A case history of effective fishery management: Chesapeake Bay striped bass

摘要

Stocks of anadromous striped bass Morone saxatilis of the Atlantic coast have supported important fisheries since colonial times. Commercial landings reached a record high in 1973, then declined by almost 90% during the following decade. Juvenile production by the Chesapeake Bay stock, a major contributor to coastal fisheries, was depressed during the 1970s. These patterns prompted efforts to identify why striped bass had declined and to rebuild the Chesapeake Bay stock. This paper reviews the history of the striped bass decline and the science, management, and legislation that led to its recovery. Historical data and modelling results indicated that recruitment overfishing was a major factor in the decline. Juvenile production may have been further depressed by water quality problems that reduced survival of early life stages. Mathematical models demonstrated that reducing fishing mortality would immediately increase population growth rate, regardless of the decline's cause. An Interstate Fishery Management Plan (the Plan) was adopted by the Atlantic States Marine Fisheries Commission in 1981 and amended in 1985 to protect females until 95% could spawn at least once, thus increasing age at entry from 2 to 8 years. The Plan was strengthened in 1984 by the Striped Bass Conservation Act (Public Law 98-613), which required states to comply with the Plan or submit to federal moratoria. In 1985, states imposed moratoria or began a progressive increase in minimum size limits scheduled to reach 97 cm(38 in) in total length by 1990. Hatchery-reared striped bass were stocked in the Chesapeake Bay beginning in 1985 and may have accelerated recovery, though the benefits of stocking were far outweighed by the benefits of reducing fishing mortality. Abundance of females on spawning grounds in Maryland doubled between 1985 and 1988, and recruitment began to improve in 1989. Coastwide recreational catches increased more than 400% between 1985 and 1989. Regulations were relaxed in 1990 and an adaptive management scheme was adopted to allow limited harvest while the stock continued to recover. Recruitment continued to improve and the Chesapeake Bay stock was declared fully recovered in 1995, 10 years after stringent management measures were implemented.