Using Autonomous Technologies to Expand Observations of Fish, Invertebrates, and their Associated Habitats.

Traditional sampling gears such as bottom trawls cannot sample in the rugged, high-relief habitats in which many fish species often reside. This limits the information available to determine the population status of species in these habitats. In order to fill this gap, more efficient fishery independent methods to obtain fish and habitat information in untrawlable areas are needed. In addition, data on finer scale species-habitats associations will help inform ecosystem studies.

We have employed a SeaBED type AUV in regional studies of fish, invertebrate and habitat distributions on the U.S. West Coast. The SeaBED AUV can be equipped with a variety of sensors, but strobe-lit digital cameras are the primary means of observation in our studies.

Our studies have shown that a bottom tracking AUV can efficiently collect information on fish abundances that cannot be acquired with traditional techniques. Using the SeaBED AUV, we have successfully assessed fish abundances in a multitude of habitats of varying relief and complexity, while providing data on fine scale habitat associations. We have also conducted studies to assess the behavioral responses of fish to the AUV. It is important to understand these responses in order to determine the “catchability” of fish to the AUV and subsequently use the information collected to determine the absolute abundances of fish.

Differences in both species composition as well as sizes of fish are evident between rocky habitats and lower-relief, trawlable areas. Fine scale analysis of fish and invertebrate distributions also show that fish may be associated with structure-forming invertebrates. In addition, we have used autonomous technologies to validate habitat information collected using acoustic methods.

In conclusion, we will highlight the advantages and challenges of using autonomous technologies to conduct large scale surveys of fish and the benthos.