LE3 .A278 2023

2023

Avery, Trevor

Acadia University

Bachelor of Science

Honours

Biology

Biology

This study monitored macroinvertebrate populations at nine sites on the Medway river, Nova Scotia in 2021 and 2022 to assess macroinvertebrate diversity, pollution tolerance, and trophic impacts and inform management of Atlantic Salmon Salmo salar Lineaus, 1758. 2084 macroinvertebrates were collected in 139 sampling sessions from June–July 2021 to May–September 2022. Insects and crustaceans were identified to family level, and other macroinvertebrates were identified to class or subclass. Ten orders and 45 families of insects and crustaceans were identified, and their photos and identification characteristics are provided in the Appendix. Ephemeroptera was the most prevalent order despite an average pH of 5.67 ± 0.51 at sampling sites. Low pH is a limiting factor for Ephemeroptera but did not impact abundance in this study. Pilou's evenness of families was 0.79. The high diversity and abundance of Ephemeroptera, Plecoptera, and Trichoptera (EPT) indicate high water quality due to their intolerance of pollution. 18 EPT families were identified, and EPT taxa comprised 52% of all samples. Hilsenhoff’s Biotic Index (HBI) was calculated to assess water quality by assigning each family a level of pollution tolerance. The HBI of all samples was 4.54, which places it in the “Good - Some organic pollution” category. Diversity, abundance, and biotic indices varied between sampling sites but did not approach statistical significance. Diversity and abundance showed a downward trend in later months, peaking in spring and decreasing in autumn. Results of macroinvertebrate sampling show a diverse ecosystem composed of pollution-intolerant taxa. This reflects positively on the use of the Medway River as salmon smolt habitat.

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https://scholar.acadiau.ca/islandora/object/theses:4002