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Category Archives: Conservation of Freshwater Fishes
Freshwater fishes are among the most imperiled groups globally with rates of decline comparable to declines in tropical rainforest species. Research in the PoeschLab focuses on developing a better understanding of the mechanisms for the decline of freshwater organisms. This research has four main themes, including: 1) threats to freshwater species at risk, 2) stream augmentation and hydrologic alteration, 3) climate change impacts to freshwater fishes, and 4) the spread and impact of invasive species. To achieve our research goals we utilize a variety of expertise in the PoeschLab and the University of Alberta. This includes expertise in: movement ecology and telemetry, assessing foodwebs using stable isotope analysis, population genetics and environmental DNA (eDNA) and morphology and swim performance.
Medinski, N.A.*, Maitland, B.M.*, Jardine, T.D., Drake, D.A.R. and M.S. Poesch (2022) A catastrophic coal mine spill in the Athabasca River watershed induces isotopic niche shifts in stream biota including an endangered rainbow trout ecotype. Canadian Journal for Fisheries and Aquatic Sciences 79(8): 1321-1334.
Abstract:
Freshwater biodiversity is declining from impacts associated with anthropogenic stressors. Here, we use carbon (δ13C) and nitrogen (δ15N) stable isotopes to assess food web effects following a coal mine spill that displaced biota and altered biophysical stream characteristics. We compared isotopic niche metrics of benthic macroinvertebrates and the fish community, including non-native brook trout (Salvelinus fontinalis) and endangered Athabasca rainbow trout (Oncorhynchus mykiss), to infer spatial differences in site-specific resource use along a habitat disturbance gradient. Predatory benthic macroinvertebrate trophic position was elevated where impacts from the spill were most pronounced. Autochthonous carbon contribution to consumer diets was lowest in biota sampled at the most highly impacted site from the mine spill, leading to an unexpected expansion of the isotopic niche size of rainbow trout and the aquatic invertebrate community. Collectively, our results suggest spatial variation in trophic resource assimilation across multiple levels of the food web, fuelled by the allochthonous energy pathway in highly impacted study sites. We conclude this reflects a biotic response to altered basal aquatic resources following a major industrial disturbance.
Citation: Medinski, N.A., Maitland, B.M., Jardine, T.D., Drake, D.A.R. and M.S. Poesch (2022) A catastrophic coal mine spill in the Athabasca River watershed induces isotopic niche shifts in stream biota including an endangered rainbow trout ecotype. Canadian Journal for Fisheries and Aquatic Sciences 79(8): 1321-1334.
Also Read:
*Lab members: Nathan Medinski, Bryan Maitland, Mark Poesch. Check out opportunities in the lab!
Roberts, K.N.*, Lund, T.*, Hayden, B. and M.S. Poesch (2022) Season and species influence stable isotope ratios between lethally and non-lethally sampled tissues in freshwater fish. Journal of Fish Biology 100 (1): 229-241.
Abstract:
The field of stable isotope ecology is moving away from lethal sampling (internal organs and muscle) towards non-lethal sampling (fins, scales and epidermal mucus). Lethally and non-lethally sampled tissues often differ in their stable isotope ratios due to differences in metabolic turnover rate and isotopic routing. If not accounted for when using non-lethal tissues, these differences may result in inaccurate estimates of resource use and trophic position derived from stable isotopes. To address this, the authors tested whether tissue type, season and their interaction influence the carbon and nitrogen stable isotope ratios of fishes and whether estimates of species trophic position and resource use are affected by tissue type, season and their interaction. This study developed linear conversion relationships between two fin types and dorsal muscle, accounting for seasonal variation. The authors focused on three common temperate freshwater fishes: northern pike Esox lucius, yellow perch Perca flavescens and lake whitefish Coregonus clupeaformis. They found that fins were enriched in 13C and depleted in 15N compared to muscle in all three species, but the effect of season and the interaction between tissue type and season were species and isotope dependent. The estimates of littoral resource use based on fin isotope ratios were between 13% and 36% greater than those based on muscle across species. Season affected this difference for some species, suggesting the potential importance of using season-specific conversions when working with non-lethal tissues. Fin and muscle stable isotopes produced similar estimates of trophic position for northern pike and yellow perch, but fin-based estimates were 0.2–0.4 trophic positions higher than muscle-based estimates for lake whitefish. The effect of season was negligible for estimates of trophic position in all species. Strong correlations existed between fin and muscle δ13C and δ15N values for all three species; thus, linear conversion relationships were developed. The results of this study support the use of non-lethal sampling in stable isotope studies of fishes. The authors suggest that researchers use tissue conversion relationships and account for seasonal variation in these relationships when differences between non-lethal tissues and muscle,
and seasonal effects on those differences, are large relative to the scale of isotope values under investigation and/or the trophic discrimination factors under use.
Citation: Roberts, K.N., Lund, T., Hayden, B. and M.S. Poesch (2022) Season and species influence stable isotope ratios between lethally and non-lethally sampled tissues in freshwater fish. Journal of Fish Biology 100 (1): 229-241. DOI: 10.1111/jfb.14939
Finalist for FSBI Huntingford Medal. Note: One of two papers that received the “Highly Commended” designation.
Also Read:
*Lab members: Karling Roberts, Mark Poesch. Check out opportunities in the lab!
Finn, K.*, Roberts, K.N.* and M.S. Poesch (2022) Cestode parasites are depleted in 15N relative to their fish hosts in northern Alberta, Canada. Fisheries Research 248: 106193..
Abstract:
The use of stable isotopes to study trophic interactions and food webs has become a common practice in ecology. Until recently, parasites were largely omitted from these analyses despite their known contribution to ecosystem complexity and function. Long-standing assumptions about the enrichment of δ15N in consumers relative to their resources occasionally placed parasites in trophic positions above their hosts. However, recent literature has shown that unlike consumers to prey, parasites do not reliably exhibit enrichment in δ15N. This is particularly true of helminth endoparasites in the class cestoda, which tend to be depleted in δ15N. We developed empirical estimates of nitrogen and carbon stable isotope ratios from a cestode parasite (Ligula intestinalis) across four fish hosts from two lakes in northern Alberta, Canada. We found that L. intestinalis were depleted in δ15N relative to their hosts across all host fish species, with mean nitrogen discrimination factors (Δ15N) ranging from -1.92 ± 0.24 ‰ to -2.91 ± 1.17 ‰. In contrast, δ 13C values did not differ significantly in any direction between hosts and their parasites. Mean carbon discrimination factors (Δ13C) ranged from -0.66 ± 2.69 ‰ to 0.04 ± 1.53 ‰. We also tested for relationships between proportional parasite biomass and discrimination factor (Δ15N & Δ13C), and found high variability in strength and direction of these correlations across species. The direction and magnitude of nitrogen discrimination we found for L. intestinalis is similar to that of previous cestode stable isotope studies and may indicate consistency across the class cestoda. However, class cestoda is incredibly diverse and relatively few studies have examined host-parasite
discrimination factors within the clade. We encourage additional research into host-parasite discrimination factors for the class cestoda, and across all parasite taxa. This could facilitate the inclusion of these widespread interactions into food web studies, thus improving our knowledge of trophic structure and dynamics.
Citation: Finn, K., Roberts, K.N. and M.S. Poesch (2022) Cestode parasites are depleted in 15N relative to their fish hosts in northern Alberta, Canada. Fisheries Research 248: 106193.
Also Read:
*Lab members: Karling Roberts, Mark Poesch. Check out opportunities in the lab!
Pereyra, P.E.R, Hallwas, G., Poesch, M.S. and R. Silvano (2021) ‘Taking fishers’ knowledge to the lab’: an interdisciplinary approach to understand fish trophic relationships in the Brazilian Amazon. Frontiers in Ecology and Evolution.
Abstract:
Trophic levels can be applied to describe the ecological role of organisms in food webs and assess changes in ecosystems. Stable isotopes analysis can assist in the understanding of trophic interactions and use of food resources by aquatic organisms. The local ecological knowledge (LEK) of fishers can be an alternative to advance understanding about fish trophic interactions and to construct aquatic food webs, especially in regions lacking research capacity. The objectives of this study are: to calculate the trophic levels of six fish species important to fishing by combining data from stable isotopes analysis and fishers’ LEK in two clear water rivers (Tapajós and Tocantins) in the Brazilian Amazon; to compare the trophic levels of these fish between the two methods (stable isotopes analysis and LEK) and the two rivers; and to develop diagrams representing the trophic webs of the main fish prey and predators based on fisher’s LEK. The fish species studied were Pescada (Plagioscion squamosissimus), Tucunaré (Cichla pinima), Piranha (Serrasalmus rhombeus), Aracu (Leporinus fasciatus), Charuto (Hemiodus unimaculatus) and Jaraqui (Semaprochilodus spp.). A total of 98 interviews and 63 samples for stable isotopes analysis were carried out in both rivers. The average fish trophic levels did not differ between the stable isotopes analysis and the LEK in the Tapajós, nor in the Tocantins Rivers. The overall trophic level of the studied fish species obtained through the LEK did not differ from data obtained through the stable isotopes analysis in both rivers, except for the Aracu in the Tapajós River. The main food items consumed by the fish according to fishers’ LEK did agree with fish diets as described in the biological literature. Fishers provided useful information on fish predators and feeding habits of endangered species, such as river dolphin and river otter. Collaboration with fishers through LEK studies can be a viable approach to produce reliable data on fish trophic ecology to improve fisheries management and species conservation in tropical freshwater environments and other regions with data limitations.
Also Read:
*Lab members: Mark Poesch. Check out opportunities in the lab!
Castaneda, R.A., Ackerman, J.D., Chapman, L.J., Cooke, S.J., Cuddington, K., Dextrase, A., Jackson, D.A., Koops, M.A., Krkosek, M., Loftus, K., Mandrak, N.E., Martel, A.L., Molnar, P., Morris, T.J., Pitcher, T.E., Poesch, M.S., Power, M., Pratt, T.C., Reid, S.M., Rodriguez, M.A., Rosenfeld, J., Wilson, C., Zanatta, D.T. and D.A.R. Drake. (2021) Approaches and research needs for advancing the protection and recovery of imperilled freshwater fishes and mussels in Canada. Canadian Journal of Fisheries and Aquatic Sciences 78 (9): 1356-1370.
Abstract:
Effective conservation requires that species recovery measures are informed by rigorous scientific research. For imperilled freshwater fishes and mussels in Canada, numerous research gaps exist, in part owing to the need for specialized research methods. The Canadian Freshwater Species at Risk Research Network (SARNET) was formed, and identified or implemented approaches to address current research gaps, including: 1) captive experimental research populations; 2) non-lethal methods for estimating abundance and distribution; 3) non-lethal field methods to measure life-history parameters; 4) species distribution models informed by co-occurring species; 5) integration of conservation physiology into habitat and threat science; 6) evidence syntheses to evaluate threats and recovery strategies; 7) disease-transmission models to understand mussel-host relationships; 8) experimental mesocosms and manipulative experiments to evaluate key habitat stressors; 9) threat and hazard models for predictive applications; and, 10) rigorous evaluation of surrogate species. Over a dozen threat and recovery-focused SARNET-research applications are summarized, demonstrating the value of a coordinated research program between academics and government to advance scientific research on, and to support the recovery of, imperilled freshwater species.
Citation: Castaneda, R.A., Ackerman, J.D., Chapman, L.J., Cooke, S.J., Cuddington, K., Dextrase, A., Jackson, D.A., Koops, M.A., Krkosek, M., Loftus, K., Mandrak, N.E., Martel, A.L., Molnar, P., Morris, T.J., Pitcher, T.E., Poesch, M.S., Power, M., Pratt, T.C., Reid, S.M., Rodriguez, M.A., Rosenfeld, J., Wilson, C., Zanatta, D.T. and D.A.R. Drake. (2021) Approaches and research needs for advancing the protection and recovery of imperilled freshwater fishes and mussels in Canada. Canadian Journal of Fisheries and Aquatic Sciences 78 (9): 1356-1370.
Also Read:
*Lab members: Mark Poesch. Check out opportunities in the lab!
Firth, B., Poesch, M.S., Koops, M., Power, M. and D.A.R. Drake. (2021) Diet overlap of common and at-risk riverine benthic fishes before and after Round Goby (Neogobius melanostomus) invasion. Biological Invasions 23(1): 1-14.
Abstract:
Round Goby (Neogobius melanostomus) has invaded high diversity tributaries of the Laurentian Great Lakes, including those supporting multiple species of conservation concern. The extent and magnitude of ecological impacts on benthic riverine fishes is poorly understood, especially changes in dietary overlap and feeding strategy. We used a before-after study design to examine the impact of Round Goby on native benthic riverine fishes, including the Threatened Eastern Sand Darter (Ammocrypta pellucida) in the Sydenham River, Ontario, Canada. To evaluate shifts in diet overlap and feeding strategy, fishes were collected with multiple gears and the direct (diet overlap with the invader) and potential indirect (diet overlap among the native benthic fishes) impacts of Round Goby were assessed. Before the arrival of Round Goby, there were a total of 6 ecologically significant diet overlaps among the studied native benthic fishes. Following the arrival of Round Goby, there were 20 ecologically significant diet overlaps, with 6 out of 8 species, including Eastern Sand Darter, showing significant diet overlap with Round Goby. Fishes exhibiting significant dietary overlap with Round Goby shifted feeding strategies to become more specialized, a change in feeding consistent with potential competitive effects. Although the long-term consequences of invasion-induced dietary and feeding shifts remain poorly understood, increased competitive interactions suggested by dietary overlap may be occurring between Round Goby and native benthic riverine fishes and may exacerbate the observed declines of native species.
Citation: Firth, B., Poesch, M.S., Koops, M., Power, M. and D.A.R. Drake. (2021) Diet overlap of common and at-risk riverine benthic fishes before and after Round Goby (Neogobius melanostomus) invasion. Biological Invasions 23(1): 1-14.
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Hamilton, K. (2020) Streamflow is changing in rivers across Alberta: assessing regional variation in changing hydrologic indices.
Thesis Title: Streamflow is changing in rivers across Alberta: assessing regional variation in changing hydrologic indices.
Author: Kyle Hamilton
Abstract
The flow regime is a crucial factor in the well-being of aquatic and riparian ecosystems. Many components of those ecosystems, ranging for nutrient transport to morphology, are impacted by various hydrologic parameters. The parameters help define and quantify five important hydrologic regime characteristics: magnitude, duration, timing, frequency, and rate of change. Our study utilized the Indicators of Hydrologic Alteration (IHA) indices to (1) determine how various ecologically relevant components of streamflow are changing across Alberta’s various biomes; and (2) examine the similarities and differences between streamflow trends and climate trends. The overarching goal of these objectives is to create a foundation upon which water management practices can be created or modified.
Region-specific water management is required to balance the residential, commercial, and industrial water needs of a particular region with ecological concerns and conservation initiatives. Understanding the trends in hydrologic parameters is an important step in recognizing the vulnerabilities of each region. Streamflow at Water Survey of Canada stations was assessed for linear trends using a Mann-Kendall Trend Analysis. Our approach of assessing overall trends on a regional basis was validated when looking at trends in magnitude. The average daily flow rate for spring and summer months was found to be decreasing in the boreal region but increasing in the grassland region. Other hydrologic indices were found to exhibit significant trends on a province-wide level. Annual minimum and maximum flow conditions over a variety of durations were observed to be merging across the province. Similarly, the rate of change of streamflow between consecutive days is decreasing across Alberta.
To determine whether these results were the function of climate oscillation patterns, a composite analysis was performed to determine the effect of the El Niño–Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO) on hydrologic indices. Only 8% of parameters were found to be significantly influenced by PDO patterns and 4% influenced by ENSO patterns.
Card, J.*, Hasler, C., Ruppert, J.*Donadt, C.* and M.S. Poesch. (2020) A three-pass electrofishing removal strategy is not effective for eradication of Prussian Carp in a North American stream network. Journal of Fish and Wildlife Management 11(2): 485-493.
Abstract:
Prussian Carp Carassius gibelio, also referred to as Gibel Carp, is a destructive aquatic invasive species, recently, found in Alberta Canada. Three-pass electrofishing is a potential approach to control some aquatic invasive fish species in stream habitats. The objectives of this study were to: 1) determine the efficacy of this strategy to control Prussian Carp in connected streams; and, 2) assess whether removal success was influenced by population size or the distance to the introduction site. We sampled sites using electrofishing in tributaries of the Red Deer River in both the summer and fall. Prussian Carp were detected at all sites prior to removal, with > 90 % probability of detection of this species within the first 120 m of electroshocking efforts. Overall, removal was deemed unsuccessful. We found that abundances of Prussian Carp were significantly higher post-removal. Removal success was significantly related to distance to the introduction site, suggesting that removal may be useful in targeted situations close to the edge of the invasion front. Additional removal and control strategies are needed by managers.
Citation: Card, J., Hasler, C., Ruppert, J., Donadt, C.* and M.S. Poesch. (2020) A three-pass electrofishing removal strategy is not effective for eradication of Prussian Carp in a North American stream network. Journal of Fish and Wildlife Management 11(2): 485-493.
Highlighted in media: (link here)
Also Read:
*Lab members: Jamie Card, Jonathan Ruppert, Caitlyn Donadt and Mark Poesch. Check out opportunities in the lab!
Research on Prussian Carp eradication highlighted in media (Magazine: Ontario Nature)
Research from a team in the Poesch lab was highlighted in Ontario Nature magazine. The story about eradication of carp, also discusses new results of a study just accepted and coming out soon in the Journal of Wildlife Management. Former post-doctoral researcher, Dr. Jonathan Ruppert, is highlighted in the piece. Other people who contributed to the study include former lab members Jamie Card and Caitlyn Donadt, and colleague Dr. Caleb Hasler from the University of Winnipeg.
