Pomoxis nigromaculatus
(black crappie)

The black crappie is a freshwater fish, which has been widely introduced as a game species throughout North America. It is omnivorous, and in the absence of predators may overpopulate areas, altering fish communities through competition and predation. It has been reported to cause salmon declines in rivers of northwest USA and also reduce populations of endemic and native prey species, including invertebrates and fish. In the USA, it has also been reported as affecting the endangered Warner sucker, Catostomus warnerensis, and the critically endangered Shasta crayfish, Pacifastacus fortis. 

The species was originally found in most of the eastern half of the USA but it has been widely translocated across the country into many US states, including the north-eastern seaboard and in the west (Page and Burr, 1991).

Non-native distribution of the species includes Panama, Japan (not established), Morocco (not established), Mexico, Canada and China (Froese and Pauly, 2016). 

Commonly found in freshwater systems as an intentionally introduced fish species, black crappie may overpopulate ecosystems, altering fish communities through competition and predation. There is a high risk of its introduction to new areas for fisheries and aquaculture (Becker, 1983; Batzer et al., 2000; Sanderson et al., 2009; US Fish and Wildlife Service, 2009; 2010; Hughes and Herlihy, 2012).

Black crappie occur in shallow parts of large lakes, ponds, reservoirs and oxbow lakes and slower sections of large streams and rivers (Ross, 2001). Black crappie are found from turbid reservoirs and rivers, to eutrophic  and highly fertile lakes, to dark water mesotrophic lakes, to clear lakes. In their natural range, they prefer densely vegetated, warm, sandy to muddy bottoms, moderately acidic, and non-turbid waters of lakes and rivers (i.e., <50 JTU) (Sigler and Sigler, 1987). They are usually found in the middle to upper sections of the water column in the summer (Ross, 2001), but in north temperate lakes that freeze during winter, black crappie are often found near the bottom in the deepest parts of the lake. They are found in open water during the day but the shore at night when they are more active (Keast and Fox, 1992). They favour pH values from 6.0 to 7.5 and oxygen of more than 5 mg/l (Ross, 2001). The preferred temperature range is 14-26°C, and the preferred spawning temperature is about 18-20°C.

Genetics

Black crappie have a diploid (2n) chromosome number of 48 and haploid/gametic (n) of 24 (Klinkhardt et al., 1995). It is known that they naturally hybridize with white crappie and artificially crossed with other genera (Schwartz, 1972; Travnichek et al., 1996).

Reproductive Biology

Although it greatly varies among populations based on where they live, black crappie usually spawn between April and June, in water temperatures of 14-20°C. Individuals reach sexual maturity at two years of age. This species aggregates in shallow waters for feeding before spawning and then males prepare nests to attract females. Female black crappie have a very high egg production potential, usually 10,000-200,000 eggs depending on the size of the female. Males guard the nest until the juveniles can swim and feed freely (Becker, 1983; Robison et al., 1988; Jenkins et al., 1994; Mettee et al., 1996). 

Physiology and Phenology

Black crappie are active in winter and during the day (Becker, 1983).

Longevity

The longevity of black crappie is 15 years (Quinn, 2001).

Activity Patterns

Winter sees higher activity patterns (Becker, 1983).

Nutrition

Black crappie mainly feed early morning. Young individuals feed on planktonic crustaceans, dipterous larvae and zooplankton such as Cyclops spp., Cladocera, and Daphnia spp. Adults on the other hand feed on insects, minnows, and fingerlings of other species (Scott and Crossman, 1973). Black crappie are known to utilize all kinds of foods in the environment at all times of the year but the peak times for feeding are midnight, dawn, noon and dusk (Becker, 1983).

Environmental Requirements

The species is highly tolerant of environmental factors such as temperature (up to 31°C) (Froese and Pauly, 2016), pH (6.0 to 7.5) and oxygen down to 5 mg/l. However, it prefers cool and moderately turbid <50 JTU) or stagnant waters <10 m/s) between 14 and 20°C (Ross, 2011). 

Large piscivorous fish, such as yellow perch (Perca flavescens), largemouth bass (Micropterus salmoides) and rock bass (Ambloplites rupestris) are potential predators of black crappie. Predatory aquatic insects and zooplankton (Diacyclops thomasi and Mesocyclops edax) may also be potential predators (Martinez, 1991).

Black crappie has been reported as infected with Gyrodactylus goerani and Gyrodactylus lineadactylus (Harris et al., 2004). The monogenes Haplocleidus dispar and Cleidodiscus vancleavei have been reported as parasites of the black crappie. Several protozoans, trematodes, cestodes, nematodes, acanthocephalans and leeches have also been recognised (Hoffman, 1967).

General

• Pet/aquarium trade
• Sociocultural value
• Sport (hunting, shooting, fishing, racing)

The black crappie is very similar in physical appearance to the white crappie (Pomoxis annularis) but the black crappie has a deeper body and a longer dorsal fin base, is silvery-green in colour and has 7/8 spines on its dorsal fin (white crappies have five or six dorsal spines) (Ross, 2001).

The black crappie can be easily distinguished from other sunfish by having less than 10 dorsal spines. 

Due to the variable regulations around (de)registration of pesticides, your national list of registered pesticides or relevant authority should be consulted to determine which products are legally allowed for use in your country when considering chemical control. Pesticides should always be used in a lawful manner, consistent with the product's label.

Prevention

Public Awareness

Due to its recreational value there is a lack of awareness of its impacts.

Control

Little is known with regards to the potential control of this species using chemicals, physical or cultural control methods.

Biological Control

There is no evidence of biological control for this species but natural enemies could be used (e.g. yellow perch (Perca flavescens), largemouth bass (Micropterus salmoides), rock bass (Ambloplites rupestris) and zooplankton; Diacyclops thomasi and Mesocyclops edax) (Martinez, 1991).

Monitoring and Surveillance (Incl. Remote Sensing)

Both telemetry and radio telemetry could be used.

There is little awareness of the invasiveness of black crappie and the extent of its impact on other native species, the ecosystem structure and services. Following documented evidence of its impacts, appropriate prevention and control measures should then be planned and implemented.

13/05/16 Original text by:

Ali Serhan Tarkan, Mugla Sitki Koçman University, Turkey