Shark Tagging - Acoustic Tags

Field surgery implanting acoustic tag

Researchers implanting an acoustic tag in a sandbar shark

The movements of juvenile sandbar sharks have been tracked in Virginia waters using acoustic tags. In Chesapeake Bay the sharks’ activities were followed by researchers tracking tagged sharks using a hydrophone. On the Eastern Shore, listening stations were set up in Wachapreague and Machipongo; these receivers recorded each timea shark with a sonic tag swam by.

In Prince William Sound, Alaska, acoustic tags were used to study the ability of salmon sharks to retain body heat. These sharks use counter-current heat exchangers (retia mirabilia) to keep their body temperature greater than that of the cold waters of their habitat. This allows them to hunt active prey like salmon.

 

Map of Wachapreague Inlet (VA Eastern Shore) listening stations used in 2004

Results

  • Sharks appear to move in the direction of the tidal current. 
  • Juvenile sandbar sharks move large distances in short periods of time, but they tend to stay within the study area during the summer and return to the area in subsequent summers.
  • Shark locations are correlated with daylight; more sharks were detected by the array during the night and early dawn hours.

Map of Wachapreague Inlet (VA Eastern Shore) listening stations used in 2004

 

 

 Reference

Conrath, C.L. 2005. Nursery delineation, movement patterns, and migration of the sandbar shark, Carcharhinus plumbeus, in the Eastern Shore of the Virginia coastal bays and lagoons. Ph.D. Dissertation. College of William and Mary, Williamsburg, Virginia.