American shad are managed by the Atlantic States Marine Fisheries Commission (ASMFC) under a Fisheries Management Plan for American shad and river herring implemented in 1985 to facilitate cooperative management and stock restoration among the states. Restoration efforts have involved habitat improvement, fish passage, stocking, and transfer programs. Despite improved returns in some major river systems such as the Susquehanna, Delaware and Connecticut Rivers, the range-wide abundance of American shad remain well below historic levels. The Fishery Management Plan was amended in 1999 with specific measures to control exploitation of shad. The amendment mandated that: (a) all intercept fisheries for American shad be phased out by the end of 2004; (b) mortality rates be reduced in in-river fisheries; and (c) an aggregate 10-fish daily creel limit in recreational fisheries be established for American and hickory shad.

The Fishery

A 1998 assessment characterized fishing mortality for 9 river stocks and resource trends for 13 river stocks of American shad. Based on a conservative definition of overfishing, F₃₀, estimates ranged from .39 - .48. Total fishing mortality rates (river and coastal) were below the overfishing definition for the nine stocks that were evaluated. In addition, juvenile shad production indices for seven of these stocks suggested recruitment failure only in Maine. Although these results suggest that recent levels of exploitation in coastal intercept fisheries had not adversely impacted these stocks, the F₃₀ values are considered rough approximations of true values and did not consider smaller stocks. However, the total range of extant American shad populations includes additional populations in small river systems and small populations in larger river systems that are actively being restored. Also, much historical shad habitat is still vacant and may be targeted for restoration in the future. For these stocks, individual states have developed fishing mortality targets to protect small stocks and rebuild others. Assessment studies have not quantitatively addressed these systems because of limited biological data. Like all mixed stock fisheries, small stocks can be at risk under conditions of uncertainty.

Landings for 2005 were at an all-time low, but this is a direct result of the closure of all ocean-intercept fisheries. At the time of the 1998 assessment, American shad stocks overall were considered fully exploited and at low levels of abundance. The current status of this resource is pending the completion of a comprehensive assessment by the ASMFC Shad and River Herring Assessment Subcommittee, which is in progress and is scheduled to be completed by the end of 2007.

Assessment Results

Assessment results are pending completion of a comprehensive 2007 assessment.

Biological Reference Points

Fishing mortality was calculated in 1998 using a threshold of F₃₀ as part of the development of Amendment 1 to Interstate Fishery Management Plan for Shad and River Herring (ASMFC 1999) (Table 39.2). The definition was to be used as a conservative estimate and managers were encouraged to consider lower levels of fishing based on the abundance of shad in the smaller stocks.

Biological reference points will be updated pending the completion of the 2007 American shad stock assessment.

Summary

Stock abundances of American shad are well below historic levels of the early 20th century as a result of overfishing and habitat destruction. Intercept fisheries for shad was phased out between the year 2000 and 2005 as mandated by the amended Fishery Management Plan. Research into the biology, habitat requirements and stock status of American shad continues, with the goal of restoring American shad to sustainable levels of spawning stock biomass.

Table 39.1 Recreational and commercial landings of American shad (thousand metric tons).

Table 39.2 Summary of MSY-based reference points for American shad.