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1
Ward, B. R., P. A. Slaney, A. R. Facchin, and R. W. Land. "Size-Biased Survival in Steelhead Trout (Oncorhynchus mykiss): Back-Calculated Lengths from Adults' Scales Compared to Migrating Smolts at the Keogh River, British Columbia." Canadian Journal of Fisheries and Aquatic Sciences 46, no. 11 (November 1, 1989): 1853–58. http://dx.doi.org/10.1139/f89-233.
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Lengths of wild, winter-run steelhead smolts, estimated by back-calculation procedures from adults' scales, were compared with observed lengths of migrating smolts sampled near the mouth of the Keogh River, Vancouver Island. Size-biased smolt-to-adult survival rates were estimated for several length categories by utilizing length frequencies from observed smolts, smolt length frequencies which were back calculated from adults' scales, smolt yield, and adult returns. Back-calculated smolt length (BSL) of adults returning from smolts of 1977 to 1982 averaged 193 mm compared to 176 mm for observed smolt length (OSL). Mean BSL was larger than OSL in every year. Adults from odd-numbered smolt years had larger BSL than adults from even-numbered smolt years similar to the pattern in OSL. BSL increased with increased years spent in salt water, based on ageing adults' scales. Males and females had different BSL based on number of years spent in fresh water and salt water, although they exhibited the same mean BSL overall. The smolt-to-adult survival estimates were in close agreement with previous estimates derived from the mean OSL. Predictability of survival in the ocean based on the length of smolts was extended over a broad range of the length distribution of wild steelhead smolts.
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Kroglund, F., B. O. Rosseland, H. C. Teien, B. Salbu, T. Kristensen, and B. Finstad. "Water quality limits for Atlantic salmon (<i>Salmo salar</i> L.) exposed to short term reductions in pH and increased aluminum simulating episodes." Hydrology and Earth System Sciences 12, no. 2 (March 5, 2008): 491–507. http://dx.doi.org/10.5194/hess-12-491-2008.
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Abstract. Acidification has caused the loss or reduction of numerous Atlantic salmon (Salmo salar L.) populations on both sides of the North Atlantic. Acid deposition peaked in the 1980's and resulted in both chronically and episodically acidified rivers. At present, water quality is improving in all affected rivers due to reduced acid deposition. However, spring snow melt, heavy rainfall and sea salt episodes can still cause short term drops in pH and elevated concentrations of bioavailable aluminum. Technical malfunction in lime dozers will cause short termed episodic spates in the limed rivers. The current situation has prompted a need for dose-response relationships based on short term exposures of Atlantic salmon to assess the potential population effects of episodic acidification. Water quality guidelines for salmon have been lacking, despite a large number of experiments, all demonstrating dose-response relationships between water chemistry and fish health. We have summarized results from 347 short-term (<14 days) exposures of salmon parr and smolt performed between 1990 and 2003 in Norway. The experiments have been performed as bioassays, where fish have been exposed in tanks fed river water, in tanks where the river water quality has been manipulated (added H+ and Al) and as Carlin-tagged smolt releases after preexposure to moderately acidic waters. The results from the various bioassays are compared to water quality limits proposed on basis of the relationship between water quality and population status/health in Norwegian rivers. The focus of this article is placed on chemical-biological interactions that can be drawn across experiments and exposure protocols. We propose dose-response relationships for acid neutralizing capacity (ANC), pH, cationic Al and gill accumulated Al, versus mortality in freshwater, effects on hypo-osmoregulatory capacity in seawater challenge tests and on smolt to adult survival in release experiments. The "no effect" dose depends on the life history stage tested and on the sensitivity of the biomarkers. Parr are more tolerant than smolt. Concentrations of Al that have no significant impact on freshwater life history stages can still have major population effects if they occur prior to smolt migration. While smolt can survive in freshwater for a prolonged period of time (>10 days) at an Al dose resulting in a gill Al concentration of up to 300 µg Alg−1 dw, a 3 day exposure resulting in a gill Al accumulation in the range of 25 to 60 µg Alg−1 dw reduces smolt to adult survival in a dose related manner by 20 to 50%. For smolt to adult survival, the biological significant response is delayed relative to the dose and occurs first after the fish enters the marine environment. In addition to exposure intensity and timing, exposure duration is important for the setting of critical limits.
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Kroglund, F., B. O. Rosseland, H. C. Teien, B. Salbu, T. Kristensen, and B. Finstad. "Water quality limits for Atlantic salmon (<i>Salmo salar</i> L.) exposed to short term reductions in pH and increased aluminum simulating episodes." Hydrology and Earth System Sciences Discussions 4, no. 5 (September 11, 2007): 3317–55. http://dx.doi.org/10.5194/hessd-4-3317-2007.
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Abstract. Acidification has caused the loss or reduction of numerous Atlantic salmon (Salmo salar L.) populations on both sides of the North Atlantic. Acid deposition peaked in the 1980's and resulted in both chronically and episodically acidified rivers. At present, water quality is improving in all affected rivers due to reduced acid deposition. However, spring snow melt, heavy rainfall and sea salt episodes can still cause short term drops in pH and elevated concentrations of bioavailable aluminum. Technical malfunction in lime dozers will cause short termed episodic spates in the limed rivers. The current situation has prompted a need for dose-response relationships based on short term exposures of Atlantic salmon to assess the potential population effects of episodic acidification. Water quality guidelines for salmon have been lacking, despite a large number of experiments, all demonstrating dose-response relationships between water chemistry and fish health. We have summarized results from 347 short-term (<14 days) exposures of salmon parr and smolt performed between 1990 and 2003 in Norway. The experiments have been performed as bioassays, where fish have been exposed in tanks fed river water, in tanks where the river water quality has been manipulated (added H+ and Al) and as Carlin-tagged smolt releases after preexposure to moderately acidic waters. The results from the various bioassays are compared to water quality limits proposed on basis of the relationship between water quality and population status/health in Norwegian rivers. The focus of this article is placed on chemical-biological interactions that can be drawn across experiments and exposure protocols. We propose dose-response relationships for acid neutralizing capacity (ANC), pH, cationic Al and gill accumulated Al, versus mortality in freshwater, effects on hypo-osmoregulatory capacity in seawater challenge tests and on smolt to adult survival in release experiments. The "no effect" dose depends on the life history stage tested and on the sensitivity of the biomarkers. Parr are more tolerant than smolt. Concentrations of Al that have no significant impact on freshwater life history stages can still have major population effects if they occur prior to smolt migration. While smolt can survive in freshwater for a prolonged period of time (>10 days) at an Al dose resulting in a gill Al concentration of up to 300 μg Alg−1 dw, a 3 day exposure resulting in a gill Al accumulation in the range of 25 to 60 μg Alg−1 dw reduces smolt to adult survival in a dose related manner by 20 to 50%. For smolt to adult survival, the biological significant response is delayed relative to the dose and occurs first after the fish enters the marine environment. In addition to exposure intensity and timing, exposure duration is important for the setting of critical limits.
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Novales Flamarique, I. "The ontogeny of ultraviolet sensitivity, cone disappearance and regeneration in the sockeye salmon Oncorhynchus nerka." Journal of Experimental Biology 203, no. 7 (April 1, 2000): 1161–72. http://dx.doi.org/10.1242/jeb.203.7.1161.
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This study examines the spectral sensitivity and cone topography of the sockeye salmon Oncorhynchus nerka throughout its life history with special emphasis on ultraviolet sensitivity. Electrophysiological recordings from the optic nerve show that ultraviolet sensitivity is greatly diminished at the smolt stage but reappears in adult fish weighing about 201 g. Concomitantly, light microscopy observations of the retina show that ultraviolet cones disappear from the dorsal and temporal retina at the smolt stage but reappear at the adult stage. These changes occur for sockeye salmon raised in fresh water or salt water after smoltification. In contrast to this ultraviolet cycle, the other cone mechanisms (short-, middle- and long-wavelength-sensitive) and the rod mechanism remain present throughout ontogeny. The natural appearance and disappearance of ultraviolet cones in salmonid retinas follows surges in blood thyroxine at critical developmental periods. Their presence coincides with times of prominent feeding on zooplankton and/or small fish that may be more visible under ultraviolet light. It is proposed that the primary function of ultraviolet cones in salmonids is to improve prey contrast.
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Holand, Trond, Øystein Evensen, Sagita Dewi, and Stig Larsen. "Randomized response surface pathway design with skewed starting point and stochastic dose window." International Journal of Clinical Trials 7, no. 1 (January 24, 2020): 18. http://dx.doi.org/10.18203/2349-3259.ijct20200202.
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<p class="abstract"><strong>Background:</strong> The aim was to introduce response surface pathway (RSP)-design with skewed starting value and stochastic dose-window to estimate optimal efficacy dose (OED) of BP-C2 after IL-1β stimulation in Atlantic salmon.</p><p class="abstract"><strong>Methods:</strong> 54 healthy smolt of Atlantic salmon between 50 and 100 g before habituated to salt water were included. The study was conducted as a one-dimensional, randomized between-patient three-level RSP designed trial with one interventional- and one response variable and odd outcomes. The interventional variable was intraperitoneal injected BPC2 with skewed starting dose of 0.10 mg/100 g related to the initial dose-window <0.02-0.5 mg/100 g. The response variable was the Ct-value of mRNA IL-1β expression 24 hours after injection.</p><p class="abstract"><strong>Results:</strong> Skewed starting value of 0.10 mg/100 g was chosen in the first design-level with a dose-window of <0.0-0.20]. The three smolt obtained a reduction in Ct-value above 15%, and the dose-window adjusted with the lower boundary equals the previous dose. The five smolt at second design-level received 0.16 mg/100g with a dose-window [0.10-0.22]. Four smolt obtained above 15% and one of 0.5% reduction in cycle threshold (Ct)-value. Six smolt in the third design-level received 0.21 mg/100 g and one 0.16 mg/100 g. The mean Ct-value was reduced from 30.0 in the unstimulated situation to 25.0, 24.8 and 26.4 after BP-C2 stimulation of 0.10, 0.16 and 0.21 mg/100 g, respectively. The OED of BP-C2 related to IL-1β was estimated to 0.14 mg/100 g.</p><p class="abstract"><strong>Conclusions: </strong>Skewed starting value in the initial dose-window made the K-adjustment factor and dose-window stochastic. The RSP-procedure works in accordance to the expectation and estimated OED of BP-C2 sufficiently.</p><strong> </strong>
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Gil, Milene, Maria Rosário Martins, Maria Luisa Carvalho, Cátia Souto, Stephane Longelin, Ana Cardoso, José Mirão, and António Estevão Candeias. "Microscopy and Microanalysis of an Extreme Case of Salt and Biodegradation in 17th Century Wall Paintings." Microscopy and Microanalysis 21, no. 3 (June 2015): 606–16. http://dx.doi.org/10.1017/s1431927615000562.
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AbstractThe present study characterizes the main deterioration mechanisms affecting the early 17th frescoes of Casa de Fresco, the only known example in Portugal of a semi-underground leisure room richly decorated with a balcony over a water well. Frescoes from the vault are at risk due to salt weathering and biodeterioration. The aim of the research was identification of the deterioration materials, determination of their origin, and their effect on the frescoes before future intervention. Scanning electron microscopy with an energy-dispersive X-ray detector (SEM-EDS) was used to determine salt morphology and microanalysis. The mineralogical characterization was performed by X-ray powder diffraction, complemented with µ-Raman and µ-Fourier transform infrared spectroscopy. Biological assessment was evaluated with optical microscopy and SEM-EDS. Bacterial and fungal isolation and identification were performed using standard culture media and methods according to Bergey’s Manual of Systematic Bacteriology and from the Compendium of Soil Fungi. The results show that Ca and Ca-Mg carbonates from the paint renderings are the predominant salt species affecting the site. Bacterial strains from the genera Bacillus and Pseudomonas and fungal strains from the Cladosporium spp. and Penicillium spp. were isolated in the salt formations, within and between the mortar layers. Azurite, malachite, and smalt paint layers are the most affected by the weathering conditions.
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Knowles, Albert H., and Robert H. Rines. "ENVIRONMENTAL CONDITIONING PROCESS OF ACCELERATING AND CONTROLLING THE DEVELOPMENT OF SALMON SMOLT AND SUBSEQUENT SALT WATER MATURATION." Journal of the World Mariculture Society 12, no. 2 (March 12, 2009): 96–97. http://dx.doi.org/10.1111/j.1749-7345.1981.tb00280.x.
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McCormick, Stephen D., Robert J. Naiman, and Ellyn T. Montgomery. "Physiological Smolt Characteristics of Anadromous and Non-anadromous Brook Trout (Salvelinus fontinalis) and Atlantic Salmon (Salmo salar)." Canadian Journal of Fisheries and Aquatic Sciences 42, no. 3 (March 1, 1985): 529–38. http://dx.doi.org/10.1139/f85-070.
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Anadromous brook trout, Salvelinus fontinalis, of rivière à la Truite, Quebec, were examined for physiological changes associated with smoltification, and compared with non-anadromous brook trout from the adjacent Matamek River. There were no statistical differences in plasma thyroxine concentration, gill Na+, K+-ATPase activity, hematocrit, or osmoregulatory ability between the populations. Moisture content was different between the populations, but both had the same pattern of declining moisture content as summer progressed. Silver coloration of brook trout in rivière à la Truite was associated with larger fish and higher gill Na+, K+-ATPase activity, but not with changes in plasma thyroxine concentrations, moisture content, hematocrit, or condition factor. Brook trout at high-salinity estuarine sites had greater gill Na+, K+-ATPase activity and hypoosmoregulatory ability than those from low-salinity sites. Silvering of Atlantic salmon (Salmo salar) in rivière à la Truite was associated with larger fish, higher gill Na+, K+-ATPase activity, and higher plasma thyroxine. Gill Na+, K+-ATPase activity of highly silvered freshwater Atlantic salmon was greater than that of highly silvered brook trout. Estuarine Atlantic salmon had significantly higher plasma thyroxine concentration and gill Na+, K+-ATPase activity than estuarine brook trout. Based on these physiological factors, we conclude that smoltification is undeveloped in brook trout and that estuarine residence is important for salt water acclimation and eventual seaward migration.
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Moore, A., E. C. E. Potter, N. J. Milner, and S. Bamber. "The migratory behaviour of wild Atlantic salmon (Salmo salar) smolts in the estuary of the River Conwy, North Wales." Canadian Journal of Fisheries and Aquatic Sciences 52, no. 9 (September 1, 1995): 1923–35. http://dx.doi.org/10.1139/f95-784.
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Thirty-two wild Atlantic salmon (Salmo salar) smolts, tagged with miniature acoustic transmitters, were tracked in the River Conwy, North Wales, to describe the freshwater and estuarine patterns of migration. Migration in fresh water was predominantly nocturnal, although there was a seasonal change in this pattern with later run fish moving during both the day and night. Smolts tagged earlier in the study spent significantly longer in the river (mean 456 ± 43 h) before migrating into coastal waters than fish tagged later in the study (mean 201 ± 30 h). The movement of smolts through the estuary was indicative of a nocturnal selective ebb tide transport pattern of migration. All of the smolts migrated seawards on an ebb tide close to the surface and within the fastest moving section of the water column. The nocturnal pattern of migration would appear to be the result of an endogenous rhythm of swimming activity that results in the smolts moving up into the water column after dusk and migrating seawards. Smolt migration in the lower portion of the estuary was indicative of active directed swimming and there was no apparent period of acclimation required when moving from fresh to salt water.
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Shrimpton, J. Mark, Nicholas J. Bernier, George K. Iwama, and David J. Randall. "Differences in Measurements of Smolt Development Between Wild and Hatchery-Reared Juvenile Coho Salmon (Oncorhynchus kisutch) Before and After Saltwater Exposure." Canadian Journal of Fisheries and Aquatic Sciences 51, no. 10 (October 1, 1994): 2170–78. http://dx.doi.org/10.1139/f94-218.
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We compared the saltwater tolerance of coho salmon (Oncorhynchus kisutch) juveniles that were reared in different environments. The groups examined consisted of fish reared exclusively in the hatchery, a hatchery group transplanted into the upper watershed of the river (colonized), and wild fish from natural spawning broodstock in the river. Although hatchery fish were much larger than their wild or colonized counterparts, they consistently showed a reduced saltwater tolerance as assessed by a much greater perturbation in plasma sodium concentration following transfer to salt water. Within each group there was no relationship between size of the fish and saltwater tolerance. Following transfer to sea water, hatchery fish showed a significant decline in haematocrit and a significant increase in circulating plasma cortisol concentration. Neither of these changes was seen in wild smolts. Hatchery fish possessed fewer chloride cells, and lower specific activities of the enzymes Na+K+ATPase and citrate synthase. The weaker osmoregulatory ability of hatchery fish led to a greater mortality following abrupt transfer to 35‰ seawater. We believe that the differences in saltwater tolerance seen among the different groups of fish are due to rearing environment.
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Soleng, Arnulf, Tor A. Bakke, and Lars P. Hansen. "Potential for dispersal of Gyrodactylus salaris (Platyhelminthes, Monogenea) by sea-running stages of the Atlantic salmon (Salmo salar): field and laboratory studies." Canadian Journal of Fisheries and Aquatic Sciences 55, no. 2 (February 1, 1998): 507–14. http://dx.doi.org/10.1139/f97-251.
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Population growth of Gyrodactylus salaris increased exponentially on Atlantic salmon (Salmo salar) smolts in laboratory experiments conducted at 12.0°C. Furthermore, G. salaris was transmitted successfully from salmon smolt to parr at 0.0, 7.5, 10.0, and 20.0%° salinity and reproduced in fresh water after direct transfer from 7.5%° (16 days), 20.0%° (4 and 8 h), and 33.0%° (5, 15, and 30 min). No G. salaris were observed on salmon parr exposed to 33.0%° for 60 min. The prevalence of G. salaris on wild salmon smolts caught approximately 25 km from the river mouth in the Drammensfjord (surface salinity 2.0-3.5%°) was 71.2% compared with 88.0% on those from the neighbouring River Lierelva. Adult wild salmon caught as prespawners, spawners, and postspawners (kelts) in the River Drammenselva were infected with G. salaris. The prevalence and abundance increased from autumn to spring, in contrast with earlier studies on salmon parr, demonstrating the possible importance of adult salmon as reservoirs for G. salaris during winter. The results support the hypothesis of brackish water dispersal of G. salaris by infected salmonids migrating in estuaries and fjords. The use of salt as a disinfectant against G. salaris in hatcheries, and the stocking of possibly infected fish into brackish and seawater, should also be reexamined.
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González, V., BS Labbé, V. Valerio, L. Vargas-Chacoff, D. Martínez, R. Oyarzún, and JLP Muñoz. "Physicochemical parameters associated with the methds of application of salt baths and their field assessment of blood parameters of Atlantic salmon in water pre-smolt stage." Archivos de medicina veterinaria 48, no. 2 (2016): 223–30. http://dx.doi.org/10.4067/s0301-732x2016000200013.
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Gu, Min, Trond M. Kortner, Michael Penn, Anne Kristine Hansen, and Åshild Krogdahl. "Effects of dietary plant meal and soya-saponin supplementation on intestinal and hepatic lipid droplet accumulation and lipoprotein and sterol metabolism in Atlantic salmon (Salmo salarL.)." British Journal of Nutrition 111, no. 3 (September 5, 2013): 432–44. http://dx.doi.org/10.1017/s0007114513002717.
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Altered lipid metabolism has been shown in fish fed plant protein sources. The present study aimed to gain further insights into how intestinal and hepatic lipid absorption and metabolism are modulated by plant meal (PM) and soya-saponin (SA) inclusion in salmon feed. Post-smolt Atlantic salmon were fed for 10 weeks one of four diets based on fishmeal or PM, with or without 10 g/kg SA. PM inclusion resulted in decreased growth performance, excessive lipid droplet accumulation in the pyloric caeca and liver, and reduced plasma cholesterol levels. Intestinal and hepatic gene expression profiling revealed an up-regulation of the expression of genes involved in lipid absorption and lipoprotein (LP) synthesis (apo, fatty acid transporters, microsomal TAG transfer protein, acyl-CoA cholesterol acyltransferase, choline kinase and choline-phosphate cytidylyltransferase A), cholesterol synthesis (3-hydroxy-3-methylglutaryl-CoA reductase) and associated transcription factors (sterol regulatory element-binding protein 2 and PPARγ). SA inclusion resulted in reduced body pools of cholesterol and bile salts. The hepatic gene expression of the rate-limiting enzyme in bile acid biosynthesis (cytochrome P450 7A1 (cyp7a1)) as well as the transcription factor liver X receptor and the bile acid transporterabcb11(ATP-binding cassette B11) was down-regulated by SA inclusion. A significant interaction was observed between PM inclusion and SA inclusion for plasma cholesterol levels. In conclusion, gene expression profiling suggested that the capacity for LP assembly and cholesterol synthesis was up-regulated by PM exposure, probably as a compensatory mechanism for excessive lipid droplet accumulation and reduced plasma cholesterol levels. SA inclusion had hypocholesterolaemic effects on Atlantic salmon, accompanied by decreased bile salt metabolism.
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Williams, Peter E. V. "135 Production of a fifty percent functional protein concentrate from the dry grind ethanol process and use of the product in diets for Atlantic salmon." Journal of Animal Science 98, Supplement_4 (November 3, 2020): 100. http://dx.doi.org/10.1093/jas/skaa278.183.
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Abstract The corn distilling industry is a major processor of grain, but the high fiber co-product (DDGS), has limited application in feed. Simple mechanical stillage separation downstream of fermentation produces a high protein (52.4 % DM), highly digestible, low crude fiber (4.4% DM) product containing approximately 25% DM spent brewer’s yeast (high density distillers’ protein: HDDP). Currently, approximately 300 ktons of HDDP are produced annually in the USA, and the volume will double in 2020. The effect of graded inclusion levels of HDDP on growth, feed efficiency, nutrient utilization, blood chemistry and gut histology of 525 post-smolt Atlantic salmon (initial body weight 304 ± 10.7g), randomly allocated to three tanks per treatment, was tested in a salt-water recirculating aquaculture system. One control diet with no HDDP was formulated to meet the nutrient requirements of Atlantic salmon. Four test diets were formulated to contain graded levels of HDDP at 5, 10, 15 and 20% respectively. HDDP partially replaced soy protein concentrate and corn protein concentrate in the diets. Salmon were hand-fed to satiety, 3 times daily during the 84-day trial. Throughout the trial the performance of fish on all treatments exceeded commercial growth rates with thermal growth coefficients (TGC) in excess of 0.160 and feed conversion efficiency of ≤ 1.0. Overall HDDP was a nutritious feed ingredient and had no significant impact on performance. Overall TGC was highest (0.200 over the 84-day trial period) in fish fed the diet containing 10% HDDP. Both villi length and villi width in the distal intestine of salmon fed diets containing HDDP tended to be higher than in the controls. Overall, HDDP derived from the dry grind ethanol process was a safe and nutritious novel feed ingredient for Atlantic salmon, and the potential beneficial effect on gut morphology merits investigation.
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Litovka, Denis I., and Ludmila N. Khitzova. "On factors for separation of the stock of beluga whale Delphinapterus leucas in the Anadyr Gulf of the Bering Sea." Izvestiya TINRO 179, no. 4 (December 30, 2014): 113–19. http://dx.doi.org/10.26428/1606-9919-2014-179-113-119.
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New eco-ethological data on the Anadyr stock of beluga whales are presented based on 14-year (2000-2013) studies by methods of satellite tracking telemetry, multi-spectral aerial surveys and genetic analysis, as well as traditional and ecosystem-based approaches. Possible factors of the separate stock formation in the Anadyr Gulf are discussed, as geographic isolation, environmental conditions, foraging resources, elimination of the beluga whales, and biological isolation (on the results of genetic analysis). The beluga whales are well-adapted to oceanographic conditions and ice regime of the Arctic waters that is realized in their relationship with edge of the sea ice, ability to live in both salt and fresh waters (they enter rivers), and versatility in feeding. Their ice-associating, high sociality, and white protective coloration provide protection against killer whales and other predators and their eury-halinity allows to expand the feeding grounds both to the sea and rivers and hunt for both freshwater, anadromous and marine prey. The food spectrum of beluga whales in the Anadyr estuary is very wide and includes 12 fish species and 1 crustacean species. In the summer-autumn season, the salmons are the most significant part of the diet, as chum salmon Oncorhynchus keta , pink salmon O. gorbuscha and arctic char Salvelinus malma , whereas arctic smelt Osmerus mordax dentex , saffron cod Eleginus gracilis , sculpins Cottidae sp., anadyr whitefish Coregonus anaulorum , and siberian whitefish Coregonus sardinella are presented in the diet to a lesser extent. There is supposed on the base of episodic net surveys, that the beluga whales feeding in marine areas is more diverse, and the most important their prey in the sea are walleye pollock Theragra chalcogramma , pacific cod Gadus macrocephalus , flounders Pleuronectidae sp., sculpins Cottidae sp., capelin Mallotus villosus catervarius , polar cod Boreogadus saida , halibuts Pleuronectidae sp., stingrays Bathyraja , herring Clupeidae sp., and several species of decapod crustaceans Hyppolitidae sp. and Lithodidae sp. Natural enemies of beluga whales are killer whale Orcinus orca , polar bear Ursus maritimus , and predatory form of pacific walrus Odobenus rosmarus . Rather large number of beluga whales are eliminated by the sea ice, up to 80 animals annually, that exceeds in several times the aboriginal landings in Chukotka. Parasitic fauna of the beluga whale is still unclear and requires special investigations; the cases of epizooty are unknown in the Anadyr Gulf. Philopatry is proper to the Anadyr beluga whales, with preference of the Anadyr estuary and the Anadyr Gulf as their habitats, that is explained by optimal for them environments and high food capacity. Unique adaptation of beluga whales to the environments of the Anadyr estuary is their ultrasonic vocalization in the high-turbidity waters. Genetic analysis shows a differentiated distribution of the beluga whales haplotypes in different areas of the North Pacific, so the stock of the Anadyr Gulf is significantly isolated in the post-glacial times. Low anthropogenic pressure on beluga whales in the Anadyr Gulf allows them to maintain their stock there.
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Eremin, Katherine, James Tate, Alison Morrison-Low, James Berry, and Sara Stevenson. "Non-destructive analysis of Nineteenth century Scottish calotype negatives and salt prints." MRS Proceedings 712 (2002). http://dx.doi.org/10.1557/proc-712-ii10.2.
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ABSTRACTNineteenth century negatives and positives in the collections of the National Museums of Scotland (NMS) and the National Galleries of Scotland (NGS) were analysed non-destructively to identify the techniques used in their manufacture. Modern positive and negative images prepared using known nineteenth century processes were also analysed for comparison. Air-path energy dispersive x-ray fluorescence analysis and controlled pressure scanning electron microscopy with energy dispersive microanalysis enabled the images to be divided into groups based on the levels of bromine, iodine and silver, and the likely processes used inferred. An early group of positives were probably sensitised with either silver chloride or silver bromide and fixed with potassium bromide. However, most positives were probably sensitised with silver chloride and fixed with sodium thiosulphate. Most negatives were probably sensitized with silver iodide and fixed with potassium bromide (predominant), sodium thiosulphate or potassium iodide. Cobalt and arsenic are present due to the use of smalt in the production of white paper. Copper and zinc are attributed to incorporation of fragments of brass buttons left on the rags used in paper production, observed as small blue spots. The presence of iron, sometimes visible as orange spots, may be from rust off the paper making machines.
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Daniels, J., E. B. Brunsdon, G. Chaput, H. J. Dixon, H. Labadie, and J. W. Carr. "Quantifying the effects of post-surgery recovery time on the migration dynamics and survival rates in the wild of acoustically tagged Atlantic Salmon Salmo salar smolts." Animal Biotelemetry 9, no. 1 (January 29, 2021). http://dx.doi.org/10.1186/s40317-020-00228-6.
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Abstract Background The experimental effects of surgically implanting fish with acoustic transmitters are likely to have negative effects on survival and behaviour. Measuring the extent of these negative effects is important if we wish to extrapolate inferences from tagged animals to un-manipulated animals. In this study, we examine the effect of surgery and post-tagging recovery time on the survival and migration rate of acoustically tagged wild Atlantic Salmon (Salmo salar) smolts through freshwater, estuarine and ocean phases of migration. Four treatment groups were used: pre-smolt captured in the fall that overwintered in a hatchery and were tagged either 75 days prior to release (winter hatchery) or within 24 h prior to release (spring hatchery) and smolt captured during the spring smolt run, tagged 24 h prior to release and released during the day (day-released) or night (night-released). Results The spring hatchery treatment group served as a reference treatment group such that recovery time (comparison to winter hatchery treatment) and hatchery effects (comparison to day-released and night-released treatments) could both be discerned. The hatchery effect increased migration rate, whereas short recovery times and captivity in a hatchery negatively affected survival. These effects were most pronounced within the first 5 days and/or 48 km downstream post-release, however, the residual recovery time effects appeared to persist during the transition from the estuary into salt water. Conclusions Even with smolts originating from the wild and spending relatively little time within the hatchery environment, post-release survival was still negatively affected. Migration speed was faster for hatchery smolts, but is likely only due to their larger size. Recovery time effects were most prominent during the initial migration period in freshwater and again in the transition from the estuary to saltwater which may be due to added stress during these transitional zones. As surgery-related bias will likely never be completely removed from telemetry studies, it is important to quantify and account for these effects in situ when making inferences on the un-manipulated component of the population.
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Ghalambor, Cameron, Edwin Grosholtz, Edward Gross, Kenneth Jeffries, John Largier, Stephen McCormick, Ted Sommer, Johnathan Velotta, and Andrew Whitehead. "Ecological Effects of Climate-Driven Salinity Variation in the San Francisco Estuary: Can We Anticipate and Manage the Coming Changes?" San Francisco Estuary and Watershed Science 19, no. 2 (June 7, 2020). http://dx.doi.org/10.15447/sfews.2021v19iss2art3.
Full textAbstract:
Climate change-driven sea level rise and altered precipitation regimes are predicted to alter patterns of salt intrusion within the San Francisco Estuary. A central question is: Can we use existing knowledge and future projections to predict and manage the anticipated ecological impacts? This was the subject of a 2018 symposium entitled “Ecological and Physiological Impacts of Salinization of Aquatic Systems from Human Activities.” The symposium brought together an inter-disciplinary group of scientists and researchers, resource managers, and policy-makers. Here, we summarize and review the presentations and discussions that arose during the symposium. From a historical perspective, salt intrusion has changed substantially over the past 10,000 years as a result of changing climate patterns, with additional shifts from recent anthropogenic effects. Current salinity patterns in the San Francisco Estuary are driven by a suite of hydrodynamic processes within the given contexts of water management and geography. Based on climate projections for the coming century, significant changes are expected in the processes that determine the spatial and temporal patterns of salinity. Given that native species—including fishes such as the Delta Smelt and Sacramento Splittail—track favorable habitats, exhibit physiological acclimation, and can adaptively evolve, we present a framework for assessing their vulnerability to altered salinity in the San Francisco Estuary. We then present a range of regulatory and structural management tools that are available to control patterns of salinity within the San Francisco Estuary. Finally, we identify major research priorities that can help fill critical gaps in our knowledge about future salinity patterns and the consequences of climate change and sea level rise. These research projects will be most effective with strong linkages and communication between scientists and researchers, resource managers, and policy-makers.