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.

Bazan, S. (2021) Tubifex habitat analysis to assess whirling disease risk in Alberta, Canada.

Thesis Title: Tubifex habitat analysis to assess whirling disease risk in Alberta, Canada.

Author: Sergio Bazan

Abstract

During July 2021, 30 sampling sites at Bow River Watershed and 6 sampling sites at Crowsnest River were visited to perform tubifex relative abundance counts and the collection of environmental conditions associated to each site, such as stream characteristics, water physicochemical parameters, sediment composition and quality. Relative abundance of tubifex worms at Crowsnest River was significatively higher than any Hydrologic Unit 8 (HUC8) of Bow River Watershed except for Jumpingpound Creek (p-value 0.372). Higher relative abundance of tubifex worms were found in Jumpingpound Creek and Highwood River within Bow River watershed, but the difference with the other HUC8 was not statistically significant. The land use analysis results show higher relative abundance of tubifex worms around urban and farmland areas. However, the differences between all land use categories were not statistically significant (p-value 0.515), The same results were found for Silt-Clay type of sediments over of Granular sediments with no statistically significant difference (p-value 0.543). A multivariable linear model of tubifex relative abundance for the study area was built. The adjusted r-squared value was (R 2 = 0.1755). The variables included in the model were: the water pH, the wetted width, the stream velocity, the estimated flow, and the sediment classification. However, the assumption of linearity and homogeneity of variances were not meet by the proposed linear model.

Congratulations to Karling Roberts and Taylor Lund for their paper which was “Highly Commended” for the FSBI Huntingford Medal!

Congratulations to Karling Roberts and Taylor Lund, whose paper (citation below) was listed as one of two papers Highly Commended for FSBI Huntingford Medal!

  • Roberts, K.N., Lund, T., Hayden, B. and 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. (link) 

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.

Abstract:

Fishers’ local ecological knowledge (LEK) can provide new data on fish trophic ecology. The pescada (Plagioscion squamosissimus) is among the most caught fishes in small-scale fisheries in the Brazilian Amazon. Our main goal was to evaluate the abundance, size, relevance to small-scale fisheries and trophic ecology (diet and feeding interactions) of P. squamosissimus in the Tapajós and Tocantins rivers, in the Brazilian Amazon, utilizing  data from fishers’ LEK and fish sampling. We hypothesized a higher abundance, size and more prey and predators cited by fishers of P. squamosissimus in the more pristine Tapajós River. We interviewed 61 and 33 fishers and sampled fish in nine and five sites in the Tapajós and Tocantins Rivers, respectively, in 2018. The comparison between fishers’ citations and fish sampled indicated a higher relevance of P. squamosissimus to fishers in the Tapajós River, where this fish had an average larger size and where the interviewed fishers mentioned more food items of P. squamosissimus. These results show that P. squamosissimus is a generalist fish, that is resilient to fishing and environmental pressures, as well as being important to fisheries and food security, and that LEK can provide useful insights to fisheries managers. Keywords: Offsetting; Conservation policy; Biodiversity market; Preservation.

Citation: 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.

Also Read:

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.

*Lab members: Mark Poesch. Check out opportunities in the lab!

Ponton D.E., Ruelas-Inzunza J., Lavoie R., Lescord G.L., Johnston T.A., Graydon J.A., Reichert, M., Donadt C.*, Poesch M.S., Gunn, J.A., and M. Amyot. (2022) Mercury, selenium and arsenic concentrations in Canadian freshwater fish and a perspective on human consumption intake and risk. Journal of Hazardous Materials Advances 6: 100060.

Abstract:

Mercury (Hg) and arsenic (As) contamination of fish may limit its human consumption  whereas selenium (Se) can potentially protect fish and consumers from their adverse effects. We related the concentrations of these elements in Canadian freshwater fish to anthropogenic activities and ecozones and compared these concentrations to risk assessment thresholds. Mercury concentrations exceeded the retail fish Canadian threshold (0.5 ppm) in 31% of all Walleye; this proportion rose to 64% in reservoirs. Reservoirs and lakes impacted by logging and urbanization presented higher fish [Hg] than other impacted systems. In mining areas, fish [Hg] were low and negatively correlated with [Se]. Se and As concentrations exceeded Canadian guidelines in 5 and 0.2% of all fish, respectively. A previously unreported negative relationship between mean [As] and [Hg] suggested an inverse consumption risk for these two elements. The ratio Se/Hg was lower than 1 for 14% of all fish and was negatively correlated with fish length. No major differences were seen among fish lengths that reached the Hg guideline and the Se/Hg threshold of 1. Using the benefit-risk value (BRV) threshold that considers Se intake, there were no limit to fish consumption. More studies are needed to assess the role of Se against Hg toxicity and adjust fish consumption guidelines accordingly.

Citation: Ponton D.E., Ruelas-Inzunza J., Lavoie R., Lescord G.L., Johnston T.A., Graydon J.A., Reichert, M., Donadt C., Poesch M.S., Gunn, J.A., and M. Amyot. (2022) Mercury, selenium and arsenic concentrations in Canadian freshwater fish and a perspective on human consumption intake and risk. Journal of Hazardous Materials Advances 6: 100060.

Also Read:

Donadt, C.*, Cooke, C., Graydon, J. and M.S. Poesch. (2021) Mercury bioaccumulation in stream fish from an agriculturally-dominated watershed. Chemosphere 262: 128059.

*Lab members:  Caitylyn Donadt and Mark Poesch. Check out opportunities in the lab!