To establish a moratorium on large fishing vessels in Atlantic herring and mackerel fisheries.

Prohibits, notwithstanding the Magnuson-Stevens Fishery Conservation and Management Act, any large fishing vessel from fishing for Atlantic herring or Atlantic mackerel in the U.S. Exclusive Economic Zone until: (1) the National Marine Fisheries Service has completed a new population survey regarding the discrete spawning stocks of those fish; and (2) the Secretary of Commerce has approved and implemented fishery management plans, developed by the appropriate regional fishery management council for those fish, that specifically allow participation of large fishing vessels. Defines "large fishing vessel" as being at least 165 feet long and having over 3,000 horsepower. Excludes from that definition a vessel that engages only in processing fish harvested by fishing vessels of the United States.