Recent Literature Abstracts, to Oct 2017

Contents

1. Biochemistry / Physiology / Immunology3 - 8

2. Diseases / Aquaculture9 - 13

3. Fisheries Management / Reproduction / Habitat / 13 - 29

Ecology / Migration

4. Genetics/Populations/Taxonomy/Evolution 29 - 40

5. Life History 40 - 44

6. Predation 44

7. Welfare / Catch and Release 45 - 48

Grayling Specific Papers either have the term grayling or Thymallus in the title OR contain either of those terms in the abstract.

Grayling Relevant Papers contain work that can be probably applied to grayling

NB. For the first time, a grayling-specific publication on the welfare of grayling subject to catch and release was published in 2016 by Lennox et al. This paper was from the influential research group of Steven J. Cooke, which has many publications on fish welfare. The paper abstract is included below in the final section on Welfare/Catch and Release. The main impact on grayling appears to be not the hooking or catching, but post-capture exposure to air for unhooking or for photography. The importance of keeping captured fish in the water is emphasized, with a less than 10 second exposure being recommended; adequate for the removal of a barbless hook.

For convenience, the paper details including authors, affiliations, publication, title, abstract and conclusions are printed on the next page.

Robert J. Lennox1)2)*, Ian Mayer3), Torgeir B. Havn2), Martin R. Johansen2),

Kim Whoriskey4), Steven J. Cooke1), Eva B. Thorstad2) and Ingebrigt Uglem2)

1) Fish Ecology and Conservation Physiology Laboratory, Department of Biology and Institute of Environmental Science, Carleton University, 1125 Colonel By Drive, Ottawa, ON K1S 5B6, Canada

(*corresponding authors e-mail: robertlennox9@gmail.com)

2) Norwegian Institute for Nature Research, P.O. Box 5685, Sluppen, N-7485 Trondheim, Norway

3) Norwegian University of Life Sciences, Faculty of Veterinary Medicine and Biosciences, N-0033 Oslo

4) Department of Mathematics and Statistics, Dalhousie University, 1355 Oxford Street, Halifax, Nova Scotia B3H 4R2, Canada

Boreal Environment Research 21: 461470, 2016

Effects of recreational angling and air exposure on the physiological status and reflex impairment of European grayling (Thymallus thymallus)

Abstract

European grayling (Thymallus thymallus) is a popular recreational fish that may be lifted out of the water to facilitate hook removal or for admiration. To evaluate the effects of air exposure and angling-induced exhaustive exercise on released grayling condition, we assessed blood physiology and reflexes of grayling after angling and air exposure in the subarctic River Lakselva (Norway) at midsummer temperatures (i.e., 1718 C). Blood samples were drawn 30 min after angling and analyzed for lactate anions, glucose, sodium ions, and pH. Reflex impairment was determined with orientation and tail grab reflex action assessments immediately after landing, after air exposure, and after 30 min holding. Blood physiology did not indicate an exacerbating effect of air exposure relative to just angling-induced exercise, but significant and prolonged reflex impairment was associated with the 120 s air exposure interval. Anglers must take care to minimize air exposure to adhere to best handling practices.

Conclusions

Even in the absence of notable increases in physiological stress detectable in blood, increased reflex impairment associated with protracted air exposure justifies elimination or considerable reduction of air exposure to short intervals (< 10 s) by anglers targeting European grayling at summer water temperatures. Fishery sustainability concerns have led to consideration of some catch-and-release management policies for maintaining grayling populations (e.g., Aas et al . 2000). However, little if any research has previously been conducted to determine the effects of recreational angling on grayling, even though other species in the order Salmoniformes (e.g., rainbow trout, Atlantic salmon, sockeye salmon) have received considerable attention from recreational fisheries researchers (Cooke and Suski 2005). Because limited data have previously been collected to quantify the response of European grayling to angling, the actual value of catch-and-release for conservation of this species is not fully understood. Therefore, the results of this study are particularly relevant for grayling conservation initiatives. Our finding that air exposure can increase probability of reflex impairment is pertinent to grayling fisheries given that released grayling are often held out of the water by anglers for photographs or general admiration. Further research efforts directed at identifying thresholds for air exposure with a specific emphasis on short air exposure intervals will be useful for generating best practice recommendations that anglers can use to maintain the welfare status of fish in recreational fisheries.

Biochemistry / Physiology/ Immunology

Grayling Specific

2017

Yu. S. Petukhov, Yu. P. Tolmacheva, B. E. Bogdanov

Hydrobiological Journal, (2017), 52(6), 58 65: DOI: 10.1615/HydrobJ.v52.i6.70

Morphobiological Characteristic of the Baikal Grayling Thymallus baicalensis of the Gitara Lake (System of the Kurkula River, Northern Baikal Coast)

New data on biology and morphology of the isolated population of the Baikal grayling Thymallus baicalensis from the mountainous Gitara Lake are given. The features were determined that distinguish it from other populations of the species inhabiting the Lake Baikal and mountainous water bodies of the Baikal-Sayan region, which is the result of adaptation to extreme conditions of the ultraoligotrophic lake and isolation from other populations of the species.

Oliver M. Selmoni, Diane Maitre, Julien Roux, Laetitia G. E. Wilkins, Lucas Marques da Cunha,

Etienne Vermeirssen, Susanne Knrr, Marc Robinson-Rechavi, Claus Wedekind

Cold Spring Harbor Laboratory Preprint, (2017). doi: https://doi.org/10.1101/135210

Sex-Specific Changes in Gene Expression And Delayed Sex Differentiation In Response To Estrogen Pollution In Grayling (Salmonidae)

The synthetic 17-ethinylestradiol (EE2) is an estrogenic compound of oral contraceptives and therefore a common pollutant that has been suspected to affect the demography of river-dwelling salmonids. We study a population of European grayling (Thymallus thymallus) that suffers from sex ratio distortions. Here we test how ecologically relevant concentrations of EE2 affect sex-specific gene expression around early stages of sex differentiation. We collected gametes from F1s of wild spawners, used them for in vitro fertilizations, and raised the resulting embryos singly under experimentally controlled conditions. Embryos were either exposed to 1ng/L EE2 or sham-exposed. RNA was collected from samples taken 10 days before hatching, at the day of hatching, and towards the end of the yolk-sac stage, to study gene expression and relate it to genetic sex (sdY genotype). We found that EE2 affects gene expression of a very large number of genes especially at the day of hatching. The effects of EE2 on gene expression is strongly sex-specific. At the day of hatching, EE2 affected about twice as many genes in females than in males, and towards the end of the yolk-sac larval stage, EE2 effects were nearly exclusively observed in females. Among the many effects was, for example, a surprising EE2-induced molecular masculinization in the females heads. Histological examination of gonadal development of EE2-treated or sham-exposed juveniles during the first 4.5 months after hatching revealed a delaying effect of EE2 on sex differentiation. Because grayling sex determination goes through an all-male stage (a rare case of undifferentiated gonochorism), the rate of EE2-induced sex reversal could not be unequivocally determined during the observational period. However, two EE2-treated genetic males had ovarian tissues at the end of the study. We conclude that common levels of EE2 pollution affect grayling from very early stages on by interfering with male and female gene expression around the onset of sex differentiation, by delaying sex differentiation, and by feminizing some males.

2016

Salvatore D. Blair,Derrick Matheson,Yuhe He,Greg G. Goss

Conservation Physiology, (2016), 4(1), 1-11

Reduced salinity tolerance in the Arctic grayling (Thymallus arcticus) is associated with rapid development of a gill interlamellar cell mass: implications of high-saline spills on native freshwater salmonids

Arctic grayling (Thymallus arcticus) are salmonids that have a strict freshwater existence in post-glacial North America. Oil and gas development is associated with production of high volumes of hypersaline water. With planned industrial expansion into northern areas of Canada and the USA that directly overlap grayling habitat, the threat of accidental saline water release poses a significant risk. Despite this, we understand little about the responses of grayling to hypersaline waters. We compared the physiological responses and survivability of Arctic grayling and rainbow trout (Oncorhynchus mykiss) to tolerate an acute transfer to higher saline waters. Arctic grayling and rainbow trout were placed directly into 17 ppt salinity and sampled at 24 and 96 h along with control animals in freshwater at 24 h. Serum sodium, chloride and osmolality levels increased significantly in grayling at both 24 and 96 h time points, whereas trout were able to compensate for the osmo-regulatory disturbance by 96 h. Sodiumpotassium ATPase mRNA expression responses to salinity were also compared, demonstrating the inability of the grayling to up-regulate the seawater isoform nka1b. Our results demonstrated a substantially lower salinity tolerance in grayling. We also found a significant salinity-induced morphological gill remodelling by Arctic grayling, as demonstrated by the rapid growth of an inter-lamellar cell mass by 24 h that persisted at 96 h. We visualized and quantified the appearance of the inter-lamellar cell mass as a response to high salinity, although the functional significance remains to be understood fully. Compared with rainbow trout, which are used as an environmental regulatory species, Arctic grayling are unable to compensate for the osmotic stressors that would result from a highly saline produced water spill. Given these new data, collaboration between fisheries and the oil and gas industry will be vital in the long-term conservation strategies with regard to the Arctic grayling in their native habitat.

Kurt C. Heim;Matthew S. Whitman;Lawrence L. Moulton

Conservation Physiology, (2016), 4(1), https://doi.org/10.1093/conphys/cow055

Arctic grayling (Thymallus arcticus) in saltwater: a response to Blairet al. (2016) Local adaptation to salinity tolerance is common in salmonids and other genera of fishes (Schulte, 2007;Larsenet al., 2008); however, no such comparison has been made across coastal and inland populations of Arctic grayling. Therefore, it is unclear to what extent the results ofBlairet al. (2016)are influenced by their use of specimens from the landlocked providence of Alberta. The differences in osmoregulation abilities across a species range can be great; for example, after transfer to freshwater, specimens from a northern population of common killifish (Fundulus heteroclitus) experienced very little mortality, whereas 19% of fish from a southern population died (Scottet al., 2004). Local adaptation can indeed alter the molecular response of gills to salinity variation (Scott and Schulte, 2005). Furthermore, the closely related European grayling (Thymallus thymallus) has evolved an anadromous form in several locations in the Baltic Sea (Northcote, 1993;Koskinenet al., 2000;Swatdiponget al., 2009), demonstrating the adaptive potential withinThymallidae.Finally, we would also like to point out that anadromous forms of lake trout (Salvelinus namaycush)previously considered the least tolerant salmonid to saltwaterhave recently been discovered (Swansonet al., 2010), and perhaps not coincidentally, thisdiscovery was made in the Arctic. Although the specimens used byBlairet al. (2016)were members of the species Arctic grayling, discretion should be used when extrapolating results of individuals to their species. Perpetuating a strict freshwater existence of Arctic grayling could stifle future research and discovery regarding their physiology, behaviour and population dynamics. Although we do not expect Arctic grayling to have comparable salinity tolerance to rainbow trout, we suggest that coastal populations may show local adaptations that allow use of higher-salinity waters. Replicating the trials ofBlairet al. (2016)with Arctic grayling sourced from coastal watersheds could shed light on this uncertainty. In conclusion, we would like to acknowledge again the well-designed and -conducted study ofBlairet al. (2016)with regard to their main objectives. We agree with the conservation implications ofBlairet al. (2016); the anticipated effects of highly saline water spills into native salmonid habitats should not universally be judged with a euryhaline species, such as the rainbow trout. We hope that this response will lead to an increased understanding of Arctic grayling using saltwaters in coastal regions, as well as entice future research to describe the relative importance and prevalence of this potentially adaptive behaviour.

O. A. Maznikova, P. B. Mikheev

Inland Water Biology, (2016), DOI: 10.7868/S0320965216010137

A Comparative Analysis Of Two Amur Grayling Species

The results of the comparison of the Lower Amur grayling Thymallus tugarinae and the yellow-spotted grayling T. Oavomaculatus that were collected in the zone of their sympatry in the middle reaches of the Anuy River (the Lower Amur basin) for a number of osteological and morphological features are provided. The work was based on the analysis of X-ray images and a number of plastic features. Considerable differences were detected between the two species in the numbers of the bone elements of the axial skeleton. The differences in the number and topography of certain bone elements correlate with the morphological features of these species. The comparison results for certain features do not correspond with the literature data.

2013

Atif Kamil , Arnt Raae , Per Gunnar Fjelldal , Erling Olaf Koppang , Kari E. Fladmark , Ivar Hordvik

Fish & Shellfish Immunology, (2013), 34(2), 667-672

Comparative analysis of IgM sub-variants in salmonid fish and identification of a residue in 3 which is essential forMAb4C10 reactivity

In rainbow trout (Onchorhynchus mykiss) it has been shown that high affinity IgM antibodies have a higher degree of disulfide polymerization and a longer half life time. In the present study, distinct IgM sub-variants related to ancestral tetraploidy in salmonid fish were analyzed to reveal possible characteristic differences between these. A monoclonal antibody (MAb4C10) which distinguishes between IgM-A and IgM-B in Atlantic salmon (Salmo salar) and brown trout (Salmo trutta) was further characterized. It was shown that substitution of a proline located in the loop between the B and C beta strands of the third constant domain (3) of salmon A eliminated MAb4C10 reactivity. Accordingly, the reverse substitution in salmon B restored MAb4C10 reactivity. Molecular cloning of cDNA from arctic char (Salvelinus alpinus) revealed two sub-variants (A-1 and A-2), i.e. a similar situation as in Atlantic salmon and brown trout. However, arctic char IgM eluted in one peak by anion exchange chromatography, in contrast to salmon and brown trout IgM that are eluted in two peaks. The only characteristic residue of salmon and brown trout B is an additional cysteine in the C-terminal part of 4. Most likely, this cysteine is involved in inter-chain disulfide bonding and influences the elution profiles of IgM-A and IgM-B on anion exchange chromatography. Neither of the subvariants in arctic char have the additional cysteine, and char IgM, as well as salmon and brown trout IgM-A, showed a lower degree of inter-chain disulfide bonding than IgM-B when subjected to denaturation and gel electrophoresis under non-reducing conditions. Hybrids of char/salmon expressed A-1, A-2, A and B, indicating that there are two paralogous Ig heavy chain gene complexes in the haploid genome of char, like in Atlantic salmon. A comparison of salmonid sequences is presented, including representatives of Salmoninae (trout, salmon and char), Thymallinae (grayling) and Coregoninae (whitefish).

Anzhelika A. Kolmakova , Michail I. Gladyshev, Galina S. Kalachova, Elena S. Kravchuk, Elena A. Ivanova, Nadezhda N. Sushchik

Freshwater Biology,(2013) 58(10), 21802195

Amino acid composition of epilithic biofilm and benthic animals in a large Siberian river

We studied amino acid (AA) composition of epilithic biofilms and zoobenthos near the shore at a middle section of the Yenisei River (Siberia, Russia). We hypothesised that there was an imbalance between the composition and content of amino acids in the biofilm and its consumers, the zoobenthos, as well as between those in the zoobenthos and fish. Based on monthly sampling from 2007 to 2010, there was seasonal variation in AA profiles in the epilithic biofilms, probably caused by the succession of microalgal and cyanobacterial species. Overall, there was an imbalance in the percentage of the essential amino acids (lysine and histidine) between benthic animals and their food (the epilithic biofilm), which suggests that benthic animals may be limited by food quality. Moreover, the zoobenthos had a significantly higher content of AA, relative to carbon, than the biofilm. Based on sampling in 2012, there was an imbalance between the AA profiles of zoobenthos and that of their main consumer, the Siberian grayling (Thymallus arcticus), particularly in the percentages of two essential amino acids, lysine and leucine. In terms of overall content of essential amino acids, the nutritional value to fish of gammarids, which have recently invaded the river, was significantly lower than that of indigenous taxa, trichopteran and chironomid larvae.

2010

P. B. Mikheev

Journal of Ichthyology, (2010), 50(9), 745749

Seismosensory system of the Lower Amur Grayling Thymallus tugarinae (Thymallidae) from the Anyui River

Data on specific features of the seismosensory system of the Lower Amur grayling Thymallus tugarinae from the Anyui River (basin of the Lower Amur) are provided. According to the number of openings in canals of the seismosensory system, individuals from the middle course significantly differ from graylings from the lower course in greater values of interpopulation diversity and fluctuating asymmetry. According to the number of pores of canals of the seismosensory system, the Lower Amur grayling differs from the East Siberian T. arcticus pallasi, Kamchatka T. a. mertensii, and Alaska T. a. signifer graylings.

1999

Pekka J. Vuorinen, Marja Keinnen, Seppo Peuranen and Christina Tigerstedt

Boreal Environment Research 3: 405419

Effects of iron, aluminium, dissolved humic material and acidity on grayling (Thymallus

thymallus) in laboratory exposures, and a comparison of sensitivity with brown trout

(Salmo trutta)

Iron alone, as well as aluminium, can be acutely lethal in humus-free acidic water. In a simultaneous laboratory exposure to both Fe and Al the toxic effects on grayling were even more pronounced. Water acidity increased and dissolved humic material reduced the toxicity of Fe and Al. As toxic effects, the ionoregulation of yolk-sac fry was disturbed, swimming activity decreased and mortality increased. Based on mortality and swimming activity, brown trout yolk-sac fry tolerated, depending on the Al concentration, nearly half a pH unit more of acidity than those of grayling. The gills of the affected one-summer-old grayling were damaged, leading to decreased oxygen uptake and disturbed iono-regulation. In cold water (3 C), one-summer-old grayling did not recover completely from the sublethal exposure. Some tributary waters of Isojoki, a river in West-Central Finland, were toxic to grayling yolk-sac fry. These waters had rather high Al and Fe concentrations but were humic and only slightly acidic. It is concluded that increased concentrations of Fe and Al increases the harmfulness of waters in forestry land use or peat production areas even in humic and slightly acidic waters.

Grayling Relevant

2017

Monica Giulivo, Ettore Capri, Eleni Kalogianni, Radmila Milacic, BrunoMajone, Federico Ferrari, Ethel Eljarrat, Dami Barcel

Science of the Total Environment 586 (2017) 782791

Occurrence of halogenated and organophosphate flame retardants in sediment and fish samples from three European river basins

Classic (polybromodiphenyl ethers, PBDEs) and emerging halogenated flame retardants (HFRs) such as decabromodiphenyl ethane (DBDPE) and halogenated norbornenes, as well as organophosphate flame retardants (OPFRs) were analysed in 52 sediments and 27 fish samples from three European river basins, namely the Evrotas (Greece), the Adige (Italy) and the Sava (Slovenia, Croatia, Bosnia and Herzegovina and Serbia). This is the first time that FR levels have been reported in these three European river basins. The highest contamination was found in the Adige and Sava rivers, whereas lower values were obtained for the Evrotas. The levels in sediment samples ranged between 0.25 and 34.0 ng/g dw, and between 0.31 and 549 ng/g dw, for HFRs and OPFRs respectively. As regards levels in fish, concentrations ranged between 9.32 and 461 ng/g lw and between 14.4 and 650 ng/g lw, for HFRs and OPFRs, respectively. Thus, whereas OPFR values were higher in sediments, similar concentrations (in the Evrotas) and even lower concentrations than HFRs (Sava) were found for OPFRs in the fish samples, indicating the lower bioaccumulation potential of OPFRs. Biota to sediment accumulation factors (BSAFs) were calculated and higher values were obtained for HFRs compared to those assessed for OPFRs.

Stephen D. Gregory, Marie Nevoux, William D. Riley, William R. C. Beaumont,

Nicholas Jeannot, Rasmus B. Lauridsen, Frederic Marchand, Luke J. Scott, Jean-Marc Roussel

Freshwater Biology, (2017),62(7), 11171129.

Patterns on a parr: Drivers of long-term salmon parr length in U.K. and French rivers depend on geographical scale.

Understanding the geographical scales at which environmental variables affect an individual's body size, and thus their mortality risk, can inform management strategies to help conserve wild populations under climate change. Yet, our current understanding of these relationships is based on

studies done at different scales that report inconsistent findings. We predicted that temperature-related variables (e.g. winter temperature) influence body size at a regional scale, that is, affecting individuals in geographically independent catchments similarly, whereas non-temperature-related variables (e.g. conspecific competitor density) exert a local influence, that is, affecting individuals in geographically independent catchments differently. We developed statistical models to test our predictions using body length measures of a large and long-term sample of juvenile Atlantic salmon (Salmo salar) from three rivers in the U.K. and France. We developed mixture models to predict the individual juvenile salmon ages objectively from their body length. We then developed linear mixed models to describe inter-annual changes in mean length of the youngest (age 0) cohort of juvenile salmon from river-specific seasonal variables, and tested whether they exerted their influence at a local or regional scale. All models accounted for spatiotemporal differences in sampling protocols and individual reproductive strategy. We estimated and interpreted coefficients using Bayesian theory. Our findings supported our predictions. Juvenile salmon were longer in years of higher overwinter water temperature and this effect was best parameterized as a single regional coefficient applicable to all three rivers. Similarly, spring mean temperature was best parameterised with a single regional nonlinear coefficient. In contrast, juvenile salmon were shorter in years of high densities of competing conspecifics and their interaction with total mean discharge and these effects were represented by local river-specific coefficients. Summer droughts had a negative effect on juvenile salmon length but was best parameterised as a single regional coefficient, contrary to our expectations. We show that environmental variables affect biological processes at different but predictable geographical scales. Temperature-related variables affect body sizes of exothermic animals at a regional scale, whereas non-temperature variables, such as the density of conspecific competitors and water abstraction, exert their influence at a local scale. These findings highlight the importance of integrating local and regional management plans to mitigate the impacts of climate change on the body size, and ultimately the conservation, of exothermic species.

2014

Blunt, Brian

University of Alberta, (2014), M.Sc. Thesis: doi:10.7939/R3707WV8H

Fish olfaction: a biosensor for anthropogenic contaminants

Anthropogenic contaminants can impair olfactory responses to natural odorants. In fishes, these impairments may be used as a metric of sub-lethal toxicity. My studies aimed to determine the effects of two contaminant sources on fish olfaction as measured by electro-olfactography (EOG). The effects of treated municipal reuse water and oil sands process affected water were examined in two fish species, goldfish (Carassius auratus) and rainbow trout (Oncorynchus mykiss). Both contaminant sources were found to decrease olfactory responses to odorants during acute (30 min) and long term (60 and 7 d) exposures. My studies also aimed to identify a novel class of odorants (nucleosides). It was determined that nucleosides are detected, as are the nucleobases that comprise part of their structure. Overall the focus of my thesis was to investigate olfactory toxicity in fishes and to characterize a new class of odorants for future studies.

Andrew C. Johnson, John P. Sumpter

Philosophical Transactions of the Royal Society B: Biological Sciences, (2014), 369, issue 1656: DOI: 10.1098/rstb.2013.0581

Putting pharmaceuticals into the wider context of challenges to fish populations in rivers

The natural range of fish species in our rivers is related to flow, elevation, temperature, local habitat and connectivity. For over 2000 years, humans have altered to varying degrees the river habitat. In the past 200 years, we added to the environmental disruption by discharging poorly treated sewage, nutrients and industrial waste into our rivers. For many rivers, the low point arrived during the period of 1950s1970s, when rapid economic development overrode environmental concerns and dissolved oxygen concentrations dropped to zero. In these more enlightened times, gross river pollution is a thing of the past in the Developed World. However, persistent legacy chemical contaminants can be found in fish long after their discharge ceased. Changes in habitat quality and morphology caused and continue to cause the disappearance of fish species. The range of fish stressors has now increased as temperatures rise, and non-native fish introductions bring new diseases. The threat from pharmaceuticals to fish populations remains hypothetical, and no studies have yet linked change in fish populations to exposure.

A. F. Kirillov, I. B. Knizhin

Journal of Ichthyology, (2014), 54(7), 433445

Ichthyofauna of the Lena River (Laptev Sea Basin): Modern composition and historical formation

The modern ichthyofauna of the Lena River includes 46 species and subspecies: 45 bony fishes and one lamprey. In the upper reaches, 24 species have been recorded, 38 in the middle reaches, 36 in the lower reaches, and 24 in the delta. Four of the seven species intentionally introduced into water bodies of the Lena River basin have successfully naturalized; the presence of the others is unconfirmed. All areas of the river are dominated by fishes of the orders Salmoniformes and Cypriniformes. The ranges of the Amur carp Cyprinus rubrofuscus, common bream Abramis brama, ide Leuciscus idus, roach Rutilus rutilus, pike Esox lucius, and perch Perca fluviatilis have expanded over the last few years. The causes and possible ways of the historical formation of the Lena River fish population are discussed in the light of data on the Pleistocene paleo-geographical events and patterns of the distribution of species in the river and in adjacent basins

Judith S. Weis

Toxics (2014), 2(2),165 - 187

Delayed Behavioral Effects of Early Life Toxicant Exposures in Aquatic Biota

Behavioral development occurs together with the development of the nervous system. Studies on mammals indicate that exposures to some chemicals during embryonic development at concentrations that do not produce anatomical malformations may nevertheless produce behavioral deficits later in life, an example of delayed effects. There have been reports of delayed effects in aquatic organisms. Delayed behavioral effects of mercury, chlorinated and other pesticides, polycyclic aromatic hydrocarbons (PAHs), and some synthetic hormones in the environment have been reported in fishes and invertebrates; in some cases behavioral effects are manifested years after the exposure. Another type of delayed behavioral effect results from exposure of mature females before fertilization (maternal exposure). Even when embryos and larvae are reared in clean water, offspring may manifest abnormal behaviors following maternal exposure. The reported behavioral changes are generally deleterious and compromise the fitness of the animal in its natural environment. Delayed effects and their impacts on fitness are not considered in standard short-term embryo bioassays, which will therefore underestimate neurotoxicity. The literature in the field is scattered and has not been reviewed. The objective of this paper is to review and synthesize what is known about delayed behavioral effects in aquatic biota

2012

M. I. Gladyshev, O. V. Anishchenko, N. N. Sushchnik, G. S. Kalacheva, I. V. Gribovskaya, A. V. Ageev.

Contemporary Problems of Ecology, (2012), 5(4), 376385

Influence of anthropogenic pollution on content of essential polyunsaturated fatty acids in links of food chain of river ecosystem

In the course of monthly sampling in 20082010, two regions of the littoral of the Yenisei river were compared. One of these regions (conventionally pure) was situated upstream of Krasnoyarsk, while the other (conventionally polluted) was downstream of Krasnoyarsk. The concentrations of heavy metals, oil products, phenols, biogenic elements and essential polyunsaturated fatty acids (PUFAs) in various components of the river ecosystem were determined. It was discovered that the anthropogenic pollution causes a decrease in the resources of essential PUFA in the biomass of the upper links of the food chain of the river ecosystem.

Judith Weis and Alison Candelmo

Current Zoology, (2012), 58(1), 9 20

Pollutants and fish predator/prey behavior: A review of laboratory and field approaches

Fish behavior can be altered by contaminants. There is an extensive literature on laboratory behavioral assays, with many chemicals impairing feeding or predator avoidance. However, there is not extensive work on fishes that live in contaminated environments. Therefore, we then review our recent research on feeding and trophic relations of populations from contaminated estuaries compared with relatively unpolluted sites. The mummichogFundulus heteroclitus, is a non-migratory fish; those from more contaminated areas are poor predators and slower to capture active prey (grass shrimp,Palaemonetes pugio). In the field, they consume much detritus and sediment, which is not nutritious. They are less active than fish from cleaner sites and more vulnerable to predation. They have altered thyroid glands and neurotransmitter levels, which may underlie altered behaviors. Fish from the reference site kept in tanks with sediment and food from the polluted site showed bioaccumulation and reduced prey capture after two months, although fish from the polluted site did not show significant improvement when maintained in a clean environment. Poor nutrition and predator avoidance may be responsible for their being smaller and having a shorter life span than reference fish. BluefishPomatomus saltatrix, are a marine species in which the young-of-the-year spend their first summer in estuaries. We found bioaccumulation of contaminants and reduced activity, schooling, and feeding in young-of-the-year bluefish from a relatively unpolluted site that were fed prey fish from a contaminated site. They also had altered thyroid glands and neuro-transmitter levels. Many field-caught specimens had empty stomachs, which is rare in this species. In the fall, when they migrate back out to the ocean, they are smaller, slower, and more likely to starve or to be eaten than those that spent their summer in cleaner estuaries.

Diseases / Aquaculture

Grayling Specific

2015

P. Hork , P. Horky, T. Randk, J. Turek, K. Rylkov, O. Slavk

Journal of Fish Biology, (2015), 86(2), 544557

Radio-telemetry shows differences in the behaviour of wild and hatchery-reared European grayling Thymallus thymallus in response to environmental variables.

Juvenile wild and hatchery-reared European grayling Thymallus thymallus were tagged with radio-transmitters and tracked in the Blanice River, River Elbe catchment, Czech Republic, to study their behavioural response to stocking and environmental variation. Both wild and hatchery-reared T. thymallus increased their diel movements and home range with increasing light intensity, flow, temperature and turbidity, but the characteristics of their responses differed. Environmental variables influenced the movement of wild T. thymallus up to a specific threshold, whereas no such threshold was observed in hatchery-reared T. thymallus. Hatchery-reared fish displayed greater total migration distance over the study period (total migration) than did wild fish, which was caused mainly by their dispersal in the downstream direction.

Horvath, A.B., Zoltan, B.G., Urbanyi, B., Snoj, A., Susnik-Bajec, S., Jesensek, D.

Vii International Conference Water & Fish Zbornik Predavanja, (2015): http://arhiva.nara.ac.rs/handle/123456789/824

Application of Sperm Cryopreservation to The Culture and Conservation of Salmonid Species: A Slovenian-Hungarian Collaboration

Sperm cryopreservation was applied to the conservation efforts of two salmonid species autochthonous to the drainage of the Soa river in Slovenia, the marble trout (Salmo marmoratus) and the Adriatic lineage of the grayling (Thymallus thymallus). Populations of these species were seriously compromised by hybridization and introgression with allochthonous species: the brown trout (Salmo trutta m. fario) and the Danubian lineage of the grayling that were introduced to the Soa drainage during the 20th century. The Angling club of Tolmin, that manages a part of the Soa system has developed an action plan for the conservation of the genetic resources and restoration of the autochthonous species in their original habitats. This action plan includes the cessation of the stocking of any allochthonous salmonids that could hybridize with the local species, identification of existing pure populations, establishment of broodstocks of non-introgressed individuals, stocking the rivers with the progeny of the broodstocks, creation of sanctuary streams for the existing pure populations and continuous monitoring of fish populations in their watercourses. Genetic analyses of the populations are conducted by scientists from the Department of Animal Science of the University of Ljubljana. Cryopreservation of sperm from the Adriatic grayling and the marble trout has constituted an integral part of the conservation activities since 2009. In case of the grayling, no pure populations remain, thus, the objective of the conservation program is to increase the proportion of Adriatic genotype in the broodstock. Sperm and fin clips were collected from wild males on the spawning grounds. Sperm was cryopreserved and stored until the genetic analysis was completed on each sample (2-3 weeks). Cryopreserved sperm of individuals containing higher than a pre-defined proportion of Adriatic genotype was thawed and used for fertilization of eggs known Adriatic females. Progeny hatching from eggs fertilized with cryopreserved sperm was grown to broodstock and currently 70-80% of the local grayling broodstock originates from cryopreserved sperm. In case of the marble trout, sperm cryopreservation is used in the creation of sanctuary streams. Sperm is collected from wild males of a given pure population prior to the spawning season (early November) and cryopreserved. Sperm is stored in liquid nitrogen until the spawning season (December-January) when eggs of females from the identical population are fertilized with the cryopreserved sperm. Eyed eggs are then stocked into artificially created nests in the prepared sanctuary stream. Thus, a high number of males of the given pure population participates in the creation of the new population, removal of males from the original population is unnecessary, and stocking of eyed eggs ensures imprinting at the new location. The same protocol is used for cryopreservation of both species: sperm is mixed at a ratio of 1:1 with an extender containing 200 mM glucose, 40 mM KCl, 30 mM Tris (pH set to 8.0 with cc. HCl) and methanol is used as a cryoprotectant at 10% v/v final concentration. Diluted sperm is loaded into 0.5-ml straws and frozen in the vapor of liquid nitrogen at 3 cm above the level of nitrogen for 3 minutes. Following storage in liquid nitrogen, samples are thawed at a 40 C water bath for 13 sec. The developed protocol results in 50-70% hatch in both species.

2014

Bastian Fromm, Susann Burow, Christoph Hahn, Lutz Bachmann

International Journal for Parasitology, (2014), 44(11), 787-793

MicroRNA loci support conspecificity of Gyrodactylus salaris and Gyrodactylus thymalli (Platyhelminthes: Monogenea)

The monogenean flatworm Gyrodactylus salaris is a serious threat to wild and farmed Atlantic salmon stocks in Norway. Morphologically, the closely relatedbut harmless Gyrodactylus thymalli on grayling can hardly be distinguished from G. salaris. Until now, molecular approaches could not resolve unambiguously whether G. salaris and G. thymalli represent just one polytypic species, two polytypic species or a complex of more than two species. In the first known genome-wide analysis utilizing 37 conserved microRNA loci, the genetic differentiation of seven populations of G. salaris and G. thymalli was assessed. The concatenated alignment spanned 21,742 bp including 62 variable positions. A neighbor-joining cluster analysis did not support any host-based or mitochondrial haplotype-based grouping of strains. We conclude that a two species concept for G. salaris and G. thymalli does not reflect meaningful biological entities. Instead, G. salaris and G. thymalli are just one species comprising several pathogenic and non-pathogenic strains on various primary hosts. Following the International Code for Zoological Nomenclature, G. salaris Malmberg, 1957 is the valid species name with G. thymalli itan, 1960 becoming the junior synonym. Accordingly, the range of G. salaris is significantly increased, given that formerly G. salaris-free countries such as e.g., Great Britain are now within the species natural range. The synonymization of G. salaris and G. thymalli implies severe challenges to current disease management routines, which assume that G. salaris and G. thymalli are readily distinguishable. Protocols for reliable identification of pathogenic and non-pathogenic strains of G. salaris need to be developed.

Giuseppe Paladini, Haakon Hansen, Chris F Williams, Nick GH Taylor, Olga L Rubio-Meja, Scott J Denholm, Sigurd Hytterd, James E Bron and Andrew P Shinn.

Parasites & Vectors 2014, 7:576 589.

Reservoir hosts for Gyrodactylus salaris may play a more significant role in epidemics than previously thought.

Gyrodactylus salaris Malmberg, 1957 has had a devastating impact on wild Norwegian stocks of Atlantic salmon Salmo salar L., and it is the only Office International des Epizooties (OIE) listed parasitic pathogen of fish. The UK is presently recognised as G. salaris-free, and management plans for its containment and control are currently based on Scandinavian studies. The current study investigates the susceptibility of British salmonids to G. salaris, and determines whether, given the host isolation since the last glaciation and potential genetic differences, the populations under test would exhibit different levels of susceptibility, as illustrated by the parasite infection trajectory over time, from their Scandinavian counterparts. Populations of S. salar, brown trout Salmo trutta L., and grayling Thymallus thymallus (L.), raised from wild stock in UK government hatcheries, were flown to Norway and experimentally challenged with a known pathogenic strain of G. salaris. Each fish was lightly anaesthetised and marked with a unique tattoo for individual parasite counting. A single Norwegian population of S. salar from the River Lrdalselva was used as a control. Parasite numbers were assessed every seven days until day 48 and then every 14 days. Gyrodactylus salaris regularly leads to high mortalities on infected juveniles S. salar. The number of G. salaris on British S. salar rose exponentially until the experiment was terminated at 33 days due to fish welfare concerns. The numbers of parasites on S. trutta and T. thymallus increased sharply, reaching a peak of infection on days 12 and 19 post-infection respectively, before declining to a constant low level of infection until the termination of the experiment at 110 days. The ability of S. trutta and T. thymallus to carry an infection for long periods increases the window of exposure for these two hosts and the potential transfer of G. salaris to other susceptible hosts. This study demonstrates that G. salaris can persist on S. trutta for longer periods than previously thought, and that the role that S. trutta could play in disseminating G. salaris needs to be considered carefully and factored into management plans and epidemics across Europe.

2013

Tuija Gadd, Satu Viljamaa-Dirks , Riikka Holopainen , Perttu Koski , Miia Jakava-Viljanen

Diseases of Aquatic Organisms, (2013), 106: 117127.

Characterization of perch rhabdovirus (PRV) in farmed grayling Thymallus thymallus Two Finnish fish farms experienced elevated mortality rates in farmed grayling Thymallus thymallus fry during the summer months, most typically in July. The mortalities occurred during several years and were connected with a few neurological disorders and peritonitis. Virological investigation detected an infection with an unknown rhabdovirus. Based on the entire glycoprotein (G) and partial RNA polymerase (L) gene sequences, the virus was classified as a perch rhabdovirus (PRV). Pairwise comparisons of the G and L gene regions of grayling isolates revealed that all isolates were very closely related, with 99 to 100% nucleotide identity, which suggests the same origin of infection. Phylogenetic analysis demonstrated that they were closely related to the strain isolated from perch Perca fluviatilis and sea trout Salmo trutta trutta caught from the Baltic Sea. The entire G gene sequences revealed that all Finnish grayling isolates, and both the perch and sea trout isolates, were most closely related to a PRV isolated in France in 2004. According to the partial L gene sequences, all of the Finnish grayling isolates were most closely related to the Danish isolate DK5533 from pike. The genetic analysis of entire G gene and partial L gene sequences showed that the Finnish brown trout isolate ka907_87 shared only approximately 67 and 78% identity, respectively, with our grayling isolates. The grayling isolates were also analysed by an immunofluorescence antibody test. This is the first report of a PRV causing disease in grayling in Finland.

V. vinger, T. Hansen, Y. Shadrin, T. Policar, J. Kouril

Czech J. Anim. Sci., 58, 2013 (1): 814

Induction and advancement of ovulation in wild Arctic grayling (Thymallus arcticus arcticus) using D-Tle6,Pro9,NEt-mGnRHa Lecirelin

The effect of single and double injections of D-Tle6,Pro9,NEt-mGnRHa (Supergestran) on advancement and induction of ovulation in Arctic grayling was assessed. Sexually mature wild Arctic grayling females (most 24 years old) were caught in the Yenisey River at the beginning of May 2010. After a 4-day acclimatization, the females were randomly divided into four groups and intramuscularly injected as follows: group A, control group, treated with physiological saline only; group B, treated with a single injection (SI) of Supergestran at 25 g/kg body weight (BW); group C, injected twice (DI) with 25 g/kg BW 3 days apart; group D, injected twice with 10 g/kg BW 3 days apart. After stripping, the pseudo-gonadosomatic index was calculated, and an eggs sample from each female was fertilized. Only fish in the groups treated with DI protocols ovulated. No differences between the two groups were found in the timing of ovulation, ovulation rate, or mean time to ovulation. No females in either group A or B ovulated, since the experiment had to be prematurely terminated due to technical problems at the field hatchery. The DI of 10 g/kg proved sufficient to induce and advance ovulation in Arctic grayling. Hormone treatments seem to be a promising tool to obtain viable eggs of Arctic grayling in a short time window and thereby to ensure satisfactory numbers of fry for restocking programs.

2010

Mariusz Szmyt, Stefan Dobosz, Dariusz Kucharczyk, Joanna Grudniewska, Adam M. Lejk

Archives of Polish Fisheries (2012), 20, 289 297.

Impact of selected hormonal agents on the effectiveness of controlled reproduction of cultivated female European grayling

The suitability of the hormonal agents Ovopel (one granule kg-1female body weight), human chorionic gonadotropin - hCG (1000 IU kg female body weight), and carp pituitary homogenate - CPH (3 mg kg female body weight) for use in the controlled reproduction of female European grayling, Thymallus thymallus (L.), was tested. The fish from the control group were administered injections of saline solution (0.5 cm kg female body weight). The agents were administered in single intraperitoneal injections. The effectiveness of Ovopel and CPH injections was 100%, while hCG stimulation resulted in ovulation in 90% of the females. Just 40% of the females ovulated in the control group. The total latency time from injection to ovulation in the last females which ovulated was 87.9D. Embryo survival to the eyed egg stage was 29.23% for Ovopel, 20.22% for hCG, 14.80% for CPH, and 47.50% in the control group. The highest spawning effectiveness coefficient (Se) was confirmed in the group of fish administered Ovopel (0.29), while the lowest was in the CPH group (0.15). Following the administration of hCG, the Se was 0.18, while in the control group it was 0.19. Hormonal stimulation was not noted to have had a negative impact on spawner survival.

Irina A. Kaygorodova, Elena V. Dzyuba, and Nikolay M. Pronin

The Scientific World Journal

Volume 2012, Article ID 652827, 8 pages

Leech-Like Parasites (Clitellata, Acanthobdellida) Infecting Native and Endemic Eastern Siberian Salmon Fishes

Salmonoid fish bdellosis is caused by leech-like ectoparasites in the monogenetic order Acanthobdellida. Although Acanthobdella species have been known to infect several threatened species in Eurasia, little is known about their ecology and epidemiology. In this paper, we report on the mass affection (up to 70.7%) of fish in lower course of the Chechuj River, a right tributary of the Lena and provide information on finding Acanthobdella peledina on two of six salmonoid fish species inhabiting there: lenok and grayling. New and more specific data on morphological peculiarities and feeding strategy were obtained. The ratio of body length to width in studied acanthobdellid collection is significantly less than one provided for the A. livanowi and the rest A. peledina from other water systems of Eurasia. Biology and lifestyle of the parasite population are revealed for the first time.

2010

Diane P. Loopstra and Patricia A. Hansen

Alaska Department of Fish and Game, (2010), Fishery Data Series No. 10-55

Induction of Triploidy in Arctic Grayling (Thymallus arcticus) using Hydrostatic Pressure

Hydrostatic pressure was applied to fertilized Arctic grayling (Thymallus arcticus) eggs in 2004, 2005, and 2006 to induce triploidy. In 2004, eggs collected from Chena River broodstock were pressure shocked for 5 minutes beginning at 100, 175, or 250 Cumulative Temperature Minutes (CTMs) post fertilization with 9,000, 9,500, or 10,000 psi of pressure. The three treatments shocked at 100 CTMs failed to achieve a minimum average eyed-egg survival rate criterion 70% of the control group. All three treatments shocked at 175 CTMs achieved an average eyed-egg survival rate 70% of the control group. The 9,000 and 9,500 psi treatments shocked at 250 CTMs achieved an average eyed-egg survival rate 70% of the control group. Each treatment tested for ploidy in 2004 achieved a 100% triploid rate. In 2005, Arctic grayling eggs were pressure shocked at 175 CTMs post fertilization with 7,500, 8,500, or 9,500 psi of pressure for 5 minutes. Eggs shocked with 7,500 psi of pressure had a mean survival rate 20 cm was found. Trout catches by anglers increased after stocking ceased and approximately 60% of the anglers were convinced that stocking was unnecessary to maintain the brown trout stocks or angler catch satisfaction.

Nslund, T. Eriksson, D. Hannersj, L. Bergwall, G. Jacobsson, K. Leonardsson

Fisheries Management and Ecology, (2010), 17(1),5262

Time trends in angler compliance with harvest regulations in stream fisheries

Harvest regulations in stream fisheries are used to improve fisheries and protect vulnerable fish stocks, but objectives are often not fulfilled. Roving interviews of grayling, Thymallus thymallus L., and brown trout, Salmo trutta L., anglers in north Swedish streams were performed during a 15-year-period to reveal the effects of regulation changes and levels of compliance. Harvest of fish below minimum size limits declined with time in river sections with 25- and 30-cm minimum size limits. No clear time trend was found for the 35-cm size limit. In addition, the proportion of voluntary released legal-sized fish increased over time, indicating a change in angler attitudes. The overall effect of increasing the minimum size limit was lowering of angler-induced fishing mortality. Interview data revealed perception, shared by many anglers, of an acceptable fish size to take home for food. From a management perspective, the realised effect of angler behaviour on the fish populations needs to be considered.

J. Salmi, P. Salmi

Fisheries Management and Ecology, (2010), 17(2), 192198

Fishing tourism, biodiversity protection and regional politics in the River Tornionjoki, Finland

Salmon, Salmo salar L., fishing involves a broad range of interest groups and is thus a challenge for fisheries governance. This article focuses on the natural River Tornionjoki between Finland and Sweden, the most important wild salmon river in the Northern Baltic Sea. The marine salmon fisheries have been restricted to protect the declining wild salmon stocks and secure catches for fishing tourism. River fisheries interest groups have been absent from the salmon committees, but have taken other measures to influence salmon fisheries politics. This social movement has achieved its aims only partly, because of counteractions by the coastal commercial fishers and their associations. A forum for enabling dialogue between stakeholders is recommended to reduce tensions between the commercial fishery and tourism industry.

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