Oxbow Lake Study – Bluegill Abundance

131d30de-0151-4db9-92e0-350e0846395a-thumbnailOxbow Lake Study – Bluegill Abundance  

By Jason Moak, Phinizy Research Manager

Our study of four oxbow lakes along the Savannah River has ended and we are in the process of analyzing the results and drafting a study report.  During this investigation, we collected a total of 3,287 fish representing 15 families, 25 genera, and 38 species.  Numerically, bluegill were the most abundant species, representing 39% of all fish captured.  As such, it is worth taking a closer look at this common species.

The scientific (genus and species) name for bluegill is Lepomis macrochirus (Greek, lepis = scaled, pomis = gill cover (operculum); macrochirus = large hand).  Bluegill belong to the Centrarchidae fish family, native to the freshwaters of North America and commonly referred to as “sunfishes,” which include other common species such as largemouth bass and crappie.  The genus Lepomis includes 13 individual species, most of which are commonly referred to as “bream” (pronounced brim).

Bluegill are characterized by a dark-colored (blue or black) opercular (ear) flap, and have a dark blotch at the rear base of their dorsal fin.  They can have rows of dark vertical bars along their body, and breeding males often have brightly-colored orange “throats.”

Bluegill are widely distributed in north American freshwaters, especially in lentic (slow-moving water) environments such as lakes and ponds.  They are usually found in our near cover, such as aquatic vegetation, snags, docks, etc. Bluegill feed on a variety of invertebrates, incluing zooplankton, mollusks, terrestrial and aquatic insects, worms, and even small fish.

Bluegill spawn during the spring and summer, and individual fish may spawn several times during these warmer months.  Males construct nests consisting of shallow circular depressions excavated in shallow margins.  Males guard the nest until fertilized eggs hatch (2-3 days) and larvae are able to swim.