A sledge net is a bottom trawl used to
collect benthic organisms such as starfish, sea cucumbers, shellfish, and
bottom fish that live on or near the seafloor surface. Since samples are
obtained by dragging it over the seafloor surface, the underside of the frame
is shaped like a sledge so that it can move smoothly over the uneven seafloor.
Unlike fishing gear such as otter trawls, in which the shape of the net opening
changes during towing, the net opening is fixed by the frame, making it
possible to calculate the towed net area and thus collect biological samples in
a more quantitative manner. The population density of benthic organisms (number
of organisms per unit area) can be estimated from the number of organisms
collected and the tow net area.
