Use of a Remotely Operated Vehicle (ROV) to study marine phenomena: I. Pandalid shrimp densities

Abstract

A new commercially developed ROV, the 'Sea Owl Mk II', has been used to make density measurements of marine phenomena, especially pandalid shrimps, in the Gullmarfjord on the Swedish west coast. This note describes the ROV system and a simple attachment for measuring the area of a transect. An account of calibration and field procedures to make transects, together with some density and behavioural observations, are given to illustrate the usefulness of the method. In ten 260 m calibration transects, area estimates varied by only 3 %. In May 1985, shrimp density at depths of 80 to 115 m in the fjord was 0.33±0.03 shrimps m⁻². Shrimps were not attracted or repulsed by the strong light carried by the submersible. The ROV technique clearly shows potential for quantitative as well as qualitative work.