Examination of the use of intertidal weirs as fish monitoring platforms in the upper Bay of Fundy
LE3 .A278 2020
Master of Science
The upper Bay of Fundy is an area of high ecological importance for a diverse assemblage of fish species. It is also the location of tidal energy demonstration with the Fundy Ocean Research Center for Energy (FORCE) facilitating the deployment of tidal in-stream energy conversion devices and undertaking environmental effects monitoring (EEM) at its test site in Minas Passage. Since 2009, FORCE’s EEM program has utilized a variety of strategies to gain a better understanding of fish presence and activity within and near the test site. In this study, commercial intertidal weir catches and a single-beam echosounder were used to address identified information gaps, including the suitability of intertidal weirs as fish monitoring platforms. The aims of this thesis were to: 1)examine the trends in the presence and relative abundance of fishes in catches at two intertidal weirs, and 2) investigate the usefulness of an Acoustic Zooplankton Fish Profiler (AZFP) in monitoring fish moving in close proximity to an intertidal weir. Sampling was conducted near weekly during daytime low tides in spring and summer 2013 at weirs in Bramber and Five Islands, Nova Scotia. Clupeids dominated the weir catches. Relative abundance and species richness varied seasonally and reflected the movement and spawning patterns of migratory species. Considerable variation in fish catches were observed over time, with greater fish captures and acoustic backscatter during dusk/night. While intertidal weirs were shown to be useful monitoring platforms for assessing general patterns in the presence and abundance of fish in nearshore Minas Basin, such sites are not suitable for the deployment of an AZFP. Echosounders are better suited for the subtidal environment and are likely to be beneficial if used in combination with an experimental weir located in Minas Passage.
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