Abstract:Recent advances in analytical techniques have allowed cetacean pregnancy status to be diagnosed using reproductive hormones from biopsy samples. We tested the efficacy of blubber progesterone assays for diagnosing pregnancy in humpback whales, calculated pregnancy rates and examined the relationship between pregnancy and stable isotope ratios for these whales.
“…Interestingly, when another salmonid, the Arctic grayling ( Thymallus arcticus ), was exposed to moderately saline water (17 ppt), a rapid gill remodelling occurred in which the ILCM increased dramatically, likely as a protective mechanism18. Of note, a study examining the impacts of hydraulic fracturing fluid on two fish species (creek chub and green sunfish) also demonstrated significant impacts on gill morphology2728.…”
Hydraulic fracturing fluid are complex mixtures containing high concentrations of salts (up to 330,000 ppm), organic, and metal contaminants. However, little data exist on the potential mechanisms of toxicity of these flowback and produced wastewaters (FPW) on aquatic biota. Juvenile rainbow trout were exposed to either control, FPW (2.5 or 7.5%), FPW that had been treated with activated charcoal (AC), or a custom salt-matched control (SW; replicating only the salt content of FPW) for 48 hours. Gill histology revealed decreases in interlamellar cell mass (ILCM) and mean lamellar length in all treatments (FPW, AC and SW) compared to control, indicative of hyperosmotic stress. Liver CYP1A1 activity was significantly elevated by 7.5-fold in the FPW 7.5% treatment only, indicative of Phase I metabolism. Superoxide dismutase activity significantly decreased in the gills to all treatments with the lowest activity occurring in the 7.5% FPW group. Catalase activity increased in liver with the highest values noted in fish exposed to 7.5% FPW. No changes were observed with respect to glutathione-S-transferase, while increased lipid peroxidation was only observed in both FPW treatments (2.5, 7.5%). These data suggest a characteristic signature of FPW impact which may help in risk assessment and biomonitoring of FPW spills.
“…Interestingly, when another salmonid, the Arctic grayling ( Thymallus arcticus ), was exposed to moderately saline water (17 ppt), a rapid gill remodelling occurred in which the ILCM increased dramatically, likely as a protective mechanism18. Of note, a study examining the impacts of hydraulic fracturing fluid on two fish species (creek chub and green sunfish) also demonstrated significant impacts on gill morphology2728.…”
Hydraulic fracturing fluid are complex mixtures containing high concentrations of salts (up to 330,000 ppm), organic, and metal contaminants. However, little data exist on the potential mechanisms of toxicity of these flowback and produced wastewaters (FPW) on aquatic biota. Juvenile rainbow trout were exposed to either control, FPW (2.5 or 7.5%), FPW that had been treated with activated charcoal (AC), or a custom salt-matched control (SW; replicating only the salt content of FPW) for 48 hours. Gill histology revealed decreases in interlamellar cell mass (ILCM) and mean lamellar length in all treatments (FPW, AC and SW) compared to control, indicative of hyperosmotic stress. Liver CYP1A1 activity was significantly elevated by 7.5-fold in the FPW 7.5% treatment only, indicative of Phase I metabolism. Superoxide dismutase activity significantly decreased in the gills to all treatments with the lowest activity occurring in the 7.5% FPW group. Catalase activity increased in liver with the highest values noted in fish exposed to 7.5% FPW. No changes were observed with respect to glutathione-S-transferase, while increased lipid peroxidation was only observed in both FPW treatments (2.5, 7.5%). These data suggest a characteristic signature of FPW impact which may help in risk assessment and biomonitoring of FPW spills.
“…Migratory species such as the Atlantic salmon travel long distances between habitats to spawn or feed and are well adapted to optimize swimming economy (Lennox et al ., 2016). Unexpected extreme values and short-term variations of either temperature or water velocity, such as the ones that usually happen in rivers regulated for hydropower production, can alter active metabolic rates and contribute to incomplete or delayed fish migrations through difficult stretches of impounded river systems (Macdonald et al ., 2000).…”
This study revealed that Atlantic salmon smolts respond to short-term water temperature drops, like changes occurring in rivers regulated for hydropower production, by significantly reducing their rate of oxygen consumption during swimming activity. Fish show resilience by quickly returning to initial swimming costs after reestablishment of the original temperature values.
“…Data on stress status and reproductive fitness are challenging to obtain in free‐swimming populations of marine mammals but are critically needed for science‐based management and conservation plans. Steroid hormone analyses can provide key information regarding health and fitness and have been conducted previously in marine mammal tissues to determine pregnancy status, male reproductive status, and stress load . While steroid analyses have been conducted in marine mammal blow, feces, and serum, a blubber biopsy is so far the most reliably accessible, and thus suitable, sample matrix that can be collected from free‐ranging animals.…”
mentioning
confidence: 99%
“…Only three studies report on steroid analyses by ELISA in blubber biopsies from free‐swimming individuals . In all cases the sample size allowed for only one hormone to be analyzed by ELISA and this was without absolute quantitation.…”
RATIONALE: Analysis of steroids from precious blubber biopsies obtained from marine mammals, especially endangered species, can provide valuable information on their endocrine status. Challenges with currently used ELISA methodology include lack of absolute quantitation and incompatibility with multiple steroids analysis due to limited biopsy mass. Development of a sensitive, accurate analytical method for this purpose is critical. METHODS: A nanospray liquid chromatography/tandem mass spectrometry (nanoLC/MS/MS) method was validated for sensitive, specific and quantitative analysis of three steroid hormones, without derivatization, extracted from 50 mg blubber samples. Data was acquired with an LTQ XL ion trap mass spectrometer in positive ion mode, using single reaction monitoring. All three steroids were analyzed in a single run. Cholic acid was used as a surrogate internal standard for quantitation due to its steroidal structure and lack of measurable endogenous levels in blubber. RESULTS: The lowest limits of quantitation for progesterone, testosterone, and hydrocortisone were significantly improved compared to previous studies using conventional LC/MS/MS. The lowest limit of detection was 7 fg/μL using a 1 μL injection volume. Calibration curves for steroid quantification showed good linearity (r 2 >0.99) between 14 and 3620 fg/μL, and accuracy was <20% for interday and <10% for intraday. After validation, the method was successfully applied to quantification of steroids in gray whale blubber samples. CONCLUSIONS: The nanoLC/MS/MS method is more sensitive than traditional LC/MS/MS for steroid analysis. It is also compatible with other important biopsy analyses due to its small blubber mass requirement. This will benefit the reproductive and stress assessments for all marine mammals, particularly endangered populations.
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