In This Issue:

• Coastal Calendar
• FEATURE: Greening the Garden State Through Remediation, Assessment, and Restoration
• Jersey Beaches on "Shore" Footing
• Fishing for Regulatory Solutions
• Shellfish Restoration Program Enters Fifth Year
• Marine Science Competition Plumbs Oceans of Knowledge
• Shore Takes Center Stage in Survey

Fishing for Regulatory Solutions

by Kenneth Able, Ph.D., Professor, Department of Marine and Coastal Sciences, Rutgers University,
Mike Danko, Marine Fisheries Agent, New Jersey Marine Sciences Consortium/New Jersey Sea Grant,
and Thomas Grothues, Ph.D., Assistant Research Professor, Department of Marine and Coastal Sciences, Rutgers University.

(cont'd from page 1)

Researchers measure and determine the sex of the winter flounder caught.

     Numerous scientific studies report that winter flounder move into estuaries in anticipation of spawning there in the fall. However, current research results indicate that winter flounder movements are variable, and spawning may take place in estuaries and on the continental shelf. Estuaries are dynamic environments that can present hostile conditions to adults and eggs in winter, and as seen in other fish species, this can result in the evolutionary adoption of a wider spawning habitat to account for environmental conditions that can be detrimental to their survival. The validity of the current spawning habitat definitions remains unclear, with the implication that legal mechanisms for winter flounder protection are either too restrictive or not restrictive enough.

     Two research efforts to account for these variations are currently being conducted by Dr. Kenneth Able and Dr. Thomas Grothues, researchers from the Institute of Marine and Coastal Sciences at Rutgers University. The I BOAT NJ Program is funding one project in the Navesink River to determine where winter flounder prefer to lay their eggs and the New Jersey Sea Grant Program is funding a complimentary effort being conducted to determine seasonal movements between the inner continental shelf and in the Barnegat Bay – Great Bay. The goal of these research efforts is to clarify spawning habitat preferences and the seasonal and annual dynamics of adult winter flounder residency/movement in estuary/inner continental shelf ecosystems in order to protect the habitats they use while providing an improved understanding for the timing and location of spawning relative to dredging activities in New Jersey estuaries, ocean waters and other areas in the northeast United States.

     In order to track movement and spawning activity, winter flounder are taggedwith acoustic transmitters, small pingers each with its own coded signal. The fish are tagged on the outside using a saddle for the pinger sewn between the spines of the dorsal fin. The tags can be heard up to a quarter mile away by hydrophones, or underwater microphones that interpret the ping sound and record its code along with the time it was received. When several hydrophones are close enough to hear the same sound signal, the difference in the arrival time of the same sound between different hydrophones can be used to pinpoint the sound source location, a process called trialateration. The precision depends on all hydrophones having synchronized clocks, which they do from an acoustic timekeeper underwater. While winter flounder might move throughout the bay, spawning behavior can be detected by the convergence of males to a female and circular swimming. The tracks of roaming and spawning fish can be graphed on a chart along with time stamps.

     If one of these tagged fish is caught, the tag number should be noted and reported to Dr. Thomas M. Grothues at (609) 296-5260 extension 252 or grothues@marine.rutgers.edu. If the fish is released with the tag intact, valuable data can continue to be collected. However, if a fisher elects not to release the tagged fish, the tag can be reused by researchers. For more information and updates on the status of the project visit marine.rutgers.edu/navesink/index.htm.