Timing is everything

This morning I went here (see arrow):

See how it’s covered in water? I took this picture at about 13:00, probably right at high tide. And of course when I was out there this morning at 06:00, it was low tide. It wasn’t the greatest of low tides but it allowed me to see what I needed to see and have a front-row seat watching the early morning surfers going up and down on the big swell that’s blowing in.

Obviously, visits to the intertidal need to be timed with the tide cycle. At this time of the year we get our lowest spring tides in the morning every two weeks or so, which is great for me because I am a creature of the morning. I can get up hours before the sun rises, but don’t ask me to do anything that requires any intense brain activity after about 21:30.

Low tide this morning was at 05:29, when it was still almost full dark. There was plenty of light to see by the time I got out to the rocks. The tide wasn’t very low and the swell was big, a combination that makes for some pretty spectacular wave watching. Here’s a view towards the marine lab from my intertidal bench; look at all that frothy water!

So the water was big and the tide was mediocre, but it was still a glorious morning. Where I was the bench looked like this:

What a difference seven hours can make! See that tiny black dot in the ocean? That’s a surfer. While I was out there none of the three surfers I was watching did any actual surfing.

I can’t seem to stop taking pictures of anemones:

My prize of the day appeared as I was walking back. I happened to look down at the right time and saw this little guy:

I was able to watch the octopus for a couple of minutes. Its mantle was about 3 cm tall, and I’d guess that all spread out the animal was perhaps a bit larger than the palm of my hand. When I got up to move around to the other side of the pool for a different camera angle, the octopus oozed underneath the mussels and just disappeared.

Before it vanished I was able to catch it in the act of breathing.

Although it looks like a head, given the position of the animal’s eyes, the part of the animal that’s pulsating is the mantle. The visceral mass and gills are contained in the space enclosed by the mantle; not surprisingly, this space is called the mantle cavity. The octopus flushes water in and out of the mantle cavity to irrigate its gills. When it wants to swim it closes off the opening to the mantle and forces water out through a funnel which can be rotated 360° so it can jet off in any direction. But this time the octopus didn’t use jet propulsion. It just oozed away.