Journal of the Southeastern Association of Fish and Wildlife Agencies

A low voltage electrofishing device, commonly called a “monkey rig” in Florida, was used to collect catfish for a tagging study on the St. Johns River, Florida. In 40 fishing trips, 3,234 catfish were captured using the “monkey rig”. This inexpensive device was selective for catfish species only. The 16-V to 18-V alternating current agitated the catfish to the surface but fish never exhibited a complete state of tetanus. When electrofishing in waters with surface temperatures warmer than 24˚ C and around underwater structure, the “monkey rig” was an effective collecting device for catfish.

A study was conducted in 9 striped bass (Morone saxatilis), 7 Florida largemouth bass (Micropterus salmoides floridanus), and 6 smallmouth bass (M. dolomieui) rearing ponds to evaluate the effects of various traditional and experimental fertilization regimes utilizing both organic and inorganic fertilizers. No significant differences were found in water quality, zooplankton populations, or fingerling production among any of the fertilization treatments. All treatments produced adequate zooplankton densities for fry survival and growth without detrimental effects on water quality. Low chlorophyll a values revealed inorganic fertilization rates could be increased to enhance phytoplankton production. A significant (P < 0.001) negative relationship between zooplankton densities and chlorophyll a levels suggested zooplankton grazing reduced phytoplankton populations.

Three thousand pair of hand selected, 3-year-old channel catfish (Ictalurus punctatus) were stocked in 4 ponds used for brood production in Humphreys County, Mississippi. From 1 May to 13 July 1981, data were obtained on spawning in the ponds. As the water temperature increased, so did the number of spawns up to a maximum of 498 on 30 May. Total spawns and spawning rate were 603 (86% )-pond 9; 523 (75%) -pond 10; 440 (55% )-pond 11; 550 (69% )-pond 12.

Hemoglobin patterns were identified by electrophoresis for channel catfish, Ictalurus punctatus; blue catfish, I. furcatus; white catfish, I. catus; brown bullhead, I. nebulosus; and (female x male) blue x channel, channel x blue, white x blue and channel x white hybrids. Hemoglobin patterns of each species were different with channel catfish having 11 bands; blue catfish, 8; white catfish, 5; and brown bullheads having 3 different patterns of 6, 10, and 11 bands. All hybrids except channel x white (10 bands) had 11 bands. The banding pattern exhibited by the hybrids was a combination of the parental pattern except for 1 or 2 hemoglobins unique to the hybrids. Total hemoglobin and hematocrit were higher for channel catfish and brown bullheads than blue catfish and white catfish. Maternal effects were evident for total hemoglobin in crossbred channel catfish and channel-blue hybrids. White x blue hybrids exhibited overdominance for total hemoglobin and hematocrit.

Laboratory and field growth trials were conducted to determine the feasibility of using blue crab (Callinectes sapidus) or Atlantic herring (Clupea harenous) cannery waste as dietary protein substitutes in pelleted rainbow trout (Salmo gairdneri) feeds. In lab and field experiments, triplicate groups of trout were fed 3 nutritionally complete diets: (1) a commercial diet (38.8% protein); or 1 of 2 experimental diets containing either (2) blue crab scrap (35.9% protein) or (3) herring byproducts (33.9% protein). Complete replacement of conventional fish meal as a protein source in rainbow trout diets with blue crab or herring waste significantly impaired growth performance factors in both laboratory and field trials. Trout fed the experimental diets consumed less feed, grew more slowly and less efficiently and, in field growth trials, suffered higher mortalities than those fed the commercial diet.

Aquatic invertebrate fauna and crawfish (Procambarus spp.) stomachs were sampled monthly (October 1981-April 1982) in a crawfish pond dominated by rice (Oryza sativa). Invertebrate fauna only was sampled during the same period in a nearby pond dominated by alligator weed (Alternanthera philoxeroides), a perennial, semi-aquatic forb. Macroinvertebrates were affected by the gradual disappearance of rice stubble in the rice pond. Clinging insects such as dragonfly naiads and mayfly nymphs were abundant when vegetation was present but were replaced by small, bottom dwelling crustaceans (amphipods and mysid shrimps) and free swimming insects (backswimmers and water boatmen) as vegetation disappeared. Tubificids and microcrustaceans were the dominant organisms recovered from benthic cores and zooplankton samples, respectively. Stomach analyses of crawfish indicated that the balance of diet volume was composed of plant detritus and/or fresh plant material.

The freshwater aquaculture industry in Florida was surveyed by mail in 1983. Of the aquaculturists who responded, 74% raised ornamental fish; 14% raised food, bait, and/or gamefish; 9% raised alligators; and another 3% raised fish, but did not indicate the species, Respondents to the survey had 7,094 ponds that covered 264 ha with an annual production value of $6,775,719.50. Using survey data and assuming there were 300 aquaculture firms in the state, it was estimated that there were 27,300 ponds covering 1,093 ha, with an annual production value of $37,642,884. Ornamental fish culture was by far the dominant form of aquaculture in Florida.

In May 1982, 31,600 sauger (Stizostedion canadense) male x walleye (S. vitreum) female hybrids and 17,200 fingerlings from the reciprocal cross were stocked into Cherokee Reservoir, Tennessee, in an attempt to reestablish a fishery for large percids where the 2 parental species have been extirpated. Of the 217 fish that were recaptured, 184 (85%) contained food. Gizzard shad (Dorosoma cepedianum) and threadfin shad (D. petenense) were the primary prey species and were selected over other forage species. Prey/predator length ratios for Stizostedion hybrids and shad averaged approximately 0.3 over the range of lengths examined. Stizostedion hybrids grew rapidly, attaining a mean total length (N =48) of 30.5 cm by April 1983. This was better first-year growth than reported in other studies.

Survival, growth, reproductive potential, and catchability of parental, F1 hybrid, and trihybrid sunfishes were evaluated in hatchery ponds for 28 months. The longear sunfish o x redbreast sunfish o F1 hybrid, its reciprocal, and these F1 hybrids outcrossed with the reader sunfish (i.e., trihybrids) were produced artificially, but natural hybridization in ponds was erratic. Survival of all fish types was good, and growth of F1 hybrids and trihybrids was greater than that of parentals. Only 1 F1 hybrid (redbreast sunfish o x longear sunfish o) exhibited a reduced reproductive potential. F1 hybrids and trihybrids were more vulnerable to angling than parental types. Generally, trihybrids grew better and were easier to catch than F1 hybrids.

Striped bass (Morone saxatilis) x white bass (M. chrysops) hybrids were introduced into Lake Osborne, Florida, annually from 1975 to 1983 as a shad control agent and sport fish for an urban fishery. Stocking rates ranged from 21 to 337 fish per hectare. Peak season creel surveys have documented a substantial hybrid fishery in terms of harvest and effort. Creel censuses indicated 21%, 8%, 2%, and 6% stocking rate returns, respectively, during 4 creel periods from 1980 to 1984 on young-of-year fish. The majority of the hybrids were harvested by bank fishermen using bait shrimp in constricted lake areas with increased water current. Clupeid fishes were the principal food item found in stomachs of hybrids. There was no apparent impact on shad populations from intensive hybrid stockings. Fingerlings averaging 40 mm total length stocked in April demonstrated better survival and growth than those stocked <40 mm.

Otolith aging was utilized to evaluate age structure and survival of hybrid striped bass stocked in 5 central Florida lakes. Age VI and age VII hybrids collected during the study represent the oldest yet collected in Florida. High survival rates of ages 0, I, and II were observed in all lakes. Lakes stocked for more than 4 years had low survival of hybrids older than age II. It is possible that adding hybrids in a lake on an annual basis may lead to overstocking. Alternative stocking practices are being investigated.

Hybrids produced by crossing female striped bass (Morone saxatilis) with male white bass (M. chrysops) have been stocked annually in Lake Seminole, Georgia and Florida, since 1975. Fish migrating from this reservoir and subsequent stockings directly into the Apalachicola River in Florida have resulted in a very popular hybrid Morone fishery. Spring creel surveys conducted from 1979 to 1983 documented improved angler success and major increases in fishing effort. More than 15,500 hybrids weighing 28,800 kg were harvested. The monetary value of this additional fishery was more than $339,000.

In 1981, hybrid striped bass (Morone saxatilis x Morone chrysops) appeared in Lake Maumelle and Beaver Lake, Arkansas, both which had only been stocked with striped bass (Morone saxatilis). Therefore, it was suspected that natural hybridization might have occurred between striped bass and native populations of white bass (Morone chrysops). Scale sample analysis revealed that the hybrid striped bass collected from Lake Maumelle were from 1978 and 1979 year classes. Hybrids from the 1979 year class were collected from Beaver Lake. Review of historical stocking data did not reveal any potential errors in which hybrid striped bass might have been stocked in place of striped bass. Meristic counts and measurements of collected fish indicated that significant (P < 0.05) morphological differences existed between striped bass and hybrid striped bass (4 measurements) and also between white bass and hybrid striped bass (1 measurement).

A life history study of spotted seatrout (Cynoscion nebulosus) was conducted in Calcasieu Lake, Louisiana, from January 1976 through December 1983. This species was found to be essentially non-migratory, as it appears to spend most of the year within Calcasieu Lake. Most spawning takes place during July and August. Fecundity values for various length classes captured in 4.1-, 4.4-, and 5.1-cm bar mesh monofilament gill nets demonstrated that spotted seatrout taken with the 4.1-cm bar mesh contributed greater spawning power than fish caught in both the 4.4-cm and 5.1-cm combined. Spotted seatrout captured in the 3 mesh sizes approximately corresponded with age classes III, IV, and V respectively. The minimum bar mesh of 4.4 cm is recommended to allow age class III to spawn with little risk of net capture. A portion of Calcasieu Lake (West Cove) should be designated as a sportfishing area only.

Food habits of 591 sand seatrout (Cynoscion arenarius) (Ginsburg) from Barataria Bay, Louisiana, were characterized. Overall, fishes and crustaceans were the most important food organisms. Mysid shrimp were dominant food items in sand seatrout <100 mm whereas bay anchovy and brown shrimp were predominate in the larger fish. Sand seatrout generally preyed upon a relatively small number of species or taxonomic groups.

Spotted seatrout (Cynoscion nebulosus) (242-585 mm total length) were captured by hook and line in 7 Texas bay systems and placed in wire cages during June to September 1981 and December 1982 to April 1983 to estimate survival of hook-caught handled fish. No significant difference (P> 0.05) in survival was found between fish which received a wide range of handling stress such as sport fisherman might handle them and fish handled carefully as controls. No significant difference (P> 0.05) was found among summer and winter survival of hook and line caught spotted seatrout. Significant differences (P < 0.05) in survival of spotted seatrout among bay systems may be attributed to differing handling techniques by area biologists, transport distance, or differing environmental conditions. Mean survival of fish, adjusted for controls, ranged from 50% to 100% in summer and 67% to 100% in winter.

Gonadal condition of hard clams (Mercenaria mercenaria) planted at 2 tidal locations and at 3 population densities were evaluated in relation to age, size, sex, season, and culture condition. Changes in gonadal-somatic indices (GSI) reflected seasonal differences in gonadal development. Similar decreases in GSI were observed during the spring (May-Jun) and fall (Sep-Oct) spawning peaks. GSI varied significantly (P < 0.0001) with clam size and age. Larger clams had proportionally more gonadal tissue than smaller clams of the same age. Similarly, older clams had larger GSI than younger clams of the same size. No statistical difference (P> 0.05) was detected between the GSI of female and male clams of the same age and size. Clams grown at the lowest density level or at the subtidal location were larger and had proportionally more gonadal tissue than clams from higher densities or the intertidal location.

Standardized fishery independent gill net and bag seine monitoring programs in 8 Texas bays from 1976 to 1982 demonstrated significant differences among annual indices of relative abundances of spotted seatrout (Cynoscion nebulosus), red drum (Sciaenops ocellatus), black drum (Pogonias cromis), sheepshead (Archosargus probatocephalus), southern flounder (Paralichthys lethostigma), and Atlantic croaker (Micropogonias undulatus) populations. These programs provide a more complete assessment of the fish populations than do commercial landings data because of the selective fishing inherent in commercial fisheries. The impacts of management decisions based on optimum sustained yield concepts, effects of catastrophic events, and stock-recruitment relationships can be enhanced by using measures of relative abundance based on fishery independent monitoring programs.

A 1-year creel survey of New River, Virginia and West Virginia, was conducted to assess the effects of a 305-mm minimum length limit on the angler harvest of smallmouth bass (Micropterus dolomieui) and associated fishes from the Virginia portion of the New River. Anglers in Virginia harvested 0.06 smallmouth bass per hour averaging 322 mm total length (TL) and released 1.27 smallmouth bass per hour. West Virginia anglers harvested 0.40 smallmouth bass per hour averaging 242 mm TL and released 0.65 smallmouth bass per hour. Total catches per hour (1.33 in Virginia and 1.05 in West Virginia) were not significantly different. Anglers in Virginia fished significantly longer and released significantly more fish other than smallmouth bass than did anglers in West Virginia. The minimum length limit regulation has shifted size at harvest and the rates of harvest and release of smallmouth bass.

From 1977 to 1983, non-uniform probability creel surveys were conducted on Lake Norman, North Carolina, and Lake Wylie, North Carolina and South Carolina, to estimate seasonal and annual creel parameters of pressure, success, harvest, and angler preference. Despite their geographical proximity on the Catawba River, mean annual pressure and harvest estimates on Lake Wylie were >3 times higher than respective estimates on Lake Norman. Catch rates for the 2 reservoirs were similar. Based on harvest, the Lake Norman sport fishery was a crappie and largemouth bass fishery, while the Lake Wylie fishery was a catfish, largemouth bass, and crappie fishery. The substantial productivity difference for these 2 edaphically similar reservoirs was attributed to certain physical/chemical characteristics of the reservoirs.

The catchable rainbow trout (Salmo gairdneri) fishery in the tailwaters of Bull Shoals and Norfork Dams, begun in 1948, has apparently reached equilibrium with respect to angler use and harvest. Angler days during 2 creel studies (1971-1973 and 1980-81) ranged from 139,000 (1973) to 272,000 (1981). Anglers harvested 46.1 % to 98.4% of the 800,000 to 880,000 rainbow trout stocked annually. Stocking schedules were tailored to well-established patterns of spatial and seasonal angler use. The number of fish caught per hour decreased from 1971-73 to 1980-81, but the weight of fish caught per hour remained unchanged. The use of guides increased substantially from 1971-73 to 1980-81. The effects on fisherman harvest were substantially different during years of very high and very low water in the tailwaters. A discrete creel census of the Norfork tailwater was conducted during 1980-81 and results were compared to the fishery during that period in the Bull Shoals tailwater.

Creel census data for a 14-year period (1970-1983) from Lake Powell show a high quality fishery for this 25.1-ha lake. Fishing pressure averaged 203.8 hours/ha/year, and the total fish harvest averaged 191.8 kg/ha/year. Average annual harvests of the major game species were: 62.4 kg/ha, bluegill (Lepomis macrochirus); 11.6 kg/ha, redear sunfish, (L. microlophus); 11.9 kg/ha, black crappie (Pomoxis nigromaculatus); 10.5 kg/ha, largemouth bass (Micropterus salmoides); and 4.8 kg/ha, chain pickerel (Esox niger). Average weights of the creeled pan fishes were well above normal. Catch rates were exceptionally high and averaged 2.1 fish/ hour and 0.56 kg/hour. Catch rates were directly correlated with relative abundance of pan fishes in the total creel. Individual species harvest and total fish harvest were not strongly correlated with fishing pressure. It is speculated that high turbidity during some years adversely affected fishing pressure, catch rates, and harvest.

A post card survey questionnaire was used to obtain information about the catch and release practices of anglers participating in largemouth bass (Micropterus salmoides) tag reward exploitation studies at 2 North Carolina reservoirs. The surveys demonstrated that at least 60% of all tagged bass captured were released. The post card survey resulted in substantial reductions in the estimated exploitation rates at both reservoirs.

Estimates were made of the percent of sport-boat interviews and retained fish that would be missed by terminating weekend surveys early when no anglers have been seen prior to specified times. Surveys could be terminated at 1200 hours during the summer and not miss more than 2% of the total interviews within any 1 bay system. Fall, winter, and spring surveys could be terminated at 1400 hours and no more than 4% of the total interviews would be missed. The percent of surveys that could be terminated early is highest in winter (37%-67%) and lowest in summer and fall (2%-10%). The percent of fish retained by anglers that would not be seen in interviews due to early termination was never more than 4% within any bay system and season.

Suitability of silver carp (Hypophthalmichthys molitrix) as a biological agent in controlling phytoplankton was studied in situ in 3 sequential dairy farm ponds in Anderson County, South Carolina. Concentrations of chlorophyll a, soluble orthophosphate and associated water quality parameters were measured biweekly from May 1979 through May 1980 prior to introduction of silver carp (100-150 mm total length; 23.1 g average weight) to 1 pond on 12 June 1980. Water chemistry measurements continued through October 1980. Increases of chlorophyll a concentrations in 1980 over 1979 values were 5 times to 7 times in ponds without silver carp and only 2 times in the pond with silver carp. In addition, the pond with silver carp showed significantly lower total hardness and calcium concentrations during 1980. These data suggest that silver carp can effectively lower phytoplankton biomass. Silver carp were harvested during December of 1980.