Nicholas E. Mandrak

Nicholas E. Mandrak is an Associate Professor in Biological Sciences at the University of Toronto Scarborough (UTSC) in Toronto, Ontario. He is Director of the Conservation and Biodiversity stream of the professional M.Env.Sci. program at UTSC. Nick is a Research Associate of the Royal Ontario Museum and South Africa Institute of Aquatic Biodiversity. He is the Co-Chair of the Freshwater Fishes Species Specialist Subcommittee of COSEWIC. Nick is an Associate Editor of Biological Invasions and on the Editorial Board of the Journal of Aquatic Ecosystem Health and Management. His research interests are the biodiversity, biogeography, and conservation of Canadian freshwater fishes, with emphasis on endangered and invasive fishes. Nick has co-authored over 100 primary publications, over 50 government reports, 40 COSEWIC reports, and three books, including the ROM Field Guide to Ontario Fishes.

Post-Doctoral Fellows:

Dr. Nathan Lujan

I obtained my PhD from Auburn University in 2009, followed by post-doctoral research at Texas A&M University, the University of Toronto, the Academy of Natural Sciences, and the Royal Ontario Museum. I have published over 25 papers in a wide range of journals and have organized, led, or participated in 18 ichthyofaunal surveys of rivers in seven countries. Broad questions that drive my research include: How many fish species are there? What rules govern the community assembly of riverine primary consumers? How do disjunct habitats within stream and river networks affect the gene flow and evolutionary specialization of freshwater fishes? I enjoy backpacking, camping, traveling and exploring with my wife Bernadette and dog Percy. To find out more, visit my website at:

PhD Lab Members (UTSC):

Sara Campbell: I am currently a PhD Candidate examining spatio-temporal community assembly using multiple dimensions of biodiversity.  I graduated from the University of Vermont (2013) with a BSc. in Biological Sciences, where I contributed to various projects including a longterm study on the minimum viable population of fiddlehead ferns, how biodiversity impacts cattle health and well-being, and immune responses to Influenza.  Following undergrad, I spent a year volunteering in the Cadotte lab, where I expanded my interests in examining different facets of biodiversity.  My broad interests are in community ecology, specifically, species coexistence, how ecological communities are formed, and using novel tools to predict invasion success using ecological theory.  My interests outside of science include competitive running, scent detection with my dog River, and being outdoors.


Rowshyra Castañeda, MSc

I am currently a PhD Candidate with Nick Mandrak and Olaf Weyl (SAIAB) studying the detection and quantification of rare freshwater fishes. I am assessing the use of underwater cameras as a non-invasive novel method. I am combining mathematical models, experiments, and field work to develop this method. I completed my undergrad and MSc at McGill University, where I completed a variety of projects, ranging from behavioural neurobiology, to evolutionary ecology, invasion biology, and conservation biology. These research projects have allowed me to explore biodiversity at home and around the world, fulfilling my need to travel and explore new places and cultures. When I’m not doing thesis research or traveling, I spend my time doing science outreach for youth, especially for young girls interested in Science, Technology, Engineering, and Mathematics (STEM). I’ve also dabbled in microplastic research and actively help with public outreach projects. To find out more visit my website.


Fielding Montgomery

I am a PhD candidate in the Ecology and Evolutionary Biology program, co-supervised by Nick Mandrak and Scott Reid from the OMNRF. I completed my BSc in Biology at Dalhousie University, with a certificate in Environmental Impact Assessment. I am interested in applied ecology and conservation of freshwater fishes. My research focuses mainly on the impacts of habitat loss and fragmentation on local and regional fish extinction, using wetlands as a model system. I spend my summers camping by the water, and my winters in the rink! Find out more at my website.


Paul Bzonek, MSc

I am a PhD Student with Nick Mandrak at UTSC. My current research interests are centred around the behaviours and movement patterns of fish, and how this can impact movement and dispersal across geographic bottlenecks. For my MSc, I evaluated how Common Carp respond to non-physical behavioural barriers such as acoustic and visual stimuli. This work pertains to invasive Asian Carps and their potential dispersal into Great Lakes ecosystems. I completed a BSc. at the University of Guelph with a major in Ecology and minor in Zoology.  My non-academic interests include travel, Scuba diving, reading and water-skiing.


Emily Chenery, MEnvSc

I am a PhD student in the Department of Physical and Environmental Sciences, co-supervised by Péter Molnár and Nicholas Mandrak. With an undergraduate degree from the University of Warwick (UK), I graduated in 2016 from the University of Toronto with a Masters of Environmental Science, specializing in Conservation & Biodiversity.  I am interested in the application of ecological theory to conservation practice, and particularly in predicting species’ survival under changing environmental conditions.  My Masters research used a novel combination of expert opinion surveys and mechanistic modelling to investigate the transmission potential of aquatic invasive species in the Laurentian Great Lakes.  My doctoral research aims to contribute to the development of new approaches to modelling species and population dynamics, particularly those of relevance to conservation practitioners and policymakers, but also to other systems and areas of environmental science.  When not at my desk you’ll find me outdoors: hiking, practicing my slacklining skills, or cycling in Toronto’s ravines.


Tej Heer, MSc

My name is Tej and I am a PhD student in Physical and Environmental Sciences. I received my BSc in Physics from Mcgill University in 2013, followed by a MSc in Climate Change from the University of College London in 2015. My current project attempts to predict where Asian carps  would potentially spawn in the Canadian Great Lakes Basin. Specifically, I am attempting to use 3-D hydrodynamic modelling to simulate the movement of carp eggs in potential spawning tributaries. In general, I enjoy applied physics research, both in the atmosphere and in the waterways, especially those that involve climate change or conservation.



Meagan Kindree, MSc

I am a PhD student in the Department of Ecology and Evolutionary Biology, co-supervised by Nick Mandrak and Nick Jones from the OMNRF. I completed by undergraduate degree at Dalhousie University, with a certificate in Environmental Impact Assessment and Geographic Information Systems. For my MSc, studying the effect of gear type on the Index of Biotic Integrity (IBI) in the Huron-Erie Corridor Areas of Concern. I am interested in freshwater fish distribution patterns in the Great Lakes basin. My research aims to develop landscape-based distribution models of fish species and assess their change over time due to the influence of multiple stressors. This work will fill knowledge gaps in Canadian fish distribution patterns, particularly fish species at risk. I also will assess how the physical and anthropogenic connectivity between waterbodies influences the predicted future distributions of fish species. Outside of the office I spend my time fishing, hiking, scuba diving, and reading.

PhD Lab Members (McGill University):

Suncica Avlijas, MSc: PhD Candidate co-supervised with Tony Ricciardi

Dustin Raab, MSc: PhD Candidate co-supervised with Tony Ricciardi

MSc Candidates:

Brett Allen

My name is Brett and I am a master’s student in the Ecology and Evolutionary Biology Department at the University of Toronto. Previously, I attended Queen’s University where I received an undergraduate degree in biology. My current research focuses on assessing fish community change over time in the Credit River watershed, located in southern Ontario. Moreover, my research also looks at what causes this change, primarily in the form of multiple stressors such as urbanization or invasive species. Generally, I am interested in conservation biology and research that has management application. Outside of the lab, you can find me playing intramural sports or hanging with friends.


Shannon Ritchie

I am a MSc student in the Ecology and Evolutionary Biology program, co-supervised by Nicolas E. Mandrak and Marc W. Cadotte. I completed my BSc Honours in Environmental Science at University of Guelph, as well as a 3yr Environmental Engineering Technologist Diploma at Centennial College. I am interested in wetland ecology and conservation of Ontario herpetofauna (reptiles and amphibians). My research focuses on the overwintering ecology of headstated (raised in captivity and then released back into the wild) Blanding’s Turtles (Emydoidea blandingii), in a human made wetland. My research goal is to better understand if restored wetlands can provide suitable habitat for turtles specifically for population recovery programs. My passion is combining my scientific background and love to nature to educate youth on numerous conservation initiatives. I also love the outdoors! I am avid camper in my personal life with a high level of experience in backcountry canoe and hike in camping sites. In the winter you can find me hitting the slopes with my skis, or snowshoeing in one of the York Region’s beautiful forests.


Yiminxue Zheng: I’m a Master Student studying Ecology and Evolutionary Biology at the University of Toronto Scarborough Campus, supervised by Nick Mandrak. I completed my BSc at UTSC as well, with a specialization in Biodiversity, Ecology, and Evolution. I have a broad interest in ecology in the context of conservation. In a warming world driven by anthropogenic stressors, my research looks at the thermal stress response of freshwater fishes to increasing water temperatures, using Brook Trout as my study organism.  I am a writer at heart, spending most of my doing so both academically and as a hobby.

Lab Alumni:

Dr. Pasan Samarasin, Post-doc 2015-2017

Dr. Andrew Drake, Post-doc 2013-2016

Natalie Rook, MSc- 2016

Gabrielle Malcolm, MSc- 2015