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.

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:

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.

*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 9: 723026.

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.

Citation: 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 9: 723026.

Also Read:

Dutra, M.C.F., Pereyra, P.E.R., Hallwass, G., Poesch, M.S. and R.A.M. Silvano. (2023). Fishers’ knowledge on trophic ecology and of the tropical ‘super fish’ Plagioscion squamosissimus in two Brazilian Amazonian rivers. Neotropical Ichthyology 21(1): e220041.

*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:

Theis, S.*  Castellanos D.A., Hamann A. and M.S. Poesch. (2023) Small-bodied fish species from western United States will be under severe water stress by 2040. Conservation Science and Practice: e12856.

*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. 

Also Read:

Poesch, M.S., Dextrase, A.J., Schwalb, A.N., and J. Ackerman (2010) Secondary invasion of the round goby into high diversity Great Lakes tributaries and species at risk hotspots: Potential new concerns for endangered freshwater species. Biological Invasions 12: 1269-1284.

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:

Docherty, C.*, Ruppert, J.*, Rudolfsen, T.*, Hamann, A., and Poesch, M.S. (2017) Assessing the spread and potential impact of Prussian Carp (Carassius gibelio Bloch, 1782) to freshwater fishes in western North America. BioInvasions Records 6: 291-296.

*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.

McPherson, M. (2020) Habitat use by fluvial Arctic Grayling (Thymallus arcticus) across life stages in northern mountain streams.

Thesis Title: Habitat use by fluvial Arctic Grayling (Thymallus arcticus) across life stages in northern mountain streams.

Author: Morag McPherson 

Abstract

Northern aquatic ecosystems face increasing pressures from climate change and natural resource development, raising conservation concerns for species in these understudied regions.  The Arctic Grayling (Thymallus arcticus) is a widely distributed, but sensitive, northern freshwater fish that is a good indicator of general aquatic health. In the Northwest Territories (NWT), there has been little focus on studying riverine Arctic Grayling populations or their use of stream habitats within mountain river watersheds. The purpose of my research is to characterize fluvial Arctic Grayling distribution among mountain streams in the NWT, and to determine habitat characteristics and ecological factors that influence Arctic Grayling habitat use across life stages. Sampling sites (n=183) were selected in four sub-basins within the Little Nahanni River watershed in the southwest NWT. In the summer of 2015, each site (100 meters in length) was electrofished and stream habitat parameters were measured. Arctic Grayling were collected for biological analyses of age, size, weight, and reproductive development. Results showed shifts in Arctic Grayling development by size and age class that corresponded with shifts in distribution observed across the study streams. From these findings, four distinct post-emergence life stages for Arctic Grayling were identified: young-of-year (YOY), juvenile, sub-adult and adult. Step-wise logistic regression was used to explore the relationship between the occurrence of Arctic Grayling life stages and stream habitat characteristics. Multivariate regression tree (MRT) analysis was used to identify environmental thresholds and habitat-based life stage segregation, and redundancy analysis (RDA) was used to determine potential life stage-specific habitat correlations. Differences emerged in how Arctic Grayling life stages use habitat across a range of available stream conditions. YOY Arctic Grayling were found exclusively in low elevation, low gradient habitat dominated by silty-sand substrate with average water temperatures >10oC. Similarly, juvenile Arctic Grayling occupied low elevation, warm water stream habitat, but associated strongly with run habitats, as well as showing movement towards cooler water temperatures and more riffle dominated habitats. Sub-adult Arctic Grayling used the widest range of habitats across the study area, being found at a range of elevations and water temperatures, demonstrating the ability of this life stage to use a diversity of available habitats. Sub-adults showed a relationship to in-stream riffle, pool, and cascade-boulder habitats. Adults had a strong correlation to elevation and water temperature, using habitats with high elevation (>1200 m) and low temperature (7oC), and increased proportions of pool and boulder habitat. The four sub-watersheds studied provided distinct stream habitats and Arctic Grayling life stages separated across the habitat types, advancing our understanding of the life cycle habitat requirements for fluvial populations in mountain systems. It provides insight on the important and potential limiting factors, such as availability of warm water habitats, to population success in cold regions. The dynamic nature of Arctic Grayling habitat use in mountain streams highlights the need to consider habitat complexes at the watershed scale when defining species life stage requirements, managing habitats, monitoring populations, and assessing potential impacts into the future. Improved understanding of the distribution, habitat requirements and ecology of different life history types and life stages of Arctic Grayling is crucial for the effective management and monitoring of this species in northern environments

Research in the lab was highlighted in “This self cloning crayfish is scuttling into rivers and streams throughout Alberta (News: CBC)”

It’s not unusual to spot a trout species in a Calgary river but you might not expect to find a lobster-like crustacean. In the last 10 to 20 years however, the marbled crayfish — a crustacean not native to the Bow River — has begun spreading to rivers and lakes throughout Alberta. It’s a problem that Nicole Kimmel, aquatic invasive species specialist for Alberta Environment and Parks, is trying to tackle. Historically, the crustaceans are normally found in between Wainwright and Ryley in the Beaver River watershed south of Edmonton, Kimmel told The Calgary Eyeopener. But now they’ve been showing up in water bodies anywhere from the Edmonton area, down to Calgary and Medicine Hat, as well as in the Milk River region. It’s not likely that the critters are crawling between rivers and lakes, though they can move on land for short periods, Kimmel said. Instead, the province suspects the movements of the crayfish might be aided by humans either for bait use or they are potentially being brought back home and discarded in local waters.

‘Freak accident’ leads to quick reproduction

“Once they’re introduced to a breeding pair, they can breed pretty fast,” Kimmel said — the creatures can produce 200 to 400 eggs in a reproduction cycle.  Kimmel calls the marbled crayfish a kind of “freak accident” of two crayfish species that may have been imported from Florida into Germany in the ’90s and  were able to mate. Through that mating, the crayfish kept an additional set of chromosomes that allowed them to reproduce asexually, meaning all the females could lay unfertilized eggs which develop into genetically identical offspring. In essence, a self-cloning crayfish was born. To attempt to control their spread, Alberta has banned the crayfish province-wide unless it’s kept as a pet. Most pet stores have stopped carrying the specimens, but it’s still possible to find them sold online by individuals. Ducks have been munching on them, along with some humans, but Kimmel says its important to make sure the ones used for consumption are coming from clean water sources. Kimmel says the province has partnered with Mark Poesch, Associate Professor in Agricultural Life and Environmental Sciences at the University of Alberta, to understand what the effects are on the habitats the creatures are invading. “We highly suspect that they’re probably impacting food webs where they’re being moved around,” she said.

Other crayfish creeping into Canadian waters

The marbled crayfish aren’t the only species of their kind causing concerns — there’s an extensive list of crayfish-type creatures being found in Canadian waters, Kimmel explained. For example, B.C. is worried about red swamp crayfish and in Manitoba there are concerns about crusty crayfish. Meanwhile Saskatchewan, along with Alberta, has ramped up its legislation around marbled crayfish. If you spot a crayfish, Kimmel says to report it to the province along with the location it was found. “We’re very much interested in knowing the location that you’re finding them as well as if you can snap a picture of what they look like,” Kimmel said. “We don’t want any of those other invasive ones that other jurisdictions are worried about.” The province isn’t actively getting rid of the crayfish right now until there’s a better understanding of where the crayfish are located and what can be done for eradication.

Link to CBC article.