Patterns in the Local Distribution of the Sea Whip, Halipteris willemoesi, in an Area Impacted by Mobile Fishing Gear

Abstract

While conducting a larger project along the continental shelf off central California in June 2006, we encountered a large patch of sea whips (Halipteris willemoesi) in an area that was actively fished by vessels using otter trawls. A total of 10 transects were conducted using a remotely operated vehicle (ROV) to collect video imagery of seafloor communities. Video records allowed us to quantify sea whip density and to calculate the densities of upright and damaged or broken sea whips. Though the transects were sited within a dense aggregation of trawl tracks, we recorded significant variability in sea whip densities across transects. While subtle differences in water depth among transects may have contributed to the variability in sea whip density, we suggest that the distribution of trawling effort is a more likely explanation.