LE3 .A278 2020

2020

Stokesbury, Michael

Acadia University

Master of Science

Masters

Biology

Biology

Alewife (Alosa pseudoharengus Wilson, 1811) is an anadromous fish species that migrates annually to spawn in lakes along the eastern coast of Canada and the United States. Their migration provides an influx of crucial nutrients to freshwater environments through carcass decay and excretion of fecal matter, eggs and sperm. Stable isotope analysis performed o n aquatic macroinvertebrates from three lakes in Atlantic Canada determined that enriched 훿13C and 훿15N levels (indicative of marine origin) coincide with the alewife spawning migration. Significant enrichment of 훿13C was observed in Daphnia, Baetidae, and Chironomidae in Gaspereau Lake, Daphnia, Baetidae and Rhyacophilidae in Jolicure Lake, and Daphnia and Rhyacophilidae in Long Lake.The levels of 훿15N were enriched by 3-4‰ between Daphnia–Baetidae and Baetidae–Glossiphonidaein Gaspereau Lake; Baetidae–Aeshnidae, Rhyacophilidae–Aeshnidae, Chironomidae–Aeshnidae, and Glossiphonidae–Aeshnidae in Jolicure Lake; Chironomidae–Aeshnidae and Baetidae–Aeshnidae in Long Lake.I used %NCHS analysis and phosphorus assays on alewife carcasses to determine the quantity of nutrients in alewives that would be provided by mortality from the annual migration. Alewife carcasses were categorized by sex and size and I determined that there was a significant difference of %N and %S between males and females. There was no significant difference in %NCHS or P between size classes or sex. Male alewife composition is 4.95 푔푓푖푠ℎN and 0.24푔푓푖푠 ℎS, and female alewife composition is 5.35 푔푓푖푠 ℎN and 0.25 푔푓푖푠ℎ S. CHP compositions are 25.05 푔푓푖푠ℎ 3.75 푔푓푖푠ℎ and 0.42 푔푓푖푠ℎ respectively. This information can quantify total nutrient input if population abundance, mortality rate, and sex ratio are known for separate alewife populations.

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https://scholar.acadiau.ca/islandora/object/theses:3538