Journal of the Southeastern Association of Fish and Wildlife Agencies

Natural reproduction of hybrid striped bass (Marone chrysops x M.saxatiUs) was documented in Lake Palestine, Texas. Electrophoresis and isoelectric focusing analysis indicated 29% of the sampled Marone spp. were non F-l hybrids. These individuals apparently resulted when F-l hybrids reproduced with white bass and/or F-l hybrids. Age analysis revealed the non F-l hybrids were from years when hybrid striped bass were not stocked.

A 70% reduction of total reservoir area during an extended drawdown impacted Watauga Reservoir fish populations. Response to the drawdown and refilling was species specific. Abundance of alewife (Alosa Pseudoharengus) and bluegill (Lepomis macrochirus), 2 primary prey species, decreased while young of year gizzard shad (Dorosoma cepedianum) increased. Changes in growth and relative weight indicated some predators (walleye Stizostedion vitreum vitreum) benefited by the reduction of lake volume. This was not the case with black bass (Microterus spp). Species composition and relative abundance following the drawdown were similar to those which occur when a new reservoir is filled. The fishery, though affected, was not greatly impacted during the drawdown.

Relative abundance of several species of fish in the headwaters of Keowee Reservoir and in Jocassee Reservoir were estimated during the initial 9 years of operation by the Jocassee Pumped Storage Station. Several species of fish in each reservoir declined in abundance during this period, while others increased. We think the declines were related more to the chemical stabilization of these reservoirs than to pumped storage operations. The increases were related to stocking programs and natural population expansions.

Few significant differences could be detected between a high flow year and a low flow year with respect to catch, effort, catch per unit effort, or the functional composition of the multi-species tailwater fishery below Jordan Dam on the Coosa River, Alabama. Additionally, no significant or consistent correlations were evident between mean daily discharge and daily catch during the 2 surveys. Correlations between daily effort and daily catch per unit effort with mean daily flow were few, inconsistent, and restricted to winter and late summer months when fishing effort was minimal. Angler responses during interviews indicated diverse preferences relative to flow regime.

A fish die-off involving primarily threadfin shad (Dorosoma petenense) occurred from July through September 1985 in Lake Monticello, Texas. Heated water discharged from the Monticello Power Plant plus adverse climatic conditions elevated lake water temperatures influencing fish distribution and survival. Respiratory stressors due to crowding of fish in limited refuge areas and intensified by prolonged high water temperatures, are suspected to have caused the mortality of an estimated 756,000 fish valued at $47,000.

Upper thermal tolerance limits (TL50's) for early life stages of Par Pond and Florida stocks of largemouth bass (Micropterus salmoides intergrade and M. s. loridanus) were determined. Comparisons were made between 3 stages (non-feeding and feeding pro-larvae, and post-larvae), 2 initial temperatures (18° and 23° C), and instant vs. gradual (5° C/day) exposures to test temperatures between 18° and 38° C. Upper thermal tolerance limits did not differ between largemouth bass stocks, life stages, or initial temperatures. Ninety-six hour TL50 was 32.8° C for instant exposures and 34.1° C for gradual exposures (5° C/day) to high temperatures. Percent survival for 96-hour exposures to high temperatures was significantly higher for gradual exposures than instant exposures for all stocks, initial temperatures, and life stages. Calculated Maximum Weekly Average Temperature (MWAT) to protect early life stages of largemouth bass is 28.1 ° C.

Eighteen hundred and thirty-four black crappie (Pomoxis nigromaculatus) were collected from the St. Johns River, Florida, in late winter and early spring, 1982 to 1985. Differences in numbers and growth rates of males and females collected were not significant (P > 0.05). Fish were separated into age groups using length-frequency distributions and by counting annuli on otoliths. Only 2 distinct age groups were discernible by length-frequency analysis, whereas 6 to 8 groups were identified by otolith aging. Mean lengths of age groups obtained from lengthfrequency were overestimated 3 of the 4 study years when compared to otolith aging. Length range overlap from otolith aged groups varied from 15.2% to 100% and averaged 69.3%. Year class overlap occurred as early as years I and 2 and indicated a bias when relying on length-frequency evaluation alone.

Five techniques (electrofishers, hoop nets, gill nets, wire traps, and trotlines) were used to sample ictalurids in the Neuse River above New Bern, North Carolina, between July 1984 and May 1985. Hoop nets were the most effective of the sampling gears tested. They collected white catfish (lctalurus catus), channel catfish (l. punctatus), blue catfish (l. furcatus), yellow bullhead (l. natalis), and margined madtom (Noturus insignis) and accounted for 76% of the total number of fish caught. Electrofishing (low voltage) captured white catfish, yellow bullhead, and margined madtom, which represented 14% of the total number of fish caught. White catfish, channel catfish, blue catfish, and brown bullhead (l. nebulosus) were caught with trotlines, but this accounted for only 8% of the total number caught. Wire traps, gill nets, and electrofishing (high voltage) were ineffective in sampling catfish in the Neuse River.

Electrofishing for largemouth bass (Micropterus salmoides) in sites selected because they are judged to have habitat favored by bass can often yield higher catch per effort than in sites selected randomly, resulting in reduced effort or more precise estimates. Although samples selected subjectively could misrepresent relative abundance, they mayor may not affect population indices derived from lengthweight data, such as length-frequency and condition indices. We compared indices obtained at randomly-selected sites with indices obtained at subjectively-selected sites. The latter sites provided more largemouth bass, overestimated Proportional Stock Density and Relative Stock Density (P < 0.05), but did not affect Relative Condition (P > 0.05). We conclude that judgment sampling may misrepresent a largemouth bass population's abundance and structure.

Three battery-powered pulsed DC electrofishing units were built and used to collect flathead catfish (Pylodictis olivaris) in a 50-km section of the Flint River, Georgia, to study the dramatic population expansion of that species following introduction. Peak collecting efficiency was achieved at 20 Hz frequency and pulse width of 0.4-0.5 ms. Power of 250-350 volts and 3 amps were needed to collect flathead catfish effectively in conductivities of 80-155 umhos/cm. Fishing downstream in a figure-S pattern with a 12-m anode wire hanging from the stern was effective in a variety of depth, substrate, and flow conditions. Efficiency was increased when a chase boat was deployed to net fish due to the large effective electric field. Efficiency was significantly reduced below 20° C. During 35 trips and 78.4 hours of electrofishing, 3,266 flathead catfish were collected.

We compared electrofishing and underwater observations as different methods for estimating population characteristics of centrarchids in a medium-sized warmwater stream in Missouri. We evaluated how well each method determined length-frequency distribution of smallmouth bass (Micropterus dolomieui), rock bass (Ambloplites rupestris), and longear sunfish (Lepomis megalotis). Underwater observation was the more accurate technique, producing length-frequencies more typical of a catch curve. When compared to underwater observations, electrofishing sampled the largest size class of fish effectively, but not the smallest size classes. Electrofishing efficiency was species specific and was related to habitat preferences and fish behavior. Correction factors, developed from observational data, can be used to increase the accuracy of electrofishing data.

Creel surveys were conducted on 9 state-owned public fishing lakes during 1981 and 1982 to determine harvest, pressure, and angler success rates. Anglers harvested a mean 50.4 kg/ha (SD = 18.0 kg/ha) among all lakes surveyed and had a mean success rate of 0.94 fish/angler-hour and 0.18 kg/angler-hour. Mean pressure among all lakes was 318.2 angler-hours/ha (SD = 145.3 angler-hours/ha). Lepomis macrochirus was the most sought after species during the survey, followed by Pomoxis sp., Micropterus salmoides, and lctalurus punctatus, respectively. Negative relationships were detected between Micropterus salmoides mean sizes and success rates and between Pomoxis sp. mean sizes and harvest rates. Anglers tended to spend a greater percentage of their time within lakes seeking species which returned the higher success rate. Management implications derived from the surveys are discussed and include fishery-specific programs and increased emphasis on bluegill and crappie management.

This paper summarizes a framework for understanding freshwater trout fishermen and how such a framework can be used in coldwater fishery management. It is based on a sociological study of "angler specialization" and how it relates to fisherman behavior, attitudes, and fishery management preferences. Angler specialization refers to a continuum of fishermen types from the beginning fisherman to the advanced specialist, reflected by such factors as amount of participation, gear and equipment used, and commitment to the sport. Anglers identified themselves according to the independent variable of specialization level (occasional, generalist, specialist) and significant differences (P ≤: .05) were found in dependent variable categories of behavior, attitudes about fishing, and management philosophy.

Creel survey data collected from the marine recreational fishery in Alabama revealed that there were differences in harvest per unit of effort (HPUE) between the eastern and western sides of Mobile Bay. The total recreational landings from Alabama marine waters and adjacent offshore waters was 1,300,000 fish weighing 772,700 kilograms. Of the 2,250,000 angler-hours exerted on the fishery, 1,245,000 angler-hours (55%) were directed at particular species of fish, primarily flounders, red drum, speckled seatrout, Spanish mackerel and king mackerel. HPUE of Spanish mackerel and king mackerel was found to be significantly different (P ≤ 0.10) between the 2 sides of the bay and comparisons also revealed spatial differences across specific fisheries. The seasonal pattern of HPUE of flounders and red drum significantly (P ≤ 0.10) shifted from one side of the bay to the other.

Fishery data were collected from February to August 1984 for Bluff Lake, Noxubee County, Mississippi, to evaluate the effect of refuge areas and size and creel limits in reducing possible overharvest of largemouth bass (Micropterus salmoides) from previously unfished waters. During the study, 1,779 bass were marked and 150 were recaptured. The pre-fishing bass population was estimated at 7,657. Fishing mortality during opening weekend was 10%,525 parties who fished a total of 3,292 hours caught 361 bass (255 kg). Over the 6-month period, anglers fished a total of 48,796 hours and harvested 3,080 kg of bass. Largemouth bass accounted for 24% of the total weight of fish creeled; catch per hour was 0.04 kg. Although refuge areas and size and creel limits may have reduced the initial overharvest of bass during opening weekend, more than 40% of the bass population had been harvested by the end of the study and few legal-sized bass (;;'254 mm) remained.

Very little attention has been given to the penalty necessary to achieve compliance with fishery management laws. A penalty increase from $200 to $2,500 for shrimping in the area from 7.3-m deep water to the outer limit of the Texas Territorial Sea was imposed in 1981. Brown shrimp (Penaeus aztecus) and white shrimp (Penaeus setiferus) commercial catches and shrimping violations were used to determine if this increase reduced illegal shrimping in the closed area. Illegal landings of brown shrimp were reduced. However, violations were not eliminated. The potential profit from violating the law may be exceeding the potential fine, perhaps because of inflation.

The striped bass (Morone saxatilis) x white bass (M. chrysops) hybrid is widely stocked to support recreational fishing and is of interest as a commercial aquaculture candidate. Nevertheless, there is little information concerning the relative performance of these hybrids in various salinities. A replicated 126-day study compared growth, survival, standing crop, and feed conversion ofjuvenile hybrid bass (mean size 5.8 g) reared under controlled conditions at 0, 7, 14,21, 28, and 35 ppt salinity. Results indicated that growth was similar at all salinities and that fish survival was high (mean 91.7%) at all salinities except 35 ppt where survival was 60.0%. Feed conversions averaged 1.7 using a pelleted feed and average standing crop was 11 kg/m' for salinity treatments 0, 7, 21, and 28 ppt. Standing crop was 6.7 kg/m' at salinity 35 ppt due to the lower survival rate. A disease outbreak resulted in loss of all fish reared at 14 ppt after day 105.

Controlled spawning techniques for cultured striped bass (Morone saxatilis) to produce striped bass and striped bass/white bass (M. chrysops) hybrids were demonstrated. Some striped bass males matured at age 2 while almost all were mature by age 3 (mean weight 2.3 kg, 550 mm TL). In contrast, no female striped bass were mature at age 2 and only 16% were ripe at age 3 (3.4 kg, 623 mm TL). By age 4, an estimated 59% of the females were mature (4.9 kg, 692 mm TL). In 1985 and 1986, striped bass were conditioned using controlled temperatures and photoperiod regimes to spawn 1-3 months before the natural spawning season in South Carolina. Wild white bass matured in outdoor tanks and were spawned with striped bass to produce original and reciprocal cross hybrids. Reciprocal cross hybrids can easily be obtained as striped bass males and white bass females readily mature in outdoor tanks under natural conditions.

Fingerling production and post-harvest survival were compared for striped bass (Marone saxatilis) produced in ponds with low «2 mg/liter) levels of calcium and in ponds where calcium was increased (14-40 mg/liter) by the addition of calcium chloride. Production pond calcium levels were not correlated with fry survival, or biomass production in ponds. Post-harvest survival of fingerlings from treated ponds was significantly better than post-harvest survival of fish from control ponds.

Shortnose sturgeon, Acipenser brevirostrum, range from Canada to Florida and are listed as an endangered species in the United States. During 1985, a cooperative state/federal program focused on development of nursery systems for production of stockable size juveniles. Mortality was high (80%) during the first 2-3 months of tank rearing trials in spite of the use of various disease control agents and differing culture techniques. However, once a size of -180 mm T.L. (30 g) was attained, mortality essentially ceased. Indoor intensive tank systems were more suitable than ponds for producing small juveniles. Growth and survival of advanced juveniles in indoor tanks was similar among initial population densities ranging from 5.4 to 118.4 fish/m2 tank bottom area. A standing crop of 17.2 kg/m' was attained at the highest population density and overall feed conversion for all advanced juveniles was 1.4 using a soft-moist trout ration. Mean size of the 264-day-old fish was 332.8 T.L.

Increasing interest in the farming of red drum (Sciaenops ocellatus) has resulted in research and development activities with this species at the Waddell Mariculture Center in South Carolina. Red drum adults were captured from tidal impoundments and held in ponds until being moved to tanks for spawning during their natural reproductive season. Three females averaging 11 kg spawned 9 million eggs, 50% of which hatched. The fry were reared to fingerlings in fertilized ponds. Survival of fry to fingerlings was 24%. Survival of fingerlings through their first winter was 57%. Simultaneously, fingerlings from another hatchery were grown to marketable size at commercial densities in a 0.10- and later in a 0.25-ha pond. Survival of fingerlings stocked in grow-out ponds in the spring was 98% during the first 9 months. During this time, fish grew to 304 grams. Survival was again very high (e.g., 97%) during the second year of grow-out. Fish averaging 1,540 g were produced in 22 months.

Young-of-the-year mixed-sex blue tilapia (Tilapia aurea) averaging 6.1 g were stocked on 30 June 1982, at a rate of 5,000/ha in 3 O.l-ha ponds containing 10,000 channel catfish/ha. Male and female tilapia were not significantly different in weight after 55 days, averaging 111.6 g and 106.4 g respectively. After 118 days, males were significantly larger than females, averaging 248.9 g vs 211.3 g for the females. Male growth during this period averaged 2.06 glday vs 1.72 glday for the females. The tilapia ranged in weight from 164 g to 351 g at harvest on 17 November. Average tilapia production was 1,020 kg/ha, with an average survival of 91.7%. Total production, including catfish, averaged 3,971 kg/ha, with an average food conversion rate of 1.4: 1. Less than 10 kg/ha of tilapia offspring were recovered from 1 pond and none were present in the other replicates when the ponds were harvested.

Thirty-six enzyme loci were surveyed for 22 largemouth bass (Micropterus salmoides) populations from 7 watersheds in Alabama. Twenty-one loci were polymorphic. Nei's normalized genetic identity (I) and Rogers' genetic similarity (S) showed little divergence among the populations (I = 0.990 and S = 0.9792). However, several drainages contained unique alleles in frequencies greater than 0.05 and several alleles were identified that were not found in a previous nationwide survey. Significant intrapopulational heterogeneity was indicated by hierarchical F-statistics and contingency chi-square analysis. Clinal distribution of MDH-B alleles significantly affected populational differentiation. Allelic variation at MDH, AAT and IDH loci accounted for 82% of the total population differences. Variability of largemouth bass populations differed among the physiographic regions of Alabama. Frequencies of alleles from the Florida subspecies, M. s. floridanus.

Age composition, growth, and mortality of largemouth bass (Micropterus salmoides floridanus) populations in 6 major Florida resources were determined. Most largemouth bass were in the first 4 or 5 year classes; however, 6 and 7 year old fish were not uncommon, and largemouth bass up to 12 years of age were collected. Females grew faster and exhibited greater longevity than males. Total annual mortality (A) estimated from catch curves ranged from 0.37 for the Suwannee River to 0.54 in Lake Weir and was within the range reported from other localities. Backcalculated lengths based on transversely sectioned otoliths did not differ significantly (P < 0.05) from empirical lengths for largemouth bass from Lake Kissimmee. Florida largemouth bass typically reached harvestable-size (>242 mm) during age 1+, but slower growing fish did not recruit into the sportfishery until age 2 or older. Trophy-size largemouth bass (>3.63 kg) ranged from 6 to 12 years of age.

Redbreast sunfish (Lepomis auritus) is an abundant member comprising 30% of total biomass of the fish community in beaver ponds in piedmont South Carolina. Total length-weight relationship for 534 redbreast sunfish collected from 36 beaver ponds was: 10g10Wg = - 5.06 + 3.12 log10TLmm• Mean back-calculated TL for age classes I-V were 41,75, 102, 128, and 147 mm, respectively. Growth of males was faster than the growth of females, and males appeared to have better survival. Sex ratio favored males 1.00: 1.32. Redbreast sunfish spawned from May through August after water temperatures reached 23° C. Mature females (>76 mm TL) contained approximately 3,000 ova. Most of the redbreast sunfish (96.6%) examined contained food. Redbreast sunfish feed primarily on aquatic insects such as chironomids, ceratopogonids, ephemeropterans, trichopterans, and odonate larvae. Fish occurred infrequently in redbreast stomachs but comprised 26.5% of the total stomach volume.