Marine mammals are a common sight during the survey, and if they are present when we're setting up to fish, we hold operations until they leave the area. While preparing for a trawl in southern California, over 50 common dolphins (Delphinus) swam by the Bell M. Shimada, and their vocalizations were visible on the acoustic echograms. The acoustic image illustrates that the dolphin sounds were "heard" primarily by the 120 kHz, so they may have been primarily higher frequency "clicks" rather than lower frequency "whistles" (listen to common dolphin sounds).
Meet the Blogger
The Main Deck blog tracks the research and sea-going activities of the Fisheries Engineering and Acoustic Technologies (FEAT) Team from NOAA's Northwest Fisheries Science Center. Follow us as we use acoustics, trawling, and oceanographic sampling to learn about the Northeast Pacific Ocean.