Osmerus Mordax Research Articles

Reproductive Biology of Rainbow Smelt Osmerus dentex (Osmeridae) of the Amur River

Spawning flocks of rainbow smelt Osmerus dentex, in an anadromous migration in the Amur River were represented by individuals of length 15–25 cm at ages 3–5, among which males predominated (1 : 2). Histologic analysis shows that rainbow smelt is an iteroparous species with determinate fecundity, group-synchronous ovary organization and total spawning. Absolute fecundity (AF) varied from 20.9 to 31.2 oocytes per female; relative fecundity (RF) ranged between 679 and 776 oocytes/g of body weight between 2014–2018. AF statistically correlated and increased with length and age; such correlation between RF and length and age parameters did not occur.

Genetic versus demographic stock structure of rainbow smelt in a large fragmented lake

Identification of fish stocks plays an important role in fisheries management, but stock identification often depends on the techniques used and the management goals as much as on actual population structure. Historically, stocks were identified by place of capture, population demography and morphology, but genetic stock identification has become a standard approach. Here, we evaluate the stock structure of rainbow smelt (Osmerus mordax) in three basins of Lake Champlain separated by causeways using genotype data from six microsatellite loci and 26 years of demographic data. No genetic differences among rainbow smelt from the different basins were evident, which suggests that gene flow occurs among basins. However, length, age, and catch-per-unit-effort of rainbow smelt suggests asynchronous population dynamics in the different basins, and thus each basin may hold populations that are at least partially isolated from one another. Consequently, we conclude that while rainbow smelt in Lake Champlain consist of at least three demographic stocks they may form only a single genetic stock. Our results concur with other studies that suggest care should be taken when only a single method of stock identification is used.

Diversity, abundance and size structure of fishes and invertebrates captured by an intertidal fishing weir at Bramber, Minas Basin, Nova Scotia

Capturing fish using a weir or trap on the intertidal flats of the Bay of Fundy was developed by native Mi’kamaq who later taught the method to the European settlers. Between 1800-1910 fish weirs were a significant part of the important American shad fishery in the inner Bay of Fundy before the collapse of the northwest Atlantic population from pollution and damming of major spawning rivers in the United States. Weirs remain an important segment of the Minas Basin fisheries but now the largest commercial catches consist of Atlantic herring, gaspereau and flounders. Studies on the fishes captured in Minas Basin weirs were published in 1852, 1924, 1984 and 2014, but all lacked a sampling intensity which would fully describe the diversity, abundance and size structure of the catch. An intertidal weir at Bramber, Minas Basin was surveyed during April-July, 2017 where catches were examined at each low tide. The weir was constructed on the intertidal flat during early April after Minas Basin cleared of drift ice. During the study period mean daily tide range was 10.46 m with a maximum spring tide range of 13.72 m. A total of eight neap and eight spring tide cycles were observed. Daily water temperature of Minas Basin was 8.0 C° during late May and increased to a maximum of 21.4 C° in late July. Fish and invertebrate collections began on April 10 and continued daily until July 22 when water temperatures in the trap became too warm for by-catch species to survive (+25 C°). During the study period an estimated total of 674,402 fishes consisting of 45 species were captured and of these 57,950 were measured. The most abundant fishes observed were gaspereau (alewife and blueback herring 51.9%), rainbow smelt (13.9%), Atlantic herring (13.0%) and tomcod (10.1%). Other commonly captured fishes were American shad, skate (little and winter), winter flounder, windowpane flounder, striped bass, mackerel and Atlantic sturgeon. A total of 18,511 invertebrates were captured and counted. The most abundant were long-fin squid (13.8%) and crustaceans (rock crab, lady crab; 84.0%). Keywords: Bay of Fundy; Canada; Clupeidae; commercial fishing; temperatures; tides

Niche Partitioning among Native Ciscoes and Nonnative Rainbow Smelt in Lake Superior

AbstractSeveral species of ciscoesCoregonus, subgenusLeucichthysthat are native to the Laurentian Great Lakes are rare or extirpated. The restoration ofCoregonusfishes is being actively pursued through stocking, and success may depend on the availability of unoccupied niche space. We described the spring–summer habitat occupancy and diets of three native cisco species (BloaterCoregonus hoyi, CiscoC. artedi,and KiyiC. Kiyi) and invasive Rainbow SmeltOsmerus mordaxin Lake Superior and measured niche overlap among these species for both small and large sizes. The potential habitat area was highest for Cisco and Kiyi, followed by Bloater and Rainbow Smelt. The probability of overlap in habitat occupation, as measured by bathymetric depth, fish capture depth, distance from shore, and fish capture water temperature was highest for small Rainbow Smelt and Cisco. Trophic overlap, as measured by stomach contents and stable isotopes, was highest between small Bloater and Cisco and between large Bloater and Kiyi. All of the species showed significant ontogenetic change in both habitat occupation and diet. The overall niche overlap in spring–summer habitat and diet was greatest between small Cisco and Rainbow Smelt and between large Bloater and Kiyi; however, differences in individual niche dimensions likely limit competition for both species pairs. Synthesizing the diet and habitat niche data revealed nuanced niches that allow these seemingly similar planktivorous species to coexist. Kiyi had the least niche overlap with other cisco species and Rainbow Smelt, so from an available niche perspective Kiyi would be a strong candidate for reintroduction into lakes from which they were extirpated.

Fishway Effectiveness and Upstream Residency of Three Fish Species at Four Fishways in Prince Edward Island, Canada

We evaluated passage of Osmerus mordax (Rainbow Smelt), Salvelinus fontinalis (Brook Trout), and Alosa pseudoharengus (Alewife) at 4 fishways on Prince Edward Island, Canada. We implanted fish with passive integrated transponder (PIT) tags and recorded their movements using stationary PIT antennas. Passage at different fishway types was highly variable. Nature-like fishways passed over 96% of Brook Trout and a maximum of 41.8% of Rainbow Smelt. The latter percentage is the highest yet reported in the literature for Rainbow Smelt. Pool-and-weir fishways passed nearly 100% of Brook Trout, 13.2% of Rainbow Smelt, and only 5.6% of Alewife. After passing a fishway, upstream residency was highly variable both among species as well as among individuals within species. Rainbow Smelt were observed spawning within nature-like fishways, suggesting that this type of fishway may also provide spawning habitat. Results highlight the challenge of passing non-salmonid species and indicate nature-like fishways are more appropriate than technical designs for passing Rainbow Smelt.

Investigating population genetics of invasive rainbow smelt in the Great Lakes Region

Increasing our understanding of invasive species is important because of the negative impacts they can have on the economies and ecosystems of invaded regions. There is growing interest in how environmental variability (e.g. temperature) and stochastic invasion events (e.g. founder effects) affect the genetic composition of populations of invasive species. Rainbow smelt (Osmerus mordax) are a cold-water, planktivorous fish that spread into the Great Lakes basin in the early 1900s. We performed genetic analyses using microsatellites (N = 10) to investigate the influence stochastic invasion events have had on the genetic composition of invasive rainbow smelt populations across a broad geographic range. Genetic analyses were conducted on rainbow smelt populations (N = 30/population) from Lake Ontario, Lake Michigan, Lake Superior, and four inland lakes in Northern Wisconsin. Populations from the Great Lakes were generally less differentiated than inland populations. Additionally, we found evidence of a significant bottleneck in two inland populations and evidence for two distinct genetic strains of rainbow smelt in Lake Ontario. We also performed genetic analyses using microsatellites to determine if a thermally-induced extreme mortality event had an effect on a population of rainbow smelt and found that there was no measurable genetic effect on the population. Overall, this study provides evidence that the genetic structure and diversity of introduced populations can vary significantly, and are likely influenced by factors such as the frequency and magnitude of introductions. Also the resiliency of an invasive species can be high despite a history of bottlenecks and low genetic diversity.

Quantifying Within‐Season Repeat Spawning by Rainbow Smelt with Implications for Comparing Sex Ratios and Survey Catches among Runs

AbstractAnadromous Rainbow Smelt Osmerus mordax provide an important nearshore prey base, but they have experienced severe population declines during the last century. Population estimates from spawning run surveys have not been calculated because within‐season repeat spawning, a behavior qualitatively described for this species based on previous studies, has not been quantified. Our objective was to determine repeat spawning behavior at two spawning sites by using passive integrated transponder technology. A preliminary laboratory tag retention and mortality study was performed to determine the effect of tagging on study results, and it showed that tagging did not cause significant mortality and tags were well retained. In our field studies, continuous monitoring of tagged fish showed that Rainbow Smelt made movements to the spawning grounds against the tide and at low tide, allowing the fish to be at the spawning grounds during the darkest nighttime hours. This is in contrast to past assumptions that Rainbow Smelt only spawn during nighttime high tide. We found that repeat spawning behavior was a predominantly male behavior, consistent with past studies. The behavior of males did vary between the two sites, although at each site the behavior was consistent among study years. In contrast, the behavior of females was consistent both among study years and between the sites. This finding indicates that future assessments of spawning populations of Rainbow Smelt could be improved by using female catch numbers, similar to other species that display skewed sex ratios.

Quantitative methods to reconstruct length and weight of Great Lakes prey fishes from dietary observations of partially digested prey

Dietary studies of fish inform many aspects of fisheries science and ecosystem management, providing critical information to signify fluctuations in ecosystem functions. Bony structures are persistent, remaining in the stomach longer than soft tissue. We evaluated the utility of bony structures (cleithra, standard length, full vertebral column, and partial vertebral column) for reconstituting length and weight of thirteen prey fish species commonly found in the diets of piscivores in the Great Lakes. Standard length and full vertebral measurements were the most accurate for estimation of total length. Cleithra provided the third most accurate length estimates with exceptions for deepwater and slimy sculpin where extraction was more difficult. Partial vertebral measurements resulted in less variable results for species with low total vertebrae counts. Sculpin, a species with lower numbers of total vertebrae, produced more reliable estimates from partial vertebral measures than rainbow smelt or bloater which have more vertebrae. The accuracy of partial vertebrae measurements is improved when larger numbers or a greater proportion of the vertebral column is measured. Access to more broadly available digital X-ray technologies allowed for more rapid processing by eliminating the need for tissue removal to measure vertebrae and facilitated estimation of numeric relationships for prey length reconstitution. Using the data and mathematical relationships provided herein, investigators can easily reconstitute many of the diet items observed in Laurentian Great Lakes piscivores and can tailor methodologies and structures utilized to minimize estimation error and maximize efficiencies in evaluating stomach contents.

Thermal acclimation and gene expression in rainbow smelt: Changes in the myotomal transcriptome in the cold

Rainbow smelt, Osmerus mordax, have an impressive ability to acclimate to very cold water. Rainbow smelt exposed to cold (<5 °C) for an extended period of time have faster sustained swimming speeds and increased contraction kinetics in their myotomal muscle compared to warm acclimated fish. We used RNA Sequencing reactions (RNA-Seq) to explore how gene expression underlies thermal acclimation by muscle in these fish. Transcriptome analysis is limited in species that lack an annotated genome, such as rainbow smelt. The Trinity software package permits the de novo assembly of a rainbow smelt transcriptome with a modest learning curve. The transcriptome was then analyzed with Kallisto to quantify the abundance of each transcript represented in the full transcriptome and Sleuth to analyze the resulting RNA-seq datasets. Subsequently qPCR was used to explore patterns of thermal acclimation and gene expression for genes of metabolic and muscle contractile function. These methodologies revealed shifts in both muscle and metabolic gene expression that contribute to the thermal acclimation response in rainbow smelt. In fast-twitch, anaerobic white muscle, slow isoforms of myosin heavy and light chain tended to be down-regulated with exposure to cold in myotomal muscle, while fast isoforms were unchanged. Genes associated with protein turnover and aerobic metabolism were up-regulated in the white muscle, while those associated with anaerobic metabolism and the cell cycle were down-regulated. Collectively the results suggest that thermal acclimation to cold is complex process of apparent shifts in gene expression.

Fecundity and reproductive life history of anadromous rainbow smelt (Osmerus mordax) in coastal waters of Massachusetts

Fecundity and reproductive life history of anadromous rainbow smelt (Osmerus mordax) in coastal waters of Massachusetts

The history and ecology of Cisco Coregonus artedi in the Laurentian Great Lakes

Cisco Coregonus artedi are a schooling, coldwater, zooplanktivorous fish native to the northern United States and Canada. They were once one of the most abundant fish species in the region, supporting large commercial fisheries in all five of the Great Lakes. Overfishing, habitat degradation, and impacts from invasive species such as Rainbow Smelt Osmerus mordax and Alewife Alosa pseudoharengus lead to the collapse of these fisheries by the mid 1900’s. Recently, there has been an increased momentum for restoring Cisco populations in the Great Lakes due to their role as native prey fish species for predators such as Lake Trout Salvelinus namaycush and Atlantic Salmon Salmo salar. Here I present a general overview of Cisco biology, detail the history of the commercial fishery in the Great Lakes, and look ahead to future restoration and recovery goals.

Spatial patterns of rainbow smelt energetic condition in Lakes Huron and Erie in 2017: Evidence for Lake Huron resource limitation

Rainbow smelt (Osmerus mordax) is a key planktivore and prey fish in Lake Huron. Given the declining offshore productivity in the lake since the early 2000s, we described the energy content of rainbow smelt in 2017 across five different regions (North Channel, Georgian Bay, Saginaw Bay, northern main basin, southern main basin) where phytoplankton and zooplankton productivity likely varied. To increase contrast across the productivity gradient, rainbow smelt energy content was also estimated from western Lake Erie. Within the North Channel where large fish (≥90 mm, total length) were sampled most frequently, mean energy density (kJ/g wet weight) varied seasonally: 4.29 in April (month of spawning), 3.86 in June, 3.99 in July, and up to 4.35 in September. Energy density of rainbow smelt from higher productivity western Lake Erie was 37% (large fish ≥90 mm) to 60% higher (small fish <90 mm) than that of fish from Lake Huron. Within Lake Huron, energy density of rainbow smelt from North Channel was slightly higher than those from other regions; rainbow smelt from Georgian Bay generally had the lowest energy density. Across regions, including western Lake Erie, energy density increased with chlorophyll a concentration. Compared with Lake Huron studies prior to 2004, when oligotrophication had not yet accelerated, energy density of rainbow smelt in 2017 was up to 31% lower. The decline in rainbow smelt energy density is likely the result of declining primary and secondary pelagic production and increased resource limitation for planktivorous fish.

Microsatellite Variability of the Arctic Rainbow Smelt Osmerusdentex from the White Sea

We studied the genetic variability of ten microsatellite loci in Arctic rainbow smelt datasets from Kandalaksha and Mezen bays of the White Sea. Average estimates of expected heterozygosity ranged from 0.116 to 0.640 at different loci, with an average of 0.407. Smelt from Kandalaksha Bay is characterized by lower values of genetic diversity (HE = 0.365–0.369, AR = 3.1–3.15) compared to dataset from Mezen Bay (HE = 0.486, AR = 4.02). Significant genetic divergence between the smelt of Kandalaksha and Mezen bays is shown; the overall estimate of genetic differentiation θ = 7.8% with 95% confidence bootstrap interval [2.8–13.6%].

Observations on the Growth, Condition, and Ecology of Lake Trout in Quabbin Reservoir, Massachusetts

I report observations on the ecology and trends in growth and relative condition of Salvelinus namaycush (Lake Trout) in Quabbin Reservoir garnered from over 60 y of almost continuous monitoring. Fish were captured using gillnets during the spawn in late October and early November in 10–15 m of water. Spawning began when waters reached 17 °C, but activity was most intense between 11 °C and 13 °C. Spawning fish were 4–24 y old, and catches were typically comprised of 89.5% males. Male Lake Trout generally reached 457 mm (18 in; legal harvest size) by age 5, and since 2010, average growth of mature males was 5.8 mm per year. Length-at-capture and density have declined over the period of record but rose and fell over shorter intervals, likely in response to forage abundance, mainly Osmerus mordax (Rainbow Smelt).

Early mortality and freshwater forage fish recruitment: nonnative alewife and native rainbow smelt interactions in Lake Champlain

We studied the consequences of a nonnative species introduction and changes in temperature on early mortality and recruitment of native rainbow smelt (Osmerus mordax) and nonnative alewife (Alosa pseudoharengus) in Lake Champlain using a simulation model. Distribution patterns of adults and young-of-the-year (YOY) fish were predicted using a model based on observed distribution of different age groups as a function of temperature and light profiles simulated on a daily basis. Mortality rates averaged over the growing season were calculated as a function of fish densities and overlap between adults and YOY. Survival of YOY rainbow smelt and alewife depended on which predator was most abundant. Rainbow smelt YOY mortality rates are highest when rainbow smelt adults are abundant, and alewife YOY mortality rates are highest when alewife adults are abundant, potentially allowing coexistence. August and September mortality rates were higher in the climate change scenario because of increased overlap of adults and YOY of both species. These results indicate that accounting for spatiotemporal fish distribution patterns can be important when forecasting the interacting effects of climate change and aquatic invasive species on fish recruitment.

Development and validation of probe-based multiplex real-time PCR assays for the rapid and accurate detection of freshwater fish species.

Reliable species identification methods are important for industrial environmental monitoring programs. Probe based real-time quantitative polymerase chain reaction (qPCR) provides an accurate, cost-effective and high-throughput method for species identification. Here we present the development and validation of species-specific primers and probes for the cytochrome c oxidase (COI) gene for the identification of eight ecologically and economically important freshwater fish species: lake whitefish (Coregonus clupeaformis), yellow perch (Perca flavescens), rainbow smelt (Osmerus mordax), brook trout (Salvelinus fontinalis), smallmouth bass (Micropterus dolomieu), round whitefish (Prosopium cylindraceum), spottail shiner (Notropis hudsonius) and deepwater sculpin (Myoxocephalus thompsonii). In order to identify novel primer-probe sets with maximum species-specificity, two separate primer-probe design criteria were employed. Highest ranked primer-probe sets from both methods were assayed to identify sequences that demonstrated highest specificity. Specificity was determined using control species from same genus and non-target species from different genus. Selected primer-probe sets were optimized for annealing temperature and primer-probe concentrations to identify minimum reagent parameters. The selected primer-probe sets were highly sensitive, with DNA concentrations as low as 1 ng adequate for positive species identification. A decoder algorithm was developed based on the cumulative qPCR results that allowed for full automation of species identification. Blinded experiments revealed that the combination of the species-specific primer/probes sets with the automated species decoder resulted in target species identification with 100% accuracy. We also conducted a cost/time comparison analysis between the qPCR assays established in this study with other species identification methods. The qPCR technique was the most cost-effective and least time consuming method of species identification. In summary, probe-based multiplex qPCR assays provide a rapid and accurate method for freshwater fish species identification, and the methodology established in this study can be utilized for various other species identification initiatives.

Life-history variability and conservation status of landlocked Atlantic salmon: an overview

Nonanadromous Atlantic salmon (Salmo salar) exhibit a combination of variation in life history, habitat, and species co-existence matched by few vertebrates. Distributed in eastern North America and northern Europe, habitat ranges from hundreds of metres of river to Europe’s largest lakes. As juveniles, those with access to a lake usually migrate to feed and grow prior to reproduction. Prey such as smelt (Osmerus mordax, Osmerus eperlanus) and vendace (Coregonus albula) facilitate large body size (50–85 cm at maturity) and persistence in high-diversity (&gt;20 fish species) environments; small-bodied salmon (10–30 cm at maturity), relying on insects as prey, coexist with few (fewer than five) other fishes. At maturity, weight varies more than 400-fold (17 to 7200 g) among populations, fecundity more than 150-fold (33 to 5600), and longevity almost fivefold (3 to 14 years). Landlocked salmon are managed to support sustainable fishing, achieve conservation and restoration targets, and mitigate threats; successes are evident but multiple challenges persist. Extraordinary variability in life history coupled with extensive breadth of habitat and species co-existence render landlocked Atlantic salmon singularly impressive from a biodiversity perspective.

Prey fish communities of the Laurentian Great Lakes: A cross-basin overview of status and trends based on bottom trawl surveys, 1978-2016

Annual bottom trawl surveys were initiated in the 1970s in Laurentian Great Lakes Superior, Huron, Michigan and Ontario and in 1990 in Erie to provide annual assessments of the status and trends of prey fish communities. Native Cisco Coregonus artedi and Bloater C. hoyi dominated the prey fish community of Lake Superior. Prey fish communities in lakes Huron and Michigan were dominated by nonnative Rainbow Smelt Osmerus mordax and Alewife Alosa pseudoharengus for much of 1978-2016, but Bloater was an important species during the 1980-1990s and more recently has become the dominant prey species in these lakes. Alewife dominated the prey fish community of Lake Ontario during all 1978-2016. While nonnatives dominated the prey fish community in Lake Erie, native Emerald Shiner Notropis atherinoides was an important species and occasionally the dominant prey fish after the establishment of Round Goby Neogobius melanostomus in the late 1990s. During the 1980s-1990s Bythotrephes cederstroemi, Dreissena polymorpha, and Dreissena bugensis caused profound changes in Laurentian Great Lakes ecosystems and likely contributed to declines in fish community biomass in lakes Michigan and Huron. The impacts of these invaders were more muted in lakes Erie and Ontario. Lake Superior stands out as the Laurentian Great Lakes success story: Lake Trout Salvelinus namaycush was restored, and native prey fishes dominate and support a viable fishery. Although the abundance of Bloater has increased recently in lakes Huron and Michigan, recovery of native prey fishes remains uncertain. The absence of native species among the principal prey fish in Lake Ontario indicates a lack of progress in native fish recovery. Recovery of native prey fishes remains unclear in Lake Erie. The ever-changing state of the Laurentian Great Lakes caused by the impacts of invasive species and ongoing climate and ecosystem change will continue to challenge restoration of native fish communities in the 21st Century.

An Analysis of Microsatellite Polymorphism in the Population of the Arctic Rainbow Smelt Osmerus dentex from Eastern and Western Kamchatka

The genetic diversity of ten microsatellite loci is examined in samples of Arctic rainbow smelt. The expected heterozygosity estimates vary in the range of 12.6–83.9% (mean 55.3%). The degree of genetic differentiation is statistically significant: θ = 2.8%, 95% CI (1.4–4.9%). The greatest differences are found between datasets of smelt in Eastern and Western Kamchatka. The samples from Lake Nerpich’e demonstrate the maximum estimates of divergence from the other datasets from both the western and eastern coasts.

Phenology and species diversity in a Lake Huron ichthyoplankton community: Ecological implications of invasive species dominance

Abstract Ichthyoplankton communities are dynamic and vary spatiotemporally based on factors such as wind, water currents, and phenology. Nonetheless, ichthyoplankton are an indicator of spawning success in fish populations and examining their community diversity and composition can serve to provide information on ecosystem integrity. Although some ichthyoplankton species may be transient, understanding their distribution in space and time provides information on species composition, abundance, and habitat use during critical early life stages. We sampled the spring-summer ichthyoplankton community during 2008 and 2009 in northern Lake Huron to determine species succession, abundance, and species diversity along physical and environmental gradients. Seasonal succession of species was similar during both years, indicating well-defined patterns in spawning by northern Lake Huron fish populations. Invasive alewife, rainbow smelt, and round goby were the dominant species during both years, with native stickleback species also abundant. Shannon Entropy (H′) increased with increasing water temperature until late summer when H′ declined. H′ decreased with increasing bottom depth and distance to tributary mouth indicating the important ecological role of these habitat features during early life stages. Although ichthyoplankton diversity was comparable to or higher than that reported for other areas of the Great Lakes, the prominence of invasive species in our study is reflective of the disturbed state of the Lake Huron fish community, despite large reductions in invasive planktivorous fish since 2004. Continued monitoring of ichthyoplankton communities will be important for measuring the impacts of species invasions or other ecosystem stressors on fish community structure in the Great Lakes.