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Columnaris disease is a prevalent disease in freshwater environments caused by the ubiquitous aquatic pathogen Flavobacterium species. Adhesion to the external mucosal surfaces of fishes is the initial stage of infection, and the gills specifically have been identified as both a primary target and release site for this pathogen. Demonstrated here and in previous research, the hybrid striped bass (Morone chrysops x M. saxatilis), a prominent United States aquaculture product, is more susceptible to infection with F. covae than the maternal white bass (M. chrysops) parental species. To further elucidate the mechanisms underlying differences in resistance between these fish we examined gill gene expression profiles using RNA sequencing at different timepoints after F. covae infection. Patterns of differential gene expression and association with key enrichment terms indicate the effective immune response observed in white bass includes the up-regulation of multiple cytokines (IL-1β, IL-17C, TNF-α, G-CSF, IL-8, CCL16, CXCL9), hepcidins (HAMP and HAMP2), ribosomal subunit components (e.g., RPL13), and, interestingly, the down-regulation of leptin (LEPA) during initial (1 – 4 h) stages of infection. Conversely, up-regulation of the same genes was not detected in hybrid striped bass until 24 h after infection, indicating a delay in immune response mechanisms that is ultimately ineffective in protecting the host, as this was concurrent with the onset of mortality in these fish. Collectively, the presented results include several putative pathways and candidate genes for further investigation toward characterizing immune defense mechanisms underlying the resistance (white bass) and susceptibility (hybrid striped bass) for selective breeding efforts and/or biotechnological intervention.

The Oligocene fish fauna of the Romanian Eastern Carpathians is of great interest for the study of the extinct European perciform fish assemblages because their diversity and fine preservation. Amongst these deposits, some exceptional fossil localities such as the recently discovered outcrop from the Coza Valley and the well-known historical locations (sites) from Piatra-Neamț and Suslănești, often offer new insights about the Paratethys fish faunas. Herein, we report for the first time the discovery of a fish skeleton originating from the Bituminous Marls Formation exposed in the Coza Valley (Vrancea Half-Window, Marginal Folds Nappe) that we refer to †Dicentrarchus oligocenicus, sp. nov.. Also, we review an existing specimen previously misidentified as †Morone major (Agassiz) found in the Lower Dysodilic Shales Formation of Piatra-Neamț (Bistrița-Râșca Half-Window, Marginal Folds Nappe) that will be referred henceforth to the Percoidei incertae sedis. While the new species described herein has been classified as belonging to the family Moronidae because of obvious meristic, morphometric and osteological features, the other species has been removed from this family due to the lack of diagnostic characters. Remarks on how †Dicentrarchus oligocenicus, sp. nov. differs from all extant and extinct representatives of moronid fishes are given. [ABSTRACT FROM AUTHOR]

Four-day-old hybrid striped bass (HSB; Morone chrysops x M. saxatilis) larvae were stocked into a recirculating aquaculture system maintained at 18°C to mimic cool-water culture temperatures experienced by year-round producers to determine the earliest time HSB larvae could be weaned from Artemia to a commercial diet. After an initial 8-day rotifer feeding period where all treatments were fed three times daily with rotifers (60 rotifers/mL/tank/d), designated replicated treatments were progressively weaned from Artemia (12 Artemia/mL/tank/d) onto starter (3.0 g/tank/d) for 8 to 28 days in 4-day increments (DFA) for a total of six treatments. Survival of larvae by the end of the experiment ranged from 12.9% to 64.1% and averaged 31.2 ± 12.6% with no significant difference among treatments. At the end of the study, length of larvae ranged from 9.05 to 19.06 mm (mean 14.19 ± 1.92 mm), and body depth of larvae ranged from 1.52 to 4.35 mm (mean 2.71 ± 0.56 mm). Total length and body depth of larvae varied significantly based on DFA (P < 0.0001), with the largest larvae being the ones fed Artemia for the longest. Refinements of these feeding methods will help farmers more easily transition to tank-based production schemes, lead to year-round availability of fingerlings, and aid in expansion of the HSB aquaculture industry. [ABSTRACT FROM AUTHOR]

Striped bass, Morone saxatilis, is an anadromous fish native to the North American Atlantic Coast and is well recognized as one of the most important and highly regarded recreational fisheries in the United States. Decades of research have been conducted on striped bass and its hybrid (striped bass × white bass Morone chrysops) and culture methods have been established, particularly for the hybrid striped bass, the fourth largest finfish aquaculture industry in the United States (US $50 million). Domesticated striped bass have been developed since the 1990s and broodstock are available from the government for commercial fry production using novel hormone‐free methods along with traditional hormone‐induced tank and strip spawning. No commercial‐scale intensive larval rearing technologies have been developed at present and current fingerling production is conducted in fertilized freshwater ponds. Larval diets have not been successfully used as first feeds; however, they have been used for weaning from live feeds prior to metamorphosis. Striped bass can be grown out in marine (32 ppt) or freshwater (<5 ppt); however, they require high hardness (200+ ppm) and some salinity (8–10 ppt) to offset handling stress. Juveniles must be 1–10 g/fish prior to stocking into marine water. Commercially available fingerling, growout, and broodstock feeds are available from several vendors. Striped bass may reach 1.36 kg/fish in recirculating aquaculture by 18 months and as much as 2.27 kg/fish by 24 months. Farm gate value of striped bass has not been determined, although seasonally available wild‐harvested striped bass are valued at about US $6.50 to US $10.14 per kg and cultured hybrid striped bass are valued at about US $8.45 to US $9.25 per kg whole; the farm gate value for cultured striped bass may be as much as US $10.00 or more per kg depending on demand and market. The ideal market size is between 1.36 and 2.72 kg/fish, which is considerably larger than the traditional 0.68 to 0.90 kg/fish for the hybrid striped bass market. [ABSTRACT FROM AUTHOR]

Striped Bass in Canadian waters occur at the most northern extent of the species range. At these latitudes, overwintering represents a significant portion of annual activities (Nov- May). During the winter period, Striped Bass generally occupy inland waterways, aggregate densely, feed little, and conduct minimal movements rendering them vulnerable to fisheries exploitation, pollution and habitat alterations. Despite the importance of winter survival to population viability, the winter period remains an understudied aspect of Striped Bass ecology throughout the species range. Here we review what is known as well as the knowledge gaps regarding the overwintering ecology for Striped Bass in Canadian waters. We discuss: all reported Canadian Striped Bass overwintering locations and their characteristics; environmental conditions that may be required for Striped Bass winter survival; environmental cues that may cause Striped Bass to enter overwintering habitats in late fall and depart in early spring; possible threats to overwintering habitat; and we propose numerous research questions necessary for improving Striped Bass conservation and management both within Canada and across the species range. [ABSTRACT FROM AUTHOR]

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Abstract: The biofloc technology production system is a production‐intensifying management strategy used primarily for culturing tilapia and penaeid shrimp, both of which can consume the biofloc. Other fish can be grown in biofloc systems because the biofloc serves to maintain water quality, metabolizing the ammonia excreted by intensively fed fish. A dose–response study was conducted in an outdoor biofloc system to begin quantifying the stocking rate production function for sunshine bass, Morone chrysops × Morone saxatilis, advanced fingerlings. Sunshine bass (2.9 ± 0.2 g/fish) were stocked into tanks at 50–250 fish/m2 in 50 fish/m2 increments. After 94 d, gross yields ranged from 1.4 to 3.1 kg/m3 and were independent of stocking rate. Harvested fish were separated into two size groups: smaller than 115 mm total length (TL, target fish) and larger than 115 mm TL (jumper fish). Target fish increased linearly from 62 to 93% and jumpers decreased linearly from 38 to 7% of the population, respectively, as stocking rate increased. The outdoor biofloc system offers potential for intensifying the production of advanced sunshine bass fingerlings, but feed consumption appeared to be impeded by high total suspended solids concentrations. Further research is needed to optimize stocking rates and solids management. [ABSTRACT FROM AUTHOR]

Processed microalgae concentrates recently have been considered potentially viable alternatives to partially replace fishmeal (FM) and fish oil in aquafeeds. Two feeding trials were conducted to evaluate incremental replacement of FM and soy protein concentrate (SPC) with different types of microalgae in the diet of hybrid striped bass. Microalgae evaluated in feeding trial 1 included dried products from monocultures of Phaeodactylum tricornutum and Nanochloropsis salina , as well as mixed cultures of those two species. Several preparations of Chlorella sp. lipid extracted by various means as well as bluegreen algae biomass (BGAB) also were evaluated. In feeding trial 2, the microalgae products supporting most efficient fish performance in feeding trial 1 were reassessed along with mixed cultures of Phaeodactylum tricornutum and Nanochloropsis salina as well as BGAB. Two additional mixed cultures of Nanochloropsis salina with Amphora sp. or Cylindrotheca sp. also were evaluated. Algae products were substituted to replace either 10, 15 or 20% of protein provided equally from menhaden FM and SPC in the Reference diet. All diets were isonitrogenous (40% crude protein) and isocaloric (3.3 kcal digestible energy g −1 ), and each were fed to triplicate groups of juvenile fish with average initial weights (+SEM) of 15.1 ± 0.6 g and 21.4 ± 1.3 g/fish in feeding trials 1 and 2, respectively for 7 weeks. Weight gain and feed efficiency ratio (FER) of hybrid striped bass were high (>330% of initial weight and 0.79) but significantly (P < 0.05) affected by diet in trial 1 with no mortality. Fish fed the Reference diet and the one containing BGAB had the greatest but similar weight gain. Substitution of the other algae meals significantly reduced weight gain by 8.2 to 14.7% compared to the Reference diet. Most diets containing algae meal yielded similar FER as the Reference diet except for those containing solvent-extracted Chlorella sp . (both 10% and 20% substitution), Phaeodactylum tricornutum (10%), and Phaeodactylum tricornutum  ×  Nanochloropsis salina (10% and 20%), in which FER was significantly reduced by 5.8 to 8.1%. Whole-body proximate composition and protein retention efficiency values revealed no significant differences among diets. In feeding trial 2, the various diets with algae products substituted at 10 or 15% of dietary protein did not significantly affect growth performance or whole-body composition of hybrid striped bass compared to the Reference diet. In conclusion, replacement of up to 15% crude protein in the Reference diet with BGAB, the Phaeodactylum tricornutum and Nanochloropsis salina mixture, as well as mixtures of Nanochloropsis salina with Amphora sp. or Cylindrothecatheca sp. was possible without affecting growth performance or body composition of hybrid striped bass. [ABSTRACT FROM AUTHOR]

Performance traits and body composition of juvenile hybrid striped bass ( Morone chrysops × M. saxatilis) in response to hypoxia were evaluated in replicate tanks maintained at constant dissolved oxygen concentrations that averaged 23.0 ± 2.3%, 39.7 ± 3.0% and 105.5 ± 9.5% dissolved oxygen saturation. Fish were fed a commercially formulated feed daily to apparent satiation. Total feed intake and fish growth and yield increased linearly in response to increased dissolved oxygen concentration. Nutrient utilization was reduced significantly only at the greatest level of hypoxia. With the exception of whole body protein content, whole body compositional indices and nutrient retention efficiencies were linearly related to dissolved oxygen concentration. Results demonstrate that as hypoxia becomes more severe, juvenile hybrid striped bass feed intake is reduced, which affects growth and nutrient retention. [ABSTRACT FROM AUTHOR]

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]

The diets and energy content of sympatric populations of invasive age-0 white perch Morone americana and native age-0 white bass Morone chrysops were evaluated in Saginaw Bay, Lake Huron following >20 years of coexistence. Fish were collected during July-November in 2009 and 2010 to assess seasonal and interannual patterns of diet composition, diet similarity, feeding strategy and energy density for the two species. The diet composition by weight of age-0 white bass was dominated by various zooplankton taxa, fish, or emergent insects, depending on the month and year. Although fish occasionally comprised a large fraction of the diet biomass, they were eaten by <24% of white bass each month. The diet composition of age-0 white perch shifted from one dominated by chironomids and other benthic macroinvertebrates in 2009 to one largely consisting of Daphnia spp. in 2010. There was more overlap in standardized diet assemblages in 2010 than in 2009 due to the increased importance of Daphnia spp. in white perch diets in 2010. Contrary to expectations, complete separation of diets was not a requirement that enabled the long-term coexistence of invasive white perch and native white bass in Saginaw Bay. Both age-0 white bass and white perch had a mixed feeding strategy with varying degrees of specialization and generalization on different prey. The inter-annual variation in prey, i.e., higher densities of zooplankton in 2009 and chironomids in 2010, is directly opposite of the pattern observed in white perch diets, i.e., diets dominated by chironomids in 2009 and zooplankton in 2010. Energy density increased from July into autumn/fall for both species suggesting that food limitation was not severe. [ABSTRACT FROM AUTHOR]

In an attempt to determine the extent and periodicity of several large juvenile and adult fishes (smooth dogfish Mustelus canis, black drum Pogonias cromis, hickory shad Alosa mediocris) in a temperate estuary, we tracked acoustically tagged individuals with passive and active telemetry techniques during the summer, fall and winter. This approach confirmed summer residency for all of these species and species-specific and individual patterns of egress ranging from summer through fall. Other species (striped bass Morone saxatilis, summer flounder Paralichthys dentatus, bluefish Pomatomus saltatrix) that were previously tracked in the same estuary with the same techniques were reanalyzed for the same characteristics. There were species-specific and individual differences in residency and egress of these species as well, but all species left the estuary by the end of December. Together, these observations confirm the importance of temperate estuaries in the summer and fall, but not during the winter for the juveniles and adults of these migratory species. However, the duration of residency and timing of egress may vary if warming of estuarine waters continues. [ABSTRACT FROM AUTHOR]

Hybrid striped bass fingerlings were grown in replicated indoor tanks for 42 days to evaluate progeny performance of two growth-related traits. Analysis of variance demonstrated significant differences in length and weight of fingerlings among paternal and maternal half-sib families and high estimates of heritability for dams and sires. Based on significant sire and dam effects and high heritabilities, a substantial portion of the selection differential could be expected to be gained in offspring from selected pure-line parents. As demonstrated by these results, a breeding program could be used to select parental lines that produce faster growing hybrid offspring. [ABSTRACT FROM AUTHOR]

Gravid females of the little-known nematode species Philometra rubra (Leidy, 1856) (Philometridae) are described from specimens from the abdominal cavity of the striped bass, Morone saxatilis (Walbaum), in South Carolina and Canada. The specimens were studied with the use of light and scanning electron microscopy. This species is mainly characterized by the distribution and different sizes of cephalic papillae from the external circle, which is a unique feature compared to other philometrids. Other characteristic features are the shape of the posterior end of body, size and location of caudal projections, and the presence of a well-developed anterior esophageal inflation. The morphology of the male of P. rubra and the life cycle of this nematode are still unknown. [ABSTRACT FROM AUTHOR]

The trophic dynamics of invasive species can yield insights into the mechanisms of invasion success and aid in the prediction of potential impacts on established species. Additionally, the predicted effects of an invader may differ depending on how it integrates into the resident food web and whether its resource use changes throughout the invasion process. We investigated the trophic dynamics of populations of invasive White PerchMorone americanain three large North Carolina reservoirs and evaluated the potential for impacts on members of the resident fish community. Specifically, we used stable isotope and diet analyses to evaluate their trophic niche relative to three representative species in each reservoir chosen for their widespread range, potential overlaps with White Perch, recreational value, and representation of ecological guilds based on habitat and prey sources. The species were a native littoral generalist invertivore (BluegillLepomis macrochirus), native littoral piscivore (Largemouth BassMicropterus salmoides), and stocked pelagic piscivore (Striped BassMorone saxatilisor WalleyeSander vitreus, depending on their availability). Small (<70 mm TL), medium (120–170 mm TL), and large (>200 mm TL) White Perch occupied different trophic positions, and these positions were generally consistent among reservoirs relative to the representative species. Small and medium White Perch had the largest niche areas and high diet overlap with Bluegill in two of three lakes, whereas large White Perch had moderate diet overlap with Striped Bass, Largemouth Bass, and Walleye. As a species, White Perch occupy a wide trophic niche, which may aid in successfully establishing invasive populations. However, White Perch use resources shared by other members of the fish community, which could lead to negative impacts on these species. Received May 29, 2012; accepted December 23, 2012 [ABSTRACT FROM PUBLISHER]

We tagged fingerling white bass,Morone chrysops,with passive integrated transponders (PIT) at two body locations (peritoneal cavity and dorsal musculature) and six weight classes to evaluate survival, tag retention, and weight gain during a 28-day experimental period. The probability of survival (as calculated by logistic regression) was >95% for fingerlings>19 g for both PC and DM. Retention of PIT tags varied between PC and DM tagged white bass in 6 g and 14 g fingerlings. The probability of tag retention was 100% in all sizes of fingerlings tagged PC, and >95% for fish>19 g tagged DM. [ABSTRACT FROM AUTHOR]

The assessment of the nutritional status of fish is a central requirement of fisheries management. However, there has been little consensus on the appropriate indicator to use, and even less effort toward defining biological thresholds and reference points. With current efforts to manage fisheries in an ecosystem context, environmental effects and trophic relationships need to be considered and appropriate indicators developed. To address this concern, we compiled five different studies in which multiple indicators of nutritional status were applied to Striped Bass Morone saxatilis of different age-classes, geographical origins, and environments (cultured and wild). Proximate composition analysis was used to compare measured lipid concentrations in the anterior dorsal muscle against selected indicators, including Fulton's condition factor, relative weight, percent moisture, and an index of visceral body fat. The results suggest that weight-at-length indices are less sensitive than proximate analysis and poorly related to lipid concentration. However, models developed for both moisture and the body fat index adequately represent tissue lipids and offer clear thresholds of lipid depletion. We propose the use of the proportion of Striped Bass with anterior dorsal muscle composed of more than 80% moisture, or classified as having no observable visceral body fat, as a working protocol for thresholds of poor condition in ecosystem approaches to Chesapeake Bay Striped Bass management. Further, based on historical data we propose an interim target condition of 75% of individuals containing less than 80% moisture as a management goal. [ABSTRACT FROM AUTHOR]

Abstract: The present study assesses the effects of chronic administration of peptides to fish, termed kisspeptins, which are the products of the KISS1 and KISS2 genes, and have been shown to control the development of puberty in animals. Using ecologically and commercially important species (white bass, Morone chrysops, striped bass, Morone saxatilis, and their hybrid) as comparative models, we determined that repeated bi-weekly injections (over 7weeks) differentially accelerate puberty, as evidenced by increases in the prevalence of spermatozoa in the testes of juvenile fish. Moreover, in sexually mature fish, kisspeptin treatment led to increased gonad weight, gonadosomatic index, and spermatocrit in some white and striped bass. Additionally, mature white bass treated with kisspeptins showed an advancement in oocyte development as determined by histological examination. These gonadal changes occurred in the absence of any photothermal manipulation or hormone injections. To date, this is the first description of kisspeptin-mediated pubertal initiation in fish, and the first evidence that kisspeptins could modulate gonad maturation. Although it remains to be determined how kisspeptins may best be utilized in practice, our findings are a basis for future studies to characterize the molecular underpinnings of the KISS system in various fish species. [Copyright &y& Elsevier]

Variation in body weight and total length among 15 families of Phase I white bass, Morone chrysops, was evaluated in a communal pond. Trait heritabilities (h2) were estimated and family pedigrees were determined a posteriori using microsatellite molecular markers. Fry averaged 36.7 ± 2.6 mm and 0.53 ± 0.10 g across all families after 32 days of communal rearing. The number of offspring identified in our sample per family ranged between three and 28. There were significant differences between families in both body weight and length (P < 0.05). The families clustered into four overlapping groups, but family rankings differed by trait. Both traits showed low heritability (h 2 = 0.07, length; h 2 = 0.06, weight). Subsequent studies in white bass should include assessment of larger fish to obtain genetic estimates at different stages in the production cycle. This study represents the first effort to assess variation among white bass families for any growth-related trait using a communal rearing approach. [ABSTRACT FROM PUBLISHER]

The article discusses a study on striped bass Morone saxtilis to characterize their immune responses over the short term after challenge with Mycobacterium marinum. The study found that the expression of immunity-related genes quickly increased after infection with Morone marinum and a number of monocytes and neutrophilis also initially increased at 1 day post-infection. The study concluded that the discrete window in which inflammatory mechanisms were stimulated in striped bass may be related to the intracellular nature of Morone marinum.

Striped bass, Morone saxatilis, were captured and released with temperature-measuring data storage tags in Salem Sound, Massachusetts, to collect data on their thermal preferences in coastal and marine waters and to identify environmental factors that may influence temperatures experienced during their summer residence. Striped bass recaptured during summer of 2006 (21 of 151 releases) experienced a wide range of temperatures (6.5–28.0°C) while at-large for 1–53 days. Overall mean temperature and standard deviation selected by striped bass recaptured in Salem Sound during the longest commonly-shared duration of time (3–12 July) were 17.8 and 3.57°C, respectively. Comparison of temperature data between fish and 13 vertical arrays in Salem Sound revealed that striped bass experienced higher and more variable temperatures, and that daily changes in temperature actually experienced were unrelated to daily changes in surrounding ambient temperature. Regular cyclical changes in temperature of all striped bass and vertical arrays were identified as influences of the local tide, which contributed about a 2°C change in temperature, on average, over the complete cycle. Most striped bass appeared to limit their activities to depths shallower than the lower limit of the thermocline, above which temperatures generally exceed 9.0°C in Salem Sound. Therefore, it is likely that the vertical distribution of striped bass is restricted by the low temperatures below this depth. An implication of this finding is that the spatial distribution of striped bass may be defined coarsely by knowledge of the distribution of temperature in coastal areas. [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]