Monitoring whales by Cascadia Research Collective
- John Calambokidis
Cascadia Research Collective
Since incorporation in 1979, Cascadia Research has received grants and contracts, primarily from government agencies, to pursue research in a variety of areas. Most of this research has been in the fields of marine mammal and bird biology, animal behavior, ecology, and pollution ecology.
Members of Cascadia Research put a premium on publication of research results in the scientific literature and thus research is conducted and reported with an emphasis on high quality as well as timely completion. Cascadia also makes educational presentations to a variety of audiences from technical talks to scientists to presentations to elementary school children.
Based out of offices in downtown Olympia, Cascadia has conducted field research in the Canadian Arctic, Alaska, British Columbia, Washington, Oregon, California, Hawai'i, Mexico, and the waters off Central America.
Summary to DateOur photographic identification research has provided new information on the distribution, movements, and abundance of humpback whales along the west coast. We have discovered that a distinct feeding aggregation of humpback whales extends from southern California to central Washington, with little interchange with humpback whales north of this area (Calambokidis et al. 1996).
The primary migratory destinations for these whales are to Baja and off mainland Mexico and along Central America (Calambokidis et al. 2000, 2001; Steiger et al. 1991; Urbán et al. 2000, Rasmussen et al. 1999). Our most recent abundance estimates for 2001-2002 were 1,034 (CV=0.11, Calambokidis et al. 2003).
Humpback whale abundance steadily increased from the early to late 1990s at a rate of about 9% per year. Between 1998-1999, however, there was a drop of 25% in abundance likely as a result of the 1998 El Nino. Observed reproductive rates were lower than would be expected for an increasing population (Steiger and Calambokidis 2000).
Feeding and breeding regions showed significant differences in haplotype frequencies, even for regions known to be strongly connected by patterns of individual migration. Thus, the influence of migratory fidelity seems to operate somewhat independently on feeding and breeding grounds over an evolutionary time scale. This results in a complex population structure and the potential to define multiple units to conserve in either seasonal habitat.
- Baker et al. (2013) recently used genetic techniques to quantify the relative influence of maternal fidelity to feeding grounds and natal fidelity to breeding grounds on the population structure of humpback whales (Megaptera novaeangliae). In spite of patterns driven my individual migration, feeding and breeding grounds showed significant genetic differences, which leads to a a complex population structure and the potential to define multiple units to conserve in either seasonal habitat.
Baker et al. 2013. Strong maternal fidelity and natal philopatry shape genetic structure in North Pacific humpback whales. Marine Ecology Progress Series 494: 291–306.
DiscussionCascadia 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. 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.
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. Berman-Kowalewski et al. 2010. Association Between Blue Whale (Balaenoptera musculus)Mortality and Ship Strikes Along the California Coast. Aquatic Mammals 36(1): 59-66.
- Migration/movement patterns
- Stock assessment