Modifications to a plumb staff beam trawl for sampling uneven, complex habitats

A small (5.1 m footrope) plumb staff beam trawl was modified to sample demersal fauna in uneven, complex habitats. Several SCUBA dives were made to observe and measure the modified trawl while being towed. Additionally, an underwater camera system was used to observe footrope contact with the bottom at varying amounts of scope ratio on several bottom types including pure sand, mixed sand with emergent biotic structure, sand with shell fragments, mud with shell fragments, and gravel and shell bedforms. Net modification tests were followed by field collections at 55 stations in which 49 species of fish were captured. The modified beam trawl appears to be an effective tool for sampling demersal fishes in a variety of habitats, including those with emergent biotic structure.