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DRBC Continues to Partner to Monitor Juvenile American Shad

In September and October 2014, DRBC staff provided their expertise to count numbers of juvenile American shad in the Delaware River at two different sites that are included in a partner effort by state and federal fisheries biologists. Juvenile American shad, called young of year (YOY), are those that are born in the spring and spend their first summer in the river. As the water temperatures cool, they travel south to overwinter in the warmer waters of the Delaware Estuary and Bay before heading out to the Atlantic Ocean.

American shad, a member of the herring family, are anadromous fish, meaning they are born in fresh water, live for several years as adults in the ocean, and return to their natal waters (where they're born) to spawn (lay their eggs) in the spring. Historically, American shad have spawned in the mainstem Delaware River, as well as in several of its tributaries. Today, the Delaware River continues to support American shad, thanks in part to the absence of dams on the mainstem river and to water quality that has seen significant improvement over the years due to efforts of DRBC and other stakeholders. 

To help determine how well the fishery is doing each year, YOY shad numbers are monitored in late summer and the fall as they travel downriver to the estuary. The shad are collected by seining, using a large net to catch the fish in the river. Other fish species are also caught, and the fisheries team must then sort and identify which are YOY shad so their numbers can be recorded. In August, September, and October, four different sites - Trenton, N.J., Phillipsburg, N.J., Delaware Water Gap, Pa., and Milford, Pa. - are monitored once monthly, for a total of 12 data points annually. The data collected from these surveys supports an approved management plan that is in place to ensure that the fishery remains viable and sustainable.

In 2014, DRBC staff participated in the voluntary and cooperative survey effort twice: in September at the Trenton, N.J. monitoring location at the Marine Terminal Park and in October at the Phillipsburg, N.J. Boat Ramp. Staff helped seine, sort, and count the numbers of YOY shad collected.

Background on Non-Tidal YOY Shad Seining Surveys

From 1979-2007, the N.J. Division of Fish and Wildlife monitored the presence of YOY shad in the non-tidal Delaware River by completing the seining surveys independently, but due to limited staff resources, this effort was discontinued in 2008.

In 2012, the Delaware River Basin Fish and Wildlife Management Cooperative (Co-Op), made up of fisheries representatives from the Delaware Division of Fish and Wildlife, N.J. Division of Fish and Wildlife, New York State Division of Fish, Wildlife, and Marine Resources, Pennsylvania Fish and Boat Commission, U.S. Fish and Wildlife Service, and the National Marine Fisheries Service, reinstated this effort. The Co-Op realized that if each member agency could send a few volunteers, the non-tidal YOY seining surveys could continue with minimal resource burden on any individual agency. DRBC is a liaison member to the Co-Op. Other supporting agencies include the National Park Service, which provides volunteers at the Delaware Water Gap and Milford, Pa. survey sites, and the Philadelphia Water Department, which provides volunteers at the Trenton, N.J. survey site.

Since 2012, the Co-Op has organized the YOY surveys in the non-tidal Delaware River. Provisional data for 2014 indicate that the non-tidal YOY shad numbers ranked 11th overall compared to the time series (1980-2007; 2012-2014); while not in the top ten, Co-Op members are pleased with 2014's preliminary results.

Delaware River Sustainable Fishing Management Plan for American Shad

The Atlantic States Marine Fisheries Commission (ASMFC), formed by the Atlantic Coast states to manage, promote, and protect their shared migratory fishery resources, has required all states to submit sustainability plans for American shad or face potential closure of their recreational and commercial fisheries.

In the Delaware River Basin, the Co-Op is responsible for the management of American shad (and other fish species). It developed a sustainable fishing management plan for American shad (pdf 1.6 MB), which was accepted by ASMFC in 2011. The plan includes several indices for monitoring the shad numbers in the Delaware Basin with associated benchmarks. One of the indices measured is the non-tidal juvenile abundance index (JAI) of YOY American shad, which is supported by data from the seining surveys. The benchmarks have been set to respond to any potential decline in stock.

Monitoring how many YOY shad are caught returning to the ocean provides a relative index of abundance for comparing to a benchmark, which then allows fisheries biologists to estimate the relative status of YOY production. Should the YOY shad non-tidal JAI fall below the identified benchmark, management would be enacted to strengthen protection of the American shad population. Management action is needed when there are three consecutive years of data below the 25th percentile (see figure 21 on pg. 46 of above-linked management plan). 

Another benchmark included in the management plan is the tidal JAI, which N.J. Fish and Wildlife still collects data for independently at locations in the river's tidewaters. This monitoring effort gives additional information on shad spawning success and further supports the management plan. As with the non-tidal JAI, management action is needed when there are three consecutive years of data below the 25th percentile (see figure 22 on pg. 47 of above-linked management plan). 

The Delaware River is an important waterway for American shad, and its fishery is currently considered sustainable, albeit at low levels. Non-tidal JAI surveys and others provide important data on the status of the Delaware River's American shad population. The fact that there is an approved management plan with relative indices for monitoring trends and associated benchmarks will permit growth of the Delaware American shad stock while allowing for human use of the resource. DRBC is a strong supporter of these efforts and is committed to providing staff expertise and resources to future monitoring efforts when needed.