American Shad Monitoring
American shad (Alosa sapidissima) have played an important role in supporting recreational and commercial fisheries since colonial times. Native Americans and early settlers utilized shad as a major food supply. The Chesapeake Bay shad fishery became an important industry around 1869 and developed greatly in following years. Commercial landings of American shad in Virginia decreased from 11.5 million pounds in 1897 to less than a million pounds in 1982. Over-fishing, dam construction, pollution and loss of natural spawning grounds are a few factors that lead to this decline.
Concern about the decline in landings of American shad along the Atlantic coast prompted the development of an interstate fisheries management plan (FMP) by the Atlantic States Marine Fisheries Management Program. The main focus of the plan is to regulate exploitation and enhance stock restoration efforts. A moratorium on the taking of American shad in the Chesapeake Bay and its tributaries was established by the Virginia Marine Resources Commission (VMRC) beginning January 1, 1994. The prohibition applies to both recreational and commercial fishers. Immediately following the moratorium, there were no monitoring programs that provided direct assessment of stock recovery. To address this deficiency, a method of scientific monitoring was proposed to estimate catch rates relative to those recorded before the prohibition of in-river fishing in 1994. Catch-per-unit-effort (CPUE) were compiled from logbooks that recorded commercial landings using staked gill nets in the middle reaches of the James, York and Rappahannock rivers during the period of 1980-1992. The American shad monitoring program began in 1998 and consists of sampling techniques and locations that are consistent with and directly comparable to the historic logbook data collected by VIMS. The monitoring program is the only direct method available to determine the size of spawning runs relative to decades prior to the moratorium. The program provides information for evaluating the hatchery-based restoration program, validating the juvenile index of abundance and determining the mount of by-catch that would be expected if the fishing ban was lifted.
The primary objectives of monitoring American shad:
- Establish a time series of relative abundance indices of adult American shad during the spawning runs in the James, York and Rappahonnock rivers.
- Relate contemporary indices of abundance of American shad to historical log-book data collected during the period 1980-1992 and older data if available.
- Assess the relative contribution of hatchery-reared and released cohorts of American shad to adult stocks.
- Relate recruitment indices (young-of-the-year index of abundance) of American shad to relative year-class strength and age-structure of spawning adults.
- Determine the amount of by-catch of other species in the staked gill nets.
- Monitor the American shad by-catch fishery established by the VMRC.
The information collected by this program is reported annually to the Atlantic States Marine Fisheries Commission (ASMFC) and Virginia Marine Resources Commission. Monitoring data has also been used by the Chesapeake Bay Program of the Environmental Protection Agency in a revision of the annual on-line Chesapeake Bay Report. The American shad monitoring program has provided data used to form the basis for a coast-wide stock assessment for American shad as well as numerous reports, publications, theses and dissertations.