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Friday, February 4, 2011

Unexpected Cetacean Sightings in Puget Sound

The Ways of Whales workshop last weekend included a lecture by John Calambokidis, one of the co-founders of Cascadia Research and a local cetacean expert. One of the things he talked about was a series of bizarre whale and dolphin sightings that have occurred over the last year in Puget Sound. 

In January 2010 a dead Bryde's whale was found in Puget Sound after there had been several reported sightings of an unusual (live) whale in the region. Bryde's whales are medium-sized (relative to other whales, that is) baleen whales that are found in tropical waters. In the United States, they usually aren't found north of southern California. After conducting a necropsy, it was determined that while the whale had some evidence of propeller wounds and rope entanglement, neither of these were the apparent cause of death. Instead, due to the empty stomach and thin blubber layer, it was hypothesized that starvation may have played a role. This was the first-ever sighting of Bryde's whale in the Pacific Northwest.

The story got stranger when another live Bryde's whale was found in Puget Sound in November 2010. This animal had severe injuries along its back from a ship strike, and Calambokidis expressed that he thought it was amazing the animal had survived at all, as the most severe of the multiple injuries had actually severed off the tops of multiple vertebrae. He estimated the injuries had occurred about a month prior. Unfortunately in December 2010 this whale also died, succumbing to his injuries.

There have also been sightings of two members of another unexpected species in local waters - the bottlenose dolphin. The only previous record of a bottlenose dolphin in the Pacific Northwest goes back to a dead animal that was found in the late 1980s. The first live sighting occurred in June 2010, of an animal that was seen multiple times before it stranded in July. Then a second bottlenose appeared in December 2010, and was seen alive on numerous occasions up through January 18th, before it too was found dead. Bottlenose dolphins also tend to be a more tropical species, usually not occurring north of southern California, though they have seen as far north as San Francisco in the last 30 years.

There are anomalies in nature, so when I first heard about these sightings I figured they were wayward animals, probably sick or injured which led them to deviate from their normal range. Once you have four tropical animals showing up well out of their range within a single calendar year, however, you start to this part of some greater trend?

The instinct right away is to point to climate change and shifting ocean temperatures, but there have been no greater trends established about altered cetacean ranges. Most animals are still sticking to where they're expected to be found. Also, we're in the middle of a La NiiƱa cycle, which makes for cooler, not warmer, water temperatures.

Scientists involved aren't offering any explanation for the multiple unusual sightings, but it will be interesting to see if more tropical cetaceans are sighted throughout the rest of 2011. 


Lancashire and Lakeland Outback Adventure Wildlife Safaris said...

Our resident northerly BNG population is about 58deg N, almost the same as Juneau. Although they do have the advantage of the warmimg Atlantic gulf stream I doubt if water temperatures get above 15C, andd only 5 - 10 in winter, how does that compare to WA water?


Anonymous said...

On 2/2/2011 I saw a pod of Orcas in Tacoma, off Ruston Way. A small research boat was near them. An exciting sight, but strange indeed. Hope they are well.

Monika said...

Dave - We hover around 10 C/50 F year round. Do you get them in the winter?

Anonymous - Those were members of J and K Pods, our local Southern Residents! They make periodic trips into inland waters all throughout the year, though we see much more of them in the summertime. The research boat was probably Cascadia Research, looking to collect prey and fecal samples to find out what they're eating this time of year.

Lancashire and Lakeland Outback Adventure Wildlife Safaris said...

Hi Monika - Didn't realise your eater was so cold all year round, you got a cold current coming down from teh Arctic? will stick a theermometer in teh sea next week and let you know what it is here, air temperature currently very high for Feb at almost 10C (c40F). The Moray Firth BND's are present all year round - been several times to see em and dipped every time. Grace spotted a porpoise on our last visit which was good as the dolphins have been filmed killed the porps there.

Lancashire and Lakeland Outback Adventure Wildlife Safaris said...

Sorry for the typo - 10C is, as you righty said, 50F not forty.


Art said...

The change in the location of the magnetic north pole has been moving dramatically over the last 100 years and the pace of it's movement seems to be growing exponetially. One of the predicted affects is confusing patterns of migration. Some scientist theorize we are entering a period when the magnetic poles will switch places. Cool....

Anonymous said...

Did you see in the news that a hammerhead shark head was found at Alki? Of course there is no way to know how it got here, but it's interesting none the less.

King5 had the story last night, and the UW has sent samples in for DNA analysis.