What Do We Do?

• Project Limulus is, in its most basic form, a horseshoe crab research project that relies heavily on data gathered from physically tagging and recapturing animals.  Horseshoe crabs are tagged in two different ways:
  • A. Cinch Tagging: Basic plastic tag that is threaded through a hole in the animal’s carapace.  Each tag has a unique number and contact information.  The tags are easy to attach and are designed to last indefinitely.  The tags themselves are bright yellow and easy to identify.  Animals tagged by this method have been recovered up to five years after originally being tagged. These tags are useful in trying to answer the following questions:
    • Do females come back to lay eggs on the same beach every year?
    • Do females lay eggs every year?
    • Which habitats are critical for breeding?
    • See picture:
      
      
      photo by J. Matte
      
  • B. Sonar Tags: A more complicated method of tracking horseshoe crab populations.  The tags are attached using two kinds marine epoxy and fastened with wires.  The tags transmit a unique short-wave (kHz) ping that is audible using a hydrophone tuned to its specific frequency.  The tags run on batteries that last about 14 months.  If you find one, please let us know, there is a cash reward for the return of a crab tagged with a dead sonar beacon!  This type of tagging is useful for shedding light on these questions:
    •  What habitats are critical to survival in the winter months?
    • Do the HSC migrate out of LIS?
    • How long do HSC stay close to the beach where they spawned?
    • See picture below:
    • Sonar tags are automatically tracked by automated SUR’s (Submersible Ultrasonic Receiver) which are deployed along a strategically designed grid to best track the population of interest.  Last year, SUR’s were used in a study for PSEG Power Plant in New Haven, CT
      
      
      photo by J. Mattei