Along with other students and technicians, Goldstein has spent numerous hours tracking the lobsters using ultrasonic and handheld hydrophone tracking equipment to locate them and determine their movements. Commercial lobstermen are assisting Goldstein by helping to tag some of the creatures they find in their traps. In many cases, lobstermen who capture tagged lobsters will call Goldstein to report the tag number and location.
In addition, 15 "lobster listening stations" moored throughout Great Bay and the coastal waters allow researchers to more accurately pinpoint where the lobsters go. These stations hold special ultrasonic receivers that can identify and record tagged lobsters moving within a 400-meter radius of the equipment. For example, receivers are currently located at the Great Bay Marina, the Shafmaster dock, the Public Service of New Hampshire power stations, and the Weathervane dock in Portsmouth.
The various tracking efforts have led to a wealth of knowledge. Watson originally hypothesized that berried females would be more likely to move offshore to protect the eggs during the winter months. However, he was surprised to find out that most lobsters, regardless of size, gender or maturity, followed the same migration patterns.
The researchers also learned that relatively few berried females are located in the estuary, while male lobsters are often found there. Goldstein and Watson theorize that the estuary is too extreme an environment for most females carrying eggs, so they migrate toward the ocean when they reach sexual maturity.
In addition to studying the migrations of the adult lobsters, Watson and Goldstein are using oceanic drifters submerged box-like structures that mimic the movements of lobster larvae to learn how the movements of berried females could impact where larvae are released and the path they travel when carried by ocean currents during the three weeks the
|Contact: Rebecca Zeiber|
University of New Hampshire