Document Type

Thesis

Degree Name

Master of Science (MSc)

Department

Biology

Program Name/Specialization

Integrative Biology

Faculty/School

Faculty of Science

First Advisor

Dr Joseph Culp

Advisor Role

Supervisor

Second Advisor

Dr Michael Power

Advisor Role

Co-supervisor

Abstract

Ninespine stickleback (Pungitius pungitius) are ubiquitous in circumpolar freshwaters, but their ecological role is not well understood. Little research has been conducted on the influence of environmental variables on ninespine stickleback in stream environments, and while they are understood to be generalist feeders, their diet in stream environments is equally understudied. Determining diet is difficult due to biases inherent in all standard diet analysis methods. Morphological gut-content analysis (M-GCA), DNA metabarcoding of gut contents (D-GCA), and stable isotope analysis (SIA) are currently three of the most frequently conducted diet analyses; and while combinations of these methods are commonly used to counteract their biases, limited analyses have compared all three. The aims of this thesis were to address these knowledge gaps by determining the impacts of tundra stream characteristics on ninespine stickleback condition and abundance, characterizing their diet in these streams, and assessing the relative benefits and disadvantages of the above-mentioned diet analysis techniques for determining the diet of small stream fishes. The impacts of environmental factors (e.g. temperature, nutrient concentrations, prey and predator/competitor abundance) on condition and abundance were present but limited, likely due to both the tolerant nature of ninespine stickleback and carry-over effects from over-wintering environments. The generalist nature of ninespine stickleback was confirmed by M-GCA and D-GCA results which described a high occurrence of abundant stream invertebrates in the gut, namely Orthocladiinae and Chironominae. In contrast, SIA estimated Arachnida and Tanypodinae to be the most significant contributors to diet over a longer period, suggesting a diet shift over the summer due to either a change in stream invertebrate community composition, or prior feeding in a different environment. Biases of each diet analysis technique were consistent with prior reports, with M-GCA being biased towards hard-bodied organisms, and D-GCA being biased towards soft-bodied organisms. The findings of this thesis contribute to a growing understanding of ninespine stickleback ecology in tundra streams and indicate the importance of studying connections with lentic over-wintering environments in future research. Finally, this research complements other research being conducted in the Greiner Lake watershed on tundra stream food-web dynamics and stream metabolism.

Convocation Year

2022

Convocation Season

Spring

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