Sanctuary Integrated Monitoring Network
Monitoring Project

Photo-identification of Blue Whales

Principal Investigator(s)

  • John Calambokidis
    Cascadia Research Collective
Start Date: August 01, 1991

The focus of this project is to collect identification photographs of blue whales to examine movements, migratory destinations, stock structure, and behavior, and to estimate abundance and trends in abundance.

Cascadia has individually identified more than 800 blue whales.

Summary to Date

A population of approximately 3,000 blue whales inhabits the waters off California each summer and fall to feed. Many of these whales feed coastally but there is a large portion that also feeds farther offshore.

Recent abundance estimates from capture-recapture and line-transect estimates have been recently published by Calambokidis and Barlow (In press, Marine Mammal Science, Jan 2004).

Monitoring Trends

  • Abundance estimates suggest that blue whale populations have not been increasing over the last decade.
  • Our estimate for waters sampled off California for 2000-2002 was 1,567 blue whales(CV=0.32).
  • 1,438 individual blue whales have been identified off California.
  • We identified 312 individual blue whales off California in 2002.

Study Parameters

  • Abundance
  • Stock assessment
  • Genetics
  • Migration/movement patterns
  • Distribution

Study Methods

survey effort, sighting data and photographic identification of individual animals, skin biopsy samples