Trawl Performance and Catchability of Acoustic Targets in Lake Simcoe

Session: Poster session

Michael Pinder, ON Ministry of Natural Resources & Forestry, [email protected]
Justin Trumpickas, ON Ministry of Natural Resources & Forestry, [email protected]
Erin Dunlop, ON Ministry of Natural Resources, Trent University, [email protected]

Abstract

Fisheries acoustics is an efficient method to estimate the density and size distribution of aquatic organisms.  Information such as species identity and other biological features of fish ensonified with hydroacoustics can be determined using capture gear such as a trawl.  Since 2013, a fisheries acoustics survey with accompanying pelagic trawling has been conducted to estimate the density of pelagic fish in Lake Simcoe, with a particular emphasis on a recovering cisco (Coregonus artedi) population.  The trawl was towed from a separate vessel at the same time acoustic surveys were being conducted.  Several improvements to the trawling methodology implemented over time are discussed, such as the ability of the trawl to fish very specific depths where targets were observed acoustically in the water column. The coupling of trawling with acoustics enabled examination of the trawl's ability to capture fish targets at different depths.  To do this, fish density for different depths and different fish sizes were compared between acoustic and trawl-derived estimates.  The results from this study will help to improve assessment methods for pelagic fish and inform fisheries management.

1. Keyword
hydroacoustics

2. Keyword
Lake Simcoe

3. Keyword
fish populations

4. Additional Keyword
trawling

5. Additional Keyword
cisco