Current research

Here are the questions my research group, collaborators, and I are currently working on.

What are the impacts of wastewater effluents on aquatic communities and biodiversity?

One of the largest point sources of emerging, human-made chemical pollutants to urban freshwaters are municipal wastewater treatment plants (WWTPs) that discharge a complex mixture of pollutants and nutrients in receiving environments. I’ve used a combination of lab-exposures, caging exposures, and field sampling to understand how wastewater effluents affect fish physiology, behaviour, and shape entire aquatic communities. I’m currently studying if WWTPs act as an ecological trap that attract aquatic organisms, but increase their exposure to wastewater-associated pollutants which may detrimentally impact fitness.

Recent funding: Swedish Research Council FORMAS Early Career Research Grant 2021-2025

Select publications

Späth J, Fick J, McCallum ES, Cerveny D, Nording ML, & Brodin T (2022). Wastewater effluent affects behaviour and metabolomic endpoints in damselfly larvae. Scientific Reports, 12(1), 1-13.

McCallum ES, Nikel KE, Mehdi H, Du SNN, Bowman JE, Midwood JD, Kidd KA, Scott GR, Balshine S. (2019). Municipal wastewater effluent affects fish communities: a multi-year study involving two wastewater treatment plants. Environmental Pollution. 252, 1730-1741

Du, SNN, McCallum, ES, Vaseghi-Shanjani M; Choi J; Warriner T; Balshine S & Scott GR. (2018). Metabolic costs of exposure to wastewater effluent lead to compensatory adjustments in respiratory physiology in bluegill sunfish. Environmental Science & Technology, 52, 801-811

McCallum ES, Krutzelmann E, Fick J, Brodin T, Sundelin A & Balshine S (2017). Exposure to wastewater effluent affects fish behaviour and tissue-specific uptake of pharmaceuticals. Science of the Total Environment, 605, 578-588.

What are effects of chemical pollutants on aquatic organisms in increasingly realistic environments?

Often, testing to assess the impact of pollutants on aquatic animals like fish is done in highly artificial environments that ignore the conditions they would experience in the wild. However, certain chemical pollutants can likely alter the way animals interact socially (e.g., pharmaceuticals, endocrine disrupters), and social behaviour underpins nearly all fitness endpoints in animals. Here, I am studying the impacts of behaviour-altering pollutants under naturalistic settings (both socially and spatially) and over behaviourally-relevant and also evolutionarily-relevant timescales.

Recent funding: Swedish Research Council (VR) Starting Grant, 2023-2027

Select publications

Bose APH, McCallum ES, Avromovic M, Bertram M, Blom E, Cerveny D, Gronlund S, Leander J, Lundberg P, Martin JM, Michelangeli M, Persson L, Brodin T. (2022). Pharmaceutical pollution disrupts the behaviour and predator–prey interactions of two widespread aquatic insects. iScience, 25(12), 105672

Michelangeli M, Martin JM, Pinter-Wollman N, Ioannou CC, McCallum ES, Bertram MG, & Brodin T. (2022). Predicting the impacts of chemical pollutants on animal groups. Trends in Ecology & Evolution, 37(9), 789-802.

McCallum ES, Dey CJ, Cerveny D, Bose APH, & Brodin T. (2021). Social status modulates the behavioral and physiological consequences of a chemical pollutant in animal groups. Ecological Applications, 31(8), e02454.

Martin JM, & McCallum, ES (2021). Incorporating animal social context in ecotoxicology: can a single individual tell the collective story?. Environmental Science & Technology, 55(16), 10908-10910.

McCallum ES, Cerveny D, Fick J, Brodin T. (2019). Slow-release implants for manipulating contaminant exposures in aquatic wildlife – a new tool for field ecotoxicology. Environmental Science & Technology. 53, 8282-8290

How can we better use the primary evidence base in ecotoxicology?

Evidence synthesis techniques like meta-analysis and systematic reviewing/mapping are under-utilized in environmental toxicology, but are useful ways to collate evidence whilst minimizing bias for specific research questions or broader research topics. These approaches can elucidate gaps in the literature and connect disparate research areas together, making them a useful tool for environment management. I am currently leading a large international team of researchers to make a systematic map of the evidence for the behavioural effects of pharmaceutical pollutants in aquatic animals.

Select publications

Martin, JM, Bertram, MG, Blanchfield, PJ, Brand, JA, Brodin, T, Brooks, BW, Cerveny, D, Lagisz, M, Ligocki, IY, Michelangeli, M, Nakagawa, S, Orford, JT, Sundin, J, Tan, H, Wong, BBM, & McCallum, ES. (2021). Evidence of the impacts of pharmaceuticals on aquatic animal behaviour: a systematic map protocol. Environmental Evidence, 10(1), 1-10.

Full systematic map currently under review: Evidence of the Impacts of Pharmaceuticals on Aquatic Animal Behaviour (EIPAAB): a systematic map and open access database (https://ecoevorxiv.org/repository/view/7636/)

Do river barriers slow the spread of invasive fish?

Managing invasive species requires a fundamental understanding of their biology and ecology. Another focus of my research has been on the population dynamics, behaviour, and reproductive ecology of the invasive round goby in the Laurentian Great Lakes and more recently, the Baltic Sea. Tracking their population across different habitats, I showed that round goby thrive in areas of high pollution despite having negative effects on their behaviour and morphology. Curerntly, I am working with a consortium of researchers to assess means to limit the spread of round goby to new parts of the Baltic Sea and to inland freshwater rivers. My part of this project assesses if river barriers like dams are an effective way of slowing round goby invasions using a spatial genetics approach.

Recent funding: Naturvårdsverket special call on Invasive Species Management 2021-2025 (co-applicant).

Select publications

*McCallum ES, *Bose APH, Lobban N, Marentette JR, Pettitt-Wade H, Koops MA, Fisk AT, Balshine S. (2019). Alternative reproductive tactics, an overlooked source of life history variation in the invasive Round Goby. Canadian Journal of Fisheries & Aquatic Sciences, 76, 1562-1570. *Co-first authors

*Capelle PM, *McCallum ES, & Balshine S (2015). Aggression and sociality: conflicting or complimentary traits of a successful invader? Behaviour, 152, 127-146. *Co-first authors

McCallum ES, Charney RE, Young JAM, Marentette JR, Koops M, Earn DJD, Bolker & Balshine S (2014). Persistence of an invasive fish (Neogobius melanostomus) in a contaminated ecosystem. Biological Invasions, 16, 2449-2461.

What factors affect downstream migration behaviour and success in salmonids?

Certain fish species like anadromous salmonids undertake long distance, often dangerous, migrations over their life cycles to access new habitats or reproduce. Recently, I have been studying how pollutants may affect migration behaviour in Atlantic salmon and brown trout smolt, as well as fundamental questions about how fish age, condition, and energetics affect maturation and downstream migration success. These projects have been conducted in collaboration with a hatchery stakeholder and are broadly aimed at improving the migration success juveniles released in compensatory stocking programs.

Select publications

Shry S, McCallum ES, Alanärä A, Persson L, Hellström G. (2019). Energetic state modulates facultative migration in sea-run brown trout (Salmo trutta) differentially by age and environment. Frontiers in Ecology and Evolution. 7, 411

McCallum ES, Sundelin A, Fick J, Alanärä A, Klaminder, K., Hellström G, & Brodin T. (2019). Investigating tissue bioconcentration and the behavioural effects of two pharmaceutical pollutants on sea trout (Salmo trutta) in the laboratory and field. Aquatic Toxicology, 207, 170-178