Gray whales of Washington State: Natural history and photographic catalog

Citation

Calambokidis, J., J.R. Evenson, G.H. Steiger, and S.J. Jeffries. 1994. Gray whales of Washington State: Natural history and photographic catalog. Report to Washington Department of Fish and Wildlife, Olympia, WA.

Executive summary

This report summarizes the research conducted by Cascadia Research on gray whales in Washington State up to 1994. This included boat surveys that yielded sighting information, photographic identification of individual animals, sighting reports from the public, and examination of stranded animals. The report also includes our photographic catalog of individual animals identified through 1993. A number of conclusions can be made from the data gathered to date:

1) Lower number of gray whales entered Puget Sound in 1992 than the previous two years based on sighting reports and number of individuals identified.

2) Gray whales were only seen in the Port Susan/Whidbey Island area, southwestern Strait of Juan de Fuca, and Grays Harbor.

3) In all three areas where gray whales were seen, most individuals were identified on more than one day indicating animals were staying for an extended period rather than migrating through the area.

4) Gray whales identified in the Port Susan/Whidbey Island area in 1992 were all individuals that had been seen in two or more years indicating a high return rate of animals to this area.

5) No gray whales died in Puget Sound in 1992 and none of three found dead along the outer coast had been identified in the area while alive.

6) The photographic identification of gray whales is a valuable inexpensive way to monitor the minimum number of whales in an area, their tenure in an area, and their return rate between years. The information gathered on individual whales would have been critical if any animals had died in Puget Sound in 1992, as had occurred in previous years.

7) Two different patterns of use are apparent for gray whales in Washington State. Gray whale use of the Port Susan/Whidbey Island area and the outer coast of Washington is characterized by a high rate of return year after year and the feeding on high prey densities. Though gray whales have been found dead in these areas, we have not seen a high mortality of identified individuals suggesting the animals dying were transient to the area. A second pattern is the occurrence of gray whales to the more southern portions of Puget Sound. Gray whale use of these areas is characterized by a high mortality of identified animals, no returns in multiple years, and the absence of a clear prey base.

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