to Reduce Variability in Crappie Fisheries

Populations of crappie Pomoxis spp. usually exhibit considerable temporal variability in density and size structure and thereby pose problems for fishery management. We used an age-structured population model to explore whether length limits applied to recreational harvesting can reduce variability in crappie recruitment and adult density. Simulations showed that length limits did not reduce the magnitude of recruitment variability but did reduce fluctuations in adult population density. Our results suggest that fluctuations in crappie populations are not likely to be attenuated substantially by length limit restrictions because most of the variability stems from stochastic, density-independent recruitment. However, where recruitment variability is not excessive and stringent harvest regulations are practical, such restrictions can sustain high adult densities that cushion the effect of fluctuating recruitment on the ups and downs of the adult stock.

Evaluation of a 254-mm Minimum Length Limit on Crappies in Delaware Reservoir, Ohio

Abstract A 254-mm minimum length limit on black crappies Pomoxis nigromaculatus and white crappies P. annularus was evaluated during a 6-year trial (1991–1996) at Delaware Reservoir, Ohio. The primary objective of the length limit was to increase the size of crappies harvested without substantially reducing yield. Mean length at harvest increased up to 66 mm following implementation of the length limit. However, a 78% average decrease in total annual harvest was too great to compensate for the larger size at harvest and to compensate for annual yield (kg) reductions of 38–76% while the regulation was in effect. Annual catch-and-release rates of crappies at Delaware Reservoir increased from 35–43% to 84–97% and became the greatest in Ohio. Likewise, Delaware Reservoir had greater angler catch per effort and mean size at harvest compared with unregulated crappie fisheries in Ohio. Both crappie species maintained preregulation growth rates despite modest density increases of sublegal fish, whereas relative w...

An age-structured model for erratic crappie fisheries

White crappie Pomoxis annularis and black crappie P. nigromaculatus are important freshwater sportfishes in North America. Because of erratic recruitment (the number of fish that survive to age 1 each year) fishery yields are inconsistent. We developed a simple age-structured model to help manage crappie fisheries. The model changes population biomass by age-specific somatic growth, and population abundance through recruitment and age-specific natural and fishing mortalities. Using empirical stock-recruitment data and a stochastic component to simulate the effects of abiotic environmental fluctuations on recruitment, the model simulated empirical recruitment dynamics of a crappie population over 30 years in a large impoundment. Effects of density-dependent growth and natural mortality were modeled, but did not substantially affect the yield given the observed magnitude of recruitment fluctuations. Model predictions of population biomass and yield tended to be high relative to empirical estimates, but not unrealistic. Erratic recruitment of crappie populations has made development of management strategies elusive. This model should help fishery managers examine potential management alternatives.

Threadfin Shad Use as Supplemental Prey in Reservoir White Crappie Fisheries in Kentucky

Abstract Prey bases in two Kentucky reservoirs were supplemented with stocked prespawn adult threadfin shad Dorosoma petenense during 1991–1993 to improve fisheries for white crappies Pomoxis annularis by increasing their growth and shifting population size structure toward larger fish. Abundance of age-0 threadfin shad produced was lower than native age-0 gizzard shad D. cepedianum, but threadfin shad provided late-season prey by spawning later than gizzard shad in both reservoirs. In Rough River Lake, threadfin shad stocking rates of 15–28 fish/ha produced peak densities of 0.04 ± 0.01 to 0.46 ± 0.10 fish/m3 (mean ± SE) that represented 3. 5, and 0.3% of the annual peak gizzard shad densities from 1991 through 1993, respectively, but neither white crappie growth nor population size structure were improved. In Dewey Lake, threadfin shad stocking rates of 121–285 fish/ha produced peak threadfin shad densities of 0.40 ± 0.15 to 0.66 ± 0.08 fish/m3 that represented 89, 23, and 20% of peak gizzard shad densi...

An Evaluation of the Value of Harvest Restrictions in Managing Crappie Fisheries

We used an equilibrium yield model to simulate the effect of reducing exploitation on yield and average weight of white crappies Pomoxis annularis, based on empirical growth data and various levels of conditional natural mortality. Modeling indicated that reducing exploitation would likely increase yield as fish growth increased and natural mortality decreased; however, reducing exploitation would not substantially affect yield when conditional natural mortality exceeded 30–40%, regardless of growth. For instance, a 250-mm minimum length limit provided higher yield than a 200-mm minimum length limit only if growth was above average and conditional natural mortality was less than 30–40%. Average weight of crappies harvested increased with growth and length at recruitment to the fishery but decreased with exploitation and conditional natural mortality. Our results suggest that a length limit could improve both yield and average weight for crappie fisheries only if growth is rapid and natural mortality is low. If natural mortality is not low, a length limit could improve average weight of fish harvested without substantially reducing yield.

Population Dynamics of Black Crappies and White Crappies in Weiss Reservoir, Alabama: Implications for the Implementation of Harvest Restrictions

Abstract We examined the effects of angling and the advisability of imposing harvest restrictions on the fishery for black crappies Pomoxis nigromaculatus and white crappies P. annularis at Weiss Reservoir, Alabama. A nonuniform probability, roving creel survey was conducted in conjunction with a tag-reward program. Based on tags returned during the crappie fishing seasons of March–May 1988 and February–April 1989, total annual mortality was estimated at 73%. Targeted effort for crappies was 11.7 h/hectare in 1988 and 13.4 h/hectare in 1989. Catch per unit effort also increased slightly in 1989. Fishing mortality (F = 34%) accounted for only 20% of total annual mortality. Because of the high natural mortality and low exploitation, harvest restrictions on the Weiss Reservoir crappie fishery do not appear warranted at this time.

Responses of Bluegills and Crappies to Reduced Abundance of Largemouth Bass in Two Alabama Impoundments

Abstract Marginal poisoning with rotenone and the combination of marginal poisoning and electrofishing were used to reduce the abundance of largemouth bass Micropterus salmoides in two Alabama impoundments. Marginal poisoning targeted young-of-the-year (age-0) largemouth bass and was intended to reduce recruitment to age 1. Electrofishing was directed at reducing numbers of largemouth bass shorter than 310 mm in total length. Before treatment, abundant small largemouth bass in both impoundments limited recruitment of harvestable-size bluegills Lepomis macrochirus and virtually eliminated recruitment of harvestable-size crappies Pomoxis spp. Following treatment, largemouth bass numbers were reduced, annual numbers of bluegills harvested more than tripled, and a crappie fishery developed in both impoundments. Marginal poisoning requires few personnel and should be considered as a management option for similar waters. Poisoning age-0 largemouth bass may have to be repeated periodically to create a surge in b...

Effect of the Introduction of the Mississippi Silverside (Menidia audens) on the Growth of Black Crappie (Pomoxis nigromaculatus) and White Crappie (P. annularis) in Clear Lake, California

The growth of black crappie (Pomoxis nigromaculatus) and of white crappie (P. annularis) before a new forage fish, the Mississippi silverside (Menidia audens), became established in Clear Lake, California, was compared to their growth after the silverside had become established. Following the establishment of the silverside, growth rates of both species were slower than the presilverside growth rates for the first two years of life, and were apparently faster beyond year II. No correlation was found between changes in climatological conditions and crappie growth patterns. The overall impact of the silverside on the crappie fishery in Clear Lake may be negative if increased juvenile mortality rates result from the smaller sizes observed at the younger age classes.