Dissolved Oxygen and Temperature on the Viability of Spawning Salmon

Abstract

To observe how dissolved oxygen (DO) levels and air and water temperature affect the viability of spawning salmon at Baker Creek (BC) in Quesnel, British Columbia and at Salish Creek (SC) in Vancouver, British Columbia. BC supports spawning Oncorhynchus gorbuscha (pink salmon) and SC used to support spawning Oncorhynchus kisutch (coho salmon). At each location, samples were taken to determine DO levels, air temperatures, water temperatures and a qualitative study of plant life at an upper and lower site at each creek was observed. The three null hypotheses are: DO levels will be the same at both BC and SC, water temperatures will be the same at both BC and SC, and air temperatures will be the same at both BC and SC. The alternative hypothesis is that DO levels and temperatures will be different at BC and SC. The data for DO levels, air temperatures and water emperatures was analyzed using a Welch’s t-test in R Software. After this analysis, the three null hypotheses  were rejected and the alternative hypothesis was accepted. DO levels were significantly higher at SC compared to BC and water and air temperatures at SC were significantly higher compared to BC. The relationship between temperature and DO level is illustrated by Henry’s Law which indicates that colder temperatures equate to higher DO levels in water. Thus, our results illustrate an unexpected difference between expected DO levels and temperatures where pink salmon spawn in BC. At SC, DO levels were within a range to sustain coho salmon life, but the water temperature was outside of this range and may explain why spawning does not occur in SC.