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.
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:
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.