March 10, 2018

Race to Race Rocks: Steller Sea Lions, California Sea Lions, & Dall's Porpoises

Steller Sea Lions

[Friday - 3/9/18 - 12:00 – M/V Sea Lion – Naturalist Erick]

Banking on Wildlife

            These past few days we have had a great streak of weather that is making it really feel like spring up here in the islands. Bright, calm, sunny days with a light breeze and a small rain shower in the afternoon. The plants and animals are starting to notice too. Some of our overwintering birds are starting to head back up north and even a few flowers have started to bloom! This Friday was another one of these beautiful, early spring days in Friday Harbor. Captain Mike and I took out a small group on M/V Sea Lion and headed south. We passed through Cattle Pass in between San Juan and Lopez Islands and then pointed towards the west. We traveled across the wide expanse of the Strait of Juan de Fuca towards Vancouver Island and the city of Victoria, B.C. In the Strait of Juan de Fuca and most of the other large straits surrounding the San Juan Islands it may look like an unchanging, monotone seascape till your eyes meet the next piece of land across the way, but they are not. These straits are super dynamic and not just due to the daily tidal change and winds. Underneath the surface the underwater landscape is as wide and varied as the topography above the surface. This below surface topography is given the name bathymetry and it does shape what and where we see wildlife activity at the water’s surface. Every so often on the charts of the area you will see shallower areas in the middle of deep channels. These are often called ‘banks’ here and most of them are leftovers from the glaciers that once scoured and then retreated from this area. As the tidal flow pushes Pacific Ocean water in through the strait it hits these shallow banks and is forced to swirl around and up towards this surface causing mixing and pushing nutrients and plankton closer to the water’s surface. This brings schools of small fish to eat this concentrated food source which attracts larger fish and birds and even marine mammals. Often over these areas you will see massive groupings of sea birds swirling around and diving into the water to feed. I like to call these ‘bird-nados’. They are going crazy because they have found a big school of tiny fish like herring for example. This school has usually been pushed right up next to the surface because something in the depths below is chasing them. Sometimes it is larger fish, other times it is a group of seals or sea lions, and other times it is a cetacean. Surrounding these schools of fish that we like to call ‘bait-balls’ we often see porpoises and sometimes Minke Whales.

Sea Lion Galore at Race Rocks

            As we crossed the Strait we saw a few smaller bait-balls and although we saw a ton of different species of birds it seemed that most of these bait-ballswere either caused by schools of larger fish or Harbor Seals, so we carried on. We eventually reached Race Rocks. This is the southernmost part of Vancouver Island. It is a group of rocks that jut out into the Strait and often times can be pretty hairy because of the strong currents, ocean swells, and winds that often collide there. Today, it was pretty nice though and we cruised around the beautiful lighthouse and watched a large raft of Steller Sea Lions all pretending to be sharks in the water. Not really, but they do look like it when they float on their sides and just raise one flipper above the water. We may think they are doing it to be funny, but the real reason is much more serious. They are thermoregulating. Most of their body is covered by a thick layer of insulating blubber and fur, but just like us their ‘feet’ and ‘hands’ get cold the easiest since there they have the thinnest layer of insulation and a lot of surface area. So, here they are nice and comfortable in the cold waters, but they raise their flippers to dry and warm them up in the warm sunlight above the water. After passing that raft we saw the rest of the colony making a commotion on the rocks. Near San Juan Island we often just see Steller Sea Lions – the big guys – but out here at Race Rocks it was a mix of Stellers and California Sea Lions all hanging out. The California Sea Lions are smaller, darker, and are a lot louder. They do the more well-known barking call that we are familiar with from Idris Elba’s role as Fluke in Finding Dory. The male California Sea lions also have blonde tips just on their foreheads which I, personally, think is hilarious. After we cruised around for a bit we headed north east back into more open water and did pass by a few more bait-balls. At one of them we encountered a group of Dall’s Porpoises! These cetaceans are one of the two porpoise species that we can see in the Salish Sea and are a rare encounter for us in the southern part of the islands. This was a smaller group that was very focused on foraging the small fish all swimming about, so we got to see a lot of their grey and white chunky forms zooming through the water. They are, in fact, one of the fastest marine mammals on the planet able to speed around 35 mph when they want to. After checking them out for a while we continued on into Cattle Pass and took a stop at Whale Rocks to look at the large colony of Steller Sea Lions there. They were also super vocal today and there were even a few young ones in this group too – so cute! On top of the rocks, calmly watching the boisterous sea lions, were two adult Bald Eagles! We made our last stop of the day in the tiny pass in between Deadman Island and Lopez island to look at the heaps of Harbor Seals that like to lie there. They sleepily blinked up at us in the bright sunlight of the afternoon as we said goodbye to them and headed back to Friday Harbor.

 

What another fun day of wildlife!

 

Until next time,

Naturalist Erick

San Juan Safaris