Colleagues: I'm looking for something that might summarize the current state of knowledge and/or general evaluation on the usefulness and/or effectiveness of acoustic pingers for marine mammal deterrence. Are these devices useful or not; if useful, for what species under what circumstances? What are the limitations of marine mammal deterrence using acoustic pingers? Any suggestions or citations? Gene Buck, Specialist in Natural Resources Policy Resources, Science, and Industry Division Congressional Research Service gbuck@crs.loc.gov Phone: (202) 707-7262 *This information is intended only for the congressional addressee or other individual to whom it is addressed and may contain confidential and/or privileged material. Any review, retransmission, dissemination, or other use of this information is only at the discretion of the intended recipient. If you received this message in error, please contact me and delete the material from any computer. The foregoing has not been cleared by CRS review and is not for attribution. This response is provided to help in urgent situations.*