Evaluating the SeaBED AUV for Monitoring Groundfish in Untrawlable Habitat

Evaluating the SeaBED AUV for Monitoring Groundfish in Untrawlable Habitat

Nick Tolimieri, M. Elizabeth Clarke, Hanumant Singh, and Chris Goldfinger

Evaluating the SeaBED AUV for Monitoring Groundfish in Untrawlable HabitatThis is part of Marine Habitat Mapping Technology for Alaska
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Description

The primary benthic habitat of many U.S. West Coast groundfishes is rocky and untrawlable. Traditional methods such as bottom trawls are less than ideal for monitoring populations
of these species. New technologies need to be developed that will allow monitoring in these untrawlable areas, and non-extractive methods are needed to reduce detrimental sampling effects on organisms and their habitat. We have begun to test, modify, and employ the SeaBED AUV to survey groundfish populations and their habitat. While not optimal for all applications, the system has a number of advantages. It is relatively inexpensive, small, and untethered allowing it to be deployed from small vessels of opportunity. Precise bottom tracking, navigation, and ability to swim at low altitudes, allow the AUV to operate in complex, rocky habitat. A pilot study, conducted at Daisy and Coquille banks in 2005, quantified and detected differences in the abundance and biomass of rosethorn rockfish on different habitat types, and documented rosethorn substratum preferences. Most rosethorns on the two rocky banks were juveniles, while those near the edge or off the banks were predominantly adults. Both of these conclusions should be qualified, however, because issues related to avoidance by fish and more accurate size estimation need to be resolved. Future modification and testing will include side- or forwardlooking cameras for better species identification, DIDSON visual sonar and infrared cameras to quantify fish avoidance, and the correction of image distortion for more accurate size estimation.

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