Precision navigation for benthic surveying and sampling

An integrated system of hardware, software and methodology has been developed to provide information about the location of towed survey systems (sidescan sonar and BRUTIV), bottom sampling devices (video grab and epibenthic sled) and fishing gear (otter trawl). This technology was developed as part of a program to quantify the productive capacity of marine benthic habitat, to obtain quantitative information on the impacts of mobile fishing gear on benthic habitat (both physical structure and biological communities) and to obtain quantitative information on the recovery rate of benthic habitat after disturbance by mobile fishing gear. This ensemble of-equipment and positioning methodology has been used to conduct a three year otter trawling impact experiment on the Grand Banks of Newfoundland. Navigation equipment included a differential GPS (dGPS), a StarFix system to provide the appropriate differential corrections, the ship's autopilot for heading information and a Trackpoint II ultra-short baseline acoustic positioning system with an over-the-side transducer boom to position towed survey systems and seafloor sampling devices.