William F. Childers

Destruction and Re-establishment of Stream Fish and Invertebrates Affected by Drought

Abstract In 1953 and 1954 a severe drought virtually destroyed the fish and invertebrate populations in Smiths Branch, a small warm-water stream in Vermilion County, Illinois, and presented an opportunity to study the adaptations, survival, and repopulation of aquatic organisms exposed to the critical conditions associated with low water levels. The fish population in Smiths Branch was first studied in 1951. In the fall of 1953, the flow was discontinuous, most of the pools dried up, and the few remaining pools were treated with rotenone to eliminate the surviving fish. After that time, the fish population was studied through the use of an electric seine, minnow seine, rotenone, and night observation. The invertebrate population was studied in a series of bottom samples. Discontinuous flow reduced the aquatic habitat and exposed the fish and invertebrates to desiccation, stagnation, and predation. Stagnation was most detrimental during early fall months, in association with leaf accumulations and drastic ...

A Biochemical Genetic Evaluation of the Northern and Florida Subspecies of Largemouth Bass

Abstract Phenotypes at 28 enzyme loci were analyzed by vertical starch gel electrophoresis for each of 90 populations of largemouth bass Micropterus salmoides. Allele frequencies at each locus, as well as the mean number of alleles at each locus, the average number of polymorphic loci, and the mean level of heterozygosity, were calculated for each population. Matrices of genetic identity and distance were used to assess interpopulational relationships. These analyses clearly reveal substantial genetic differences among populations in the United States. The northern subspecies M. s. salmoides and the Florida subspecies M. s. floridanus have fixed allelic differences at two loci, isocitrate dehydrogenase-B and aspartate aminotransferase-B, that can be used to determine contributions of each subspecies to the gene pool of any population. The intergrade zone between the subspecies consists of northern Florida, Mississippi, Alabama, Georgia, South Carolina, North Carolina, Virginia, and Maryland, as well as Te...

Growth and Survival of Largemouth Bass Tagged with Floy Anchor Tags

Abstract The growth and survival of 50 largemouth bass (Micropterus salmoides) tagged with Floy anchor tags (FD-68B) and marked with a pectoral fin clip were compared to a control group of 50 untagged and unmarked bass during a 191-day study period in a 0.08 hectare pond. Survival of the experimental and control groups was 100 and 98%, respectively. There was no significant difference (P = 0.05) between the total lengths, weights, or condition values of fish in the experimental or control groups at either the start or end of the experiment. These results indicated that the use of Floy anchor tags in conjunction with an accessory mark had no significant effect on survival or growth of largemouth bass under the controlled conditions of this study and suggested that this tagging and marking combination could be used to provide reliable estimates of vital fishery statistics for this species.

The inheritance of tissue-specific lactate dehydrogenase isozymes in interspecific bass (Micropterus) hybrids

A combination of hybridization (in vivo and in vitro), immunochemical, and electrophoretic analyses reveals that both smallmouth bass, Micropterus dolomieui (Lacépède), and largemouth bass, M. salmoides (Lacépède), possess three homopolymeric lactate dehydrogenase (LDH) isozymes, A4, B4, and E4. The retinal-specific E4 isozymes of these two parental species possess different electrophoretic mobilities. The two bass species were hybridized to produce the interspecific F1 hybrids. In addition, F2 and F3 hybrid generations were produced. The genetic data from these crosses indicate that the retinal-specific LDH isozyme is the product of a distinct nuclear gene (E locus) on an autosomal chromosome. This E gene appears to segregate independently of the gene for supernatant MDH. The LDH E gene is highly active in the bass neural retina and less active in other neural tissues. However, unlike in most teleosts, the bass LDH E gene also functions in such nonneural tissues as the heart and kidney.

Hook-and-Line Vulnerability and Multiple Recapture of Largemouth Bass under a Minimum Total-Length Limit of 457 mm

Abstract Data from a catch-and-release largemouth bass (Micropterus salmoides) fishery at Ridge Lake, Illinois, in which the minimum size limit was 457 mm total length, were used to test the null hypothesis that the recapture of largemouth bass is a normally distributed random event. Comparison of recapture data with a Poisson distribution for randomly selected fish from the 1976 year class demonstrated that recapture was not a random phenomenon and implied that individual fish varied in their vulnerabilities. Low and high vulnerabilities to capture existed among individuals in the largemouth bass population in Ridge Lake. Hook-and-line vulnerability of individuals varied among fishing seasons. Approximately 15% of the largemouth bass longer than 200 mm that were recovered when the lake was drained had never been caught during the four seasons of catch-and-release fishing. However, tagged largemouth bass were caught, on the average, approximately twice in any catch-and-release season.

A comparative analysis of the tissue esterases of the white crappie (Pomoxis annularis rafinesque) and black crappie (Pomoxis nigromamaculatus lesueur) by electrophoresis and selective inhibitors

Abstract 1. 1. The multiple forms of soluble esterases were compared for the brain, liver and skeletal muscle of the white and black crappie. 2. 2. The two species exhibited a high tissue specific gene function. 3. 3. No soluble cholinesterase activity was found; however, carboxylesterase, arylesterase and acetylesterase activity was present. 4. 4. The esterases of the brain and liver were similar between species in terms of multiplicity, substrate utilization and inhibitor sensitivity. However, the skeletal muscle of the white crappie contained esterase bands inhibited by p-HMB (arylesterase) whereas the black crappie did not. 5. 5. The inhibitory properties of fourteen organophosphate and carbamate compounds were compared for the esterases of the two species.

Extensive heterozygosity at three enzyme loci in hybrid sunfish populations

Hybrid populations of sunfishes were produced in two different ponds, and the frequencies of allelic isozyme phenotypes were determined for three enzyme systems—malate dehydrogenase (NAD), esterases, and tetrazolium oxidase—in order to estimate the extent of heterozygosity at four different genetic loci. Interspecific F1 hybrid fry (red-ear male × bluegill female) were produced in vitro. These fry were stocked in ponds at the free-swimming stage. When 1 year old, the F1 hybrids produced a large F2 hybrid population. Successful hybrid reproduction occurred each year thereafter. In one pond, a 1-year-old F2 population exhibited all three isozyme phenotypes (red-ear, F1, bluegill) at most loci in the approximate ratio of the 1:2:1 expected. In a second pond, 5-year-old individuals of the F2 generation were morphologically like the F1 and were all heterozygous for the enzyme loci studied. This unusual degree of heterozygosity in the older F2 population appeared to be the result of differential survival of mature heterozygous individuals and not the result of early embryonic lethality. The increased heterozygosity at these unlinked loci was assumed to reflect the condition at other genetic loci in the F2 hybrids. Several possible mechanisms are advanced to explain this apparent heterosis.

Thermal kinetic differences between allelic isozymes of malate dehydrogenase (Mdh-B locus) of largemouth bass, Micropterus salmoides.

Two alleles are encoded at the malate dehydrogenase locus in largemouth bass, Micropterus salmodies. Populations in the extreme northern areas of the range of this fish are fixed or nearly fixed for the B1 allele, whereas populations in Florida are fixed for the alternative allele, B2. The MDH-B1B1 and MDH-B2B2 allelic isozymes were isolated by preparative starch gel electrophoresis and subjected to in vitro kinetic analyses. The apparent Km(oxaloacetate) for each of these allelic isozymes was determined at 25, 30, and 35° C. The Kmvalues for both isozymes increased with increasing temperature and were not significantly different from each other at 25 and 35° C. However, at 30° C the Kmvalue for the MDH-B1B1 allelic isozyme was higher than that for the MDH-B2B2 isozyme (i.e., 5.4×10−5 vs 3.3×10−5). These results are consistent with the hypothesis that the different environmental temperatures at different latitudes may be at least partially responsible for the north-south cline in Mdh-B allele frequencies.

Biochemical genetics of hybrid sunfish: Differential survival of heterozygotes

Allelic segregation in reciprocal backcrosses involving the largemouth bass (Micropterus salmoides) and the F1 hybrid (largemouth bass × smallmouth bass, M. dolomieui) was investigated to determine the extent of euheterosis and luxuriance. The frequencies of allelic isozymes encoded in the lactate dehydrogenase E, malate dehydrogenase B, and isocitrate dehydrogenase loci were determined for reciprocal backcross progeny subjected to different selection pressures. The progeny of the backcross (male F1 × female largemouth bass) underwent a rapid loss of heterozygous individuals in a natural pond environment. When the offspring of this same mating were placed in artificial pools, where cannibalism is the main source of mortality, heterozygosity was advantageous. There was a marked correlation of increased heterozygosity at these enzyme loci with an increased growth rate. None of the above responses to selection was observed when the F1 hybrid served as the maternal parent in the reciprocal backcross. A maternal factor in the egg cytoplasm may influence the expression of heterosis.

Genetics and Implications of the Golden Color Morph in Green Sunfish

Abstract A color mutation of green sunfish (Lepomis cyanellus), resulting in whitish, golden-colored fish, was studied to determine the inheritance and ecological significance of this mutation. The offspring of six golden green sunfish were used in this study. The color trait is recessive and is believed to be caused by a genetically induced malfunction during melanoblast differentiation. The golden green sunfish were slower growing than normal-colored green sunfish from Illinois. Both color morphs, normal and golden, preferred to mate with normal-colored green sunfish. The golden green sunfish were more susceptible to predation by largemouth bass (Micropterus salmoides) than were the normal-colored green sunfish (P<0.01).