Physics of the Interaction Between a Crab and a Seismic Test Pulse – Development of a Mathematical Model and Testing of Model via Simulation

Principal Investigator:

Dr. Geoffrey Lee-Dadswell, Cape Breton University

Start Date: June 2009

End Date: September 2011

Experimental attempts to establish whether seismic testing has any impact on crabs and the crab fishery have been hampered by a lack of theoretical work on the subject. As a result, experimenters have not known what effects to look for or what threshold sound levels might be problematic for crabs. The study has aimed at beginning the necessary theoretical work to guide future experiments examining the physical effects of seismic testing on invertebrates.
The approach has been to consider a simple model of a snow crab and, using basic acoustical theory, calculate the amplitude of vibrations inside the crab. In the first stage of the study the crab was modeled as a spherical, elastic shell, with a fluid interior. Material properties of crab tissues were estimated and combined with the calculated vibrational amplitudes to predict what minimum sound levels might cause physical damage.