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Anti-Leishmanial drug therapy faces significant challenges related to cytotoxicity and drug resistance. Thus, new and efficient anti-Leishmanial drugs need to be identified. Due to their broad-spectrum antimicrobial and also immunomodulatory activities, antimicrobial peptides (AMPs) have attracted considerable attention. In this study, we comparatively assessed the anti-Leishmanial activities of two recently identified AMPs (dicentracin-like and moronecidine-like) and the well-known AMP piscidin from the hybrid striped bass. AMPs were first assessed against Leishmania major promastigotes using MTS. Subsequently, macrophages were infected with L. major and treated with AMPs to evaluate anti-amastigotes activity of AMPs, and non-infected macrophages were treated with AMPs to determine cytotoxicity against mammalian cells using MTS. The induction of factors limiting L. major growth (IL-12, TNF-α and reactive oxygen species (ROS)) by AMPs was measured by ELISA and dichlorofluorescin-diacetate (DCFH-DA) assay, respectively. Piscidin was more efficacious against L. major promastigotes as compared to dicentracine-like or moronocidin-like peptides, whereas, dicentracine-like and moronocidin-like peptide exhibited a higher activity against L. major amastigotes compared to piscidin. In turn, piscidin was most cytotoxic in non-infected macrophages compared to the other two AMPs. A direct association was observed between hydrophobicity of AMPs and their anti-promastigote and cytotoxic activities. Dicentracine-like or moronocidin-like peptides induced higher levels of IL-12, TNF-α and ROS in macrophages compared to piscidin. Collectively, our results suggest that dicentracine-like and moronocidin-like peptides represent potentially promising multi-functional therapeutic agents that might not only directly kill L. major but also induce anti-Leishmania factors that can limit L. major growth and intracellular survival. [ABSTRACT FROM AUTHOR]

The development and testing of a visible implant elastomer pedigree-marking system was evaluated in sunshine bass, Morone chrysops× Morone saxatilis, and white bass, M. chrysops (Rafinesque). These tags were tested in sunshine bass fingerlings at one of four subdermal body locations (posterior to the eye, dorsal fin musculature, caudal fin musculature or anal fin musculature). Tag visibility decreased with increased sunshine bass growth (63% after 56 days). Visibility differed among body locations, with the caudal and anal tagging locations having lower visibility. White bass fingerlings representing eight genetic groups were then tagged at one of two body locations (left or right subdermal along the dorsal musculature) using one of four fluorescent colours and reared for 42 days in a common garden growth trial. Tag visibility in white bass was 99.5% at 14 days, 98.2% at 28 days and 94.9% at 42 days after tagging. There was a significant change in weight among the eight genetic groups of white bass fingerlings after 42 days ( P=0.03). Testing of this pedigree tagging system successfully identified phenotypically different groups of white bass fingerlings. [ABSTRACT FROM AUTHOR]

The article offers information on a research conducted to ascertain the cause of Eustrongylides ignotus infection among commercial bass, Morone chrysops female X Morone saxatilis male, and other fish in the southeastern U.S. As reported, this strain causes mortality among commercially produced fish. Species of Eustrongylides have complex life cycles involving a definitive host. It was inferred that bass has acquired the infections of E. ignotus in ponds directly from oligochaetes.

Abstract  Rockfishes (Sebastes spp.) represent a speciose and ecologically important group of marine fishes found in both the Pacific and Atlantic oceans, with approximately 105 species found world-wide (Hyde and Vetter 2007). They also comprise the majority of species found in the Pacific groundfish fishery. Thorough species assessments in terms of harvest management have been done for only 11 species, and of the 11 species, seven have been declared overfished. Having accurate genetic information is critical to the continuing effort at stock assessments, but sampling is often difficult in marine fishes. Genetic techniques are a powerful tool in the effort to better characterize the ecology of these species. These techniques can be used to investigate multiple biological traits, including species identity, intra- and interspecific genetic variation, migration patterns, and effective population size. There are important caveats and limitations when applying specific genetic methods, especially in marine species that lack discrete spawning aggregates. Nevertheless, it is clear from a review of recent literature that genetic tools have already provided very specific insight regarding rockfish population dynamics. The results are diverse and difficult to synthesize; however, existing studies show five primary patterns to population groupings in rockfishes: no obvious pattern of structure, structure consistent with isolation by distance, structure evident but inconsistent with isolation by distance, structure that correlates to oceanographic features, and potential genetic introgression. Clearly the study of rockfish population genetics is poised for rapid expansion that will unquestionably aid management of the rockfish fisheries and general understanding of rockfish evolutionary systematics. A principle challenge at this point is to derive generalized inferences from such a diverse array of study results across the vast North Pacific range of Sebastes. This review summarizes existing genetic studies in Sebastes spp. in the North Pacific to assist in identifying knowledge gaps for this ecologically important and diverse group. [ABSTRACT FROM AUTHOR]

Compensatory growth (CG) is a period of growth acceleration that exceeds normal rates after animals are alleviated of certain growth-stunting conditions. In hybrid striped bass (HSB, Morone chrysopsxMorone saxatilis), 3 weeks of complete feed restriction results in a catabolic state that, when relieved, renders a subsequent phase of CG. The catabolic state was characterized by depressed levels of hepatic Type I and II GH receptor (ghr1, ghr2) and igf1 mRNA, along with considerable decreases in plasma Igf1. The state of catabolism also resulted in significant declines in hepatic igf2 mRNA and in circulating 40 kDa Igf-binding protein (Igfbp). Skeletal muscle expression of ghr2 mRNA was significantly increased. Upon realimentation, specific growth rates (SGRs) were significantly higher than sized-matched controls, indicating a period of CG. Hepatic ghr1, ghr2, igf1 and igf2 mRNA levels along with plasma Igf1 and 40 kDa Igfbp increased rapidly during realimentation. Plasma Igf1 and total hepatic igf2 mRNA were significantly correlated to SGR throughout the study. Skeletal muscle igf1 mRNA also increased tenfold during CG. These data suggest that endocrine and paracrine/autocrine components of the GH–Igf axis, namely igf1, igf2, and ghr1 and ghr2, may be involved in CG responses in HSB, with several of the gene expression variables exceeding normal levels during CG. We also demonstrate that normalization of hepatic mRNA as a function of total liver production, rather than as a fraction of total RNA, may be a more biologically appropriate method of quantifying hepatic gene expression when using real-time PCR. [ABSTRACT FROM AUTHOR]

Abstract: In previous studies, we found that rapidly confined hybrid striped bass (Morone saxatilis male×Morone chrysops female) developed a syndrome characterized by the immediate and dramatic loss of their skin. We have named this phenomenon the Acute Ulceration Response (AUR). AUR is characterized by the rapid onset of severe epidermal degeneration, erosion, and ulceration on the body skin and fins, as well as corneal ulceration, in stressed hybrid striped bass. In the present study, we have shown that acute confinement stress can also cause AUR in a taxonomically wide array of fish species, including guppy (Poecilia reticulata), freshwater angelfish (Pterophyllum scalare) and channel catfish (Ictalurus punctatus) after a 2-h stress. However, we could not induce AUR in rainbow trout (Oncorhynchus mykiss). The AUR lesions were similar to those seen previously in hybrid striped bass. As AUR might be expected to predispose fish to secondary microbial infections, we examined the skin of hybrid striped bass for bacterial infection after experimental induction of AUR. These experiments showed that even fish with severe skin damage could rapidly heal their wounds without obvious consequences within several days. Bacterial numbers in AUR lesions remained low, ∼104 cfu/g of fin tissue, throughout the recovery period. However, if hybrid striped bass with AUR were exposed to even low doses (1 zoospore/ml) of the water mold Saprolegnia, a relatively weak, opportunistic pathogen, the fish developed severe saprolegniosis as soon as 48 h after challenge, with 87.5% infected and 87.5% dead within 4 days post-challenge. In contrast, none of the control fish (no AUR, but exposed to Saprolegnia) developed saprolegniosis. These data provide strong evidence that AUR might play a critical role in skin ulcer epidemics of many fish species that are preceded by an acute stress. Furthermore, our data suggest that environmental pathogen load plays a critical role in determining if AUR lesions will heal spontaneously or instead will lead to devastating disease losses. [Copyright &y& Elsevier]

Determines the effects of feeding different sources of brine shrimp nauplii with different fatty acid compositions on the growth, survival and fatty acid composition of striped bass and palmetto bass. High eicosapentaenoic acid percentage in Chinese brine shrimp; Shrimp sources from the San Francisco Bay, California; Great Salt Lake in Utah.

The article reports on the response of striped bass phagocytes to different species of Vibrio for which the virulence for striped bass had been previously determined. The vibrio cultures used in these studies have been grouped on the basis of cultural and biochemical characteristics as well as DNA homology studies. Logarithmically growing cultures were washed three times with phosphate-buffered saline and standard curves relating optical density of washed cultures to colony-forming units per ml were used to adjust bacterial concentrations. The actual numbers of viable bacteria were determined by plating just prior to use in the assay, and all bacterial concentrations reported here were calculated from direct plate counts of adjusted suspensions.

The article offers information on a hybrid striped bass, Morone saxatilis, and a white bass Morone chrysops. Researchers found the specimens of these species in Danube River. Observations made during the study of their physical and geographical properties are being elaborated in detail in the article.

Striped bass ( Morone saxatilis ), white bass ( Morone chrysops ), and their hybrid are an important group of fish prized for recreational angling in the United States, and there and abroad as a high-value farmed fish. Regardless of habitat, it is not uncommon for fish of the genus Morone to encounter and cope with conditions of scarce oxygen availability. Previously, we determined that hybrid striped bass reared under conditions of chronic hypoxia exhibited reduced feed intake, lower lipid and nutrient retention, and poor growth. To better understand the molecular mechanisms governing these phenotypes, in the present study, we examined the transcriptomic profiles of hepatic tissue in hybrid striped bass exposed to chronic hypoxia (90 days at 25% oxygen saturation) and acute hypoxia (6 h at 25% oxygen saturation). Using high-throughput RNA-seq, we found that over 1400 genes were differentially expressed under disparate oxygen conditions, with the vast majority of transcriptional changes occurring in the acute hypoxia treatment. Gene pathway and bioenergetics analyses revealed hypoxia-mediated perturbation of genes and gene networks related to lipid metabolism, cell death, and changes in hepatic mitochondrial content and cellular respiration. This study offers a more comprehensive view of the temporal and tissue-specific transcriptional changes that occur during hypoxia, and reveals new and shared mechanisms of hypoxia tolerance in teleosts. [ABSTRACT FROM AUTHOR]

Abstract: The structure and mechanics of fish scales display unusual and attractive features which could inspire new protective materials and systems. This natural material is therefore attracting attention over the past few years, and recent work demonstrated the remarkable performance of individual fish scales. A puncture event as would occur from a predator's attack however involves more than one scale, and in this article we therefore investigate collective mechanisms occurring within the scaled skin of a fish in the event of a predator's attack. We first demonstrate that in striped bass (Morone saxatilis), the scales increase by four to five times the force required to puncture the skin. We show that individual scales from striped bass provide a remarkable barrier against sharp puncture, regardless of the stiffness of the substrate. The scalation pattern in striped bass is such that three scales overlap at any point on the surface of the fish, which we show effectively multiplies the puncture force by three. We determined that the friction between scales is negligible and therefore it does not contribute to increasing puncture force. Likewise, we found that the local arrangement of the scales had little effect on the puncture performance. Interestingly, because the scales are several orders of magnitude stiffer than the substrate, indenting a few isolated scales results in “sinking” of the scales into the substrate. The high local deflections and strain within the soft tissue may then result in blunt injury before the sharp indenter penetrates the scales. Stereo-imaging and image correlation performed around a puncture site in fish reveal that the surrounding scales collectively contribute to redistributing the puncture force over large volume, limiting local deflections and strains in the soft tissues. The structure and mechanisms of natural fish scales therefore offer an effective protection against several types of threat, and may inspire novel versatile protective systems with attractive flexural properties. [Copyright &y& Elsevier]

Strong genetic change over short spatial scales is surprising among marine species with high dispersal potential. Concordant breaks among several species signals a role for geographic barriers to dispersal. Along the coast of California, such breaks have not been seen across the biogeographic barrier of Point Conception, but other potential geographic boundaries have been surveyed less often. We tested for strong-population structure in 11 species of Sebastes sampled across two regions containing potential dispersal barriers, and conducted a meta-analysis including four additional species. We show two strong breaks north of Monterey Bay, spanning an oceanographic gradient and an upwelling jet. Moderate genetic structure is just as common in the north as it is in the south, across the biogeographic break at Point Conception. Gene flow is generally higher among deep-water species, but these conclusions are confounded by phylogeny. Species in the subgenus Sebastosomus have higher structure than those in the subgenus Pteropodus, despite having larvae with longer pelagic phases. Differences in settlement behavior in the face of ocean currents might help explain these differences. Across similar species across the same coastal environment, we document a wide variety of patterns in gene flow, suggesting that interaction of individual species traits such as settlement behavior with environmental factors such as oceanography can strongly impact population structure. [ABSTRACT FROM AUTHOR]

The effect of feeding three commercial diets on production characteristics and body composition of juvenile cobia Rachycentron canadum reared using recirculating aquaculture systems (RASs) was assessed in a 56-d growth trial. Juvenile cobia (mean weight ± SE, 29.2 ± 0.7 g) were stocked into three 8-m³ tanks in each of four RASs at an initial density of 1.2 kg/m³. After stocking, fish were fed one of three commercial diets: Hybrid Striped Bass diet (HSB; 44% protein, 12% lipid), Finfish Gold diet (GOLD; 42% protein, 16% lipid), or Marine Grower diet (MG; 50% protein, 15% lipid), all at a targeted feed rate of 3-5% of body weight per day. At 2-week intervals, 10% of the population of each tank was collected to determine mean weight, weight gain, specific growth rate (SGR), feed conversion efficiency (FCE), and biomass. At the end of the rearing trial, the entire population of each tank was harvested to determine production characteristics and survival. In addition, fish were sampled to determine whole-body composition, hepatosomatic index, intraperitoneal fat ratio, energy retention (ER), protein efficiency ratio (PER), and protein productive value (PPV). Final weight (311.0 g), weight gain (281.8 g), SGR (4.23% per day), FCE (85.7%), biomass (11.20 kg/m³), and ER (32.7%) of fish fed the MG diet were significantly greater than those of fish fed the HSB and GOLD diets. No differences in survival, gross energy, ash, or crude lipid content existed among fish fed the three diets. Lowest dry matter content, lowest PPV, and highest protein content were observed in fish fed the HSB diet. Highest PER was observed in fish fed the GOLD diet. Although the cost of production per kilogram for rearing juvenile cobia with the MG diet would be greater, this cost could be offset by the 15% reduction in rearing time required as compared with the HSB and GOLD diets. [ABSTRACT FROM AUTHOR]

For organisms with great fecundity and high mortality in early life stages, such as shellfish or fishes, the need to match reproductive activity with environmental conditions conducive to spawning, fertilization, larval development and recruitment may result in extreme variance in reproductive success among individuals. The main objective of this study was to investigate evidence of large variance in the reproductive success of the striped bass Morone saxatilis in the Santee–Cooper system, South Carolina, USA. Seven microsatellite loci were analysed in 603 recruits representing three yearly cohorts from 1992 to 1994, and a group analysis was performed to identify full-sib families. Large variance in reproductive success was detected, with a few large, full-sib families contributing disproportionately to each of the cohorts. The severity of sweepstakes reproductive success varied among cohorts depending on environmentally imposed mortality. Estimations of the effective number of breeders in these long-lived fish ranged from 24 in 1992 to 44 in 1994. Furthermore, the estimated genetic effective population size ( Ne = 93) is approximately four orders of magnitude lower than estimates of adult census size ( N = 362 000). Furthermore, the presence of large full-sib families indicates that striped bass engage in pair mating in the wild. Heterogeneity in genetic composition was also observed among cohorts, suggesting that genetically different adults contribute to different cohorts and that chance rather than fitness variation determines reproductive success. [ABSTRACT FROM AUTHOR]

Data from entrainment survival sampling programs conducted in 1979, 1980, and 1988 at the Indian Point generating stations and in 1977, 1978, and 1980 at the Roseton generating station, both located on the tidal Hudson River estuary, were reanalyzed using a series of failure time models to estimate the survival of entrained striped bass Morone saxatilis based on sampling stress, mechanical entrainment stress, and thermal stress. The model with the lowest Akaike information criterion value was the most complex model examined, with year- and station-specific parameters for both sampling and entrainment. However, the lowest Bayesian information criterion was achieved with a model that had year- and station-specific sampling parameters but only station-specific entrainment parameters. The models indicated that survival was positively related to fish length and salinity and negatively related to discharge temperatures above 30°. Parameter uncertainty was addressed via a bootstrap resampling procedure to estimate parameters for the station-specific model, and the results were applied to entrainment abundance data from each facility from 1983 to 1987. The distribution of the estimated mean annual entrainment survival after 1 d for Indian Point had modes at 0.48, 0.60, 0.70, and 0.81. For Roseton, the distribution of mean annual entrainment survival was normal, with a mean of 0.41 and a variance of 0.0028. Survival differences between the two stations were due to inherent differences in entrainment stresses, as indicated by differences in the parameters for the model as well as differences in the length of entrained striped bass, discharge temperature, and salinity. [ABSTRACT FROM AUTHOR]

The article presents a study which examines the historical presence of mycobacteriosis in Chesapeake Bay striped bass Morone saxatilis from 1975 to 1985. For the stud, researchers analyzed paraffin-embedded tissue samples of age 1+ wild-captured striped bass taken from the Oxford Laboratory archives. Researchers found that of 37 cases available from the study period, two fish were positive according to histopathology and genus-specific polymerase chain reaction (PCR). Results showed that mycobacteriosis is not a new condition of Chesapeake Bay striped bass.

Pop-up satellite archival tags (PSATs) have been used to study movements, habitat use, and postrelease survival of large pelagic vertebrates, but the size of these tags has historically precluded their use on smaller coastal species. To evaluate a new generation of smaller PSATs for the study of postrelease survival and habitat use of coastal species, we attached Microwave Telemetry, Inc., X-tags to ten striped bass (Morone saxatilis) 94-112 cm total length (TL) caught on J hooks and circle hooks during the winter recreational fishery in Virginia. Tags collected temperature and depth information every five minutes and detached from the fish after 30 days. Nine of the ten tags released on schedule and eight transmitted 30% to 96% (mean 78.6%) of the archived data. Three tags were physically recovered during or after the transmission period, allowing retrieval of all archived data. All eight striped bass whose tags transmitted data survived for 30 days after release, including two fish that were hooked deeply with J hooks. The eight fish spent more than 90% of their time at depths less than 10 m and in temperatures of 6-9°C, demonstrated no significant diel differences in depth or temperature utilization (P>0.05), and exhibited weak periodicities in vertical movements consistent with daily and tidal cycles. [ABSTRACT FROM AUTHOR]

Determining the optimum conditions for tank culture of sunshine bass (female white bass Morone chrysops X male striped bass M. saxatilis) fingerlings will facilitate a year-round supply of seed for the production cycle of this increasingly popular food fish. This study determined the relationship between temperature and larval sunshine bass growth and survival to the time when fish were trained to accept commercial feeds. At 4 d posthatch (dph), larvae were stocked at five temperatures from 20°C to 32°C at 3°C increments. There were two replicates for each temperature. The larvae were fed rotifers through 8 dph. Conversion to a diet of brine shrimp Artemia spp. nauplii began at 6 dph, and training for acceptance of dry starter feed began at 20 dph. At harvest, average total length and average weight of the fish increased in a linear relationship with temperature, while relative survival and number of fish harvested decreased linearly with temperature. Tank yield had a curvilinear relationship with temperature. The temperature that provided maximum yield was 23.1°C. Although growth was faster at warmer temperatures, relative survival and yield were not. These relationships between tank culture conditions and production characteristics support optimization of tank culture to meet specific production goals. This should eliminate some of the logistical constraints to expanded tank culture of sunshine bass fingerlings. [ABSTRACT FROM AUTHOR]

A study was undertaken to determine whether stress responses and associated mortality in hybrid striped bass (white bass Morone chrysops X striped bass M. saxatilis) during and after transport could be mitigated by use of anesthesia with low concentrations of clove oil (10 µL/L of water) during transport. Stress indicators, including plasma cortisol, glucose, chloride (CI-), sodium (Na+), potassium (K+), and calcium (Ca++) concentrations, were determined for hybrid striped bass sampled (l) initially from ponds, (2) after seining (45 min), (3) immediately after a 3-h transport, and (4) at 24 h posttransport (recovery); these values were compared with those of captive control fish. Fish anesthetized with clove oil during transport exhibited prolonged elevation of cortisol concentrations (124.3 ± 13.2 ng/mL, mean ± SE) at 24 h posttransport, while fish not exposed to anesthetic during transport recovered rapidly (to 34.1 ± 13.3 ng/mL) within 24 h. Plasma glucose concentrations in hybrid striped bass exposed to clove oil during transport were significantly (α = 0.05, P < 0.05) elevated (135.1 ± 5.6 mg/dL) immediately after transport and then decreased by 24 h posttransport (84.3 ± 3.4 mg/dL) compared with the 24-h posttransport level for fish transported without anesthetic (101.0 ± 5.0 mg/dL). Plasma electrolyte (Na+ CI-, and K+) concentrations indicated that osmoregulatory distress occurred after transport in hybrid striped bass transported with clove oil, while electrolyte changes were less severe in fish transported without anesthesia. No hydromineral imbalance occurred based upon plasma Ca-H- concentrations in either treatment. High mortality occurred within 7 d posttransport in both treatment groups but was not significantly different (P < 0.05) between the treatments. Observed mortality was primarily, if not entirely, due to Flavobacterium columnare infection. Hybrid striped bass transported during light clove oil sedation took longer to recover and exhibited no improved survival or disease resistance compared with fish transported without anesthesia. No potential benefit of transporting hybrid striped bass under anesthesia induced by clove oil is evident. [ABSTRACT FROM AUTHOR]

A previously reported protocol for culture of larval sunshine bass (female white bass Morone chrysops X male striped bass M. saxatilis) to fingerling size in tanks involved an initial feeding of rotifers for several days before the larvae were weaned to nauplii of brine shrimp Artemia spp. and prepared feed. Maintaining rotifer cultures requires space, time, equipment, supplies, and trained culturists. The rotifer cultures are often unstable, which increases risk of poor sunshine bass fingerling production in tanks. Elimination of the use of rotifers would greatly enhance the feasibility of reliable tank culture of fingerlings and should reduce production cost. This experiment compared three treatments with three replicates per treatment. In one treatment, larvae were initially fed rotifers Brachionus plicatilis and then were weaned to brine shrimp nauplii (0.48 X 0.19 mm). In a second treatment, larvae were fed brine shrimp nauplii throughout the experiment. In a third treatment, larvae were fed microcyst brine shrimp nauplii (0.43 X 0.18 mm) for the entire experiment. At 4 d posthatch (dph), sunshine bass larvae were stocked into 100-L tanks at 75 larvae/L. Larvae were fed according to the three treatments to 14 dph. Survival was significantly higher for larvae fed rotifers plus brine shrimp nauplii and for larvae fed microcyst brine shrimp nauplii (93.6% and 37.9%, respectively) than for larvae fed only brine shrimp nauplii (4.3%). Larvae (7.13 mm standard length [SL]) that were fed rotifers plus brine shrimp nauplii and larvae (7.26 mm SL) that were fed microcyst nauplii were significantly longer than those (6.86 mm SL) fed brine shrimp nauplii. This experiment is the first time that sunshine bass have been cultured to 14 dph on brine shrimp nauplii without rotifers at first feeding. [ABSTRACT FROM AUTHOR]

Trophic adaptability is a term used to describe feeding flexibility in fishes. Though a useful conceptual starting point, fishes often face constraints on their ability to switch prey that could limit feeding success even when prey switching is observed. We compared striped bass diet compositions summarized from previously published studies in California’s Sacramento-San Joaquin Delta during two time periods (1963–1964 and 2001–2003), which allowed us to evaluate trophic adaptability in San Francisco Estuary striped bass at multiple time scales, ranging from intra-annual to multidecadal. The Delta is the landward region of the San Francisco Estuary; over time between the study periods, the Delta underwent substantial changes in potential prey availability for striped bass. We found evidence for trophic adaptability in San Francisco Estuary (SFE) striped bass at all temporal scales examined. Despite this ability to adapt to changes in prey availability, the relative abundance and carrying capacity of young striped bass have declined. This decline has previously been associated with substantial declines in their dominant historical prey—mysid shrimp. Our results, coupled with these previous findings, indicate that trophic adaptability may have limited usefulness as a conceptual model to predict foraging success when other food web constraints are not considered. We speculate that this is particularly true in highly invaded ecosystems like the San Francisco Estuary because invading species often introduce substantial and permanent changes into food webs, decreasing the likelihood that a predator will find prey assemblages that fully replace historical prey assemblages. [ABSTRACT FROM AUTHOR]

One method of increasing the value of aquacultured product is to produce fillets that are fortified with minerals that are beneficial to human health – that is enhance the functionality of an already healthy product. A good candidate mineral in this regard is selenium (Se) which is of vital importance to normal metabolism in humans. In order to evaluate the dose response and tissue accumulation of supplemental dietary Se, a study was undertaken with hybrid striped bass (HSB). Animals were fed diets supplemented with either organic (0–3.2 mg kg−1 as SelPlex®) or inorganic (0.2 and 0.4 mg kg−1 as sodium selenite) Se for 6 weeks. Because basal fishmeal-based diets contained 1.22 mg Se kg−1, doses of Se delivered equated to 1.22–4.42 mg kg−1. At trial end, greatest weight gain was observed in fish receiving 0.2 mg Se kg−1, irrespective of form (organic/inorganic). Se accumulation in HSB liver and fillet revealed a classical dose-response once a threshold level of 0.2 mg Se kg−1 was surpassed. Greatest tissue accumulation of Se was observed in fish fed the 3.2 mg Se kg−1 level ( P > 0.0001). A 100 g portion of Se-enhanced HSB fillet would contain between 33 and 109 μg Se, amounting to a dietary intake of between 25 and 80 μg Se; a level that would satisfy present daily intake recommendations. Comparison of tissue Se levels indicated that the muscle provides a more conspicuous gauge of dietary Se dose-response than does liver. Dietary treatments of between 0.4 and 1.6 mg organic Se kg−1 reduced ( P < 0.024) plasma glutathione peroxidase (GSH-Px) activity. No differences were observed in ceruloplasmin, lysozyme or GSH-Px activities between organic and inorganic Se when delivered at the 0.2 mg Se kg−1 level. Ceruloplasmin, lysozyme and GSH-Px levels were elevated ( P ≥ 0.025) in fish fed the diet containing 0.4 mg inorganic Se kg−1. [ABSTRACT FROM AUTHOR]

Striped bass ( Morone saxatilis), white perch ( Morone Americana), and largemouth bass ( Micropterus salmoides) were collected in the Chesapeake Bay mainstem and tributaries and analyzed for total mercury (Hg) and methylmercury (MeHg) content. Striped bass are anadromous, whereas white perch and largemouth bass are resident species, and the largemouth bass are also restricted to the tidal fresh portion of the Bay. Total Hg and MeHg concentrations in striped bass increased with fish size, and large fish (>7.5 kg wet weight) tended to have MeHg concentrations of 300 ng g−1 or greater. On average, the striped bass MeHg concentration was 120 ± 100 ng g−1 and the fraction of the total Hg as MeHg was 65 ± 22%. Reasons for the lower relative MeHg content are discussed. Otolith strontium/calcium ratios were also determined to examine whether migration had a significant impact on MeHg content in striped bass. Resident fish did appear to have a higher MeHg burden than the more migratory fish of similar size. Largemouth bass and white perch tended to have low MeHg content (respectively, 14 ± 7 and 13 ± 11 ng g−1; all fish <1 kg wet weight), and the white perch also had a low %MeHg (28 ± 14%), reflecting their mostly planktivorous lifestyle. A comparison of largemouth bass and striped bass MeHg concentrations for the estuarine fish with those of fish in Maryland reservoirs of similar size showed that the estuarine fish have much lower MeHg burdens. Differences in MeHg concentration in the estuarine waters compared to the reservoir waters likely account for much of this difference, although the importance of other factors is also discussed. [ABSTRACT FROM AUTHOR]

Female striped bass Morone saxatilis with eggs in early stages of development were successfully spawned after being given a priming injection of luteinizing hormone releasing hormone analog followed by a resolving injection of human chorionic gonadotropin (HCG). Over 2 years, 18 of 19 injected fish spawned, producing over 3.5 million viable fry. Egg fertilization rates for all fish that spawned averaged 41%. This procedure, which differs from the traditional spawning method of HCG injection, can increase production by increasing the duration of the production season. In addition, broodfish that once would have been released at capture because they contained early egg developmental stages can now be spawned and used in production. [ABSTRACT FROM AUTHOR]

The article discusses the isolation of glycoconjugates from the skin mucus of Morone saxatilis fish. Mucous gel is a common substance in fish. Epithelial mucus proects the skin, gastrointestinal zones, and gill's outer surface of fish. Fish mucus is also the protector against physical, mechanical, and biological attacks in fishes.

Channel catfish, Ictalurus punctatus (Rafinesque 1818), and sunshine bass, female white bass Morone chrysops (Rafinesque 1820) X male striped bass M. saxatilis (Walbaum 1792), juveniles (10 and 12 g, respectively) were exposed to copper sulfate (CuSO4)in a series of static toxicity tests to observe species sensitivity. The water used in this study was 18.9°C filtered well water with initial pH of 8.71, and total alkalinity and total hardness of 224 and 110 mg/L, respectively. Estimates of mean 96-hour median lethal concentration (LC50) values were 1.75 mg/L Cu (6.89 mg/L CuSO4) for channel catfish and 0.85 mg/ L Cu (3.35 mg/L CuSO4) ) for sunshine bass; LC50 values were calculated using nominal CuSO4) concentrations. These values differed significantly. This study demonstrates that sunshine bass juveniles are less tolerant of CuSO4 than channel catfish fingerlings when exposed concurrently in waters from the same source. [ABSTRACT FROM PUBLISHER]

Lymphocystis disease virus (LCDV) is the causative agent of lymphocystis disease. In this study, nucleotide sequences of the major capsid protein (MCP) gene were analyzed among LCDV isolates from Japanese flounder and rockfish. A phylogenetic tree revealed three clusters for lymphocystiviruses. The first cluster included Japanese flounder isolates; the second cluster consisted of rockfish isolates; and the remaining one consisted of LCDV-1. Nucleotide sequence identities were ≥99.6% among Japanese flounder isolates and 100% among rockfish isolates, while between each cluster they were ≤85.2%. Experimental infections with Japanese flounder and rockfish isolates revealed that Japanese flounder and rockfish were infected by the respective homologous isolate but not by the heterologous isolate. These findings suggest that at least three genotypes exist in the genus Lymphocystivirus. [ABSTRACT FROM AUTHOR]

Genome segment 10 (S10) of Threadfin aquareovirus (TFV) was cloned, sequenced, analyzed and found to be 987 bp long encoding a protein of 298 aa with a predicted molecular mass of 32.0 kDa. The TFV S10 gene possesses terminal motifs, (5′ GTTTTA and ATTCATC 3′) which are also conserved in the S6 and S11 TFV gene segments. Sequence comparison revealed that the TFV S10 gene was similar to the Striped bass reovirus (SBR) VP7 outer capsid protein (OCP). A conserved putative zinc-finger motif, CCHC, present in the mammalian reovirus (MRV) δ3 protein, was identified in TFV and other aquareovirus VP7 protein. Phylogenetic analysis of the TFV VP7 protein indicated that TFV is closely related to SBR and Chum salmon reovirus (CSV) and possibly belong to the same species Aquareovirus A as SBR and CSV. The TFV VP7 protein was expressed in E. coli, purified and injected into mice. Serum specific antibodies were generated, however, the serum showed weak neutralizing activity. In contrast, co-incubation of this serum with another serum obtained from mice immunized with another OCP encoded by the TFV S6 gene segment resulted in a highly elevated antibody neutralization titer. [ABSTRACT FROM AUTHOR]

Resources fluctuate in space and time, and animals routinely experience temporally varying opportunities for resource intake, and variation in intake itself. We investigate consequences of such variation in intake on growth and growth efficiency (growth per unit intake) in juvenile hybrid striped bass. We observed, after statistically accounting for the effects of total consumption and initial body size, that individuals receiving a low ration followed by a higher ration (the fluctuating ration) grew faster than individuals receiving a temporally constant ration (the normal ration). To interpret this increase in growth efficiency, we consider a set of alternative models representing different physiological hypotheses of the growth process. Using a simple growth model, an analytical result shows that the fluctuating ration as typically applied in experiments (a low ration followed by a high ration), independent of any change in physiology, increases growth efficiency relative to individuals on the normal ration. Growth efficiency increases because cumulative maintenance costs are lower for individuals that stay small initially and then grow rapidly in comparison to individuals that grow steadily. Further, a statistical analysis of alternative models inferred that fish receiving a variable ration show higher assimilation and/or conversion efficiencies of food and lower mass-specific maintenance costs. Our analysis suggests that the lower cumulative maintenance costs incurred over a time interval with low consumption followed by high consumption act in association with higher assimilation-conversion efficiencies, and lower overall mass-specific maintenance costs to increase growth efficiency in hybrid striped bass. [ABSTRACT FROM AUTHOR]

The coastal rivers of South Carolina possess reproducing populations of striped bass Morone saxatilis. Historically, all of these populations have been augmented with hatchery stocks from the Santee-Cooper drainage. Concern has been expressed that locally adapted, reproductively isolated populations may exist in these coastal rivers. Thus, the objective of this effort was to assess the distinctiveness of reproducing striped bass populations in these coastal rivers. Tagging studies indicated that the interriver movement of striped bass was minimal. A population estimate of 406 striped bass longer than 30 cm was obtained for the Combahee River, suggesting a relatively small breeding population. Genetic assays at three nuclear restriction fragment length polymorphism sites showed highly significant allele frequency differences among seven coastal rivers, suggesting reproductive isolation. Partially or fully isolated populations can develop beneficial adaptations to local environmental conditions. Thus, we recommend the use of endemic stock to augment striped bass populations in the coastal rivers of South Carolina. [ABSTRACT FROM AUTHOR]

Estimates of total mortality, fishing mortality, and natural mortality in the fishery for the adult striped bass Morone saxatilis in J. Strom Thurmond Reservoir, South Carolina-Georgia, were determined from long-term radiotelemetry data and high-reward radio transmitter return data using catch curve analyses. Annual total mortality rates were 0.81 ± 0.06 (mean ± SE) for year 1 (July 1999-June 2000) and 0.42 ± 0.04 for year 2 (July 2000-June 2001). We observed that the force of fishing was much greater than the force of natural death on total mortality in this fishery. Total exploitation of all implanted striped bass over the 2-year study period was 48%. Fishing mortality rates were 0.67 ± 0.04 for year 1 and 0.33 ± 0.02 for year 2, and natural mortality rates were 0.14 ± 0.02 for year 1 and 0.09 ± 0.02 for year 2. We also identified seasonal increases in total and fishing mortality rates from July to September. Fishing mortality was highest temporally and spatially during late spring and late summer near the tailrace below Richard B. Russell Dam owing to high angling pressure for striped bass while the fish were congregated in summer refugia. Natural mortality occurred only during mid to late summer in the middle section of the reservoir. These deaths were attributed to striped bass's becoming trapped in unsuitable summer habitat in the lower and middle sections of the reservoir. Mean postsurgery growth from 15 harvested study fish at large for a mean of 1.16 ± 0.81 years was estimated to be 1.71 ± 0.73 kg/year. Internal implantation of telemetry devices appeared to have no negative effect on long-term growth, health, and survival of adult striped bass and did not bias mortality and survival estimates. [ABSTRACT FROM AUTHOR]

As nearshore fish populations decline, many commercial fishermen have shifted fishing effort to deeper continental slope habitats to target fishes for which biological information is limited. One such fishery that developed in the northeastern Pacific Ocean in the early 1980s was for the blackgill rockfish (Sebastes melanostomus), a deep-dwelling (300-800 m) species that congregates over rocky pinnacles, mainly from southern California to southern Oregon. Growth zone-derived age estimates from otolith thin sections were compared to ages obtained from the radioactive disequilibria of 210Pb, in relation to its parent, 226Ra, in otolith cores of blackgill rockfish. Age estimates were validated up to 41 years, and a strong pattern of agreement supported a longevity exceeding 90 years. Age and length data fitted to the yon Bertalanffy growth function indicated that blackgill rockfish are slow-growing (k=0.040 females, 0.068 males) and that females grow slower than males, but reach a greater length. Age at 50% maturity, derived from previously published length-at-maturity estimates, was 17 years for males and 21 years for females. The results of this study agree with general life history traits already recognized for many Sebastes species, such as long life, slow growth, and late age at maturation. These traits may undermine the sustainability of blackgill rockfish populations when heavy fishing pressure, such as that which occurred in the 1980s, is applied. [ABSTRACT FROM AUTHOR]

A developmental series of larval and pelagic juvenile pygmy rockfish (Sebastes wilsoni) from central California is illustrated and described. Sebastes wilsoni is a noncommercially, but ecologically, important rockfish, and the ability to differentiate its young stages will aid researchers in population abundance studies. Pigment patterns, meristic characters, morphometric measurements, and head spination were recorded from specimens that ranged from 8.1 to 34.4 mm in standard length. Larvae were identified initially by meristic characters and the absence of ventral and lateral midline pigment. Pelagic juveniles developed a prominent pigment pattern of three body bars that did not extend to the ventral surface. Species identification was confirmed subsequently by using mitochondrial sequence data of four representative specimens of various sizes. As determined from the examination of otoliths, the growth rate of larval and pelagic juvenile pygmy rockfish was 0.28 mm/day, which is relatively slow in comparison to the growth rate of other species of Sebastes. These data will aid researchers in determining species abundance. [ABSTRACT FROM AUTHOR]

From 1995 to 1998, we collected female black rockfish (Sebastes melanops) off Oregon in order to describe their basic reproductive life history and determine age-specific fecundity and temporal patterns in parturition. Female black rockfish had a 50% probability of being mature at 394 mm fork length and 7.5 years-of-age. The proportion of mature fish age 10 or older significantly decreased each year of this study, from 0.511 in 1996 to 0.145 in 1998. Parturition occurred between mid-January and mid-March, and peaked in February. We observed a trend of older females extruding larvae earlier in the spawning season and of younger fish primarily responsible for larval production during the later part of the season. There were differences in absolute fecundity at age between female black rockfish with prefertilization oocytes and female black rockfish with fertilized eggs; fertilized-egg fecundity estimates were considered superior. The likelihood of yolked oocytes reaching the developing embryo stage increased with maternal age. Absolute fecundity estimates (based on fertilized eggs) ranged from 299,302 embryos for a 6-year-old female to 948,152 embryos for a 16-year-old female. Relative fecundity (based on fertilized eggs) increased with age from 374 eggs/g for fish age 6 to 549 eggs/g for fish age 16. [ABSTRACT FROM AUTHOR]

A floating vertical raceway is a system designed to provide a constant, unidirectional flow of water to fish confined in a flexible raceway that is suspended vertically in the water column. This study evaluated the potential of floating vertical raceways for the culture of phase-II sunshine bass (female white bass Morone chrysops X male striped bass M. saxatilis) reared at two densities (125 and 188 fish/m³). Fish with a mean starting weight of 0.7 g were fed a diet containing 40% crude protein to satiation for 121 d. Fish in the low-density treatment reached a significantly higher final mean weight (160.0 g) than those in the high-density treatment (136.9 g). Survival was also significantly higher in the low-density treatment (81.1%) than in the high-density treatment (73.8%). No significant differences in water quality were detected for dissolved oxygen, total ammonia, un-ionized ammonia, or temperature between high-density and low-density treatments. Unlike the surrounding reservoir, water temperature inside the raceways remained destratified throughout the growing period. Based on the performance offish, the high water quality maintained inside the enclosures, and ease of use, the floating vertical raceway system offers considerable promise as an alternative rearing system for deepwater impoundments. [ABSTRACT FROM AUTHOR]

Alaskan shortraker rockfish population structure was analyzed by examining allelic variation at eight microsatellite loci. Samples were collected along the continental shelf and upper slope from the south end of Baranof Island to the western Aleutian Islands, and collections were pooled into eight geographically distinct groups. An exact test of homogeneity indicated population structure (p < 0.0006) among groups. The proportion of the total variation that was attributable to divergence among populations (θ = 0.0014) was not statistically significant, and no evidence of a geographic cline of structure was detected. Finer scale analyses that compared adjacent collections indicated that the collection from the southern end of the range differed from all remaining collections at three loci. Structure related to geographic location was detected by partitioning the variation among populations. The size distributions of shortraker rockfish varied among collections from east to west. The size differences may reflect divergent oceanographic and biological factors acting on populations that have restricted migration and movement. Alternatively, if there is substantial movement accompanied by lengthy reverse migration to natal grounds, the size differences may be related to ages of cohorts that are differentially distributed along the Pacific Rim. Further biological information including size, age composition, and age of maturity data, as well as information on other life history characteristics will be required to explain shortraker rockfish population structure. [ABSTRACT FROM AUTHOR]

Total mercury (Hg) concentrations were determined in the skeletal muscle of 339 fish collected during the fall of 1998 and spring of 1999 from Lake Mead, USA, the nation's largest human-made reservoir. Five species of fish representing a range of trophic levels and the lake's principal game fishes were studied. Hg generally increased with trophic level and fish size. Median Hg concentrations (ng/g wet mass) were 277 in striped bass, 168 in channel catfish, 160 in largemouth bass, 75 in bluegill, and 8 in blue tilapia. Overall, fish from Las Vegas Bay and Boulder Basin had the lowest Hg concentrations, possibly a result of biodilution in this biologically productive area. In general, fish-mercury advisories might include a warning about consuming fillet from emaciated fish, based on the finding that Hg concentrations in 59 striped bass (captured during a scarce-food season) correlated inversely (r = -0.89, p < 0.001) with a fish nutritional-status factor. This is consistent with starvation-concentration, whereby Hg in fish muscle is lost at a slower rate than the muscle mass. The median concentration found for 139 striped bass corresponds to a recommended risk-based consumption limit of three 8-oz. (227-g) meals per month for a 70-kg adult. Finally, this paper serves as a useful archive for future research and long-term studies of Hg in Lake Mead fish. Correspondence to: J. V. Cizdziel; email: cizdziej@unlv.edu --> [ABSTRACT FROM AUTHOR]

Since the early 1960s, the Chesapeake Bay striped bass population has undergone a large cycle of abundance, recovering to record levels during the 1990s. Changes in age structure over this period were examined to determine contributions of old females (>13 yr) to the recovery. In 1992, in a sample of large female striped bass, 10 yr of absent year classes (1972–1981) were observed corresponding to a period of recruitment overfishing. Fishery-independent stock assessments conducted 1985–1990 by Maryland Department of Natural Resources indicated that old females, while present in small numbers, made relatively small contributions to annual egg production during the period of recovery. Abundances, weighted for age-specific fecundity, indicated that older fish were probably the most important contributors to recruitment throughout the 1970s and early 1980s. Egg production after 1986 was principally contributed by young females, those produced after 1981. Demographic analysis also supports the view that a Maryland fishing moratorium designed to protect year classes after 1981 stimulated recovery. Longevities of >30 yr documented in this study suggest that striped bass populations can persist during long periods of poor recruitment due to a long reproductive lifespan. Longevity may have also conferred resiliency against an extended period of recruitment overfishing in the Chesapeake Bay [ABSTRACT FROM PUBLISHER]

Net avoidance rate increases as a function of larval striped bass size. This causes under-estimation of abundance and overestimation of mortality rate. We modeled net avoidance by assuming that fish avoid the net by swimming a radial distance at a right angle to the net axis. This distance, the evasion radius, was estimated by comparing the calculated densities of striped bass larvae from a series of paired tows involving a large and a small net. Iteration and solution models were used to estimate the evasion radius for each millimeter size group of fish in order to estimate the actual density in the environment. Avoidance of the nets increased with fish length. The ratio of actual density in the environment to the measured density in the small net was used to adjust abundances measured in our ichthyoplankton surveys. After adjusting for net avoidance, mortality rates of striped bass larvae from the Sacramento-San Joaquin Estuary were reduced by 10% compared to the unadjusted rates. [ABSTRACT FROM PUBLISHER]

An experiment using differently marked larval striped bass, Morone saxatilis (Walbaum), and its hybrid (M. saxatilis x M. chrysops (Rafinesque)) was performed in two grow-out ponds. Larval striped bass were immersed in oxytetracycline solution to mark their otoliths; hybrids received no treatment. Larvae from both groups were mixed and stocked at 8 days post hatch into the ponds. Striped bass and hybrid larvae grew to a significantly larger size at 3 5 days in one pond. In both ponds, hybrid lengths at 3 5 days after hatch were significantly greater than striped bass lengths. However, the magnitude of the size difference between hybrids and striped bass was twofold greater (10%) in one pond than in the other (5%). The proportion of striped bass juveniles at 3 5 days differed from the initial stocking proportion (0.5 3) only in one pond, where hybrids showed 12% greater survival than striped bass. Results suggested that the relative survival of hybrids was influenced by growth conditions in the ponds. Based on the ease of protocol and analysis of the marking experiment, we recommend its use to (1) investigate relative performance between genetic groups of young fish in common environments; and (2) predict the effects of introductions of genetically altered fishes. [ABSTRACT FROM AUTHOR]

A consumer survey of the northeastern United States was conducted to gather market information regarding the decision to purchase fresh hybrid striped bass, trout and salmon. Logit techniques were used to model the experience, perceptions, preferences, and choices of consumers for seafood products based on a modified evoked set framework. Factors such as knowledge that the products are farm-raised, having previous experience with purchasing seafood along with the perception that seafood is healthful with good taste were found to significantly influence the consumer's decision to purchase these finfish products. The results of this study and the techniques used allow market researchers to objectively quantify the impact of experience, perceptions, and preferences of products on the ultimate decision of the consumer to purchase fresh hybrid striped bass, trout and salmon products. [ABSTRACT FROM AUTHOR]