Female Striped Bass Morone Saxatilis Research Articles

Evaluation of Precision and Sample Sizes Using Standardized Sampling in Kansas Reservoirs

AbstractWe evaluated the precision of samples and the number of stock‐length fish collected by means of standard methods used for sampling North American freshwater fishes from 2010 to 2013 in Kansas. Additionally, we used resampling procedures to determine the number of gear deployments needed to achieve a relative standard error (RSE) of 25% for the CPUE and collect 100 stock‐length individuals. Median RSE of electrofishing samples was generally less than 25% for Largemouth Bass Micropterus salmoides in all sizes of reservoirs and for Channel Catfish Ictalurus punctatus in medium (251–1,000 acres) and large reservoirs (greater than 1,000 acres). The RSE estimates were generally >25% for Bluegill Lepomis macrochirus and crappies Pomoxis spp. collected in trap nets and palmetto bass (female Striped Bass Morone saxatilis × male White Bass M. chrysops) and Walleye Sander vitreus sampled in gill nets. With few exceptions, 100 stock‐length individuals of all target species (e.g., Largemouth Bass, Bluegill, crappies, palmetto bass, Channel Catfish, Walleye) were not sampled at current levels of effort. Resampling procedures indicated that fewer than 20 deployments were usually needed to obtain an RSE ≤ 25% and 100 stock‐length fish for Largemouth Bass in smaller impoundments (i.e., <250 acres); however, more than 20 deployments were needed in larger impoundments. The median effort needed to achieve an RSE ≤ 25% for Bluegills and crappies in trap nets varied and may exceed what some biologists find practical. Fewer gill‐net deployments were needed to reach an RSE ≤ 25% for palmetto bass and Walleyes than to collect 100 stock‐length fish. Our results indicate that more samples than are currently prescribed are generally needed to precisely sample sport fishes by means of standardized protocols in Kansas reservoirs. In some instances, obtaining precise samples may not be logistically feasible. In these situations, biologists should be aware of the potential shortcomings of sampling protocols and set objectives accordingly.Received May 12, 2014; accepted August 23, 2014

Responses of gizzard shad and white crappie to introductions of palmetto bass

Palmetto bass (female striped bass Morone saxatilis × male white bass Morone chrysops) were stocked into Long Branch Lake, Missouri, USA in an effort to restructure the gizzard shad Dorosoma cepedianum population via predation. The goal of this restructuring was to provide more suitable-size prey for white crappie Pomoxis annularis, thereby improving growth of this important sport fish. Secondarily, palmetto bass may prey on the abundant white crappie population which may reduce density-dependent effects on growth. Trends in abundance and mean total length (TL) at age of white crappie and gizzard shad were examined over an eight-year period which spanned years before, during, and after stocking of palmetto bass. Also, trends in water quality and zooplankton variables, which may influence gizzard shad demographics, were examined during this period. Following stockings of palmetto bass, mean TL at age of adults and abundance of age-0 gizzard shad increased. Water quality variables and zooplankton biomass that may have influenced gizzard shad showed no temporal trends except for turbidity which increased over time. Despite the changes in the gizzard shad population, mean TL at age of white crappie did not improve and their abundance did not decline. Age-0 gizzard shad still quickly outgrew their vulnerability to most white crappie. It may be necessary to incorporate other management strategies in addition to stocking palmetto bass to improve growth of white crappie in this reservoir.

A Standardized Method and Analytical Approach for Predicting Female Reproductive Stage in Teleosts by Using Ovary Color and Female Characteristics

AbstractDetermining and understanding patterns in the reproductive status of fishes are essential for assessing individual and population reproductive potential. The least biased method for determining reproductive stage is through the use of ovarian histology; however, this method can be time consuming and expensive. To overcome these restrictions, we developed models to predict the reproductive stage of female striped bass Morone saxatilis by using ovary color and other female characteristics. We provide a standardized and calibrated method for quantifying ovary color, and we outline an analytical approach that utilizes binary and ordinal logistic regression. Our results indicated that binary models had high accuracy (<6% error) in distinguishing between the regressing phase (i.e., recently spawned) and the nonregressing phase (i.e., all other reproductive phases); we found even better accuracy (4% error) for ordinal models in discriminating among four nonregressing reproductive phases. All of the best‐fitting models required the inclusion of an ovary color variable and ovary energy density; however, good predictive accuracy was also obtained when we replaced ovary energy density with ovary percent water to produce models requiring minimal laboratory processing time and cost. Although tested on striped bass, our method could be used to develop similar models for other species.

A Proposed Change to Palmetto Bass Proportional Size Distribution Length Categories

AbstractPalmetto bass (female striped bass Morone saxatilis × male white bass M. chrysops) are an important sport fish in the Southeast and Midwest regions of the United States. Because palmetto bass populations must be established and maintained by regular stocking, population assessments are necessary to evaluate and refine stocking plans. A commonly used metric for fish population assessment is the proportional size distribution (PSD). However, the value of this metric is limited for palmetto bass because the original lengths designated for the stock (8 in), quality (12 in), preferred (15 in), memorable (20 in), and trophy length categories (25 in) were based on the old world‐record length of 31 in, which is much shorter than the current length of 39 in. Thus, new lengths of 10, 16, 20, 24, and 28 in are proposed for assessing palmetto bass populations via PSD indices. These proposed lengths more accurately reflect the maximal length and life history characteristics (i.e., fast growing, short lived, and seldom stunting) of palmetto bass than the current PSD length categories. With the proposed length categories, PSD estimates are likely to provide a more useful index of the growth, mortality, and recruitment of palmetto bass and improve communication among fisheries managers.Received February 21, 2011; accepted May 8, 2011

Growth Performance and Body Composition of Palmetto Bass Fed Five Levels of Dietary Protein at Two Energy‐to‐Protein Ratios

AbstractA feeding trial was conducted to determine the effects of dietary crude protein (CP) level and digestible energy‐to‐protein (DE:P) ratio on the growth performance and body composition of palmetto bass (female striped bass Morone saxatilis × male white bass M. chrysops). Ten soybean‐meal‐based diets were prepared to contain 30, 35, 40, 45, or 50% CP at DE:P ratios of 33.48 or 41.85 kJ/g CP. The diets contained lyophilized palmetto bass muscle as the sole animal protein source to improve dietary amino acid composition. Wheat middlings and corn grain were the major sources of carbohydrates, and the diets were formulated to meet the known nutritional requirements of palmetto bass. Fish fed 35% or 40% CP at 33.48 or 41.85 kJ/g CP had significantly (P ≤ 0.05) greater weight gains and higher feed efficiency ratios than fish fed the other diets. The protein efficiency ratio (g weight gain/g CP consumed) decreased and visceral fat ([g visceral fat × 100]/g body weight) increased as the dietary protein level increased in both DE:P treatments. The hepatosomatic index ([g liver weight × 100]/g body weight) increased with the dietary protein level up to 40–45% CP. Whole‐body muscle content and fillet yield did not differ significantly among fish fed any of the diets at either DE:P ratio. The lipid content of fillets was higher among fish fed 45–50% CP than among those fed up to 40% CP. Hematocrit and serum protein concentrations were not affected by the dietary CP level or the DE:P treatment. Overall, the DE:P ratio had little or no effect on most of the parameters of interest. Based on our comparisons of weight gain, diet utilization efficiency, and body composition among treatment groups, a 35% CP diet with 41.85 kJ/g CP was considered optimum for palmetto bass under the conditions of this study.

Effects of Phase‐Shifted Photoperiod Regimes on Oocyte Growth and Hormonal Profiles in Female Striped Bass Morone saxatilis

Abstract.— The use of 12–mo long, but phase‐shifted advanced and delayed photoperiod cycles in the regulation of the reproductive cycle was investigated in captive‐reared female striped bass Morone saxatilis during the 3‐yr study in an attempt to control the timing of sexual maturation under simulated photoperiod conditions. Phase‐shifted photoperiod cycles did not induce a full shift in oogenesis during the first year cycles, but did in the following years. Spawning time, indicated by maximum oocyte diameters, was advanced up to 4 mo in females maintained under the phase‐shifted advanced photoperiod, and delayed up to 4 mo when they exposed to the phase‐shifted delayed photoperiod, compared to the natural spawning time in Spring (March‐May). Phase‐shifted photoperiod regimes shifted the profiles of plasma testosterone (T) and estradiol (E2), corresponding to the shift of oogenesis in the respective groups. Significant increases in T and E2 levels occurred during the vitellogenic phase, and these levels peaked before the occurrence of maximum oocyte diameters. The studies demonstrate that phase‐shifted photoperiod regimes can be used to control oogenesis, and have implications for ensuring the year‐round supply of mature female striped bass, particularly in domesticated striped bass.

Impacts of Increased Tempering Lengths on Twenty-Four-Hour Survival of Hybrid Striped Bass Fry

Abstract We evaluated the impacts of different tempering rates on the 24-h survival of 4-d-old palmetto bass (female striped bass Morone saxatilis × male white bass M. chrysops). We used the increase rate of pH as a measure of water quality change. Four tempering rates were conducted concurrently to determine the importance of extended tempering time on the survival of fry following an adjustment to an increase in pH, alkalinity, and hardness. Fry were tempered to increases of 0.6–1.9 pH units over periods from 11 to 330 min, producing pH tempering rates of 11.4–0.02/h. The study produced average tempering rates and average survival rates for a set of controls and four treatment groups. Average fry survival rates ranged from 75% in the control replicates with a pH tempering rate of +0.01/h to 48% for fry subjected to an increase of 1.9 pH units in 10 min or a tempering rate of +11.4 pH/h.

Correlation of Transforming Growth Factor-β Messenger RNA (TGF-β mRNA) Expression with Cellular Immunoassays in Triamcinolone-Treated Captive Hybrid Striped Bass.

Assessing fish immune status with molecular markers has been hampered by a lack of specific reagents. A quantitative polymerase chain reaction (PCR) method (reverse transcription quantitative-competitive PCR, RT-qcPCR) for measuring transforming growth factor-β (TGF-β) transcription from a broad range of teleost fish has recently been developed. The quantitative PCR now permits monitoring production of this important immunosuppressive cytokine in response to immunomodulating agents and conditions. We examined anterior kidney and spleen mononuclear cells from hybrid striped bass (female striped bass Morone saxatilis × male white bass M. chrysops) for production of TGF-β messenger RNA (mRNA) in response to administration of the synthetic glucocorticoid triamcinolone. We also compared TGF-β transcription with anterior kidney macrophage bactericidal activity and splenic lymphocyte blastogenesis. Anterior kidney mononuclear cell TGF-β mRNA levels decreased, whereas bactericidal activity increased. Spleen TGF-β mRNA levels did not change significantly, and splenic lymphocyte pokeweed mitogen stimulation index increased in triamcinolone-treated fish. Since triamcinolone is used therapeutically as a suppressive immunomodulator, the enhanced immune functions indicated by the cellular immunoassays were unexpected; however, the inverse response of TGF-β production and macrophage bactericidal activity was consistent with the known relationship between TGF-β and macrophage activation in mammals. Induced immunomodulation in hybrid striped bass was detectable by both traditional cellular immunoassays and the new RT-qcPCR for TGF-β.

Palmetto Bass Movements and Habitat Use in a Fluctuating Colorado Irrigation Reservoir

Abstract Movement and habitat use by adult palmetto bass (female striped bass Morone saxatilis × male white bass M. chrysops) were monitored with ultrasonic transmitters in a 1,166-ha fluctuating irrigation reservoir in eastern Colorado. Movement varied by diel periods, and heterogeneity was recorded among individuals. Minimum estimates for displacement ranged from 30 to 558 m/h. Factors that appeared to influence movement included water clarity, water temperature, and barometric pressure, although these relationships explained little variability in the multiple-regression model used. Palmetto bass exhibited a preference for nearshore areas, but they did not select for cover types within that region. As the water level in the reservoir was reduced through irrigation drawdown, the fish used deeper areas of the lake than during periods of water level stability. Knowledge of the influence of these variables on activity patterns should help improve catch rates for anglers and sampling efficiency for biologists.

Effects of Dietary Catfish and Menhaden Oils on Hybrid Striped Bass Production

Abstract Hybrids of female striped bass Morone saxatilis and male white bass M. chrysops were stocked at 14,000 fish/ha in earthen ponds and fed an experimental diet supplementally sprayed (2.5% by weight) with either catfish oil (CO) or menhaden oil (MO). The sprayed diet contained n-3 highly unsaturated fatty acids (HUFA, with four or more double bonds) at 1.10% and 1.54% of diet for CO and MO, respectively. Fish were fed to apparent satiation twice daily for 212 d in three replicate 0.05-ha ponds per diet. There were no significant differences (P < 0.05) between CO and MO diets in mean total weight offish at harvest (590 and 585 g, respectively), percent weight gain (584% and 576%), survival (87% and 91%), or feed conversion (weight of feed as fed/fish weight gain: 2.50 and 2.31). Mean intraperitoneal fat (IPF) to body weight ratios of fish were not different (4.8% for CO and 4.4% for MO). Females had a significantly higher IPF ratio (5.2%) than males (4.7%) across both diets. There were no significant...

Volitional Tank Spawning of Female Striped Bass with Male White Bass Produces Hybrid Offspring

We report the first volitional tank spawning of female striped bass Morone saxatilis with male white bass M. chrysops. The female striped bass were reared for 6 or 8 years from larvae to mature adults in captivity. The wild-caught male white bass were acclimated to captivity 1 year before spawning trials. The fish were induced to mature with implanted pellets containing synthetic analogue of mammalian gonadotropinreleasing hormone, [D-Ala6-Pro9-NEt]-LHRH, at 10 μg/ kg body weight in a cholesterol and cellulose matrix. Males later received an additional injection of human chorionic gonadotropin at 500 IU/kg body weight to maintain spenniation. At hormone implantation, females were in an advanced state of maturity with oocyte diameters ranging from 650 to 1,000 μm and males were producing milt. Eight females were placed in tanks with three or six males for spawning. Three females did not release eggs within 14 d. The remaining five females spawned, but only two produced fertilized eggs and hybrid offspring. All spawnings had large numbers of overripe eggs, which suggests that striped bass females had a behavioral aversion to spawning with white bass males.

Age-at-Maturity Estimates for Atlantic Coast Female Striped Bass

Abstract This study was undertaken to estimate the percentage of mature female striped bass Morone saxatilis present in each age-class during annual coastal feeding migration. Migratory striped bass (N = 302) were sampled in coastal Rhode Island waters during spring (May–June) and fall (September–November) from 1985 to 1987. Stocks were identified by analysis of morphometric characters and isoelectric focusing of eye-lens proteins. Histological sections of ovarian tissue were used to categorize maturity state. Fish were considered mature if a class of oocytes measuring at least 150 μm and containing cytoplasmic inclusions was found in the ovarian sections. All females whose age at next potential spawning was 7 and older were mature. Our empirical observations indicated that 12% of fish in age-class 4, 34% of fish in age-class 5, and 77% of fish in age-class 6 were mature. The estimate of the proportion of mature fish in age-class 5 differs significantly from that of Merriman (1941), who also examined coas...

Communications: Detection of Anti-Amyloodinium ocellatumAntibody from Cultured Hybrid Striped Bass (Morone saxatilis×M. chrysops) during an Epizootic of Amyloodiniosis

After an epizootic of amyloodiniosis (caused by the protozoan Amyloodinium ocellatum) in a commercial aquaculture facility for hybrid striped bass (female striped bass Morone saxatilis × male white bass M. chrysops), sera from these fish, as well as from others that had been experimentally immunized with the parasite, were evaluated by an enzyme-linked immunosorbent assay for antibody specific for the parasite. Titers were similar between the fish infested in culture and the experimentally immunized fish, and were significantly higher in both the cultured and artificially exposed fish than in unexposed fish. These results suggest that an infestation of A. ocellatum can stimulate the production of humoral antibodies to the parasite, providing further evidence that natural infestations of the parasite may confer protective resistance in fish that survive the initial parasitic infestation.

Maturation and Fecundity of Roanoke River-Albemarle Sound Striped Bass

Abstract Since the early 1940s, several investigators have determined age-at-maturity schedules for female striped bass Morone saxatilis at various locations along the Atlantic coast of the USA. These researchers have used one of two sets of criteria to determine whether a female is sexually mature; however, recent work suggests that these methods may underestimate the number of females entering the spawning population at an early age (e.g., ages 3 and 4). The objectives of our study were (1) to compare three methods and criteria for establishing sexual maturity and (2) to use all three methods in establishing a maturity schedule for female striped bass. Also, we estimated potential fecundity of the fish as a function of size, weight, and age. Two hundred sixty-five female striped bass were collected from the Roanoke River–Albemarle Sound system of North Carolina during the prespawning and spawning seasons (March–May) of 1989 and 1990. Females ranged in size from 344 to 1,172 mm fork length and in age fro...

Effects of Temperature, Photoperiod, and Ration Size on Growth of Hybrid Striped Bass X White Bass

Abstract Growth and food conversion efficiency of hybrid bass juveniles (female striped bass Morone saxatilis × male white bass M. chrysops) were measured as a function of diel oscillating and constant temperatures, spring (increasing day length) and autumnal (decreasing day length) photoperiods, and ration sizes ranging from no food to daily satiation. The optimum temperatures for growth and peak conversion efficiency were estimated to be 26.8 and 21.2°C, respectively, for fish under constant temperatures, 12 h of daylight, and a maximum ration size. Springtime photoperiod significantly increased growth, and autumnal photoperiod significantly reduced growth. There was a significant temperature-photoperiod interaction; maximum growth occurred at 27.9°C under the springtime photoperiod and at 25.7°C under the autumnal photoperiod. Diel temperature oscillations with an amplitude of ±4, 6, and 8°C did not influence growth rate or conversion efficiency. Reduced ration sizes led to a lower optimum temperature ...