The Peter A. Larkin Award for Excellence in Fisheries at a Canadian Institution is given yearly to two deserving graduate students (one PhD student and one MSc student). The award recognizes one of Canada’s great fisheries scientists who was passionate about students. The Peter A. Larkin Memorial Fund was established in memory of Peter Anthony Larkin, C.M., O.B.C., F.R.S.C.; M.A. (Sask.), D.Phil. (Oxon), D.Sc. (UBC), University Professor Emeritus, world-renowned leader in fisheries science, and an active and honoured member of the American Fisheries Society (more about Dr. Larkin can be found here). Successful applicants will be chosen by CARS based on academic qualifications, a proposal of their research, and their AFS involvement.

Applications are now being accepted for the 2022 Larkin Award. The purpose of the award is to identify the top current Masters and PhD level students that are conducting fisheries research at a Canadian institution. The award is not restricted to students with Canadian citizenship. For specific details and to download the application instructions, click here.
Deadline: June 17, 2022 (4pm EDT)

The award is administered and supported by the Canadian Aquatic Resources Section (CARS) of the American Fisheries Society (AFS). To be eligible for the award, you must be a current member of AFS (go to fisheries.org). You can join at the time of applying to this award. We also encourage you to check the box to be a CARS member in the AFS application form, which comes as no additional cost for students. Note if you are already an AFS member but didn’t know about CARS, you should be able to make changes to your membership by logging into the AFS membership page.

2021 Larkin Award Results

In 2021, we received 30 applications for the Larkin Award (16 PhD and 14 MSc). The Larkin Award program is run by Dr. Sarah Lehnert (DFO). Thanks to our judges for the award, who in 2021 were Dr. Marianne Geisler (U Winnipeg), Dr. Kyle Wellband (DFO), Dr. Ben Sutherland (DFO), and Dr. Clare Venney (Laval).

Winner (PhD level): Paul Bzonek

I recently completed (Nov 2021) my PhD at the University of Toronto Scarborough under the supervision of Dr. Nicholas Mandrak. My research interests were broadly centered around the movement and behaviour of invasive fishes. To address these interests, I employed lab and field techniques such as acoustic telemetry, video-recorded behavioural trials, and respirometry experiments. I also collaborated with partners, including Fisheries and Oceans Canada, Royal Botanical Gardens, and the South African Institute for Aquatic Biodiversity, to apply concepts of behavioural ecology to conservation efforts.

I evaluated non-structural fish deterrents (think sounds, lights, carbon dioxide) as potential tools to limit the dispersal and range expansion of invasive cyprinids. Freshwater ecosystems have received proportionately more invasive species than terrestrial ecosystems, which can lead to losses in ecosystem resilience and resistance. Non-structural deterrents are a promising conservation tool as they can limit invasive fish dispersal at low costs and without altering stream flow and functioning. Cyprinids, such as Common Carp and Goldfish, have degraded Great Lakes wetlands for decades where they uproot submerged vegetation and increase turbidity. Furthermore, invasive Asian carps (Black, Bighead, Grass, Silver) are currently dispersing throughout the Mississippi River basin. If these species were to become established within the Great Lakes ecosystems, they could have dramatic and detrimental impacts on native fish, invertebrate, plant, and plankton communities.

I deployed non-structural deterrents within the Royal Botanical Gardens fishway to evaluate deterrent efficiency. I then brought a subset of captured Common Carp back to the laboratory to determine if deterrent success was correlated with repeatable metrics of sociability, activity, and exploration. After laboratory trials, fish were released back into the field where they were tracked with acoustic telemetry to determine if movement in the field was correlated with behaviour in the lab and with successful dispersal across the fishway barrier. In a separate telemetry experiment, I investigated the social movement patterns of Common Carp in relation to hunting efforts targeted to control carp abundance in a South African lake.

Throughout my laboratory chapters, I determined that Common Carp express consistent inter-individual variation in behaviour. I also found that some individuals will consistently avoid deterrent stimuli to a greater extent than others. By deploying deterrents in the field, I was able to evaluate deterrent efficacy and quantify how fish avoidance responses to acoustic deterrents may express a phylogenetic signal across a wetland fish community. We also found that consistent movement behaviours in the field can lead to important consequences for dispersive success and habitat suitability.

Runner-up (PhD level): Jordanna Bergman

Hi! My name is Jordanna Bergman and I’m a PhD Candidate at Carleton University, co-supervised by Dr. Steven Cooke and Dr. Joseph Bennett. My thesis research is focused on investigating the ecological connectivity of Canada’s historic Rideau Canal, specifically as experienced by native and invasive fishes. The Rideau Canal, located in eastern Ontario, forms a 202-kilometre continuous, navigation route between Lake Ontario and the Ottawa River. The system is interconnected by 24 operating lockstations, many with associated water-control dams. When the Rideau Canal was constructed in the 1830s, previously disconnected aquatic habitats and watersheds were connected, enabling movement to new geographic areas to both invasive and native species. To date, it is unclear to what extent fishes move through anthropogenic barriers in the system (e.g., navigation locks, dams) or if movements are species- or season-specific. As invasive species pose one of the greatest threats to the biotic integrity of freshwater ecosystems, with potentially adverse socio-economic effects on human welfare, it is vital for us to consider how lock infrastructure and/or operations could be refined to reduce their spread. To do so, and without compromising connectivity to native fish species, we must first assess how “connected” the waterway is and determine the factors supporting (or preventing) movements.

To evaluate the fine- and broad-scale movements of fishes in the Rideau Canal, I am using acoustic telemetry and mark-recapture (FLOY tags) methods, respectively. With the help of many, we have externally tagged ~8,000 fish across 13 species, and I have acoustically tagged close to 300 individuals – including native muskellunge (E. masquinongy), largemouth bass (M. salmoides), and northern pike (E. lucius), and invasive round goby (N. melanostomus) and common carp (C. carpio) – across 80-kilometres of the waterway. The Rideau Canal is an inherently social-ecological system: it was constructed with human-use in mind and is still operated primarily for recreation today (i.e., the social aspect), however it also houses diverse biodiversity and several species at risk (i.e., the ecological aspect). Thus, to evaluate fish connectivity and movements in respect to anthropogenic barriers and water management, we’ve collaborated with experts in other disciplines, like social scientists and hydraulic engineers, as well as Parks Canada (the federal agency that stewards the canal). It’s been a favourite part of my thesis to partner with, and learn from, experts in other fields to develop comprehensive research products that can be used by managers. For example, the first chapter of my thesis investigates how lock infrastructure and operations may support the spread of a new round goby invasion, and my second chapter examines the effects of drastic winter water drawdowns on muskellunge overwintering movements – neither of these projects would be possible without multi-disciplinary efforts. I am excited to next dive into our three-year, multi-species lock-connectivity project, and see how native and invasive species move throughout the system.

As of the 20th century, more than 60,000-kilometres of canals with barriers exist worldwide, heavily fragmenting the longitudinal connectivity of freshwater systems and posing a critical threat to biodiversity. We aim to use results from my thesis to support conservation actions and develop strategies to protect and enhance Ontario’s economically-important, and beautiful, freshwater ecosystems. Broadly, our hope is to inform not only conservation and management of fish within the Rideau Canal, but also other waterways in Canada and beyond.

Winner (MSc level): Jamie Card

I recently completed my Master of Science in the fall of 2021, supervised by Dr. Caleb Hasler at the University of Winnipeg. My research focused on quantifying the biological consequences of catch and release angling on understudied fish species, freshwater drum (Aplodinotus grunniens) and during understudied conditions, such as ice angling.

Many catch-and-release angling events involve air exposure and exhaustive exercise that elicit a physiological stress response, and depending on a variety of factors, delayed mortality is a possible outcome. There have been ample studies in this area, however, significant gaps exist in the literature for species that are not commonly promoted as popular sportfish species, such as freshwater drum, as freshwater drum have never before been studied in a catch-and-release angling setting. To address this knowledge gap, I quantified physiological and reflex responses in freshwater drum following angling, across seasons for the first data chapter of my thesis. Once a fish was on the line, the fight duration and time exposed to air were varied to account for differences in angler skill level. Location and severity of injury were determined, blood biopsies were taken to quantify physiological stress, and reflex impairment was assessed. Thirty-one percent of fish captured were deeply hooked in the esophagus tissue. Freshwater drum experienced a disruption in homeostasis as blood glucose, plasma cortisol, and plasma lactate increased significantly from baseline values following angling. Additionally, seasonal differences were observed for blood glucose and plasma cortisol as higher values were observed in the summer when compared to the spring. The ‘orientation’ reflex was the most frequently impaired (29 % of fish lacked this reflex), but impairment did not differ seasonally. Because freshwater drum have the largest latitudinal range of any North American freshwater fish and are being targeted more frequently by anglers as of late, it is important to fill this knowledge gap regarding their responses to angling events to develop best practices for anglers to promote conservation.

For the second data chapter of my thesis, I shifted my focus to a different species and an entirely different season, as ice-angling is a popular activity practiced across northern regions during the winter season. Despite this popularity and due to inherent issues with sampling fish in the wintertime, few studies have quantified the sublethal impacts of ice-angling and ice and air exposure on fish species that will be released back into the water. To address this knowledge gap, I exposed yellow perch to an ice-angling event followed by a 3 min ice/air exposure period where I quantified surface temperature of important tissues, reflex impairment, and assessed tissues for damage due to freezing using histological methods. Results showed that reflexes were impaired following ice-angling, heat loss occurred throughout the exposure treatment in the midbody, other important tissues (eye, gills, caudal fin) remained below 0 °C throughout the exposure, and aneurysms within the secondary lamellae of the gills were found in 68.75 % of all fish (both control and treatment individuals) that were caught via ice-angling. These aneurysms may result from exposure to sub-zero temperatures that may have compromised pillar cells, although further study is warranted. It is recommended that anglers limit air exposure when ice-angling in sub-zero temperatures by keeping fish submerged in water or releasing any fish immediately that they do not intend on harvesting, to limit negative biological consequences of cold air exposure coupled with the stress of an ice-angling event.

Runner-up (MSc level): Shannon Clarke

I am an MSc student supervised by Dr. Dylan Fraser and Dr. James Grant at Concordia University, and am working in collaboration with Dr. Daniel Ruzzante at Dalhousie University. I study how size-selective fisheries impact the genetics and demographics of alpine brook trout (Salvelinus fontinalis) populations, using whole-lake experiments in the Canadian Rocky Mountains.

In fisheries, it is critical to incorporate both demographic and genetic considerations into assessments, as both can determine harvest yields and population persistence. This is especially important in populations subjected to size-selective harvest, which has the potential to results in significant demographic, life history, and genetic changes. One important parameter used to assess genetic changes and predict future population viability is the effective population size, or Ne, which is often compared with the census size (Nc) to integrate genetic and demographic changes. Measuring Ne in wild populations, however, is difficult because of the need for multiple temporal samples, or in-depth data about a population’s life history. Instead, we can use the effective number of breeders, or Nb, a measure of effective size from a single-age cohort, to compare with Nc.

I use data from whole-lake experiments to test how Nb and Nc change during size-selective harvest of alpine brook trout populations in Banff and Kootenay National Parks. These lakes have populations of non-native brook trout that were stocked in the early 1900s, and this project took advantage of Parks Canada’s mandate to restore aquatic ecosystems by removing non-native species. We had three treatment lakes, where we harvested ~60% of the largest individuals over a three-year period, and three control lakes that were monitored throughout the study period. We measured Nc in all populations using mark-recapture methods, and measured Nb through sequencing tissue samples from young-of-the-year (YOY) fish.

Our results show that while demographic variables, such as Nc, changed rapidly after harvest, the effective size was resilient to short-term change, likely due to density-dependent processes such as genetic compensation. These results can help inform future management of fisheries, and while they highlight the potential for density-dependent processes to buffer short-term change in Nb, it still remains important to monitor effective size of harvested populations to ensure their long-term sustainability.