Skipjack tuna commercial tunas, and its population is considered sustainable against its current consumption. Its fishing is still controversial due to the methodology, with rod and reel or fishery options being promoted as ecologically preferable. Purse seine methods are considered unsustainable by some authorities due to excess bycatch, although bycatch is said to be much reduced if fish aggregation devices are not used. These considerations have led to the availability of canned skipjack marked with the fishing method used to catch it. Skipjack is considered to have "moderate" mercury contamination. As a result, pregnant women are advised against eating large quantities. In
USS Skipjack (SSN-585) the wings of an airplane, were moved from the hull to this new sail, with the periscopes and antenna masts. Thus, they could be useful only when the submarine is in its natural environment—like the control surfaces on an airplane. Also, a single propeller behind the rudder now propelled "Skipjack", making it more maneuverable. Other experiments in design also benefited "Skipjack" by allowing the vessel to be built with improved steel. Areas from the control room (featuring push-button control of pneumatic and trim systems), to the anchor (streamlined to reduce drag and flow noise) were changed in the development of