Category Archives: Mark Poesch

My research focuses on issues related to aquatic biodiversity, including: conservation of freshwater fishes (e.g. species at risk, invasive species), sustainable resource development and developing robust restoration and reclamation activities. My goals are to: build effective collaborations across Alberta and North America; to train the next generation of research leaders; to provide an atmosphere of respect and learning; to engage the public and stakeholders; and, to develop leading edge novel research to solve applied problems.

New Award – Editor’s Choice 2026: Theis, S.*, Shirton, J.*, Barbeau, M.*, Ruppert, J. W. L.* and M.S. Poesch (2025) Growth and diet of Northern Pike (Esox lucius) in Boreal lakes: Implications for Ecosystem Management. Hydrobiologia 4(1): 1.

Abstract: 

An important top-down predator, the northern pike (Esox lucius), faces harsh environmental conditions in the northern boreal ecoregion. They are often managed for recreational fishing and, more recently, to create environmental offsets; strategies aimed at balancing ecological impacts by enhancing or restoring habitats. Our study examines northern pike populations in two remote boreal lakes in northern Alberta: Steepbank and Wappau. The lakes differ in size, vegetation cover, and trophic status, providing a natural experiment for investigating northern pike growth, condition, diet, and population density. Over three years (2018–2020), northern pike were sampled using gill nets. Population metrics, including growth, condition, and stomach contents, were compared between the lakes. Steepbank, a smaller, oligotrophic lake with low vegetation cover, showed lower prey fish densities compared to the larger, eutrophic Wappau, but it did not differ in northern pike catch per unit effort. Growth rates and body condition varied significantly between the lakes, with the northern pike in Wappau exhibiting faster growth and a better condition in the older age groups, while the younger northern pike in Steepbank had higher relative weights. A diet analysis revealed significant differences in prey consumption: Steepbank northern pike displayed higher rates of conspecific predation and invertebrate consumption, particularly in the younger age classes. These findings highlight how lake characteristics and prey availability shape northern pike population dynamics, offering valuable insights for lake management approaches in northern Alberta.

Citation: Theis S., Shirton J., Barbeau M., Ruppert J. W. L. and M.S. Poesch (2025) Growth and diet of Northern Pike (Esox lucius) in Boreal lakes: Implications for Ecosystem Management. Hydrobiologia 4(1): 1.

Also Read:

Theis, S.*, Ruppert, J. L. W. and M. S. Poesch. (2023) Coarse woody habitat use by local fish species and structural integrity of enhancements over time in a shallow northern boreal lake assessed in a Bayesian modeling approach. Ecological Solutions and Evidence 4(2): e12200.

*Lab members: Sebastian Theis, Jonathan Ruppert (former member) and Mark Poesch. Check out opportunities in the lab!

Schmid J., Simmons S., Lewis M., Poesch, M. S. and R. Pouria. (2026) Website visits can predict angler presence using machine learning. FACETS 11:1-10.

Abstract:
Understanding and predicting recreational angler effort is important for sustainable fisheries management. However, conventional methods of measuring angler effort, such as surveys, can be costly and limited in both time and spatial extent. Models that predict angler effort based on environmental or economic factors typically rely on revealed data (past observed behavior), which often limits their spatial and temporal generizability due to data scarcity. In this study, high-resolution data from an online fishing platform and easily accessible auxiliary data were tested to predict daily boat presence and aerial counts of boats at almost 200 lakes over 5 years in Ontario, Canada. Lake-information website visits alone enabled predicting daily angler boat presence with 78% accuracy. While incorporating additional environmental, socio-ecological, weather, and angler-reported features into machine learning models did not remarkably improve prediction performance of boat presence, they were substantial for the prediction of boat counts. Models achieved an R2 of up to 0.77 at known lakes included in the model training, but they performed poorly for unknown lakes (R2 = 0.21). The results demonstrate the value of integrating data from online fishing platforms into predictive models and highlight the potential of machine learning models to enhance fisheries management.

Citation: Schmid J., Simmons S., Lewis M., Poesch, M. S. and R. Pouria. (2026) Website visits can predict angler presence using machine learning. FACETS 11: 1-10.

.

Also Read:

Schmid J., Simmons S., Poesch M. S., Ramazi P. and M. Lewis. (2025) Analyzing fisher effort – Gender differences and the impact of Covid-19. Canadian Journal of Fisheries and Aquatic Sciences.

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

Congratulations to Jessica Serbu, Vince St. Louis and team for being named ‘Most Viewed’ on our article on climate change (see info)!

Jessica’s paper develops a comprehensive overview of glaciers by the Rocky Mountains.

Citation: Serbu, J. A., St. Louis, V. L., Emmerton, C. A., Tank S., Criscitello, A., Silins, U., Bhatia, M., Cavaco, M., Christenson, C., Cooke, C., Drapeau, H., Enns, S. J., Flett, J., Holland, K., Lavelle-Whiffen, J., Ma, M., Muir, C., Poesch, M. S., and J. Shin. (2023). A comprehensive biogeochemical assessment of climate-threatened glacial river headwaters on the eastern slopes of the Canadian Rocky Mountains. JGR Biogeosciences 129: e2023JG007745. 

Hambrook J., Kimmel N., Robinson R., Foster D., Poesch M.S. and P. Hanington. (2025) Development, validation and implementation of eDNA-focused qPCR assays to detect and distinguish between Goldfish (Carassius auratus) and Prussian Carp (Carassius gibelio). Environmental DNA 7(2): e70092.

Abstract: 

The ability to accurately detect harmful aquatic invasive species in a species-specific manner is crucial to monitoring and management efforts. The Canadian province of Alberta currently harbors North America’s only invasive Prussian Carp populations, in addition to invasive Goldfish populations. The ability to quickly and accurately distinguish between these phenotypically similar fish, while also determining their presence in various waterbodies, is important in tracking invasions. In this work, we develop a cytochrome B–based assay, as well as an ND2-based assay to distinguish between these two fish. The 84-bp-long CytB assay featured a limit of detection of 5.8 and 4.8 copies/sample for Prussian Carp and Goldfish, respectively, while the 95-bp-long ND2 assay featured LODs of 6.3 and 1.6 copies/sample, respectively. We demonstrate that each of these assays fails to amplify these markers in closely related fish species common to Alberta. They also fail to amplify key invasive carp species, apart from the Goldfish ND2 assay, which cross-reacts with Common Carp. We then implement these assays and find 13 Goldfish and 47 Prussian Carp environmental DNA detection events throughout the Canadian province of Alberta. Finally, we show that assays broadly agree with visual observation data gathered from various reporting mechanisms, highlighting their validity in a monitoring program.

Citation: Hambrook J., Kimmel N., Robinson R., Foster D., Poesch M.S. and P. Hanington. (2025) Development, validation and implementation of eDNA-focused qPCR assays to detect and distinguish between Goldfish (Carassius auratus) and Prussian Carp (Carassius gibelio). Environmental DNA 7(2): e70092. 

Also Read:

Veilleux, H., McPherson, M.*, Cott, P., Poesch, M., S., Glover, C., and G. Goss. (2025) Environmental DNA as a tool to detect Arctic grayling and their habitat preferences in the Northwest Territories, Canada. Arctic Science 11: 1-12.

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

Tayebi A. T., Schmid J., Simmons S., Poesch M. S., Ramazi P. and M. Lewis. (2025) Website views as a proxy for angler pressure and effort: Insight from Bayesian networks. Canadian Journal of Fisheries and Aquatic Sciences.

Abstract:

Reliable angler activity data inform fisheries management. Traditionally, such data are gathered through surveys, but an innovative cost-effective approach involves utilizing online platforms and smartphone applications. These citizen-sourced data were reported to correlate with conventional survey information. However, the nature of this correlation—whether direct or mediated by intermediate variables—remains unclear. We applied Bayesian networks to data from conventional surveys, the Angler’s Atlas website, the MyCatch smartphone application, and environmental data across Alberta and Ontario, Canada, to detect probabilistic dependencies. Using Bayesian model averaging, we quantified the strength of connections between variables. Waterbody webpage views were directly related to daily- and weekly-aggregated boat counts in Ontario (51% and 100% probability) and to weekly-aggregated creel survey-reported fishing duration in Alberta (100%). This highlights the value of citizen-sourced data in providing unique insights beyond meteorological factors, with online interest serving as a potentially reliable proxy for angler pressure and effort.

Citation: Tayebi A. T., Schmid J., Simmons S., Poesch M. S., Ramazi P. and M. Lewis. (2025) Website views as a proxy for angler pressure and effort: Insight from Bayesian networks. Canadian Journal of Fisheries and Aquatic Sciences.

Also Read:

Theis, S.*, Shirton, J.*, Barbeau, M.*, Ruppert, J. W. L.* and M.S. Poesch (2025) Growth and diet of Northern Pike (Esox lucius) in Boreal lakes: Implications for Ecosystem Management. Hydrobiologia 4(1): 1.

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

Schmid J., Simmons S., Poesch M. S., Ramazi P. and M. Lewis. (2025) Analyzing fisher effort – Gender differences and the impact of Covid-19. Canadian Journal of Fisheries and Aquatic Sciences.

Abstract: 

Fishing is a valuable recreational activity in our society. To assess future fishing activity, identifying variables related to differences in fishing activity, such as gender or Covid-19, is helpful. We conducted a Canada-wide email survey of users of an online fishing platform and analyzed responses with a focus on gender, the impact of Covid-19, and variables directly related to fisher effort. Genders (90.1% male and 9.9% female respondents) significantly differed in demographics, socioeconomic status, and fishing skills but were similar in fishing preferences, fisher effort in terms of trip frequency, and travel distance. For almost half of the fishers, Covid-19 caused a change in trip frequency, determined by the activity level and gender of the fisher. A Bayesian network revealed that travel distance was the main determinant of trip frequency and negatively impacted the fishing activity of 61% of the fishers. Fisher effort was also directly related to fishing expertise. The study shows how online surveys and Bayesian networks can help understand the relationship between fishers’ characteristics and activity and predict future fishing trends.

Citation: Schmid J., Simmons S., Poesch M. S., Ramazi P. and M. Lewis. (2025) Analyzing fisher effort – Gender differences and the impact of Covid-19. Canadian Journal of Fisheries and Aquatic Sciences.

Also Read:

Theis, S.*, Shirton, J.*, Barbeau, M.*, Ruppert, J. W. L.* and M.S. Poesch (2025) Growth and diet of Northern Pike (Esox lucius) in Boreal lakes: Implications for Ecosystem Management. Hydrobiologia 4(1): 1.

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

Theis, S.*, Shirton, J.*, Barbeau, M.*, Ruppert, J. W. L.* and M.S. Poesch (2025) Growth and diet of Northern Pike (Esox lucius) in Boreal lakes: Implications for Ecosystem Management. Hydrobiologia 4(1): 1.

Abstract: 

An important top-down predator, the northern pike (Esox lucius), faces harsh environmental conditions in the northern boreal ecoregion. They are often managed for recreational fishing and, more recently, to create environmental offsets; strategies aimed at balancing ecological impacts by enhancing or restoring habitats. Our study examines northern pike populations in two remote boreal lakes in northern Alberta: Steepbank and Wappau. The lakes differ in size, vegetation cover, and trophic status, providing a natural experiment for investigating northern pike growth, condition, diet, and population density. Over three years (2018–2020), northern pike were sampled using gill nets. Population metrics, including growth, condition, and stomach contents, were compared between the lakes. Steepbank, a smaller, oligotrophic lake with low vegetation cover, showed lower prey fish densities compared to the larger, eutrophic Wappau, but it did not differ in northern pike catch per unit effort. Growth rates and body condition varied significantly between the lakes, with the northern pike in Wappau exhibiting faster growth and a better condition in the older age groups, while the younger northern pike in Steepbank had higher relative weights. A diet analysis revealed significant differences in prey consumption: Steepbank northern pike displayed higher rates of conspecific predation and invertebrate consumption, particularly in the younger age classes. These findings highlight how lake characteristics and prey availability shape northern pike population dynamics, offering valuable insights for lake management approaches in northern Alberta.

Citation: Theis S., Shirton J., Barbeau M., Ruppert J. W. L. and M.S. Poesch (2025) Growth and diet of Northern Pike (Esox lucius) in Boreal lakes: Implications for Ecosystem Management. Hydrobiologia 4(1): 1.

Also Read:

Theis, S.*, Ruppert, J. L. W. and M. S. Poesch. (2023) Coarse woody habitat use by local fish species and structural integrity of enhancements over time in a shallow northern boreal lake assessed in a Bayesian modeling approach. Ecological Solutions and Evidence 4(2): e12200.

*Lab members: Sebastian Theis, Jonathan Ruppert (former member) and Mark Poesch. Check out opportunities in the lab!