Research Document 1997/72
Standardization of Otter Trawlers Participating in the Sentinel Fisheries in the Northern Gulf of St. Lawrence in 1996
By Alain Fréchet
The mobile gear sentinel survey follows a stratified random survey protocol similar to what is used in regular DFO conducted surveys. In contrast to these latter surveys, the sentinel surveys are done with multiple vessels. Each boat has a specific area to sample. It is thus necessary to standardize the fishing gear, the wing spread in particular. We present here results of calibrations done with a restrictor cable.
The calibration done with the restrictor cable allowed to reduce the inter-vessel variability of 25% to 6% with no bias due to depth. In the future, all nine sentinel boats using otter trawl will use these restrictor cables. The calculation of abundance indices will use 16.5 meters (54 feet) as wing spread distance for all boats.
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