Day of the Dolphin Census Project

Orange County Chapter

© Sergeant John Hollenbeck, Newport Harbor Patrol

Originally called “Mass Sighting Day” by project founder Prof. Dennis Kelly of Orange Coast College, the renamed Day of the Dolphin Census Project documents the abundance, recruitment, behavior, mortality, and general health of resident coastal bottlenose dolphin (Tursiops truncatus) populations from fourteen shore-based census stations, each two mile apart, along the Orange County Coast.  Sightings are done in January, April, July and October of each year.

Day of the Dolphin objectives include: 1) determine the number of dolphin pods, and positively identify individual animals based on morphological characteristics within the study area during observation periods; 2) determine the location, distribution, and density of the animals observed; 3) record specific observed behaviors of individuals; and 4) involve the general public, to educate people and increase their awareness of, interest in, and sensitivity to these magnificent animals.

© Sergeant John Hollenbeck, Newport Harbor Patrol

Data is shared with researchers from the National Oceanographic and Atmospheric Administration-National Marine Fisheries Service (NOAA-NMFS) to assess human impacts (entanglement in gear, contaminants, pollution, ocean noise, coastal development, harassment, etc.) on recruitment and mortality rates, safety, and welfare of resident coastal bottlenose dolphin populations.

“The census can give us a baseline population estimate for this species, track the health and reproductive status of individual animals, and give us insight into the state of the coastal ecosystems these dolphins inhabit,” says Project Coordinator Bert Vogler.  As with all of ACS’s chapter-based programs, the Day of the Dolphin Census Program is coordinated and carried out exclusively by our members, and is an exemplary model of citizen science at its finest.

Learn more about this fun, action-based, citizen science conservation program and how you can get involved by emailing the coordinator at