Structure and biomass of small-bodied fish populations in Oakland Lake, Nova Scotia
LE3 .A278 2013
2013
Avery, Trevor
Acadia University
Bachelor of Science
Honours
Biology
From 2009 to 2012, American eel (Anguilla rostrata) population dynamics and habitat use has been studied within Oakland Lake – a municipal water supply – as part of the American Eel Habitat Assessment Project. Habitat use was determined using baited eel traps. In 2012, minnow traps were added to catch smaller eels. Eel traps were set at fixed stations and minnow traps were periodically moved. Both eel and minnow traps also caught small-bodied fishes affording the opportunity to: 1) determine the population structure and biomass of small-bodied fishes, and 2) relate these to biomass of bait added to traps. Of 1,359 small-bodied fishes captured, four species were caught regularly: white perch (Morone americana), yellow perch (Perca flavescens), banded killifish (Fundulus diaphanus), and golden shiners (Notemigonus crysoleucas), along with many tadpoles. Fishes were sampled for total length and fin clipped to estimate population sizes. Fish weights were estimated using known weight-length relationships. A total of three mean weight estimates were found for each of the four fish species based on calculated weight-length coefficients ± confidence limits. Population estimates were variable and low recaptures infers low confidence in these estimates. Across the four species, there were 12,011 (95% CI: 3954 to 25,165) fishes. Population estimates and mean weights were then used to estimate the biomass of each fish species. Of nine biomass estimates for each species, total biomass of all fishes was estimated to be between 131 and 295 kg whereas biomass of bait added to the lake was 174 kg. This result suggests that bait loading in Oakland Lake is greater than the naturally available food biomass which may have consequences on small-bodied fishes population dynamics within this system.
The author retains copyright in this thesis. Any substantial copying or any other actions that exceed fair dealing or other exceptions in the Copyright Act require the permission of the author.
https://scholar.acadiau.ca/islandora/object/theses:1053