The Whale Museum News & Events
Updated: May 20, 2003
Historical Information on Porpoise Strandings in San Juan County Relative to the May 5th Navy Sonar Incident
Richard Osborne, Research Director, The Whale Museum
The Whale Museum has been documenting and responding to porpoise strandings in the San Juan Islands since 1980, and has operated at a heightened effort since the early '90s. Since 1992 the stranding network has documented an average of 5.8 porpoises a year, and 70% of those strandings have occurred between March and June, with the peak in May.
In 1997 and in 2001 we had unusually high spring die-offs of mostly harbor porpoise, that we could not readily explain. When the 12 strandings we had in the San Juans in 1997 were added to the strandings collected on southern Vancouver Island, and the few that were documented off Whidbey and the Olympic Peninsula that year, there were over thirty strandings within a 3-week period. In light of recent developments it would be interesting to know if the Navy had any operations in the area that year.
However, so far this year we are showing a normal pattern of porpoise strandings (3) in the San Juans (see graph below). Due to the extra attention to porpoise strandings this year, especially around Whidbey Island, I would guess at this point we are still seeing a normal pattern, but now, thanks to Orca Network (and the U.S. Navy) we are getting better than usual coverage. This extra effort is great, and should prove very useful for understanding how to better conserve our local porpoise populations, no matter what the reason behind these recent strandings.