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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.

Information on the contribution of offshore oil and gas (O&G) platforms to fish productivity is required to contribute to the decision-making process to remove, partially remove, or retain these structures during decommissioning after petroleum production ceases. The present study assesses the biomass and fish production of one common and abundant fish species (Caesioperca lepidoptera – butterfly perch) and two commercially fished species (Helicolenus percoides – reef ocean perch; Nemadactylus macropterus – jackass morwong) on eight O&G platforms and in surrounding natural habitats in the Bass Strait, south-east Australia, where options for decommissioning are being assessed. High-definition stereo-video imagery was collected by remotely operated vehicle (ROV) from eight platform facilities, their immediate benthic surrounds, reference areas reflective of the likely pre-installation seabed state (sand-dominated) and a nearby natural 'reef' area referred to as south-east reef (some limestone foundation). The biomass of all three species was low in the benthic surrounds of platforms, at reference locations and at south-east reef where minimal cover by benthic organisms was recorded and, as such, there was little to no fish production for the three study species in these areas. We observed a total fish biomass of 2.85 tonnes across the eight platforms for the three fish species surveyed, with high variability across platforms. Total production (P) across all platforms was estimated at 1244 kg/year for the three species, with a mean fish production density of 82 g/m2/year. Approximately 79% of total production is considered 'new' production (984 kg/year i.e., the production attributed to the presence of the platforms; with a mean production density of 64 g/m2/year). The remaining 21% could be retained or redistributed into the surrounding area if platforms were removed. C. lepidoptera accounted for the majority (90%) of biomass and of total production for all three species across all locations surveyed. Despite only accounting for a small proportion of platform surface area, the bottom 5 m sections of platforms had 41% of the total biomass observed and accounted for 46% of total production of these three study species. Production measures for platforms surveyed here are relatively high compared to other artificial reefs and habitats around the world. Total removal of these platforms will likely result in a reduction of fish biomass and fish productivity (incl. several fishery species) in the immediate vicinity. • Platforms promote fish diversity and abundance in areas where it would be otherwise be minimal. • Platform production measures were relatively high compared to other artificial reefs and habitats around the world. • The bottom 5 m sections of platforms contained 41% of the total biomass observed and accounted for 46% of total production. • Complete removal of infrastructure would likely eliminate most fish production at that location. [ABSTRACT FROM AUTHOR]

Hatchery-reared fingerling Guadalupe BassMicropterus treculiiare stocked into central Texas rivers to restore threatened populations and combat hybridization with Smallmouth BassM. dolomieu. Fry survival in hatchery rearing ponds has declined by more than 50% in recent years, and pilot investigations indicated that exposure to high dissolved oxygen (DO) concentrations (>20 mg/L; hyperoxia) during tempering might have contributed to fry mortality. To test this hypothesis, Guadalupe Bass swim-up fry (11 d posthatch; 8.45 ± 0.25 mm TL [mean ± SD]) were exposed to normbaric DO concentrations ranging from 7.9 to 33.3 mg/L at 18°C, mimicking the hatchery tempering protocols followed during 2014 and 2015. After a 30-min exposure to the DO treatment (flow rate = 18 L/h), jars were flushed with nonoxygenated water for 1 min to rapidly lower the DO, mimicking the release of fry into ponds after tempering. Jars were then supplied with freshwater at a rate of 36 L/h and were monitored for 72 h. One control (A) was subjected to the same protocol but without oxygen supplementation; the other control (B) was not subjected to the 30-min exposure or flushing. Dead fry among treatments were recorded and removed every 24 h. Mortalities were observed within 6 h. Surviving fry were counted and measured after 72 h. Fry survival at 72 h was negatively correlated with increasing DO concentrations (Pearson’s product-moment correlation coefficient = –0.79) and declined significantly above 20 mg/L. Fry populations exposed to the highest oxygen concentration visually appeared more lethargic than fry in other treatments. The results of our study suggest that hyperoxia contributed to the low survival of fry in recent years. We recommend DO concentrations below 15 mg/L and avoiding DO levels above 20 mg/L (212% saturation at 18°C) when transporting and tempering Guadalupe Bass fry. We also recommend verifying the oxygen limits of other black bassMicropterusspp. Received April 26, 2017; accepted June 2, 2017Published online August 2, 2017 [ABSTRACT FROM AUTHOR]

The article presents a case study of a dead adult largemouth bass that was found floating in a pond. At necropsy, dozens of thin nematodes and rare cestodes were found within the coelomic cavity. The histological examination of other organs including the gills revealed normalcy. Morphological diagnosis revealed granulomatous coelomitis, hepatitis and enteritis with intralesional nematodes. The cause of the death of the fish could not be determined.

The article discusses the development and inheritance of molecular markers in the kelp bass Paralabrax clathratus. It focuses on genetic methods developed for the kelp bass Paralabrax clathratus. It focuses on a series of controlled crosses to confirm Mendelian inheritance for previously published microsatellite markers.

PCBs and OCPs were analyzed in fish (bass) taken along Chinese coastal fisheries. In the bass muscle, PCB, DDT and HCH concentrations were in the range of 1.02–2.2 ng/g, 0.44–1.74 and 2.84–106.11 ng/g ww, respectively. Spatial distribution showed that the concentrations of target contaminants in bass from south fisheries were in general much lower than those from north fisheries in China. The ratios of OCP congeners suggested that technical DDT was not the main input and a recent usage of lindane or old technical HCH residuals could be the source of HCHs. The OCC concentrations in liver (127–442.43 ng/g ww) from selected samples were 8–12 and 10–14 times higher than those in gills and muscles, respectively. Based on the maximum allowable fish assumption rate ( CR lim and CR mm ), it could cause human health risk, by consuming bass samples taken from highly contaminated fisheries including QD and ST. [ABSTRACT FROM AUTHOR]

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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 genus Edwardsiella is composed of a diverse group of facultative anaerobic, gram-negative bacteria that can produce disease in a wide variety of hosts, including birds, reptiles, mammals, and fish. Our report describes the isolation and identification of Edwardsiella piscicida associated with chronic mortality events in 2 separate captive largemouth bass (Micropterus salmoides) populations in New York and Florida. Wet-mount biopsies of skin mucus, gill, kidney, and spleen from several affected largemouth bass contained significant numbers of motile bacteria. Histologic examination revealed multifocal areas of necrosis scattered throughout the heart, liver, anterior kidney, posterior kidney, and spleen. Many of the necrotic foci were encapsulated or replaced by discrete granulomas and associated with colonies of gram-negative bacteria. Initial phenotypic and matrix-assisted laser desorption ionization–time of flight mass spectrometric analysis against existing spectral databases of recovered isolates identified these bacteria as Edwardsiella tarda. Subsequent molecular analysis using repetitive sequence mediated and species-specific PCR, as well as 16S rRNA, rpoB, and gyrB sequences, classified these isolates as E. piscicida. As a newly designated taxon, E. piscicida should be considered as a differential for multiorgan necrosis and granulomas in largemouth bass. [ABSTRACT FROM AUTHOR]

The Neotropics harbor the world's most diverse freshwater fish fauna, with many of these species supporting major commercial, subsistence, or sport fisheries. Knowledge of population genetic structure is available for very few Neotropical fishes, thereby restricting management. To address this need, we examined population genetic variation in mtDNA control region sequences and twelve microsatellite loci in the speckled or barred peacock bass, Cichla temensis. Moderate and statistically significant genetic divergence among localities indicates that migration is low in this species, implying that populations inhabiting tributaries or even smaller spatial units should constitute management units. Analysis of molecular variance of mtDNA sequences identified six areas with largely exclusive haplotype clades, and a seventh area of high admixture, but major drainage basins harbored non-monophyletic haplotype groups. On the other hand, molecular variation in the microsatellite data was best explained by drainage basin and, subsequently, by the seven areas. Populations in these seven areas could be considered evolutionarily significant units (ESUs), and, therefore, we tested hypotheses explaining the discordant signal of mtDNA and microsatellite data using approximate Bayesian computation. This analysis indicated that the divergence of mtDNA clades preceded the divergence of contemporary ESUs across basins, with subsequent lineage sorting among ESUs due to reduced gene flow. Available genetic and ecological information indicates that C. temensis populations of major tributary rivers should be managed as separate stocks that likely are adapted to local environmental conditions. [ABSTRACT FROM AUTHOR]