Journal of the Southeastern Association of Fish and Wildlife Agencies

Estimates of mortality and survival obtained from angler tag returns over a 10month period following tagging were used to define the population changes that occurred in the largemouth bass (Micropterus salmoides) population of Lake Tobesofkee. Total mortality (A) of 30-cm and larger fish over the period was estimated at 0.911 and the exploitation rate (u) of these sizes was 0.564. The conditional rate of natural mortality was 0.602. These estimates were used to predict the relative abundance of various sizes of largemouth based on 1977 harvest and abundance data. Also the effects of various minimum length limits were predicted. Increased minimum legal size would have cut harvest to 23.7% and increased survival from 0.089 to 0.308.

The population of largemouth bass (Micropterus salmoides) in 2314-ha Melton Hill Reservoir, TN, was estimated by 2 mark and recapture methods. Shoreline electrofishing was used to capture fish for marking, while shoreline electrofishing and a bass fishing tournament were used to obtain recaptures. Both methods yielded estimates of the same magnitude; however, slightly different size selectivities were found with the 2 recapture methods. Species selectivity of shoreline electrofishing and the bass tournament are also compared. The population structure of the black bass population in Melton Hill Reservoir is examined and possible causes for this structure are presented.

Bass club catch records from tournaments held on Norris. Douglas, and Cherokee Reservoirs during 1976 were compared with creel censuses. While not statistically significant, both numbers and weights per hour of bass caught by tournament anglers were less than catch rates by nontournament fishermen. Average weight of bass caught in tournaments was higher than that found in creel censuses. Some advantages of using tournament catch records in evaluating bass fisheries are discussed.

A tag-and-reward procedure was used to estimate exploitation rates of black bass (Micropterussp.) during 1975 and 1976 in Center Hill Reservoir, Tennessee. Returns of reward tags by anglers indicated annual exploitation rates of 13.3 (22.2%) for largemouth ·(M. saltnoides), [2.9 (15.6%) for smallmouth (M. dolomieUl) and [4.8 (18.5%) for spotted bass (M. punctulatus). Within each year, exploitation rates were not significantly different between species or size groups. Rates were lower in 1976 than in [975 for all species, but the difference was significant only for largemouth bass. In [975, when tag reward values were publicly announced, most data suggested that tags with no reward value were returned at rates [ower than those observed for reward tags. In [976, when a random-reward procedure was used, differential rates of return were not detected.

An estimate of the total recreational use of the Thomas Hill Wildlife Area (1,778 ha reservoir and 2,424 ha of adjoining lands) in northern Missouri was made from I July 1972 to 30 June 1974. Recreational activity was determined by interviewing departing recreationists utilizing the non-uniform probability sampling technique. There were an estimated 219,700 recreational trips totaling 1,398,900 hours during the 2-year study. Twenty-two recreational activities were measured. Seven recreational uses; sightseeing, boating, fishing, camping, swimming, picnicking, and hunting accounted for over 99% of all the trips and hours. Sight-seeing made up 25%, boating 21 %, angling 20%, camping 16%, and swimming 9% of the total trips. However in hours, camping made up 42%, boating 22%, angling 21 %, and swimming 6% of the total. There were 63 trips per water surface ha and approximtely 45 trips per land surface ha. Anglers caught an estimated 172,100 fish during the study.

A survey of Federal fish hatcheries in the United States was conducted to determine the extent and severity of avian predation on fish stocks as well as to determine which avian species were the most serious predators. A list of 58 bird species in 14 families was provided. Managers of hatcheries were asked to indicate which species or members of what family caused problems by predation in their hatcheries. They were asked to provide their estimate of the severity of the problem; i.e. severe, significant, trivial, or none. They were also asked which fish species were preyed upon and also to identify any bird predators not on the list provided. The survey elicited a 66% response from 121 managers. Of the 58 species on the survey form, 28 species in 9 families were mentioned by managers as predators visiting fish hatcheries. Additionally, 8 species from 6 other families or subfamilies were added by managers as being pests at hatcheries.

A method of sampling fish populations in the littoral area of reservoirs was developed to estimate the number and standing stock of young-of-the-year (YOY) and adult fishes in West Point Reservoir, Alabama-Georgia. A surface area of 0.0 I ha was surrounded with a net (30.5 m x 2.7 m) and the fish were poisoned with rotenone. The sample sites were chosen randomly by using a grid system. The average monthly standing stock (kg/ hal from April to September 1977 ranged from 74.2 in September to 126.1 in June. The weekly samples yielded data that enabled us to estimate the reproductive success and time of spawning for many species. We determined a weekly mortality rate of YOY largemouth bass (Micropterus salmoides) and could assess the availability of prey species.

Food of larval (5.0-10.9 mm, TL) black crappies (Pomoxis nigromaculatus) from Keowee Reservoir, SC, was determined in 1973, before commercial power generation began from a 2,580-MW nuclear power plant, and in 1976 after 3 years of commercial power generation. Although water temperatures were higher in 1976 than in 1973, food of the larvae appeared to be unchanged by operation of the plant. The principal organisms eaten were Diaphanosoma sp._and copepod nauplii.

Production of gulf killifish (Fundulus grandis) was investigated from 17 November 1977 to 10 July 1978 in 0.08 ha, brackish-water, earthen ponds at the Claude Peteet Mariculture Center. Gulf killifish averaging 30.7 g and stocked at 12,500fishjha deposited eggs on Spanish moss spawning mats from 21 March through 16 May 1978. Fifty mats with eggs were transferred to a hatching pond which yielded 82,500 juvenile killifish averaging 0.1 g at harvest on 16 May. Stocked at 250,000 fishj ha in 3 grow-out ponds on 19 May and fed a commercial minnow feed, the juveniles averaged 2.0 g (marketable size) on 10 July 1978 with mean survival of 82%, feed conversion of 1.9, and production of 427 kgjha.

Implementation of minimum size limits is an administratively simple method of maximizing yield-per-recruit and, probably, total yield from reef fisheries. However, size limits may not guarantee ample escapement to older ages and, consequently, adequate reproduction of those species which undergo sex reversal. Further, size limits may place unnacceptably severe restriction on certain portions of reef fisheries. Finally, most undersize reef fishes taken by hook and line from deep water will likely die of injuries caused by pressure change.

Contamination of the James River in Virginia by the organochlorine pesticide Kepone R prompted depuration studies of commercially important species. Approximately 400 croaker (Micropogonias undulatus) were taken from the James River and placed in Kepone-free York River water. Groups of 20 fish, maintained at ambient temperature, were sampled over time to determine depuration rate. Results suggest that there is no substantial depuration of Kepone by croaker until water temperature exceeds 15 C.

Data collected from rotenone samples of 3 coves before (1959-65) and after (1977) infestation by Eurasian water-milfoil (Myriophyllum spicatum) were compared to document changes in the fish populations. Using the mean of the 3 areas for comparison, both weight and number per hectare increased after water-milfoil infestation. The average weight per individual decreased from 0.02 kg (1959-65) to 0.008 kg (1977). The species were separated into 7 groups. Six of the groups had higher mean numbers per hectare and all groups had higher mean weights per hectare. Multivariate analyses of variance showed that the population structure had changed for numbers and weights per hectare. Ictalurids and yellow perch (Perca flavescens) had the greatest proportionate increases in numbers, whereas largemouth bass (Micropterus salmoides) and white perch (Morone americana) had the greatest proportionate decreases.

The distributional responses of fishes to operation of a newly constructed power plant were assessed for indigenous populations of the Anclote Anchorage and River, Florida. Studies conducted during 1976 compared stations removed from potential plant effects with data collected from areas adjacent to plant intake and discharge. Comparisons were also made with preoperational information collected in the vicinity of the Anclote site. Beach seine collections exhibited a marked seasonal pattern related to the inshoreoffshore migration of nonresident species and the nursery function of the estuary. Abundance and species richness were greatest during the warmer months. as reported during preoperational surveys. Fishes at the shore zone station most affected by thermal discharges were more abundant during the coldest months and exhibited decreases during the hottest periods. This reversal of normally expected abundance was attributed to the thermal effluent.

The food habits of Micropogon undulatus, Leiostomus xanthurus, Fundulus similis. Cyprinodon variegatus. Menidia beryllina and Membras martinica were studied in conjunction with the development of a man-made salt marsh planted during 1976 on Bolivar Peninsula, Galveston Bay, TX. Each of the fishes studied fed to a considerable extent on the benthos community, and utilized at least some zooplanktonic and terrestrial insect foods. The dominant food organisms in the fish stomachs examined corresponded, in general, with those previously reported by other investigators. The artificially created salt marsh on Bolivar Peninsula appeared to provide habitats, both for fishes and their foods, similar to those of natural marshland areas along the coasts of the Gulf of Mexico and the southeastern United States.

A tide gate on the Savannah Back River, constructed by U.S. Army Corps of Engineers, might decrease survival of the striped bass (Marone saxatilis) eggs and larvae spawned near Savannah, Georgia. An initial season of sampling, with the tide gate held open, yielded striped bass eggs and larvae both up- and downstream from the gate. The distribution of eggs and larvae under normal conditions was established. Maximum numbers of striped bass eggs did not reveal 21m 3 • Spawning occurred at temperatures between 17 and 23 C but 3 spawning peaks coincided with temperatures between 19.5 and 21 C. Slightly more eggs were found farther upstream during the last spawning peak. All stations sampled yielded eggs or larvae at some time, but stations in Back River generally produced the most eggs. Significant numbers of eggs were found in sections of the river flanked by industry but many of these eggs originated in other areas ofthe river.

During 1974, 1975 and 1976, stomachs of 467 adult striped bass (Morone saxatilis) from Keystone Reservoir and its tailwaters were collected and examined for content. Gizzard shad (f)orosol11a cepedianum) was the most abundant food item found in striped bass stomachs. The relationship between the length of striped bass and the length of gizzard shad consumed was not significant (.05%). Seasonal and habitat variations in the diet were not significant (.05%).

Between March and October 1977, methods of local commercial fishermen were simulated to evaluate species composition, catch rates, and potential impact of the commercial fishery on striped bass (Morone saxatilis) in 2 Tennessee River mainstream impoundments. Estimated total commercial harvest rates during the sampling period were 26.6 kg/ ha and 23.1 kg/ ha in Watts Bar and Chickamauga Reservoirs. Because commercial fishing was concentrated in tailwater regions of both reservoirs, experimental catch rates and high estimated commercial harvest rates were probably not representative throughout each reservoir. Low catch rates of striped bass and other game fishes suggested that commercial netting had no negative influence on these species. It does appear, however, that the commercial fishery may be influencing rough fish species composition. Standing crops of buffalofish (fetiohus spp.) have declined in recent years while carp (C.I'prinus carpio) biomass h.as increased.

This study was conducted to identify habitat factors responsible for the success or failure of a striped bass (Morone saxatilis) x white bass (Morone chrysops) hybrid introduction and to measure fisherman benefits from the stocking. Hybrids were introduced into Lake Bastrop, Texas, at a rate of approximately 25 fish! ha in 1973, 1974, and 1975. From 1973 through 1977 water samples were analyzed to monitor physicochemical conditions; seining, gillnetting and cove rotenone sampling were accomplished to estimate composition offish populations; and creel surveys were conducted to measure fisherman effort and harvest. Hybrids exhibited high survival rates but apparently there was insufficient forage to sustain their initial rapid growth. Despite this condition, hybrids attained weights up to 2.0 kg and provided substantial fisherman benefits in terms of harvest and recreation.

Many ponds in the southeastern United States have waters with less than 20 mg/ I total alkalinity and should be limed to insure good response to inorganic fertilization. Water analysis is the only technique for determining if a pond needs liming, and the liming rate can best be estimated from a lime requirement determination of the bottom mud. In some waters total alkalinity may be high, but total hardness low. Such waters frequently develop dangerously high pH when fertilized. Alum rather than acid forming fertilizers should be used as emergency treatment to prevent fish kills during periods of high pH. Data on alkalinity and hardness are therefore needed when making fertilizer recommendations for individual ponds. Sufficiently accurate water analyses may be made with water analysis kits, provided reasonable care is exercised.

Fish populations of Belews Lake, North Carolina, declined during the period of operation of the Belews Creek Steam Station from 1974 through 1977. Reproduction of fish in the main lake was almost completely absent in 1976 and 1977. A survey of trace elements in water and fish fro.m Belews Lake indicated that selenium concentrations were elevated in Belews Lake water, and that fish in the lake had accumulated unusual amounts of selenium. Fish from a remote area of Belews Lake where normal reproduction took place in 1976 and 1977 had much lower selenium concentrations in their tissues than fish from the main basin. Only trace elements of selenium occur naturally in water, soil, or mineral deposits in the Belews Lake drainage. Selenium entered Belews Lake in soluble form by way of the power plant fly ash sluice water return. Selenium concentrations in Belews Lake water were not high enough to be directly toxic to fish.

Characteristics of the intragravel environment of Southern Appalachian trout streams have not been studied. It was the purpose of this study to measure intragravel ~ermeability,apparent velocity, temperature, dissolved oxygen, and bottom composition in areas that visually appeared suitable for trout spawning in 8 relatively undisturbed streams in the Pisgah National Forest of western North Carolina. Comparisons were made between these measurements and the development requirements of salmonid embryos. Two types of standpipes were used, the Mark VI groundwater standpipe and polyvinyl chloride (PVC) standpipes. The lowest mean intragravel dissolved oxygen was 3.2 mg/l. Dissolved oxygen measured by the Mark VI was consistently higher than when measured by the PVC standpipes which indicates that the Mark VI gives a better measure of the true intragravel dissolved oxygen than does the PVC standpipes.

The results from cove rotenone sampling and electrofishing population estimates for largemouth bass (Micropterus sa!moides) were compared with the total largemouth bass populations obtained through draining of Sherwood Lake, a 67 ha impoundment in southeastern West Virginia. Rotenone samples over-estimated all size groups of largemouth bass (fingerling, intermediate and harvestable) both in number and weight. Electrofishing (Schnabel population estimates) more closely represented the numbers and weight of largemouth bass recovered at the lake draining. Schnabel estimates were 10,096 (7,870-14,07.9) while total draining produced 9,224 bass. Electrofishing standing crop was estimated at 151 fish/ ha and 8.3 kg/ ha while draining totals were 138 fish I ha and 9.9 kg! ha.

A seining survey of the fish fauna of the beach zone in the James River, Virginia, was conducted from July to December 1977. Weekly collections were made at 4 stations resulting in the capture of 17,602 individuals representing 36 species. Abundance and diversity were influenced by large catches ofschooling and migratory species utilizing nearshore areas as a nursery ground. Freshwater species diversity peaked in August and September, while mesohaline species diversity peaked in July, September, and November. Cluster analysis was used to define 3 freshwater station groups representing warm, moderate, and cool water temperatures, but was not helpful in analyzing mesohaline stations.

Yellow Floy FD-67 internal anchor tags were utilized in an experimental and field study of tag discoloration, tag legibility and fouling organisms. Most tags exhibited some degree of discoloration over time. The rate and extent of discoloration varied between two batches of tags purchased in different years. The legibility of a tag was not affected to a great extent by the degree of discoloration. Legends of some completely discolored tags were still readable. Fouling organisms eroded the vinylite covering and deteriorated the legends of some tags. Bryozoans, barnacles and tunicates were the most commonly encountered fouling organisms. Barnacles were the most erosive of these organisms. Other causes of tag discoloration were believed to be chemical reactions between the vinylite covering and environmental factors such as salt concentration.

A telephone survey was conducted of a stratified, random sample of people holding Florida fishing licenses and of a random sample of members of selected fishing clubs. Questions were asked concerning demographic characteristics, their fishing habits and preferences, opinions about the Florida Game and Fresh Water Fish Commission and its projects, and their sources of information on freshwater fishing topics. A statistically significant difference was found between the responses of the average fishermen and the fishing club members in 72% of the questions asked in the survey.