On the trail of the New-dibranchs

    A bit more than a week ago, our friend Hai, the Godfather of Kawaihae, sent a us text to the effect that the water at Kawaihae had cleared and nudibranchs were in a state of wild perfusion.  Unfortunately, we were not able to get away the next day.  Or the day after that.  In that short period, our pals Peter and Marla had met with Hai and seen several species of the fascinating and beautiful

The River God Arno snorkels in the Vatican Musem

sea slugs.

    As soon as we could, we headed north.  Not only were we unable to meet with Hai that morning (he was getting a new tire on his truck, which required him to come all the way south from Waimea to Kailua),  but as we made the final turn to nudibranch central, we discovered the army landing craft tied up to the very platforms we were hoping to snorkel.

    We had an alternative in mind and headed another fourteen miles north to Mahukona.  As we prepared to go down the ladder we encountered a gentleman with a scraggly white beard.  He was reclining against the cement wall and reminded us of one of those mythical river gods one might encounter in one of those half forgotten church yards in Palermo.  The river God took our measure and said, "There's nothing out there but one turtle."

A fine leatherback pauses for a photo.  Mahukona April 2019

   For the first two thirds of our swim the River God looked like a latter day Nostradamus. As we made our turn for home, out on the south cusp, we didn't even see the usual school of milletseeds.  Closer to the pier, our luck changed in a hurry.  A nice Leatherback jack swam by and then stopped within range for a quick snapshot.  This is a fast moving fish that is rarely, if ever, so accommodating

    While I was getting my shot Sandra saw something good.  I thought she said it was a bird wrasse.  I looked around, saw nothing and asked for a clarification.  It was a surge wrasse!  A nice male with a face pattern...and long gone.  As we were looking for the wrasse, what should break cover but a large great barracuda.  He swam away fairly quickly and was never in range for a photo.  This was a big animal, possibly four feet long.  The color of oxidized silver with dark vertical wedges.  I was longing for a picture, but truth be told, if he had turned and approached us I

Great Barracuda, Paul Allen's Reef  February 2012

would have been more than a little concerned.  Despite being potentially ciguatoxic, this fish finds himself on the menu with some regularity, so I was glad for his sake that he was shy.

    Here I am including a picture of a great barracuda taken on Paul Allen's Reef in 2012.  Aside from one that was stalking the fishball about three years ago, I haven't seen a big one since.  And the one we saw at mahukano was dramatically bigger.  With luck, he is out making baby barracudas even as you read this blog.

    On the way in, just opposite the ladder, we played hide and seek with a small yellowtail filefish.   As a final treat, a female pearl wrasse went shooting by.  The female pearl wrasse is a fish we used to see commonly at the Kailua pier and occasionally at Kahalu'u, but I haven't seen one there in over a year.  Leave it to Mahukona to harbor our long lost friends. Despite missing on the nudibranchs, Sandra and I were pleased with our morning fish watching.  The only thing we missed was the turtle.

    For the next few days, life continued to interrupt our quest for nudibranchs, During that short interval, Peter and Marla joined Hai again, snorkeled by the actual dock at Kawaihae, right among the pilings, 

The south end of a north bound trembling nudibranch.  Kawaihae April 2019

and saw a variety of cool animals including six species of nudibranchs!

   Finally today we got together with Hai, and snorkeled the pylons.  We saw lots of good stuff, mostly on the first pylon.  Trembling nudibranch and a pair of banded coral shrimp came early,.  then on the far side of the platform Hai found a decorated nudibranch. He was back in a niche between two pylons, very difficult to see,  and for me, impossible to photograph.  From our perspective, it looked like a tiny bit of something, two centimeters long and four millimeters across, white down the middle with an orange fringe.  Earlier in the week Hai had gotten a better look and took the accompanying photograph, seen in its glory below..  Not only is he  very good at finding these difficult little animals, but he does a fine job getting them in a photo.

      We would also see a gloomy nudi on the same first platform.  This was an excellent look, so even I could get a passable picture.  Before we saw the gloomy, our sharp eyed guide spotted something that none of us could identify.  On first blush, it looked like the siphon of a sponge poking out through an encrusting coral. This siphon, though was thinner and fluted outwards.  The inside of this fluting

Gloomy Nudibranch, Kawaihae April 2019

siphon was a psychedelic dream, as if someone had taken a back gammon board, cut in half and the made the background a bright orange and the pips dark, but filled with multicolored fluorescent spots. As we were obviously looking at a siphon, I figured it must me one heck of a sponge hiding under the other, encrusting sponge.

    When we got home, I repaired to my Hoover's critter book.  I had studied sponges less than a year ago, when we first went to Kawaihae, and I didn't recall anything like this psychedelic siphon,  but I was willing to learn.  However, as I suspected, John Hoover pictured no such sponge.  I thought he might have an addendum of new species at the end of the book, so I started from the back pages.  There was no addendum, but, as it turned out, the last chapter was devoted to tunicates.  Tunicates in Hawaii appear as sessile colonies that the snorkeler sees as encrusting colonies  with ovaloid openings.   Not very interesting once one knows what these rather common encrustaceans are.  However, the tunicate story is very interesting, and it explains why tunicates are at the end of the

Hermandia momus  Your second cousin from a phylogenetic point of view

book.

    As you know, many sea animals release their products of conception into the sea, they get together and form free swimming animals until they attach to a substrate.  In the case of tunicates, these free swimming juveniles possess backbones and tails.  Hence, they are classified as the most primitive group in Phylum Chordata.  Same as us. Most tunicates in Hawaii are colonial and appear as those hard, encrusting colonies .  Elsewhere, like in the Western Pacific, there are species that live as individual animals,  and to the uninitiated, look a lot like sponges.  These are sea squirts, so named because if you dislodge one to examine it, it squirts at you.  So, about five pages short from his magnificent treatise on Hawaiian critters, John Hoover deals with sea squirts.  Low and behold, our psychedelic sponge was the siphon of a native Hawaiian sea squirt. Hermandia momus.

     After a turn around the the second platform, Sandra headed for the beach.  Hai and I looked at the third platform with similarly disappointing results, if you don't count a nice plump cushion star.

   We swam for an hour and a half in the cold water and had a great time.  If you happen to find yourself in Kawaihae look for Hai.  you won't be disappointed.

jeff

Caloria #3 Nudibranch,  Photograph courtesy of the Redoubtable Hai On,  Kawaihae  2019

We received a helpful bit of identification, perhaps from Pauline Fiene.  Clearly Sandra and i did not see the nudibranch that Hai identified as decorated well enough to identify it ourselves.  And there are a huge number of nudibranchs found in Hawaii.  Thanks to whoever helped with the identification.  As a well-intentioned dilletante, i promise to try a little harder to get it right.