By Sarah Walton, M.Sc. candidate, Carleton University

I am an MSc candidate co-supervised by Dr. Steven Cooke in the Fish Ecology and Conservation Physiology Laboratory at Carleton University and Dr. John Farrell from the State University of New York (SUNY) College of Environmental Science and Forestry (ESF). My research investigates spatiotemporal and behavioural ecology of age zero esocids – Muskellunge (Esox masquinogy) and Northern Pike (Esox lucius) – in the St. Lawrence River.

Sarah and a large female Muskellunge captured in the Thousand Islands, St. Lawrence River.  Gametes will be extracted, juveniles reared at the Thousand Islands Biological Station (TIBS), and released. Photo Credit: John Paul Leblanc

Sarah and a large female Muskellunge captured in the Thousand Islands, St. Lawrence River.
Gametes will be extracted, juveniles reared at the Thousand Islands Biological Station (TIBS), and released.
Photo Credit: John Paul Leblanc

Exploring the spatiotemporal ecology of fish is necessary to elucidate life history strategies, delineate and conserve core habitats, and appropriately manage populations. While nursery habitat requirements for age zero esocids in the St. Lawrence River are well understood, little is known about the influence of physical habitat on residency, behaviour, and survival during fall dispersal and overwintering periods. In my research, we captured age zero Muskellunge and Northern Pike from known nursery bays via seine netting between August and October. Fish were surgically implanted individuals with the smallest, commercially-available acoustic transmitters, known as JSAT tags. Detection data was passively collected using arrays of acoustic receivers within and beyond nursery bay entrances. I modeled core space use against environmental and biological covariates (e.g. temperature, depth, total length), to examine their influence on movement, habitat use, and survival throughout the fall and winter seasons.

Sarah preparing to deploy a Lotek receiver to collect detection data on juvenile Muskellunge. Photo Credit: John Paul Leblanc

Sarah preparing to deploy a Lotek receiver to collect detection data on juvenile Muskellunge.
Photo Credit: John Paul Leblanc

I completed a complementary hatchery study, in collaboration with Fleming College, to evaluate the effects of surgical procedures and tag implantation on captive-reared age zero Muskellunge. I wanted to quantify tag retention, survival and growth rates, rate of healing due to surgical wounds, and flight initiation response to a moving object post-anesthetic exposure. To conduct this work, fish were randomly selected for one of three treatment groups – control, sham, or tagged. Sham fish underwent anesthetization and surgery, without tag implantation, while tagged fish received anesthetic, surgery, and a JSAT tag. Fish were measured and photographed once a month from November to February. Post-anesthetic response was quantified promptly upon recovery and one-week post-anesthesia. I used mixed modeling to determine if end points were significantly different between treatment groups over time.

My work broadly aims to elucidate spatiotemporal ecology of juvenile Muskellunge and Northern Pike, inform wetland restoration efforts to establish and promote core esocid nursery habitat, and evaluate the use of telemetry tools to study juvenile esocids.