Aerial Surveys of Distribution and Abundance of Marine Birds and Mammals 

1

FINAL TECHNICAL SUMMARY 

STUDY TITLE: Aerial Surveys of Distribution and Abundance of Marine Birds and Mammals 

in Santa Barbara Channel and the Santa Maria Basin 

REPORT TITLE: Aerial Surveys of Distribution and Abundance of Marine Birds and 

Mammals in Santa Barbara Channel and the Santa Maria Basin 

CONTRACT NUMBER: 14-35-0001-30758 

SPONSORING OCS REGION: Pacific 

APPLICABLE PLANNING AREA: Southern California 

FISCAL YEARS OF PROJECT FUNDING: FY 96, FY 97 

COMPLETION DATE OF THE REPORT: September 1998 

COSTS: FY 96 - $22,261, FY 97 – $24,739 

CUMULATIVE PROJECT COST: $47,000

PROJECT MANAGER: Russell J. Schmitt 

AFFILIATION: University of California, Santa Barbara 

ADDRESS: Coastal Research Center, Marine Science Institute, University of California, Santa 

Barbara, CA 93106 

PRINCIPAL INVESTIGATORS: 1

Russell J. Schmitt, 2Michael L. Bonnell (deceased) 

ADDRESSES: 1 Coastal Research Center, Marine Science Institute, University of California, 

Santa Barbara, CA 93106; 2Institute of Ocean Sciences, University of California, Santa Cruz, 

CA 95064

BACKGROUND: In November of 1994 an ambitious project was undertaken to provide 

detailed mapping of abundance and distribution of seabirds and marine mammals in the Santa 

Barbara Channel and the Santa Maria Basin (Pacific OCS Region). Our task was to separate the 

background noise from the significant patterns of use of the more than 100 species that occupy 

these waters. This series of bi-monthly aerial surveys was supported by the Marine Science 

Institute (MSI), UCSB, and the California Department of Fish and Game, Office of Spill 

Prevention and Response (OSPR). OSPR provided matching funds in the form of aircraft 

services and this work served their needs as well as the Minerals Management Service (MMS). 

OBJECTIVES: Surveys continued through 1998 to gather additional data for geographical 

stratification of this area of development, abandonment, seismic profiling, and vessel traffic. 
Final Technical Summary – Schmitt and Bonnell 

2

Stratification was based on an analysis of variance for the many species of birds that nest, roost, 

or migrate through this area. Regions with the highest variance received the greatest effort on 

surveys; regions with the lowest variance (i.e., most predictable patterns of use) received less 

effort. 

 

DESCRIPTION AND RESULTS: Aerial Surveys were flown in a high-wing, twin-engine 

Partenavia PN68 Observer aircraft supplied by the CDFG Department of Air Services. The 

navigation was by GPS (Global Positioning System) with time/position entries into a computer at 

approximately eight-second intervals. The computer operator also entered important sightings 

(flocks of birds, marine mammals, water-mass boundaries, sea state, etc.) as well as number of 

observer(s) on watch. Typically only the observer on the shaded side of the aircraft was on duty; 

however, on northbound transects both observers were on watch searching a 50-meter corridor (a 

strip-census), with incidental sightings along the shore or outside the clinometer-defined search 

corridor noted. Sightings were recorded on voice-tape and later transcribed for computer entry 

by observation/time by the MMS. Time was then used to determine the position of sightings by 

melding the sighting file with the GPS record of time and latitude/longitude of the aircraft. All 

transects were flown at 200-feet (60-meters) altitude. To collect data on especially interesting 

sightings (e.g., flocks of birds near fishing boats, large whales, etc.), the aircraft increased 

altitude to approximately 600 ft. 

From the beginning of this project, a total of 38 surveys were conducted (exclusive of commutes) 

in 130 hours in the air. Transects thus far include nearly 15,700 km (8,631 nautical miles) 

making this the most effort-intensive study conducted in any MMS-OCS Region. The prospects 

of this study are exciting; the last time systematic surveys were conducted in the Santa Barbara 

Channel and Santa Maria Basin was more than a decade ago. 

SIGNIFICANT CONCLUSIONS: Over 50,000 sightings have been recorded, representing 

several hundred-thousand birds ─ this within a search swath of, at most, 100 meters. The 

numbers are astounding, in and of themselves, but we have also noted some remarkable findings 

─ sightings of alcids (auklets and murrelets) appear sparse, numbers of gulls and pelicans seem 

stable, multiple observations of common dolphins are stable but expanding within their range, 

and large numbers of blue whales and humpback whales are clearly occupying the outer Santa 

Barbara Channel and Santa Maria Basin in mating/migration season. 

STUDY PRODUCTS: 

Bonnell, M. L. and R. G. Ford. 1996. Assessment of historical data for sampling design of the 

MMS seabird study. Prepared for Minerals Management Service, Pacific OCS Region, 

Camarillo, California, by Ecological Consulting, Inc., Portland, OR. 16 pp. 

Pierson, Mark O., Michael D. McCrary, and Michael L. Bonnell. 1999. Seasonal Abundance 

and Distribution of Coastal Seabirds Offshore Santa Barbara and Ventura Counties, 

California. Fifth California Islands Symposium, OCS Study, MMS 99-0038: 428-434.