Shad Restoration

Shad Eggs

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 and several partners 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. Methods were developed to induce spawning in both American and Hickory Shad brood stock 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 Hickory Shad female using this method. Traditional strip spawning is performed on American Shad. Larvae and juveniles are marked and stocked into target tributaries. Hatchery 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.

Shad

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 now 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 American Shad 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 was occurring to out-migrating young-of-year shad or sub-adults in coastal waters. After careful consideration of those 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 in the Choptank River. In 2017, the project’s efforts to sample adult American Shad in the Choptank River were rewarded with the capture of 50 individuals. Of those 50 samples, 47 otoliths were successfully analyzed and origin was determined.  The samples comprised 28 larval origin (56%), 14 early juvenile origin (28%) and five wild origin (10%). This is only the second year with sufficient captures of returning American Shad, and a larger data set is needed for robust analysis using origin composition. 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. Data collected from increased adult recaptures will further aid in Choptank River progress analysis. As hatchery-produced adults recruit to the spawning stock, the wild component of the juvenile population should exhibit corresponding growth. Restoration goals will be met when wild origin adults return to contribute to natural reproduction that will overwhelm the contribution of hatchery-produced fish in the adult population.

Hickory Shad Restoration Summary:

Shad Map

The department incorporated Hickory Shad into the project in 1996. The Choptank and Patuxent rivers were designated as primary restoration target tributaries. The Marshyhope Creek, a major tributary of the Nanticoke River became an additional target tributary in 2001.

In 2007, Hickory Shad populations in the Patuxent River were determined to be self-sustaining after years of stocking effort. Stockings in Marshyhope Creek concluded in 2009 to focus stocking efforts in the Choptank River. In 2014, Wild origin adult Hickory Shad contributed more than 75% of the total population for the last three years of stocking. For this reason, the Hickory Shad population in the Choptank River was designated as restored. Limited monitoring of adults will continue every three years in the Choptank and Patuxent rivers in order to maintain trend data.

In 2015 and 2016 the program shifted focus to determine additional Hickory Shad restoration need in Maryland's Chesapeake Bay. Electofishing surveys were conducted on the Pocomoke River, Chester River, Sassafras River, Elk River, Northeast River, and the Patapsco River for baseline Hickory Shad abundance data. In 2017 the department was authorized to extend the Sportfish Restoration Program F-57-R grant (F16AF00933) to add the Patapsco River to current restoration activities.

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 was 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 2017, the department stocked 300,000 American Shad, and 837,000 Hickory Shad in the Patapsco River.  Since the inception of this project 2,280,000 American Shad and 3,827,000 Hickory Shad have been stocked across all life stages into the Patapsco River.

In 2018, Sportfish Restoration Program F-57-R grant (F16AF00933) will fund the restoration efforts in the Patapsco River. The map indicates the program’s historic survey locations, along with the current target restoration river. The Patapsco River restoration project will add angling opportunities for the local community by re-establishing anadromous species such as American and Hickory Shad to the Patapsco River