The Daily Bucket is a regular feature of the Backyard Science group. It is a place to note any observations you have made of the world around you. Insects, weather, meteorites, climate, birds and/or flowers. All are worthy additions to the bucket. Please let us know what is going on around you in a comment. Include, as close as is comfortable for you, where you are located. Each note is a record that we can refer to in the future as we try to understand the patterns that are quietly unwinding around us.
|
One week ago ms mole and I took the day off for a wonderful excursion. The Victoria Clipper is a passenger ferry service between Seattle and Victoria, BC that makes a daily round trip, all year round. In the summer the same company also makes a separate daily trip to the town of Friday Harbor, in the San Juan Islands. An 'add-on' to this trip is 2.5 hours of whale-watching in the San Juans. Thursday was the last forecast day of warm sunny weather for a while and so it seemed like the perfect opportunity to get out of town (weekdays are also cheaper than weekends).
It was great day in which we saw six (or seven depending on your taxonomy, see below) species of marine mammal. I don't think I've ever seen that many in one day before. For context I estimated how many I'd seen in my life time which turned out to be eleven species of cetaceans (one non-marine) and six pinnipeds as well as Manatees and Sea Otters. This is a conservative list as I'm not really sure of how many dolphin species I've seen and I took the minimum number. But in any event the total from last Thursday is over a quarter and possibly close to a third of all the species of marine mammal I've ever seen - in one day! The crew and the ship's naturalist were very helpful and informative. My only complaint is that the craft probably wasn't built with wildlife observation in mind. It has an upper outside deck that can accommodate less than a third of the capacity of the ship and when we stopped for something interesting it could be difficult to get an unobstructed view. The boat could have really used outdoor side decks on at least one level where you could stand outside and be at least somewhat out of the wind.
Unfortunately I don't have photos of two of the species. We saw a single Minke whale which surfaced twice briefly and disappeared. Based on my prior experience and what I've heard this is pretty typical. The other species, harbour porpoise I saw several times. Harbor porpoises are among the smallest cetaceans and typically are found by themselves or in a group of two or three. As a result of these two things they are hard to spot (I would imagine almost impossible from a small boat unless they were close to you) and they are generally at the surface only briefly. The naturalist said she didn't usually point out porpoises because by the time she finished alerting us they would be gone. I saw them at least three times on the trip although it was just a glimpse of back and dorsal fin each time.
The first marine mammal we saw was a California Sea Lion perched on a buoy. I snagged a photo as we went by but got a much better shot of two sea lions on the same buoy at the end of the day. Only males come this far north. They can be told from the larger Steller Sea Lion by their darker color.
The most frequently seen marine mammals were harbour seals which should be familiar to residents along the Pacific coast of North America as well as the more northerly parts of the Atlantic coast. Wikipedia claims they are the most widespread species of pinniped and certainly they are the species of true seal that is most widely distributed along highly populated coastlines. Here we see two groups of harbour seals basking in the morning near the inner coast of Whidbey Island. The rather odd-looking posture is an attempt to minimize contact with cold water/rocks and maximize contact with warm air.
In very shallow flat area. I forget the name.
Near the entrance to Deception Pass, a scenic highlight of the trip up. I had to crop someone's head out of this photo.
By the time we got to Friday harbor we had already seen five marine mammal species (we got a brief glimpse of a Steller sea lion going by rocks at cattle pass between San Juan Island and Lopez Island (aka home of our own OceanDiver). However now we switched into wildlife observation mode and stopped frequently which made photography much easier. Spotting the Minke on the way up had encouraged our naturalist to hope for a 'trifecta', meaning we would see Minke and Humpback whales and Orcas.
First stop though was to revisit, in a more leisurely fashion the rocks at cattle pass which had a number of massive Steller's sea lions. I took these pictures from inside the cabin through the windows so they are a bit dark. The second picture shows a branded seal - they are marked as pups for future identification.
A group of harbour seals was on the same mini-island but well separated from the much larger sea lions.
Then it was on to the orcas which are the primary focus of the whale-watching in this area. Other boats had already spotted part of the 'L' pod of resident orcas a fairly short distance away in the Strait of Juan de Fuca, just off the southwestern side of San Juan island. Orcas or Killer Whales are very well known animals which are widely shown on nature programs and displayed in marine parks. They are known for their striking black and white coloration, their intelligence and highly social nature, and for being among the very top predators in marine ecosystems, at times feeding on other cetaceans larger than themselves (how often this happens seems unclear, it may have been much more common in the past see more on their diet below).
Orcas have been the subject of considerable study over the years. This NOAA web page provides a lot of detailed information and a myriad of links to other sources. It has been recognized for many years that different groups of orcas differ in their feeding behavior and in 2010 genetic differences among some of these groups were discovered. In particular in the eastern Pacific three different forms or ecotypes of orcas are known. Resident orcas, as the name indicates, have a definite home range although they may wander a bit. The residents feed mostly on fish, primarily salmon in the Pacific North West. There are three groups (J, K, and L) of resident orcas in US waters and they are the primary focus of whale watching in this region. The transient or Briggs orcas feed primarily on marine mammals and wander widely in coastal waters in search of their prey. The third ecotype are offshore orcas (guess where they live) and much less is known about them than the other two (see the NOAA link for more details). The different ecotypes differ in many ways beyond the ones already described such as size, color pattern, group size, amount and type of vocalization, and so on.
Other ecotypes of orcas have been identified elsewhere in the world. See this poster made by NOAA. Many people now argue that the different ecotypes should be considered different species. This change in taxonomy is likely to happen at some point but additional research is needed in other regions of the world. Although the orca is strongly associated with the Pacific Northwest and eastern Pacific orca populations are probably the best studied on earth it should be emphasized that whether you consider them a single species, a species complex, or many species in a genus, orcas have an enormous geographic range being found in most of the oceans of the world (pdf) although their densities are very low in tropical and subtropical waters relative to cold water habitats. This paper for 2013 suggests that the southern hemisphere orcas may not be forming the same discrete forms that we see in the north and further study is needed before they are classified the same way. Orcas in other parts of the world such as off eastern Canada seem to have been relatively little studied.
The images shown are of individuals of a single matriline from the 'L' group of resident orcas. There were about half a dozen of them in the area although I never saw more than three at once. Males are easily distinguished by their larger size and much larger dorsal fin. There was at least one juvenile, possibly one that was born this year. The resident orcas have been struggling. Salmon abundance is down and the orcas are top predators in an enclosed area of water with lots of humans living around it and dumping in toxins. Due to biological magnification the poor orcas have very high concentrations of some nasty things inside them.
When we saw them they seemed to be taking a break from foraging as they were moving in a very leisurely fashion and spending a lot of time at the surface. A female jumped twice which I failed to capture. A male came very close to our boat (those photos are not cropped).
Eventually it was time to go back to Friday Harbor. And then, at 430, start making our way back to Seattle. Suddenly when the city was in sight and I was positioning myself for some photos as we approached, the ferry slowed dramatically. It was announced that a group of transient (Briggs) orcas had been spotted. By good chance my position at the rear of the boat was perfect for photos. Portions of Seattle (Ballard neighborhood and Discovery Park) can be seen in the background of a couple.
I didn't have the experience to pick out the morphological differences between the two types of orcas but they were obviously different behaviorally. The residents were moving slowly but deliberately and in a fairly loose group. The transients were moving more rapidly and erratically and in a fairly tight group with individuals quite close to one another.
Well that's it from me. What's up in your neck of the woods?
**
"Spotlight on Green News & Views" will be posted every Saturday at noon Pacific Time and every Wednesday at 3:30 Pacific Time on the Daily Kos front page. Be sure to recommend and comment in the diary.
**