White and Black Crappies in Clear Lake, Summer, 1960

Studies of white crappie, Pomoxis annularis, and black crappie, Pomoxis nigromaculatus, showed a shift in the population in Clear Lake during the past 10 years from a dominance of black to white crappies. A decrease in the rate of growth of black crappies was shown for this period although the rate of growth of white crappies has remained constant. The food habits of white and black crappies were very similar. The three most important food items were Cladocera, fish, and insect larvae, in that order. Young-of-the-year samples indicated that the trend toward white crappies was continuing. Turbidity was suggested as a possible reason for these changes

The Effects of Seasonal Changes and Turbidity on Swimming Performance in White Crappie Pomoxis Annularis and Black Crappie Pomoxis Nigromaculatus.

Factors that affect swimming performance in fish can also affect fitness. I tested the effects of time of day, season and turbidity on swimming performance in black crappie Pomoxis nigromaculatus and white crappie Pomoxis annularis. These closely related fish co-occur and their relative abundance is thought to be governed by the levels of turbidity in the form of suspended sediments. Black crappie predominate in clear bodies of water and exhibited significantly greater critical swimming speeds in clear water than did white crappie during spring days and winter nights. A significant reduction in critical swimming speed was observed in black crappie as turbidity increased. White crappie predominate in turbid bodies of water and exhibited no significant reduction in critical swimming speed in relation to increasing turbidity. Both species displayed a significant increase in oxygen consumption in response to elevated turbidity. There were no differences in oxygen consumption rates between the two species within any of the four seasons or at the three levels of turbidity tested

Food, Growth, and Reproduction of White Crappies (Pomixis Annularis) and Black Crappies (P. Nigromaculatus) in Lake Poinsett, South Dakota

The food habits, food selectivity, growth, condition, and population structures of the white crappies (Pomoxis annularis) and black crappies (P. nigromaculatus) in Lake Poinsett, South Dakota, were studied from May, 1975, to May, 1976. The total food volume of 173 adult white crappies consisted of 59.0% plankton1o crustaceans, 25.2 % insects, 14.5 % fish, and 1.3 % miscellaneous organisms. The food volume of 39 adult black crappies consisted of 39.0 % planktonic crustaceans, 3.5 % insects, 57.8 % fish, and 0.7 % miscellaneous organisms. Both species selected Daphnia pulex over other zooplankton and probably contributed to its decline from 193.8/l on June 27 to 0.0/1 on August 21. Both species preyed indiscriminately on forage fish. Growth rates were comparable to those found in similar temperate lakes. The growth rates of the crappies increased while their population densities declined. The population decline appeared to be due to a lack of spawning habitat caused by low water levels

Effect of Increased Water Temperature on Warm Water Fish Feeding Behavior and Habitat Use

Global warming could cause changes in species behavior and life history. Stream fish may be significantly affected by climate change because individuals are restricted in their movements by water systems and other physical factors, preventing migration to locations more thermally suitable. The effect of warmer waters on stream fish could change behavior and affect the fish species survival and ultimately ecosystem function. During my experiment I observed the effects of increased water temperature on the feeding behavior and habitat use of two native Minnesota fish species, black crappie (Pomoxis nigromaculatus) and black bullhead (Ameiurus melas). An increase of 2oC over a period of 4 weeks resulted in a 35% decrease in the number of feeding events by black bullheads and an increase of 22.2% for black crappies. Significant changes in habitat use were also observed during the study, with bullheads increasing their use of open areas, plant cover, and swimming behavior, while decreasing their use of brick interior for cover and searching behavior. Crappies were found to increase their use of open areas and swimming behavior, while decreasing their use of the brick exterior for cover. These results provide insight about the future effects of increased water temperature on the feeding behavior, habitat use, and ecosystems of fish species

Environmental characteristics of black crappie (\u3ci\u3ePomoxis nigromaculatus\u3c/i\u3e) nesting sites in two South Dakota waters

A biotelemetry study was undertaken during spring 1995 to identify black crappie (Pomoxis nigromaculatus) nesting sites in two South Dakota water bodies. Individually coded ultrasonic transmitters were implanted into the body cavity of 15 adult male black crappie in each water body prior to spawning. Available habitat characteristics were recorded at 75 randomly selected sites within each water body, and habitat characteristics at nesting sites were recorded for each male black crappie believed to be nesting. Of the habitat characteristics analyzed, only substrate firmness did not differ (P=0.79) between water bodies. In Richmond Lake, black crappie selected nesting sites with live cattails (Typha spp.) that were protected from prevailing south winds. In Brant Lake, black crappie selected nest sites with vegetation (usually woody debris) and silty substrate that had warmer water and were protected from wind and waves. It appeared that black crappie nested in the most protected areas available

Habitat Characteristics of Black Crappie Nest Sites in an Illinois Impoundment

Ten nest colonies of black crappie Pomoxis nigromaculatus were visually located and verified by angling in Campus Lake, a small urban impoundment in southern Illinois. Habitat characteristics were measured at these nest sites and compared to habitat measurements obtained from 45 unused sites. Seven habitat characteristics (substrate firmness, temperature, dissolved oxygen, distance to deep water [3.8-m depth contour], substrate type, vegetation height, and vegetation density) were significantly different between nest sites and unused sites. Although temperature and dissolved oxygen were significantly different between nest sites and unused sites, all values were within the suitable range for black crappie spawning to occur. Black crappies selected nest sites close to deep water with firm substrates and low vegetation height and density. Our results present insight on habitat characteristics of black crappie spawning locations in a small urban impoundment. Interestingly, we located several black crappie nesting colonies with more than 10 individual nests in close proximity to one another; colonial nesting by black crappies has not previously been reported in the literature. Furthermore, we suggest that degree of shoreline modification and other anthropogenic influences in and adjacent to Campus Lake did not affect black crappie nest site selection. Black crappie nest sites in Campus Lake were always located near deep water (3.8 m), in low-density, short vegetation, and on firm clay or sand substrate; because nest site selection can influence earlylife survival and recruitment of black crappie, the availability of these habitat characteristics may regulate black crappie population demographics in Campus Lake. Efforts to limit sediment inputs will be important for maintaining suitable black crappie spawning habitat in Campus Lake and other small impoundments

Larval Black Crappie Distribution: Implications for Sampling Impoundments and Natural Lakes

An understanding of larval fish distributions is essential for developing an appropriate sampling design to monitor larval abundances. We monitored abundance of larval black crappie Pomoxis nigromaculatus to assess spatial differences in Richmond Lake (a 336-ha impoundment) and Brant Lake (a 405-ha natural lake), South Dakota, during 1994–1996. Age-0 black crappies were collected with a 500-µm mesh ichthyoplankton trawl from fixed sites within each water body. In the impoundment, larval black crappies were collected over a longer period at the upper site than at the dam site during 1994 and 1995. In the natural lake, larval black crappie abundances were similar between east and west sites during all 3 years. In light of our results, biologists should spatially stratify sampling sites when collecting larval black crappies in impoundments such as Richmond Lake, whereas random sites may be more appropriate in natural lakes such as Brant Lake

Egg Development in a High-Density Black Crappie (\u3ci\u3ePomoxis nigromacuIatus\u3c/i\u3e) Population

Female black crappie (Pomoxis nigromaculatus) were collected from Richmond Lake, South Dakota and egg-diameter frequencies were examined to document spawning strategy during 1994. Two hundred and sixteen adult females [mean total length (TL) ±SE = 204 ± 1 mm] were collected and 85,572 egg diameters were measured. Female black crappie gonadosomatic-index (GSI) values exceeded 8% from 18 May to 22 June 1994, and the density of larval black crappie caught with an ichthyoplankton net peaked on 8 June 1994. The GSI values and larval catches indicated that the population, as a whole, had a single extended spawn from mid-May through mid-June. However, patterns of egg-diameter distributions were inconsistent among individual female black crappie. It appeared that some females spawned only once during 1994, while others probably spawned twice

Prey Selection by Larval Fishes as Influenced by Available Zooplankton and Gape Limitation

Feeding success during the first weeks of life is critical to determining survival and ultimate year-class strength of fishes. To compare the relative influence of gape limitation and available zooplankton on prey size selection among the larvae of three species of freshwater fishes, we gathered data on fish gape size, prey size, and size-specific prey selection in lakes and reservoirs. These variables were compared among black crappies Pomoxis nigromaculatus from a lake that contained large zooplankton as prey and white crappies P. annularis and gizzard shad Dorosoma cepedianum (a potential competitor of white crappie) from reservoirs that contained small zooplankton. In three Ohio reservoirs (i.e., small-zooplankton systems), available zooplankton and larval stages of white crappies and gizzard shad were collected once per week during April through September 1987 and 1988. Although mean prey size of white crappies continued to increase with fish size, mean prey size of smaller-gaped gizzard shad did not. However, as documented for black crappies in north-temperate lakes, white crappies in reservoirs continued to consume prey that were smaller than other available prey, even when they were no longer gape limited. Thus, although the potential for gape limitation differed between large- and small-zooplankton assemblages, prey selection did not differ as expected. Given between-species prey size selection, gizzard shad (that prefer small zooplankton) should be relatively more successful in reservoirs with small zooplankton, whereas white and black crappies (that prefer large zooplankton) should have better success in lakes with large zooplankton.This work was supported in part by DEB- 9108986 and DEB-9410323 to D.R.D., and by NSF BSR-8705518, DEB-9107173, DEB-9407859, and Federal Aid in Fish Restoration, project F-57-R to R.A.S., administered through the Ohio Division of Wildlife