Document Type

Thesis

Degree Name

Master of Science (MSc)

Department

Biology

Program Name/Specialization

Integrative Biology

Faculty/School

Faculty of Science

First Advisor

Michael Wilkie

Advisor Role

Suprevisor

Second Advisor

Hugo Flavio

Advisor Role

Project Manager

Abstract

The invasion of the Laurentian Great Lakes by sea lamprey (Petromyzon marinus) in the early-mid 1900s caused serious harm to commercial, recreational and Indigenous fisheries. They continue to threaten these fisheries due to the blood-feeding behaviour of parasitic juvenile lamprey. Sea lamprey have a complex life cycle which begins with a filter-feeding larval stage, before they undergo metamorphosis and enter the parasitic juvenile stage, during which time they feed on the blood of fishes using their oral disc and dagger-like tongue. Following this stage, they migrate up freshwater streams, as spawning adults. One of the challenges in managing this invasive species is understanding the early movements and behaviour of the parasitic juvenile life-stage in the wild. The small size and elongated shape of these anguilliform animals make it difficult to implant tracking devices on or within the animals without causing potentially confounding physiological and behavioural responses. Fitting juvenile sea lamprey with tags to better understand their movements and behaviour would generate new knowledge that could be used to strengthen the sea lamprey control program in the Great Lakes. Recently, a small eel and lamprey acoustic tag (ELAT) was developed to study this poorly understood life-stage, but an understanding of how ELAT implantation affects the behaviour or physiology of the tagged animals is essential prior to its wider application in the field.

This thesis focused on determining what sub-lethal effects were experienced by juvenile sea lamprey due to tagging procedures and the burden of carrying the ELAT. Intermittent flow respirometry was used to determine the resting and maximum metabolic rates of three different groups of fish (control, sham surgery, and tagged) at 10-, 20-, and 30-days post-surgery to explore possible metabolic rate differences between treatment groups. Importantly, we found significant decreases in maximum metabolic rate and aerobic scope for tagged juveniles. ELAT implantation also affected feeding behaviour, as demonstrated in feeding trials where animals were implanted with ELATs and held with a single lake trout for 10 days. ELAT implantation in juvenile sea lamprey resulted in significantly lower probabilities of tagged juveniles attempting to and successfully attaching to the host, compared to control and sham surgery juveniles. In conclusion, high survival and tag retention following ELAT implantation suggests that this method may have value for tracking juvenile sea lamprey movements in the field, but the impairment of aerobic scope and feeding behaviour by the ELAT suggests that the interpretation of such data should be done with caution.

Convocation Year

2026

Convocation Season

Spring

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Available for download on Saturday, December 19, 2026

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