Thursday, July 30, 2009

Orcas and Ecotourism

How much of our fascination with orcas is too much? How many boats, how much underwater noise can they take? At what point, given the dwindling salmon supply, are the whales either going to leave this area permanently or gradually succumb to the environmental stressors and just die off?

CWR 2009 Photo by Erin Heydenreich

No one knows. And that is the problem.

We do know that they are endangered locally, and their survival depends upon our ability to figure it out and set sustainable guidelines…compromises between our desire to watch them as they live their lives as wild, free, and peaceful animals and their ability to cope with us. And in these rotten economic times, we do have to take into serious consideration the businesses and individuals that rely upon the income generated by whale watching tourism. But the whales may not be able to endure it much longer.

In previous posts we have discussed how our resident orcas are constrained in their movements by where they can find salmon, and how the geographic and oceanographic features of the area put the orcas so close to us as they forage. They really can't get away from our boats and noise without leaving. And for them to look elsewhere for food means acquiring a new culture, new ways to hunt fish and to find each other for mating. And still, we would dog them wherever we spotted them because they are so enchanting to us.

The government proposes to give them a break in one small part of their range while we figure it all out - while we learn how much the orcas really can tolerate - and we concentrate on restoring salmon stocks.

We'll just have to adjust, adapt to new rules, and take the long view. After all, they have been adapting to us for centuries.

Wednesday, July 29, 2009

Resident Orcas Live in a Dynamic Environment

Bubbles (Photo by Erin Heydenreich)
Do orcas use bubbles similarly to other dolphins? We really don't know for sure - nor can we say with certainty if they use their sonar ability to detect currents and water masses. However, we do have some idea of the nature of the marine environment where our local resident orcas spend much of their time, and we can speculate on the rest as we continue to explore the intelligence of these animals. Future posts will delve more deeply into the marine environment, but for now we are staying focused on the qualities that characterize intelligence in mammals.

Resident orcas spent a lot of their time in Haro Strait which is the body of water that runs along the west side of San Juan Island, generally from the Strait of Juan de Fuca and up to Boundary Pass by the Gulf Islands. Underneath is a deep trough, which bumps up against San Juan Island and rises steeply along the area where the whale watch park is located (about where the orca icon is placed). On either end of the strait are shallow areas, called "sills".

Haro Strait Bathymetry
Divins, D.L., and D. Metzger, NGDC Coastal Relief Model,

Salmon returning from the ocean on their way to spawn up in the Fraser River (near Vancouver B.C.) come through the Strait of Juan de Fuca, then most of them head up Haro Strait. Orcas are present frequently during the time the salmon are running, and often appear to hunt them right along the edge of the island, over the sills or any geographic feature that tends to force the fish into an area where they are easier to catch - and fortunately brings the whales close to shore where we can see them.

When watching the whales you might notice that the surface of the water shows some subtle variations in texture - but those surface changes can belie the intensity of what may be going on beneath. Masses of water collide in this region, the tides push through, underwater waves stream, and curtains of bubbles get dragged down below at impressive speeds.

Haro Strait off Whale Watch Park (Photo by Elliot Whiting)

These graphs illustrate the dynamic nature of Haro Strait, and show a mass of bubbles moving at a clip of 50 centimeters per second downward and extending to a depth of almost 100 meters. That is a little over a foot and a half per second, to a depth of just under 300 feet. This type of event is transitory, but occurs frequently. It is certainly possible that these bubbles and vertical currents could be detected by the orcas - the entrained bubbles were measured using equipment that works similarly to dolphin sonar.

Entrainment of bubbles.
(Graph prepared by the Ocean Dynamics Laboratory at the University of British Columbia (except for the added clip art) To be accurate the whale icons should be about half the size shown, but they are too hard to see when made to scale).

The middle graph shows the temperature difference of the water masses, and the blocks of salmon illustrate that as the fish move from salt to fresh water on their journey home, they move around the water column to track the river source (the river water is warmer and lighter than regional ocean temperatures - we will cover river plumes and salmon in later posts).

The bottom graph shows the speed of the currents as they moved vertically up and down the water column, and the whale icons show the direction of movement.

If you have spent much time whale watching, you will be familiar with the whales' ability to pull a vanishing act at times...they just seem to submerge and disappear, or surface a mile a way. Maybe the orcas are hitching rides on deep waves or currents.

It is certainly possible...

Wednesday, July 22, 2009

How Dolphins Make The Bubble Rings

So how do the dolphins make those bubble rings (previous post) that seem to defy what we know about physics? According to a Scientific American article on the subject, the dolphins are able to create and control the movement of the rings by controlling the movement of the water around their own bodies.

Probably the easiest way to visualize this is to think of a whirlpool, similar to what is created around the drain of a bathtub when we let the water out, except in this case the vortex consists entirely of water.

Whirlpool (Creative Commons Photo)
After first creating the whirling vortex of water with their body motion, the dolphins then blow a huge bubble of air such that the water vortex pushes through the center and traps a ring of bubbles around it's edges. The dolphins then continue to manipulate and control the water… and thus control the bubble rings.

But how do the dolphins know where the vortexes are once they make them? Scientists think the dolphins "see" them by using their sonar, and the implications of that are stunning.

Much like we can see these shafts of light, dolphins can "see" water layers with sonar (Creative Commons photo).

Because we know that some of the brain structures of odontocetes (toothed whales and dolphins) are arranged in such a way that what they "hear" might be easily processed in the same parts that process what they see, it is not surprising to understand that at least some of the cetaceans actually create mental pictures of what they detect with their sonar. And although most of us don't think of it that way, oceanographers know that the ocean is not a uniform body of water at all, but a complicated mass of layers and swirls. So if you think about it, what we see as uniform in texture and varying only in light and temperature – how we see the ocean - could be perceived, or 'seen', by the cetaceans in much greater complexity.

In the presence of algae or plankton, we too can see water motion (Creative Commons photo).

If you add to that the fact that some of the dolphins and whales most likely 'see' underwater shapes of currents and vortexes with their sonar,though, you begin to understand their amazing adaptation to the richness of their ocean world.

Photo by Erin Heydenreich

In our next post, we'll talk about how our local orcas may use these properties of water and sound in their search for food.

Friday, July 17, 2009

Is It Art, Culture, or Play?

The dolphins show complex play behavior and cultural transmission in this video, and maybe it can be said to be art as well.

The following video was produced by SeaWorld, and although it is informative, it is not clear as to whether the dolphins were born in captivity or wild caught, in which case the dolphins might have brought the skill with them when captured.

It is not inconceivable that the orcas manipulate water and air for their amusement too!

Orca Surfacing (Center for Whale Research photo)

Monday, July 13, 2009

Orca Brains Are Large and Complex

Cetacean brain development is an example of parallel evolution, adapted to the ocean environment. The brains of orcas are roughly four times larger than ours, have a greater surface area relative to brain weight, have enhanced development in different areas, and some of their nerve transmission speeds greatly exceed ours. Naturally enough we humans don't much like the idea that another species might rival us in that which we feel sets us apart from the rest of the animal kingdom: our intelligence, and so we have come up with many ways to explain it all away. At first it seemed obvious to make the claim that bigger animals just needed bigger brains...except that animals like the stegosaurus, close in size to orcas, had a brain about the size of a walnut. Not that they were mental giants - but they got by.

The next idea to come along was "brain to body weight ratio", a comparison between the size of an animal and how large it's brain is, and by that measure an orca would clearly be smarter than a stegosaurus, but not as smart as we humans. Unfortunately for us, both hummingbirds and squirrel monkeys beat us in that measurement (we are about 2%, while hummingbirds are about 4%).

Presently we have come up with a way of comparing brain size called "Encephalization Quotient", or EQ, in which
we compare how big an animal's brain is versus how big you would expect it to be relative to the overall size. Ah ha! At last we win, our brains are 7 times bigger than you would expect them to be for our size, while our closest rivals are dolphins and toothed whales, which come in at the 2 to 5 times range. Whew! Except...

Their brains have a greater surface to volume ratio than ours. What this means, basically, is that the part of the brain that integrates information is much greater. Although scientists at first dismissed this by assuming that the tissue was 'primitive' because it differs in structure from ours, current research disputes that. Research also overturns the notions that the types of cells are related to adapting to ocean temperatures, or that the large brains are dedicated to processing echolocation information.

The layout of their brains is different from ours - some regions (such as those associated with smell) are diminished or absent, while others, such as the vision center, are moved around, and the structures associated with hearing are enhanced - but it is every bit as capable of intelligent thought.

Fortunately now though, scientists are beginning to concentrate more on learning how the cetaceans use their massive brains, and less on coming up with ways to dismiss and diminish the evidence that we share this planet with other intelligent beings.

. The recent discovery that cetaceans have a special type of cell (called a spindle cell) previously found only in humans and the great apes implies that they aren’t just intelligent: those cells are associated with our deeper emotions and social bonds.

Candace Calloway Whiting