White Sucker Research Articles

Attraction, Entrance, and Passage Efficiency of Arctic Grayling, Trout, and Suckers at Denil Fishways in the Big Hole River Basin, Montana

AbstractThe Big Hole River basin in southwestern Montana supports the only indigenous, self‐sustaining fluvial population of Arctic Grayling Thymallus arcticus in the conterminous United States, but the basin is fragmented by numerous low‐head irrigation diversion dams. Denil fishways at 63 diversion dams provide Arctic Grayling and other fishes opportunities for year‐round access to critical habitats; however, their efficiency has not been evaluated. We quantified attraction, entrance, and passage for hatchery‐reared Arctic Grayling, wild trout (Brook Trout Salvelinus fontinalis and Brown Trout Salmo trutta), and wild suckers (White Sucker Catostomus commersonii and Longnose Sucker C. catostomus) during 14 field trials conducted at six Denil fishways over a representative range of fishway slopes and hydraulic conditions using passive integrated transponder telemetry. Attraction (60.4–84.3%) and entrance (44.3–78.6%) efficiencies were variable across test conditions and reduced overall fishway efficiencies (19.1–55.8%). In contrast, upon entry, passage efficiencies were high (96.2–97.0%) for all taxa across all test conditions. Attraction of hatchery‐reared Arctic Grayling increased with upstream depth (a surrogate for fishway discharge) and attraction flow, but attraction of wild fish was less affected by these conditions. Entrance of Arctic Grayling, Brook Trout, and Brown Trout decreased with upstream depth and fishway slope, especially when plunging entrance conditions associated with shallow downstream depths were present. However, entrance of Arctic Grayling and both trout species increased with downstream depth, and submerged fishway entrances demonstrated promise for increasing entrance efficiency at fishways with high discharges and steep slopes. We demonstrate that comprehensive evaluations of fishway efficiency components can identify specific solutions that improve fishway efficiency; application of these engineering solutions at individual fishways (as needed) could improve their efficiency and further enhance aquatic connectivity for fishes in the Big Hole River basin and elsewhere.

Comparison of Marine Ecosystems of Haizhou Bay and Lvsi Fishing Ground in China Based on the Ecopath Model

Recently, under the impacts of environmental shifts and human activities, marine ecosystem conservation and recovery have become increasingly important for the management and sustainable development of fishery resources. We construct two Ecopath models to describe and compare the similarities and differences in the structure and function of the ecosystems in Haizhou Bay (HZB) for 2020–2021 and Lvsi Fishing Ground (LSFG) for 2018–2019 in this study. Our results highlight the similarities of the two ecosystems in which plankton (e.g., zooplankton and phytoplankton) are important functional groups with bottom-up effect control and congers control the top-down effect. The differences between the two ecosystems indicate that the HZB ecosystem is relatively mature due to higher Finn’s cycling index (FCI), Finn’s mean path length (FMPL), Connectance Index (CI), System Omnivory Index (SOI), and Ascendency/capacity (A/C). However the food web structure in the LSFG is more diverse and stable with higher Overhead/capacity (O/C) and Overhead/capacity (H). The differences are possibly due to the low trophic level (TL) species composition in the two ecosystems. Therefore, we suggest that stock enhancement and release methods should be deployed to release high TL species into designated water areas to increase food web complexity and ecosystem maturity in HZB and LSFG. This study will help inform ecosystem and fishery regulations in different ways and facilitate discussion towards the establishment of strategic conservation planning and adaptive management.

Influence of beaver mimicry restoration on habitat availability for fishes, including Arctic grayling (Thymallus arcticus)

AbstractBeaver dam mimicry is an emergent conservation practice. We evaluated the influence of constructed riffles, a unique type of beaver mimicry aimed to store water and allow fish passage, on habitat for fishes in one control reach and one manipulated reach with mimicry structures added. The beaver mimicry reach had deeper pool habitats and deeper and wider riffle habitats compared to an unmanipulated control reach. Dissolved oxygen was similar among reaches, averaging 8.7 ± 0.2 and 8.9 mg/L in the beaver mimicry and control reaches, respectively. Sediment size was also similar among reaches, with a D50 of 8.1 and 10.6 mm in the beaver mimicry and control reaches, respectively. The beaver mimicry reach had little to no overhanging bank vegetation or riparian vegetation shade cover, while the control had 38% of its bank covered by canopy and 56% overhung by vegetation. These riparian characteristics result from a legacy of livestock grazing and lack of consistent vegetation planting during restoration. Longnose dace (Rhinichthys cataractae) and white sucker (Catostomus commersonii) dominated in the beaver mimicry reach, together comprising 70% of the fish assemblage post‐structure installation. Arctic grayling (Thymallus arcticus) was not found in the beaver mimicry reach but was present in the control, albeit in small numbers of only 3% of the assemblage post‐structure installation. These results highlight the need to consider both in‐stream and riparian habitat features for fishes, as well as timescales of both hydrological and ecological outcomes in restoration design.

Comparison of catch in multifilament and monofilament gill nets in a long-term survey on Lake Michigan

Long-term fishery independent surveys provide metrics of relative abundance and contribute biological information critical to effective fisheries management. Improvements in technology and manufacturing processes have had profound effects on gear efficiency. In Lake Michigan, a standardized multi-agency fish community survey was adopted in 1998 which used multifilament nets to survey nearshore fish communities. Contemporary commercial gill netting operations largely utilize monofilament nets because they’re less expensive, more durable and thought to be less visible and therefore more efficient. As such, interest in converting long-term agency surveys to monofilament nets has grown. To compare catch rates and the size of fish collected, we set similarly configured nets of both mesh materials on the same day at standard survey locations. The most common species captured in the survey were lake trout (52%), yellow perch (19%), lake whitefish (15%), longnose sucker (8%), white sucker (4%) and burbot (1%). Monofilament nets were more efficient in capturing lake whitefish and longnose sucker and equally efficient in capturing other species. On average, nearly three times (2.85) as many lake whitefish were captured in monofilaments nets, and two times as many longnose suckers (2.13). Larger lake whitefish and yellow perch were captured in monofilament nets, whereas lake trout were slightly smaller. For other fish species, similar sizes were captured in each net material. This evaluation incorporated broad replication (298 paired nets) and representation from diverse locations and depth strata in Lake Michigan to inform gear conversion efforts and allow for adjustments as needed in gear conversion efforts.

Interactions of a temperate North American fish community with a very low head hydropower facility in Ontario, Canada

AbstractEfforts are underway to re‐evaluate the use of existing instream infrastructure (e.g., weirs, water control dams) for the purposes of hydroelectric generation, with new very low head turbine technology that is purportedly “fish friendly” making retrofitting a viable option. This is the case at Wasdell Falls on the Severn River, ON, Canada, where the first very low head (VLH) turbines in Canada were put into operation at a long‐standing low‐head dam site. There is little information regarding fish usage of areas upstream from these structures and how this may relate to entrainment risk. Therefore, we assessed the risk of entrainment based on fish use of the forebay areas upstream from the infrastructure, including the forebay of three operating VLH turbines. Acoustic telemetry was used to determine movements and entrainment events of eight north temperate fish species. Entrainment through the VLH turbines did not occur over the course of one year, however, several fish did move downstream via other paths (e.g., over the water control structure). Forebay use was exclusive to rock bass, smallmouth bass, northern pike and largemouth bass, whereas channel catfish, walleye, white sucker and pumpkinseed avoided the forebay. When near the dam, fish tended to select deeper areas located away from the VLH forebay. Fish use of the VLH forebay was limited to brief forays indicating exploratory movements rather than prolonged residence. The findings suggest that entrainment risk at this VLH turbine site is low for the species and life stages studied.

The Morphology and Description of Glaridacris catostomi Cooper, 1920 (Cestode: Caryophyllidae) from Catostomid Fishes in Lakes and Rivers of Wisconsin, with Morphological Observations

Thirteen species in 8 genera of caryophyllid cestodes including Glaridacris catostomi Cooper, 1920 were found in Catostomus commersoni (Lacépède), Cyprinus carpio (Raf.), and Erimyzon sucetta (Lacépède) in 2 lakes and 2 streams in SE Wisconsin and/or SW Lake Michigan. The morphology of the Wisconsin populations of G. catostomi is revisited using light microscopy revealing new features of the scolex and reproductive organs. The development of scolex and some reproductive structures were observed in maturing specimens. We describe new specimens and provide a comparative morphometric data with other earlier descriptions by Cooper, Hunter, and Mackiewicz. Our specimens were largest compared to those examined by other observers and many structures were correspondingly larger. The status of the genus Glaridacris was discussed in terms of most recent taxonomy and its evolutionary relationships.

A Morphological Study and Description of Biacetabulum biloculoides Mackiewicz and Mccrae, 1965 (Cestoda: Caryophyllidae) From Catostomid Fishes in Lakes and Rivers of Wisconsin, With Special Notes on Concurrent Infections

Thirteen species in 8 genera of caryophyllid cestodes including Biacetabulum biloculoides Mackiewicz and McCrae, 1965 were found in Catostomus commersoni (Lacépède), Cyprinus carpio (Raf.), and Erimyzon sucetta (Lacépède) in 2 lakes and 2 rivers in SE Wisconsin and/or SW Lake Michigan. The morphology of the Wisconsin populations of B. biloculoides is revisited and missing information from the original description and ours were completed and all measurements compared. The posterior movement of Acanthocephalus dirus (Van Cleave, 1931) Van Cleave and Townsend, 1936 and the anterior movement of B. biloculoides and Glaridacris catostomi Cooper, 1920 in concurrent infections of the intestine of C. commersoni were discussed as a clear case of competitive exclusion. Light microscopy revealed new features especially of the scolex and reproductive structures.

Diel Movement by White Suckers (Catostomus commersonii) in Connected Northern Lakes

Consistently repeated daily habitat shifts by fish can expose or protect individuals from a variety of threats and influence nutrient transport between systems, yet logistical constraints make individual horizontal movement difficult to study on short time scales. As a result, diel movements by fish are often poorly documented. Suckers (Catostomidae) are a key group of fish that have been frequently examined with this in mind, as many species are large, long-lived, and comprise a large proportion of biotic biomass in many waters. Previous studies in rivers have shown that multiple sucker species exhibit complex, diel movement. We investigated the prevalence of short-term movement by the widely distributed Catostomus commersonii (White Sucker) in an interconnected, remote lake system within New York's Adirondack region using PIT telemetry. These 2 lakes were in a remote setting of New York's Adirondacks, and our tracking studies indicated a subset of the sucker population regularly traveled back and forth daily through a short, shallow channel. Direction of movement was strongly associated with time of day, and larger individuals were far more likely to engage in this repetitive behavior. Overall, these findings highlight the potential for extensive, yet generally unobserved, movement by White Suckers within connected lake systems.

Measurable Levels of Short-Chain Chlorinated Paraffins in Western Hudson Bay Fishes but Limited Biomagnification from Fish to Ringed Seals.

We investigated short-chain (C10-13 ) chlorinated paraffins (SCCP) in an Arctic marine food web. In zooplankton, fishes, and ringed seals from western Hudson Bay, Canada, SCCP concentrations ranged from 38.3 to 687 ng g-1 lipid weight. Monte Carlo-simulated trophic-adjusted biomagnification factors of individual SCCP congeners ranged from 0.07 to 0.55 for small pelagic fishes to seals. Despite relatively high concentrations in fishes, biomagnification of SCCPs within this food web appears limited. Environ Toxicol Chem 2021;40:2990-2999. © 2021 SETAC.

Parallel evolution of morphological traits and body shape in littoral and pelagic brook charr, Salvelinus fontinalis, along a gradient of interspecific competition.

The parallel evolution of similar ecotypes in response to comparable environmental conditions is believed to reveal the importance of divergent selection in phenotypic diversifying processes. Systems characterized by the presence of multiple replicate populations expressing resource polymorphism thus provide an ideal opportunity to address the occurrence and factors affecting the parallel evolution of ecotypes. Previous studies have shown that brook charr (Salvelinus fontinalis) exhibit resource polymorphism in some Canadian Shield lakes, where a littoral ecotype feeds mainly on zoobenthos and a pelagic ecotype feeds mostly on zooplankton. Using morphological traits and geometric morphometric analyses on 18 native brook charr populations, we explicitly tested (i) whether brook charr ecotypes show parallel evolution across populations (i.e. the same morphological traits discriminate ecotypes among lakes) and (ii) whether interspecific competition decreases the amplitude of morphological differentiation between ecotypes, if any, because brook charr experience some level of competitive exclusion from the littoral habitat in the presence of creek chub or white sucker. We observed a low level of parallel evolution, where the littoral ecotype was overall stouter with longer fins and smaller eyes than the pelagic ecotype. Interspecific competition had no clear impacts on the amplitude of morphological differentiation. We also observed that inter-lake morphological differences are greater than between ecotypes within lakes, suggesting an important effect of local environmental factors on population morphology. Early-stage of diversification as well as phenotypic plasticity and morphological integration could explain why resource polymorphism is still subtle in brook charr populations.

A species-specific fish passage model based on hydraulic conditions and water temperature

Stream corridors contain many features that act as barriers to fish during migration. We built a model to determine the likelihood that each of 776 dams, culverts and waterfalls in New Jersey act as barriers to each of thirteen fish species during migration. We assessed each fish species at each potential barrier to determine if the fish could jump high enough to clear the barrier, swim fast enough to overcome the velocity of water to reach the barrier, dive deep enough in the plunge pool to reach maximum jump height, and persist with migration given predicted water temperatures. If all four were possible, the potential barrier was deemed passable. Blockages were mostly the result of predicted weak jumping abilities and water temperatures outside the acceptable range during migration. The model successfully predicted presence and absence above potential barriers for all species except the ubiquitous white sucker (C. commersonii). All locations with possible barriers were predicted to block at least two migratory fish species; 89% were predicted to block all species. Alewife (A. pseudoharengus) and blueback herring (A. aestivalis) were predicted to be blocked the most. Results allow prediction of which potential barriers block passage for each species, the length of waterways blocked by each barrier, and the reasons each barrier is predicted to block each species. We present our fish passage model as a tool for identifying possible barriers which if restored or removed, given appropriate field assessment, might reconnect migratory fish species with additional spawning habitat.

THE LEGALITY OF THE AUTOMATIC TERMINATION OF CONTRACTS OF EMPLOYMENT

The Labour Relations Act (66 of 1995) (LRA) protects employees against unfair dismissal. In terms of section 186(1)(a) dismissal means that “an employer terminated a contract of employment with or without notice”. In order to fall within the ambit of this provision and benefit from the protections afforded by the LRA, an employee must prove that an overt act on the part of the employer has resulted in the termination of the employment contract (Ouwehand v Hout Bay Fishing Industries 2004 25 ILJ 731 (LC)). The onus then shifts to the employer to prove that the dismissal is both substantively and procedurally fair, failing which the employee will be entitled to theremedies afforded by section 193 of the LRA. However, not every termination of an employment contract constitutes a dismissal and a number of scenarios exist where an employment contract terminates lawfully by operation of law. The termination of a fixed-term contract by effluxion of time, termination of the contract due to supervening impossibility of performance and the attainment of a contractually agreed or implied retirement age all give rise to the lawful termination of an employment contract. Similarly the statutory “deemed-dismissal” provisions of application to employees in the public sector provide for the automatic termination of employment contracts in circumstances that the employee is absent without authorisation for a designated period of time. The effect of such automatic termination is that the employment contract terminates by operation of law and not by means of an act of the employer, resulting in the dismissal provisions of the LRA being legitimately circumvented. Labour-broking contracts typically include automatic termination clauses that provide for the automatic termination of employment contracts, between labour-brokers and their employees, when the broker’s client no longer requires the services of such employees. Similarly employers have sought to rely upon grounds of supervening impossibility of performance in order to argue that an employment contract has automatically terminated in the instance of absconding and imprisoned employees. This article will be examining the legality of the automatic termination of employment contracts in these contexts and the impact on employees’ rights to protection against unfair dismissal.

It's complicated: Heterogeneous patterns of genetic structure in five fish species from a fragmented river suggest multiple processes can drive differentiation.

Fragmentation of river systems by dams can have substantial genetic impacts on fish populations. However, genetic structure can exist naturally at small scales through processes other than isolation by physical barriers. We sampled individuals from five native fish species with varying life histories above and below a dam in the lower Boardman River, Michigan, USA, and used RADseq to investigate processes influencing genetic structure in this system. Species assessed were white sucker Catostomus commersonii, yellow perch Perca flavescens, walleye Sander vitreus, smallmouth bass Micropterus dolomieu, and rock bass Ambloplites rupestris. We detected significant differentiation within each species, but patterns of population structure varied substantially. Interestingly, genetic structure did not appear to be solely the result of fragmentation by the dam. While genetic structure in yellow perch and walleye generally coincided with “above dam” and “below dam” sampling locations, samples from our other three species did not. Specifically, samples from rock bass, smallmouth bass, and, to a much lesser extent, white sucker, aligned with a putative Great Lakes (GL) group that contained mostly individuals sampled below the dam and a putative Boardman River (BR) group that contained individuals sampled both above and below the dam, with some evidence of admixture among groups. We hypothesize that the GL and BR groups formed prior to dam construction and our samples largely represent a mixed stock that was sampled sympatrically outside of the spawning season. Support for this hypothesis is especially strong in smallmouth bass, where GL fish were 151 mm smaller than BR fish on average, suggesting a potential ontogenetic habitat shift of young GL fish into the lower river for feeding and/or refuge. Our study illuminates the complex dynamics shaping genetic structure in fragmented river systems and indicates that conclusions drawn for a single species cannot be generalized.

Effect of temperature on 13C and 15N incorporation rates and discrimination factors in two North American fishes

The biological parameters needed to interpret isotopic field data on food webs — namely isotopic incorporation and discrimination (Δ13C and Δ15N) — are unknown for many animals. We investigated the effects of temperature on carbon and nitrogen incorporation and discrimination in creek chub (Semotilus atromaculatus) and white sucker (Catostomus commersonii) by rearing wild-caught fish on a distinct diet at 12 and 20 °C for 160 days. Mass specific growth rates were higher at 20 °C. Isotopic turnover was mainly influenced by metabolic processes as opposed to growth in both species, especially white sucker. Cold-reared fish had slower rates of isotopic incorporation and higher isotopic residence times than warm-reared fish. Discrimination factors were generally smaller for Δ15N (range = 1.9 to 3.0) and larger for Δ13C (range = 1.4 to 2.3) than values reported for other fishes. Variable temperature effects on discrimination suggests unmeasured effects of the experimental diet which will require additional experimentation to tease apart. These results support the hypothesis that metabolic rates are correlated with isotopic incorporation rates in animals dependent on environmental temperature.

A 30-Year Study of Impacts, Recovery, and Development of Critical Effect Sizes for Endocrine Disruption in White Sucker (Catostomus commersonii) Exposed to Bleached-Kraft Pulp Mill Effluent at Jackfish Bay, Ontario, Canada.

Jackfish Bay is an isolated bay on the north shore of Lake Superior, Canada that has received effluent from a large bleached-kraft pulp mill since the 1940s. Studies conducted in the late 1980s found evidence of reductions in sex steroid hormone levels in multiple fish species living in the Bay, and increased growth, condition and relative liver weights, with a reduction in internal fat storage, reduced gonadal sizes, delayed sexual maturation, and altered levels of circulating sex steroid hormones in white sucker (Catostomus commersonii). These early studies provided some of the first pieces of evidence of endocrine disruption in wild animals. Studies on white sucker have continued at Jackfish Bay, monitoring fish health after the installation of secondary waste treatment (1989), changes in the pulp bleaching process (1990s), during facility maintenance shutdowns and during a series of facility closures associated with changing ownership (2000s), and were carried through to 2019 resulting in a 30-year study of fish health impacts, endocrine disruption, chemical exposure, and ecosystem recovery. The objective of the present study was to summarize and understand more than 75 physiological, endocrine, chemical and whole organism endpoints that have been studied providing important context for the complexity of endocrine responses, species differences, and challenges with extrapolation. Differences in body size, liver size, gonad size and condition persist, although changes in liver and gonad indices are much smaller than in the early years. Population modeling of the initial reproductive alterations predicted a 30% reduction in the population size, however with improvements over the last couple of decades those population impacts improved considerably. Reflection on these 30 years of detailed studies, on environmental conditions, physiological, and whole organism endpoints, gives insight into the complexity of endocrine responses to environmental change and mitigation.

Environmental factors influencing annual sucker (Catostomus sp.) migration into a Great Lakes tributary

Fish migration in rivers is a growing area of concern as mounting anthropogenic influences, particularly fragmentation from dams and barriers, constitute major threats to global river species diversity. Barriers can impede the movement of fishes between areas critical to the completion of their lifecycle, affecting both population and ecosystem viability. In response, fish passage solutions have been identified as a critical need to maintain fisheries viability in the Laurentian Great Lakes, and around the world. Pivotal to the success of these fish passage solutions is a more complete understanding of the movement phenology and environmental cues that instigate migration. We used a dual-frequency identification sonar (DIDSON) to evaluate environmental triggers of river entry during spring and summer for three size classes of migratory fishes in the Boardman River, a Lake Michigan tributary. Our results indicate that medium size fish (>30 cm and < 50 cm), primarily composed of white sucker Catostomus commersonii and longnose sucker Catostomus catostomus were 21% more likely to enter the river at sunset and 25% less likely at midnight in comparison to midday. Entry rates of medium fish increased 6% for every 1 °C increase in river temperature, 4% for every 1 m3/s increase in river discharge from the day prior, and were reduced by 1% for every 10 cm increase in lake level. Understanding these processes in the tributaries of the Great Lakes is important to inform the fish passage solutions currently being developed for the Boardman River, and to inform management regulations for Great Lakes migratory fishes.

Benthic macroinvertebrate community response to environmental changes over seven decades in an urbanized estuary in the northeastern United States

Narragansett Bay is representative of New England, USA urbanized estuaries, with colonization in the early 17th century, and development into industrial and transportation centers in the late 18th and early 20th century. Increasing nationwide population and lack of infrastructure maintenance led to environmental degradation, and then eventual improvement after implementation of contaminant control and sewage treatment starting in the 1970s. Benthic macroinvertebrate community structure was expected to respond to these environmental changes. This study assembled data sets from the 1950s through 2010s to examine whether quantitative aggregate patterns in the benthic community corresponded qualitatively to stressors and management actions in the watershed. In Greenwich Bay and Providence River, patterns of benthic response corresponded to the decline and then improvement in sewage treatment at the Fields Point wastewater treatment plant. In Mount Hope Bay, the benthos corresponded to changes in bay fish populations due to thermal discharge from the Brayton Point power plant. The benthos of the Upper West Passage corresponded to climatic changes that caused regime shifts in the plankton and fish communities. Future work will examine the effects of further environmental improvements in the face of continued climatic changes and population growth.

Assessment of sea lamprey (Petromyzon marinus) diet using DNA metabarcoding of feces

Sea lamprey (Petromyzon marinus) are invasive in the Laurentian Great Lakes, parasitize large-bodied fishes, and therefore are the focus of an international control program. However, damage caused by sea lamprey to modern day fish stocks remains uncertain because diet analysis of juvenile sea lamprey has been challenging; they feed on blood and are difficult to randomly sample in the lakes. Here, both challenges were addressed by showing that DNA metabarcoding of fecal material can be used to identify the diet of actively feeding juvenile sea lamprey, and can also be used to determine what non-feeding adult sea lamprey captured in streams fed on while parasitizing fish. Fecal samples from juvenile sea lamprey that were feeding on lake trout in northern Lake Huron overwhelmingly contained lake trout (Salvelinus namaycush) DNA (90%), while smaller percentages contained lake whitefish (Coregonus clupeaformis; 5%) and longnose sucker (Catostomus catostomus; 5%) DNA. Fecal samples from adult sea lamprey captured from a tributary to northern Lake Huron overwhelmingly contained longnose and white sucker DNA (Catostomus spp.; 80%), while a smaller percentage contained lake trout DNA (10%). Diet composition of adult sea lamprey sampled in the tributary (Black Mallard Creek) was more diverse than juvenile diet composition. DNA metabarcoding suggests that Catostomus spp. may be an important host fish in northern Lake Huron for sea lamprey prior to spawning. Future research could investigate how diet varies across years and lakes and the prevalence and sources of DNA contamination. Application of DNA metabarcoding for diet assessment may be practical for identifying populations of invasive sea lamprey that feed on highly valued fishes and help guide restoration of lampreys worldwide.

Genome Sequences of 26 White Sucker Hepatitis B Virus Isolates from White Sucker, Catostomus commersonii, Inhabiting Transboundary Waters from Alberta, Canada, to the Great Lakes, USA.

We report 26 genome sequences of the white sucker hepatitis B virus (WSHBV) from the white sucker, Catostomus commersonii The genome length ranged from 3,541 to 3,543 bp, and nucleotide identity was 96.7% or greater across genomes. This work suggests a geographical range of this virus that minimally extends from the Athabasca River, Alberta, Canada, to the Great Lakes, USA.

Edremit Körfezi’nden yakalanan barbunya (Mullus barbatus) ve bakalyaro (Merluccius merluccius) balıklarında alifatik hidrokarbonların incelenmesi

In this study, aliphatic hydrocarbon levels were investigated in red mullet and european hake fish caught by trawler from Edremit Bay (Western Aegean, Turkey) in spring and autumn 2015. For this purpose, trawling was carried out from 3 different regions of the Edremit Bay in both seasons. As a result of the analyzes, total aliphatic hydrocarbon (TAH) levels in red mullet were found to be higher than that of european hake. TAH concentrations found for red mullet were in the range of 456-2090 ng/g, while it was found in the range of 61-746 ng/g for european hake. In general, TAH concentrations in red mullet were higher than that of european hake for both seasons. In addition, EOM amounts were found higher in red mullet like TAH. According to correlation, cluster and primary component analysis results, it was observed that the compounds affecting TAH levels in red mullet are C11 and C12 aliphatic hydrocarbon compounds, while european hake have C15, C17 and Pristane compounds. These results indicate that the source of aliphatic hydrocarbons in Edremit Bay fish is biogenic in european hake samples, although not exact, it may be petrogenic in red mullet samples.