Cephalopods: Part 1

This year, we saw octopus or squid on almost 40% (9 our of 23) of our dives at Sunset House…and that wasn’t by accident. I’ll get to the actual encounters in a bit, but I would like to start this blog with a few words about the value and benefits of your dive log.

Some readers that know me, know I am a bit of a data fanatic. While my day job requires attention to patterns and trends as a tool for early identification of issues or predictions of future behavior, those same practices with data from my log have helped improve my diving as well.

Not only do I know exactly how many dives I have made with my camera, which triggers a regular overhaul, I can also see patterns with the creatures we have seen.  For example, on the plane ride down to Grand Cayman, I found a few entries that mentioned octopus and squid.

David's Dive Log Entry
David’s Dive Log Entry

April 16, 2012 7:07pm – Sunset House (north) – Soldier fish, parrot fish, flamingo tongue, christmas tree worms, tube sponge, wrasse, trunk fish, butterfly fish, slipper lobster, Caribbean lobster, octopus, lion fish

April 19, 2012 8:44pm – Sunset House (north) – Soldier fish, parrot fish, flamingo tongue, christmas tree worms, tube sponge, trunk fish, butterfly fish, Caribbean lobster, brittle starfish, arrow crabs, banded coral shrimp, other varieties of shrimp. Leslie found on octopus, but he was hiding in a small coral head. I saw a southern stingray that was curious. He passed twice, the second time right under me.

I had a small issue with my right ear. I couldn’t clear it so we stayed around 30 feet.

Well, the tarpon showed up. We had five or six with us for the second half of the dive. Some came quite close and weren’t afraid of the lights. At the end of the dive, Leslie spotted a squid. It wasn’t skittish, so I taped it for a while.

OK, perhaps that exceeds the TMI threshold, but you get the point. Having that information as a reference is not only entertaining, but it can be useful…which brings me back to the focus of this blog. Our 2012 encounters were a bit random as we saw them while swimming around looking for anything interesting. Our goal in 2016 was specifically for octopus, so we had to approach it with a plan. We saw octopus a few times on the north end of the Sunset House reef the last time we were there, so we should try that again this time.

As you swim out from the sea pool and turn right (north), you enter a very large open grassy area. Since we didn’t have a Marauder’s Map showing the precise location of any octopus, we approached the search using a grid pattern.

Once over the grass, we swam parallel to the sand path toward the reef. When we started seeing the large coral heads, we turned north, swam about 15-20 feed and turned back toward the shore. When we got close to the rocks, we turned north, went another 15-20 feet and headed deeper. Lather, rinse, repeat.

The first night we tried this search technique it took approximately 50 minutes, but we spotted a Caribbean Reef Octopus hunting small fish and crustaceans around a large sponge and coral encrusted rock. Leslie and I followed for about 25 minutes it as it explored the reef for food.

Watching an octopus hunt is just fascinating. Its tentacles bend in whatever direction or shape needed to form a framework while it spreads its skin between them to form a highly effective cloak to capture its prey. It doesn’t matter if it needs to cover a sizable hole in the rocks or envelop a waving patch of algae. Our octopus’ stretched skin turned a brilliant blue/green and was a bit translucent at times when it got spread very thin.

We approached the next Sunset House night dive the same way. Again, fifty minutes into the dive we spotted an octopus, although this one was a Common Octopus. There are two significantly visible ways to distinguish the Common from the Caribbean Reef Octopus

  • Suckers – The suckers on Common Octopus tentacles have dark edges, while those on the Caribbean Reef Octopus do not.
  • Eye Ring – There is a dark ring around the eye on the Caribbean Reef Octopus that is not present on the Common Octopus

Unfortunately, our octopus that night appeared a little beat up as two of its tentacles were truncated, perhaps by previous attacks. I am not sure if that impacted its movement, because we saw it “walking” most of the time instead of the slithering we saw the previous night. His head and mantle had a lot more texture than the Caribbean Reef Octopus we saw showing several one inch protrusions.

But octopuses weren’t the only cephalopods we saw… We also saw plenty of squid.

OCTOPUS

David Howell

David Howell

I have been diving since 2002. While my technical and editing skills have not risen as fast as my passion for shooting video, I am enjoying the opportunities I get to learn and grow. Many thanks to Leslie for her love, partnership, suggestions, wit and equally compulsive technology interest. Must...get...more diving in...

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