Journal of the Southeastern Association of Fish and Wildlife Agencies

Bioassays were conducted with Aqualin, a herbicide manufactured by the Shell Chemical Company, to investigate its possibilities in collecting fishes from lotic waters as well as to determine its relativity to toxicity to five species of fishes. A narrow range of toxicity was found between the largemouth bass, b1uegill, bowfin, mosquitofish, and the fathead minnow. The 24-hour TLm (median tolerance limit) values ranged from 0.062 to 0.183 ppm at 71 º F. Bowfin were the most sensitive fish tested. Aqualin was found to be less toxic than rotenone in short exposures; however, a lethal dose of either was required to effectively repel fishes. It was concluded that there is a narrow range of susceptibility between different species of fishes to Aqualin and that, in no case, was it sufficiently wide to indicate any promise for collecting fishes in lotic waters.

During the period 1960-1962 a state-wide fish tagging program employing substantial rewards to sport fishermen for tag returns was conducted in Florida. A total of 19,470 fish including 5,328 largemouth bass were captured, tagged, and released. There were 24.2 percent of the tagged bass, 4.5 percent of the bluegill, 3.8 percent of the shellcracker, and 8.9 percent of the crappie returned. Little difference in returns was noted between fish which were transported prior to release and those which were released into the waters from which they were captured.

The chemical and physical properties and phytocidal activity of diquat (1:1'-ethylene- 2 :2'-bipyridylium cation) and paraquat (1 :l'-dimethyl-4 :4'-bipyridylium cation) are discussed. Data are presented on the evaluation of herbicidal activity of the various salts of these 2 chemicals under controlled laboratory conditions, in plastic pools, and in earthen ponds. Research indicates that a majority of common submersed and many emergent aquatic weeds may be killed by concentrations of 0.2 to 0.5 ppm cation of these 2 chemicals. Fish toxicity studies indicate a threshold toxic concentration for diquat in excess of 10 ppm cation, and for paraquat in excess of 5 ppm cation. Two new quaternary bipyridyl chemicals, diquat and paraquat, have been subjected to extensive aquatic herbicide evaluation tests for the past 3 years. These tests have been conducted in the laboratory, in plastic pools, and to a limited extent in ponds, lakes, and drainage canals.

The Florida Game and Fresh Water Fish Commission's Fishery Division obtained 3,000 Tilapia nilotica fingerlings from Auburn University on August 30, 1961. These were used as brood fish and were stocked in a 3-acre naturally fertile mined-out phosphate pit in Central Florida at the rate of 1,000 per acre. From time of stocking until May, 1962, there was an estimated 7 inches of growth. During the latter part of May this pond appeared to go into an overcrowded condition. Twelve ponds totaling 65 acres have been stocked with tilapia from the brood pond. Stocking rates have varied from 2 adults to 1,000 fingerlings per acre. Minimum water temperature at the blood pit last winter was 53 º F. Apparently no mortality occurred from this cold. It was estimated that 1,810 pounds of tilapia were produced per acre in the brood pit during a 369 day period. The fish were not fed and the pond was not fertilized.

Two boat-mounted machines for applying herbicides or other similar materials to small ponds are described. A dry materials spreader was assembled from three lawn-type fertilizer spreaders. Powered by a small air-cooled gasoline engine the spreader operated effectively to uniformly distribute granular herbicides, lime or similar materials. Distribution of granular material at rates ranging from 100-1,000 Ibs. per acre was possible. A boat-mounted spray rig employing a 15-foot boom eliminated the need for a two-man crew for treating small ponds with liquid materials. The spraying operation could be controlled by the boat operator once the spray tank has been filled and the sprayer was started. Both of the machines can be assembled from commercially available parts by a good mechanic in a relatively short period of time.

The De1ury Method was used to estimate the number of channel catfish in three ponds of different years from the catch records of 20,790 anglers at the Farm Pond Project, Auburn, Alabama. The ponds were drained, and the accuracy of the estimates was determined. Estimates for each pond were made using the average number of channel catfish caught per angler per hour at intervals of: 1 day, 500 angling hours, 800 angling hours, 1,000 angling hours, and one week. The error of these estimates varied between 0.0 and 10.3 percent from the theoretical true number (the total cumulative catch plus the number recovered upon draining). Estimates obtained using the average catch per unit of effort for the different intervals of effort were not significantly different. The assumptions of the Delury Method were investigated.

The purpose of the cooperative fishery and wildlife units, as stated by Congress, is "to facilitate cooperation between the Federal Government, colleges and universities, the States, and private organizations for cooperative unit programs of research and education relating to fish and wildlife and for other purposes." This paper describes only the fishery phase of the program which is now getting underway. The training of fishery biologists for professional employment is considered the primary objective at this stage. The conduct of research is also recognized as having high importance. Limited attention is given to extension-type programs involving preparation of literature, short courses in fishery methods, preparation of exhibits and demonstrations. Each fishery unit is a cooperative venture involving the Bureau of Sport Fisheries and Wildlife, a university, and usually a State fish and game department.

The development of self-contained underwater breathing apparatus (SCUBA) in recent years has opened an entirely new world to those who are physically able to enjoy it. SCUBA is now used extensively in marine biology and is beginning to find its place in fresh water fisheries research and management. More aquatic biologists would probably utilize SCUBA if they were more familiar with its possibilities and its limitations. It is the purpose of this paper to present information which will assist fisheries administrators and biologists in determining whether or not diving techniques could be used in their programs.

Two farm ponds in south Florida were treated with a concentration of 0.5 part per million by weight of 1,1'-ethylene-2,2'-dipyridylium dibromide (diquat) on April 4, and May 21, 1962, to determine the effect this aquatic herbicide may have on the bottom fauna and plankton naturally existing in these two bodies of water. Bottom samples were taken from the ponds with a 6" by 6" Ekman dredge before and after treatment. The organisms were sorted from the debris and counted. Plankton samples were also taken before and after treatment to evaluate the effect of this herbicide on the plankton. The results in pond number one indicated no change in the number of bottom organisms before and after treatment. However, Chironomids failed to appear in the samples for the first 2 weeks after treatment. The second pond failed to show any reduction in numbers of this particular group of organisms.

A study was made to determine the level of dietary protein needed by channel catfish for optimum growth. The experimental work was conducted in the Farm Ponds Laboratory of Auburn University, Auburn, Alabama. Each of 40 stainless steel troughs was stocked with 25 six- to seven-inch fish. These fish were fed experimental diets at a rate of 2.5 percent of their body weight per day. Every 14 to 21 days from June 22 to September 3, 1961, the fish were re-weighed and their daily amount of food adjusted to the new weight. Eight purified diets were fed, each to five randomly-assigned troughs. These diets contained protein levels of 6.3, 15.8, 25.3 and 34.8 percent at carbohydrate levels of 9.8 and 18.6 percent. Samples of fish were randomly selected at the beginning and at the end of the experiment for carcass analysis. Growth for each diet was compared along with the amount of protein deposited in an effort to determine the level of protein which produced optimum growth.

A study comparing pressed cottonseed cake with fresh cut fish as baits for catfish baskets was conducted at High Rock Reservoir in Piedmont North Carolina. The average weight of catfish taken in cut-fish baited baskets was 0.29 lb. while those taken in cake-baited baskets averaged only 0.14 lb. Catch per basket-day in cut-fish baited baskets was: catfish, 1.170 lb.; carp, 0.009 lb. ; crappie, 0.025 lb.; sunfish, 0.001 lb.; and miscellaneous fishes, 0.003 lb. Comparable data from cottonseed cake-baited baskets were: catfish, 1.135 lb.; carp, 00405 lb.; crappie, 0.080 lb.; sunfish, 0.002 lb.; and miscellaneous fishes, 0.002 lb. The total weights of catfish caught by the two baits differed by only 3 percent. Cake-baited baskets caught carp while fish-baited baskets caught very few. Cake-baited baskets also caught more crappie and sunfish than fish-baited baskets.

The toxicity to bluegill sunfish, Lepomis macrochirus, Rafinesque, of granular formulations of ten commercial herbicides is presented. The following chemicals are included: three esters of 2,4-dichlorophenoxyacetic acid; potassium salt of 2- (2,4,5-trichlorophenoxy) propionic acid; disodium salt of 3,6-endoxohexahydrophthalic acid; a mixture of the latter two materials; 2,3,6-trichlorophenylacetic acid; 2-methoxy-3,6-dichlorobenzoic acid; isopropyl n- (3-chlorophenyl) carbamate; and 2,6-dichlorobenzonitrile. The difference in the median tolerance limit of bluegill sunfish to liquid and granular formulations is discussed. Of the ten herbicides tested, most proved less toxic as granular formulations than as liquid formulations. The difference in toxicity as affected by granule size and type is also discussed.

Experiments were conducted to determine the preferred temperatures and the final preferenda of Pimephales promelas and Lepomis cyanellus. Specimens of P. promelas and L. cyanellus were acclimated to five and four different temperatures for 30 days. A gradient tank was built permitting a temperature gradient of 2° C. per chamber. Openings in the partitions between the chambers let the fish move freely throughout the tank. One fish was used to a test and ten tests for each acclimation level. Recordings of the position of each fish were made every 15 seconds for 40 minutes. The temperatures corresponding to the modes were averaged to obtain the preferred temperature for the acclimation level. Pimephales promelas and L. cyanellus acclimated rapidly to high temperatures but required about two weeks to acclimate to low temperatures. Preferred temperatures increased as the acclimation temperatures increased for both species until the final preferendum was reached.

The age and rate of growth of channel and blue catfish were determined by the pectoral spine section aging technique. At the end of their first year's growth, channel catfish weighed 0.10 pound and were 4.3 inches in length (total length), and blue catfish weighed 0.12 pound and were 5.3 inches in length. At the end of ten years, channel catfish weighed 9.2 pounds and were 25.2 inches long, and blue catfish weighed 24.26 and were 33.3 inches long.

Channel catfish fry, ranging in age from one day old to about two weeks old, are routinely transported in polyethylene plastic bags with an oxygen atmosphere between fish hatcheries in Arkansas. Approximately 10,000 fry are transported per 18" X 32" bag in 1.5 gallons of well-oxygenated spring water of moderate hardness. These fish are transported by both airplanes and station wagons.

Potassium permanganate is dissolved in fish hatchery ponds and minnow hatchery ponds at the rate of from two to six parts per million to produce oxygen during acute oxygen shortage caused by excessive organic decay and to counteract hydrogen sulfide gas during seining operations. Potassium premanganate treatments are also used as prophylactic measures to prevent expected oxygen depletion. Empirical evidence indicates the efficaciousness of these treatments. A specially designated boat for the application of the chemical to the water was developed.

A pied or variegated six inch fingerling channel catfish, letalurus puntatus, was discovered when a pond of normal colored fingerling channel catfish was harvested in the fall of 1959 at the Joe Hogan State Fish Hatchery, Lonoke, Arkansas. This fish was saved and reared for two additional years before it was finally lost in the spring of 1962. The authors believe this to be further evidence supporting the belief held by many fish culturists that the "Arkansas Strain" of channel catfish is domesticated. Previous color mutations discovered in this strain was a solid, sooty-black individual and albinism which is common.

Methods and results of population investigation and alteration in Georgia farm ponds for approximately seven years is presented. Results of fishing pressure is also included.

A study was conducted which tested the orientation of the slotted opening in welded wire catfish baskets. Comparisons were made as to the catfish and gamefish catches when the slotted openings were set horizontally, vertically, or at random. Catch rates are presented in 48, 72, 96, and 120-hour set periods. Catfish (primarily white catfish) comprised 97.79 percent of the total weight, and were caught at an overall rate of 1.16 pounds per basket-day. The random, horizontal, and vertical opening baskets yielded 1.28, 1.06, and 1.15 pounds of catfish per basket-day, respectively. Catch rates for crappie were 0.021, 0.005, and 0.023 pounds per basket-day in the same order. The catch of gamefish species other than crappie was insignificant when compared with the total catch.

Studies by the U. S. Study Commission, Southeast River Basins, and cooperating agencies have disclosed that utilization of many streams in the study area is curtailed in part by excessively low stages and sometimes by excessively high stages during the fishing season. The U. S. Study Commission has considered the regulation of low flows by controlled discharge from upstream storage reservoirs as one means of improving such streams for fishing. Concepts and methods employed in the determination of flow-storage relationships, flow-fishery relationships, storage required to regulate flows, and measurement of fishery benefits are described in this paper. Results of the study indicate that the utility of some streams may be increased from two to five times with low-flow regulation; however, a much better understanding is needed of flow-storage-fishing relationships on which to base more accurate determinations of desired stages and potential benefits.