Shad Restoration

Shad Restoration

American Shad Alosa sapidissima and Hickory Shad Alosa mediocris were two of the most important commercial and recreational fish species in the Chesapeake Bay. In response to severe population declines from 1900 to the 1970s, Maryland closed its fishery in 1980. The fishing moratorium, habitat improvements, pollution mitigation and fish passage construction did not result in recovery, primarily due to lack of adult spawners. In 1994, Maryland Department of Natural Resources (MDNR) and several Shad Eggspartners began a program to reintroduce shad spawning runs to selected tributaries through restorative hatchery stocking.  Traditional strip spawn culture methods require access to large numbers of ripe adults. We developed methods to induce spawning in broodfish collected from the Susquehanna River using synthetic reproductive hormone implants and tank spawning systems (Mylonas et al. 1995). Fertilized eggs can be produced from any migratory pre-spawned female using this method. Traditional strip spawning is also performed. Larvae and juveniles are marked and stocked into target tributaries. Surveys are conducted to sample larval, juvenile and adult shad. From 1994 to 2015 the program stocked 44.5 million American Shad and 111.6 million Hickory Shad in the Choptank River, Patuxent River, Patapsco River and Nanticoke River.

ShadHatchery contributions are intended to provide adult spawners that will produce self-sustaining populations in the target tributary. These fish have tremendous value for stock assessment purposes at the larval, juvenile and adult life stages since all shad are marked prior to stocking.

American Shad Restoration Summary:

The department began a pilot project in 1993 to assess the response of American Shad adult broodstock during collection, handling and captive holding. In 1994, experimental spawning was conducted using timed-release hormone implants. The success of these trials encouraged development of a long-term spawning, culture, stocking and assessment program. In 1995, a non-funded, full-scale hatchery production effort was conducted with positive results. The project continued over the next three years through various short-term funding sources. In 1998, it was determined that a long term funding source would be required, since it would take years of additional stocking and assessment to successfully support restoration. Federal Aid in Sport Fish Restoration funds support this long-term effort. Federally funded Choptank River and Patuxent River restoration work began in 1999. Marshyhope Creek, a tributary to the Nanticoke River, was added in 2001.

In 2001, the decision was made to collect ripe fish on the spawning grounds and manually strip eggs and milt from mature brood fish. The Potomac River was chosen as the source population due to its strong American Shad spawning population. The department previously documented some encouraging progress with restoration of these species in Maryland. Beginning in 2006 however, most Atlantic coast states began to observe decreased numbers in migratory shad stocks. It is hypothesized that undocumented mortality is occurring to out-migrating young-of-year shad or sub-adults in coastal waters. After careful consideration of recent shad population trends, project biologists determined that a change in approach was warranted for this restoration project. In 2010, the grant proposal was amended to suspend stocking the Patuxent River and Marshyhope Creek and to focus all project resources towards stocking and monitoring in the Choptank River. Limited monitoring of adults will continue every three years in the Patuxent River in order to maintain trend data.

American Shad restoration efforts continue to occur in the Choptank River. In 2016, the project’s efforts to sample Adult American Shad in the Choptank River were rewarded with the capture of 45 individuals. Of the 45 fish sampled, 11 were larval stocked (25%), 19 were early juvenile stocked (43%) and 14 were wild origin (32%). This is encouraging compared to a recovered Patuxent River population. One year of sampling does not indicate restoration efficacy, but it is encouraging to discover that 32% of the sampled adults were wild origin, and there is a robust juvenile population. Project staff will continue to sample different areas of the Choptank River using gill nets to determine where American Shad are staging and spawning in the river. Project staff can now assess the adult composition in conjunction with wild caught juvenile American Shad component to estimate Choptank River restoration progress. The data collected from increased adult recaptures will further aid in Choptank River progress analysis. As hatchery-produced adult spawning stocks increase, the wild component of the juvenile population should exhibit corresponding growth. Restoration goals will be met when natural reproduction overwhelms the contribution of hatchery-produced fish in the juvenile population.

Hickory Shad Restoration Summary:

The department incorporated Hickory Shad into the project in 1996. The Choptank and Patuxent rivers were designated as the restoration target tributaries.

Hickory Shad populations in the Patuxent River were determined to be self sustaining in 2007, after years of stocking effort. In 2014, Hickory Shad populations were also designated as restored in the Choptank River. Shad Map Data analysis from an adult recapture survey indicates that wild contributions steadily increased each year, from a low of 26% in 2001 to a high of 75% in 2014. Wild contribution exceeded 75% since 2011. Trend data will be maintained in these rivers by sampling on a three year rotation.

Currently the program is shifting focus to determine additional restoration need in Maryland's Chesapeake Bay. In 2015 and 2016, preliminary surveys were conducted on the Pocomoke River, Marshyhope Creek, Chester River, Sassafras River, Elk River, Northeast River, and the Patapsco River for baseline Hickory Shad abundance data. The map indicates potential survey locations, along with the program's historic survey locations. Future target tributaries will be chosen based on historical data, angling opportunities, and potential for Hickory Shad spawning and nursery habitat.

Patapsco American Shad, Hickory Shad, and River Herring Restoration Summary:

To offset habitat impacts associated with dredging, the Maryland Port Administration (MPA) was required to develop a compensatory mitigation package. The Patapsco River shad and herring restoration project is part of this plan and receives MPA funding to conduct fish production, stocking, and assessment activities.

In 2013, the department began stocking larval and juvenile American Shad, Hickory Shad, Alewife, and Blueback Herring into the Patapsco River. After determining there were abundant stocks of spawning Blueback Herring and Alewife​, stocking of these species ceased in 2014. In 2016, the department stocked 290,000 American Shad, and 615,000 Hickory Shad in the Patapsco River.  Since the inception of this project 1.98 million American Shad and 2.99 million Hickory Shad have been stocked across all life stages into the Patapsco River.

The Patapsco River restoration project will hopefully add fishing opportunities for the local community by re-establishing anadromous species such as American and Hickory Shad to the Patapsco River.