Gerald E. Gunning

Repopulation of Experimentally Decimated Sections of Streams by Longear Sunfish, Lepomis megalotis megalotis (Rafinesque)

Abstract Repopulation by longear sunfish of stream segments decimated by electrofishing was studied in six areas on four streams in Louisiana. Lepomis m. megalotis (Rafinesque) repopulated the decimated areas to a level as great or greater (3.5 times) than the biomass of the decimation sample at four of the six areas within one year. Repopulation occurred between March and late summer and was accomplished by fish at least two years old. A principal factor allowing rapid repopulation of longear sunfish in the decimated segments may have been an apparent lack of repopulation by large predatory species.

Occupancy of home range by longear sunfish, Lepomis m. megalotis (Rafinesque), and bluegill, Lepomis m. macrochirus Rafinesque

Summary 1. Size of home range in terms of linear feet of stream is estimated to be approximately 70 feet for the longear sunfish and approximately 125 feet for the bluegill. 2. The longer a given sunfish is at large subsequent to fin-clipping, the greater is the tendency for this fish to stray outside the limits of a restricted segment. 3. Older longear sunfish and bluegill appear to have larger home ranges than younger individuals. 4. Bluegill strays tend to move upstream. 5. Space-temporal aspects of home range must be considered concomitantly. 6. Short-term occupancy of home range by longear sunfish and bluegill is easily demonstrable; continuous occupancy for a period of several months is difficult to prove in that the number of recaptures diminishes greatly with the passage of time.

Fish Repopulation of Experimentally Decimated Segments in the Headwaters of Two Streams

Abstract Fish repopulation of experimentally decimated segments in the headwaters of two Louisiana streams was studied over a period of two years. Fishes were decimated using an electrical shocking device. The sharpfin chubsucker, Erimyzon tenuis, was able to repopulate the decimated segment of Talisheek Creek in excess of the total weight of suckers that were collected when the section of stream was originally decimated. The repopulation sample exceeded the decimation sample on a total weight basis for two successive years at Talisheek Creek. Repopulation did not occur to this extent at Bayou Lacombe where the repopulation sample was 52 percent of the decimation sample on a total weight basis. Decimation was accomplished without disturbing the environment to any significant degree, hence fish were returning to the decimated area under the same conditions, for all practical purposes, that prevailed at the time of decimation.

The Locomotor Activity of Fish: An Analogy to the Kinetics of an Opposed First-Order Chemical Reaction

Abstract The kinetic behavior of a laboratory population of bluegill (Lepomis macrochirus) under defined laboratory conditions is shown to be analogous to the reaction kinetics described by a population of molecules engaged in an opposed (reversible) first-order reaction. Thus as in chemical kinetics, the locomotor activity of fish can be described quantitatively in the form of rate constants.

The Concepts of Home Range and Homing in Stream Fishes

Home range may be defined as the area over which an animal normally travels. Gerking (1950, 1953) found that longear sunfish (Lepomis megalotis)1, rock bass (Ambloplites rupestris), and green sunfish (Lepomis cyanellus) in two Indiana streams moved about very little from one year to the next. These sunfishes were estimated to have remained within a home range of 100–200 linear feet of stream. The home ranges of smallmouth bass (Micropterus dolomieui) and spotted bass (Micropterus punctulatus) were believed to range from 200–400 linear feet of stream. In a later paper, Gerking (1959) listed 33 species of fishes which exhibit restricted movement or occupy home ranges.

Reclamation of the Pearl River: A Perspective of Unpolluted versus Polluted Waters

Abstract Historically the Pearl River received large amounts of municipal sewage and industrial wastes. The river was ultimately reclaimed by installation of primary and secondary treatment facilities for both effluents. No violations of state or federal water quality criteria were observed in the 10-year period subsequent to installation of treatment facilities. Positive results of pollution abatement and river reclamation were: (1) an increase in clean water species of fishes and invertebrates, (2) a decrease in pollution tolerant species such as the annelid Tubifex, (3) reestablishment of unionid mussel populations in the reclaimed river segment, and (4) increased growth rates for some species of fishes.