Field of Science

Empire of the Sunfish

Do you remember when this particular nightmare was vomited forth from the jaws of pop culture hell?

Yes, this was the execrable Billy the Bass, just one more reason we can all be glad that the 90s aren't around any more. But what was it supposed to be?

Smallmouth bass Micropterus dolomieu, photographed by Eric Engbretson.

The bass and sunfishes of the family Centrarchidae are a group of more than thirty species of freshwater fish mostly native to North America east of the Rocky Mountains. A single species, the Sacramento perch Archoplites interruptus, is native to northern California. The family was more widely distributed in the past: the Oligocene–Miocene genera Plioparchus and Boreocentrarchus hail from Alaska, Oregon and the Dakotas (Near & Koppelman 2009). They will also be much more widely distributed in the future: species of the genera Lepomis and Micropterus have been introduced to numerous places around the world as sportfish. The centrarchids are all carnivorous, though the nature of their prey varies from zooplankton to insects to other fish.

White crappie Pomoxis annularis, photographed by D. Ross Robertson.

The molecular analysis of the Centrarchidae by Near et al. (2005) identified the mud sunfish Acantharchus pomotis as sister to all other centrarchids, contrary to its previous inclusion in the subfamily Centrarchinae with other centrarchids possessing more than three spines in the anal fin (Near & Koppelman 2009). Instead, the two genera whose species possess only three anal spines, Lepomis and Micropterus, form a clade that is sister to the remaining 'centrarchine' genera. These are the aforementioned Archoplites, the flier Centrarchus macropterus, the banded sunfishes Enneacanthus, the rock basses Ambloplites and the somewhat unfortunately named crappies of the genus Pomoxis. These are mostly deep-bodied feeders on small invertebrates, though the larger species may also take small fish. Archoplites is a more dedicated piscivore. This latter species is also notable for having less elaborate mating behaviour than other centrarchids: in contrast to the elaborate courtship rituals and nests of other centrarchids, Archoplites males do little more than use the tail fin to dig a small depression (Berra 2007). One can't resist wondering if Archoplites' lax behaviour is connected with its geographic isolation from other species.

Pumpkinseed Lepomis gibbosus, photographed by Cliff.

The genera Micropterus and Lepomis are each more diverse than the centrarchine genera. The black basses of the genus Micropterus are relatively long-bodied compared to other centrarchids, and are all piscivores. Lepomis, with twelve species, is the most diverse centrarchid genus both numerically and ecologically; as well as numerous insectivorous species, it contains the piscivorous warmouth Lepomis gulosus, the specialised planktivorous bluegill L. macrochirus, and two molluscivorous species, the redear sunfish L. microlophus and the pumpkinseed L.gibbosus. Phylogenetic relationships within Lepomis indicate a certain dynamism of ecology as well: a number of species pairs can be identified connecting large and small species, while the two molluscivores are not immediate relatives within the genus (Near et al. 2005).


Berra, T. M. 2007. Freshwater Fish Distribution. University of Chicago Press.

Near, T. J., D. I. Bolnick & P. C. Wainwright. 2005. Fossil calibrations and molecular divergence time estimates in centrarchid fishes (Teleostei: Centrarchidae). Evolution 59 (8): 1768-1782.

Near, T. J., & J. B. Koppelman. 2009. Species diversity, phylogeny and phylogeography of the Centrarchidae. In: Cooke, S. J., & D. P. Philipp (eds) Centrarchid Fishes: Diversity, biology and conservation, pp. 1-38. Blackwell Publishing.


  1. I have noticed that fish ID books and web pages for these fish typically ignore sex differences, as though they did not exist, within species. What's up with that?

  2. I'm not familiar with how much the sexes differ in centrarchids. Are they obviously different?

  3. No.. they're not. Male Lepomis spp. have breeding colors, but what sexual dimorphism there is is subtle and not a factor in identification.

    Fundulidae on the other hand...


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