Document Type

Thesis

Degree Name

Master of Science (MSc)

Department

Biology

Program Name/Specialization

Integrative Biology

Faculty/School

Faculty of Science

First Advisor

Jonathan Wilson

Advisor Role

Primary supervisor

Second Advisor

Mathilakath Vijayan

Advisor Role

Co-supervisor

Abstract

Total suspended solids (TSS) naturally occur in aquatic habitats, but climate change and other anthropogenic disturbances can lead to increased levels. Exposure to high levels of TSS has the potential to damage fish gills through abrasion, leading to impairment of gill function and fish physiology. However, little work has been done exploring the linkages between TSS-induced gill damage and animal performance. Therefore, we tested the hypothesis that TSS damages gill structure, causing gill dysfunction and reducing swimming performance. We exposed salmonids (rainbow trout, brook trout and cutthroat trout) and non-salmonids (fathead minnow and longnose dace) to different TSS concentrations (0-1000 mg/L) for four days in a static exposure system. We assessed gill morphometrics indicative of gill damage, expression of genes and proteins involved in ion regulation [ Na+/K+-ATPase and vacuolar-type proton pump], ionocyte distribution, and markers of animal swimming performance [critical swimming speed (U­­crit), oxygen consumption rate (ṀO2) and aerobic capacity [standard metabolic rate (SMR), maximum metabolic rate (MMR) and aerobic scope (AS)]]. At 100 mg/L and higher, TSS increased lamellae thickness due to increase in epithelial lifting and oxygen diffusion distance. These changes corresponded with a reduced respiratory surface area in rainbow trout, leading to a reduction in ṀO2 and Ucrit. While ṀO2 did not change in fathead minnows, the MMR was reduced, and they also showed a reduction in Ucrit. TSS did not affect the gene and protein markers in the gills. Overall, elevated TSS damages gill structure, leading to impaired aerobic metabolism and swimming performance of fish.

Convocation Year

2024

Convocation Season

Spring

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Available for download on Wednesday, April 30, 2025

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