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Transgenerational isotopic marking has been recognised as an efficient tool for mass marking of high numbers of fish larvae by injecting female spawners with enriched isotope solutions. So far, mainly enriched stable barium isotopes have been applied for this purpose. Here, we present an alternative approach for individual-specific transgenerational marking using strontium 86Sr/ 84Sr double spikes. Four isotonic double-spike solutions with different molar fractions of 86Sr and 84Sr and different total Sr concentrations were administered to four female spawners of common carp, Cyprinus carpio, L., by intraperitoneal injection, and one additional female spawner was injected a blank isotonic solution as control. Otoliths (lapilli) were sampled from juvenile offspring and analysed for their Sr isotopic composition by laser ablation-multi collector-inductively coupled plasma-mass spectrometry. Central otolith regions of the progeny of female carps treated with concentrations of at least 0.45 mg 84Sr kg-1 bodyweight and 2.28 mg 86Sr kg-1 bodyweight showed a significant shift of the absolute 88Sr/86Sr and 88Sr/84Sr isotope ratios from the natural baseline. Isotope pattern deconvolution was successfully applied for the identification of the originally injected 86Sr/84Sr molar fraction ratios of the individual double spikes. Enriched stable Sr isotope double spikes represent an important alternative to enriched stable Ba isotopes for transgenerational marking, especially in freshwater systems. Transgenerational isotopic marking has been recognised as an efficient tool for mass marking of high numbers of fish larvae by injecting female spawners with enriched isotope solutions. In this study, 86Sr/84Sr double spikes in combination with isotope pattern deconvolution for the identification of the originally injected 86Sr/84Sr molar fraction ratios in otolith cores were successfully applied for individual-specific marking of the offspring of a typical freshwater fish species, the common carp (Cyprinus carpio). Enriched stable Sr isotope double spikes represent an important alternative to enriched stable Ba isotopes for transgenerational marking, especially in freshwater systems. [ABSTRACT FROM AUTHOR]

The maternal transmission of a naturally occurring and non-toxic minor isotope of strontium (84 Sr) to the central otolith region of the progeny of a typical European freshwater fish species, brown trout, Salmo trutta f.f. L. was accomplished. The focus was to apply minimum doses of a non-toxic solution at physiological salt concentration to minimise potential adverse effects on the fish. Female spawners were intraperitoneally injected with doses of 12.5 and 30.2 μg 84 Sr kg−1 fish. Eggs were stripped and the resulting progeny were reared in a hatchery for about 1 year before sampling the otoliths. Strontium isotope ratios in the otoliths of the offspring were measured by cross-sectional line scans using laser ablation-multiple collector-inductively coupled plasma mass spectrometry ( LA- MC- ICPMS). Otolith cores of marked juveniles showed a significantly elevated 84 Sr/86 Sr ratio compared with control fish and to otolith regions created after hatching. Mass marking of cohorts of progeny from individually spiked brown trout with Sr isotopes is therefore possible for dispersal and migration studies without the necessity of handling eggs and applying other larval marking methods like immersion. [ABSTRACT FROM AUTHOR]

The study tested the efficiency of hydrostatic pressure triploidization methods for Salmo trutta f. lacustris and Salvelinus umbla and investigated the effects on survival rate, skeletal malformation, and on morphometrics and cellular composition of gills, spleen, liver, kidney, intestine, and blood. In Salmo trutta f. lacustris a 100% triploidy rate in combination with high larvae survival rate (80% in comparison to control) was obtained when treating eggs with a pressure of 66 × 10 3  kPa 360 °C temperature minutes (CTM) post fertilization for 5 min, in Salvelinus umbla with a similar pressure after 270 CTM. Juvenile triploid Salmo trutta f. lacustris and Salvelinus umbla (145 days post hatch) had neither an increased rate of mortality, nor an increased rate of malformations. In triploid Salmo trutta f. lacustris and Salvelinus umbla the erythrocyte volume was 50% higher and the erythrocyte concentration in peripheral blood 25-35% lower relative to diploids. In triploids also the erythrocytes surface area: volume ratio was reduced. Gills of triploid Salmo trutta f. lacustris and Salvelinus umbla had increased width of primary lamellae and increased length of secondary lamellae which might compensate for unfavorable erythrocytes surface area: volume ratio. Length of the digestive tract and histology of kidney, liver, spleen, and gills were only investigated in Salmo trutta f. lacustris. In triploids the hematopoietic tissue of the kidney was decreased by 12%, the spleen index by 53%, and the erythroblast concentrations of the spleen by 42% relative to diploids, possibly indicating reduced erythropoiesis. Length of the digestive tract and cellular arrangement of intestine, liver, and gills were not affected. In summary, the used triploidization procedure seems a reliable method not counteracting the principles of animal welfare., (Copyright © 2018 Elsevier Inc. All rights reserved.)

To investigate the effect of water temperature on gamete maturation and gamete quality, European grayling (Thymalus thymallus) were held under different temperature regimes prior to spawning. Maturation of males and females and their gamete quality depended strongly on temperature regime. The highest percentages of maturing fish and highest gamete quality were obtained under a creek water temperature regime with natural seasonal fluctuations. In warmed creek water (3-4°C), at a constant temperature of 8-9°C, and under an abruptly increasing temperature, regime maturation rates and gamete quality were reduced. The effect was more pronounced in females than in males. The spawning dates of different wild Austrian grayling populations were also correlated with water temperature data collected during the last 10-15 years. The mean spawning date expressed as the number of days from 21 December until spawning ranged from 98 to 111 days for lower elevation populations, while it was considerably delayed for an alpine population. All populations spawned at water temperatures of 5.5-7.2°C. Regression analysis indicated that spawning date correlated with (1) the overall mean water temperature from 21 December until spawning, (2) the mean water temperature during both the last 10 days and 15 days before spawning, and (3) the difference between mean January temperature and that of the last 15 days before spawning. The regression functions indicate that an increase in water temperature from 21 December to spawning of 1°C advances spawning by 5½ days, and an increase of 1°C in the last 10-15 days advances spawning by 3½ days.

In the present study male and female brown trout (Salmo trutta f. fario) were exposed to environmentally relevant concentrations of bisphenol A (1.75, 2.40, 5.00 microg l(-1)) during the late prespawning and spawning period and the effect of this contaminant on maturation, quantity and quality of semen and eggs was investigated. In males exposed to estimated BPA concentrations of 1.75 and 2.40 microg l(-1) semen quality was lower than in the control in the beginning of spawning (reduced sperm density, motility rate, and swimming velocity) and in the middle of spawning (reduced swimming velocity, at 2.40 microg l(-1) BPA also reduced sperm motility rate). Therefore, production of high quality semen was restricted to the end of the spawning season and delayed for approximately 4 weeks in comparison to the control. At BPA exposure levels of 5.00 microg l(-1) only one of eight males gave semen of low quality (reduced semen mass, motility rate, and swimming velocity). The percentage of ovulated females was similar for the control group and the groups exposed to estimated BPA concentrations of 1.75 and 2.40 microg l(-1), whereas at 5.00 microg l(-1) BPA females did not ovulate during the investigation. While brown trout of the control group ovulated between the 28 October and 12 November, brown trout exposed to estimated BPA concentrations of 1.75 microg l(-1) BPA ovulated approximately 2 weeks later and brown trout exposed to 2.40 microg l(-1) BPA approximately 3 weeks later. Therefore, the tested BPA concentrations affected the percentage of ovulated females and the time point of ovulation. No effect was observed on the quality of eggs (egg mass, percentile mass increase during hardening, egg fertility).

A seven-year-old iatrogenically immunosuppressed girl developed simultaneous bilateral iris tumors associated with granulomatous iridocyclitis, splenomegaly, and an immunoblastic pleocytosis. Serologic studies suggested a current active Epstein-Barr virus infection. Tumor biopsy showed a polyclonal plasmacytoid lymphoproliferative process, establishing the diagnosis of posttransplant lymphoproliferative disorder. Low-dose local irradiation produced rapid and complete iris tumor regression with restoration of vision in both eyes. To our knowledge, this is the first report of ocular involvement in posttransplant lymphoproliferative disorder.