Research on blue whales and ship strikes

    Cascadia Research has been conducting work to better understand the causes and potential solutions to the mortality of blue and other large whales due to ship strikes. This issue became a priority after at least five blue whales were killed in fall 2007 as a result of ship strikes in the southern California area (see publication on blue whale ship strike mortality off California, March 2010). Three of these animals were discovered in the vicinity of the Santa Barbara Channel. This level of mortality was far higher than had been seen in any previous year and if there were additional deaths of animals that did not wash up, could be significant to this endangered species. Only a small proportion of large whale mortality is documented as strandings because most large whales sink or do not wash ashore. True mortality could be ten times or more higher than suggested by the documented strandings and could be a significant factor preventing the recovery of blue whales. This species has not shown the type of recovery that other species like gray, humpback, and fin whales have shown since the end of large scale commercial whaling. In the eastern North Pacific, blue whale numbers have not increased and by some measures have decreased. Cascadia Research in collaboration with Scripps Institution of Oceanography and with the support of the Channel Islands National Marine Sanctuary and National Marine Fisheries Service initiated research in 2008 on some of the factors possibly responsible for this mortality.

 Our observations and the data from these tags will help us address several of our key objectives:

  1. Determine how animals are distributed in relation to shipping routes and what shifts in shipping lanes might reduce the incidence of ship strikes

  2. Examine the behavior of blue whales in the shipping lanes including documenting their specific feeding and diving pattern in this area.

  3. Use GPS tags to provide detailed movement patterns of the whales in and around the shipping lanes in the day and throughout the night (something we could not do before).

  4. Monitor whale reaction to ship close approaches (less than 1nmi) including to <200m of our tagged whales to determine how whales react to ships and gain insights into how different strategies like slowing ships would alter the incidence of ship strikes. 

Most recently we have worked to apply our research finding to management solutions (see for example Joint Working Group report below). 


More detailed descriptions of Cascadia's work on ship strikes and recent reports and activities::

Publication on blue whale response to ship approaches and implications for ship strikes (2015)

New developments on ship strikes and whales featured in ACS Spyhopper (9 Nov 2013)

Alterations in shipping lanes to protect whales off California: see articles in Wired and AP (1 June 2013)

New publications titled; Assessing the risk of ships striking large whales in marine spatial planning published in Conservation Biology

Joint Working group recommendations on ship strikes and acoustics (June 2012)

Associated Press story on Joint Working Group proposal to reduce ship strikes off San Francisco (July 2012)

New York Times article on increasing threat of ship strikes to blue whales (July 2012)

Review of ship strike issue for ACS newsletter by John Calambokidis (2011)

Update of ship strike research off S California in 2011 (24 October 2011)

New publication on baleen whale feeding (13 October 2011)

LA Times story on Cascadia and blue whales (7 October 2011)

Publication on blue whale ship strike mortality off California, March 2010

Links to photographs:

A blue whale in the shipping lanes being monitored with a suction-cup attached tag dives as a car carrier approaches. Photo 15 August 2008 by John Calambokidis, Cascadia Research.

One of a pair of monitored blue whales in the shipping lanes in the Santa Barbara Channel surfaces just after a cargo ship passes approximately 200 yards from the whales. Photo 16 August 2008 by John Calambokidis, Cascadia Research.

Two blue whales being studied in the Santa Barbara Channel shipping lanes. The whale to the left has two suction-cup attached instruments to monitor underwater behavior and reaction to ships. Photo 15 August 2008 by John Calambokidis, Cascadia Research.