Gear Types and Selectivity
Fishing gear varies enormously in its selectivity (ability to catch target species while avoiding bycatch) and habitat impact. Highly selective gear includes hook-and-line (one fish at a time, size-selective), traps/pots (species and size selective, allow release of non-targets alive), and harpoons (individual targeting). Moderately selective gear includes purse seines (encircle surface schools—effective for tuna and sardines but can entangle dolphins and sharks) and gillnets (mesh size selects for target size but catch anything of that size swimming into them—responsible for significant marine mammal and seabird bycatch). Non-selective and high-impact gear includes bottom trawls (heavy nets dragged across the seafloor that catch everything in their path and destroy benthic habitat) and dredges (metal frames scraped through sediment for shellfish, causing severe seafloor disturbance).