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Friday, May 18, 2018

Those emerald eyes

Every now and then you get to see something really special.  Yesterday, Dane let us know that Aaron Orsini, a local fisherman, had found a mysterious cephalopod in a crab trap.  It was brought to the marine lab where the Aquatic Resources Group identified it.

What a beautiful animal!  This is a North Pacific Bobtail Squid (Rossia pacifica).  Luckily, Eric had a few minutes to take some pictures and some video (don't miss the video clip below!).

Bobtail Squid are impressive color-changers.  Sometimes the squid appeared almost white; other times it was brick red.  (Watch the video clip to see the waves of color spread across the body.)

This animal spent a lot of time on the bottom, which might make you wonder if it's an octopus.  But then it would start swimming and its fins would be revealed (watch for the fins in the video below).  Octopus generally lack fins (with the exception of some specialized deep-sea octopus).

Bobtail squid are not true squid, but are actually more closely related to cuttlefish (but not the same as cuttlefish).  Note that the body of the bobtail squid is short and rounded and that the fins are also rounded and attached midway along the mantle.  In contrast, the bodies of most true squid are elongate and the fins are attached further back.  [And although not visible, the internal shells of bobtail squid are rudimentary and chitinous, rather than well developed like the "pens" of true squid or the calcareous internal shells (or "cuttlebones") of cuttlefish.]

A few fun facts about North Pacific Bobtail Squid:

- They're distributed along the Pacific Rim, from Japan to the Aleutian Islands to Baja.

- They're primarily subtidal, living at depths from ~10-300 meters, on sandy or muddy bottoms. (They're known for burying themselves in the sand.)

- They're pretty small the mantle (portion of the body behind the head) reaches lengths of ~3-5 cm (females are larger than males).

- They feed primarily on shrimp.

Now for the real treat.  Check out this amazing video.  We're excited to share this footage of our first observation of a North Pacific Bobtail Squid (also called a Stubby Squid because of its short, rounded mantle.)

In the video, be sure to watch for the amazing color changes caused by the dynamic action of the chromatophores (pigment cells) in the skin.  And have you ever seen such beautiful emerald green eyes?

P.S.  Many thanks to Aaron, Dane, Bodega Marine Lab's Aquatic Resources Group, and Eric for making it possible to introduce you to Rossia pacifica.

1 comment:

Linda Schneider said...

Wow, what a gorgeous animal! The chromatophore action is stunning, thank you for this.