Monthly Archives: November 2016

Wrong again

So the day after the previous post in which I stated that we no longer see Heller’s barracuda at Mahukona, Marla and I were snorkeling there in about thirty feet of water, and what do you think we saw?  Barely visible in the distance I spotted a dense, stationary school of silvery-blue fish.  I temporarily lost it, but Marla quickly relocated it maybe forty feet offshore from us.  Swimming out for a closer look, we identified the fish as adult Heller’s.  They kept their distance, moving away in unison as we approached, but I managed a marginal photo or two.

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Heller’s barracuda spend their days in tight, stationary schools, dispersing at night to hunt. These fish have a distinctive underbite, just visible in the photo.

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A small group of juvenile Heller’s barracuda at Mahukona in 2013. A fairly common sight previous to 2014, we’ve not seen the juveniles since.  Again, the distinctive underbite is barely visible.

Heller’s barracuda are related to the much larger great barracuda, another Mahukona denizen.  Unlike the harmless Heller’s, great barracuda can potentially do a great deal of damage to a human who is foolish enough to severely harass it, but they are really no threat unless you do something really stupid, like spear one.  We see great barracuda fairly regularly at Mahukona.

Just when I thought it was boring to go back in the water

Earlier this week, still suffering from an election hangover, I found myself taking a long, solo snorkel at Mahukona.  I was thinking about the devastation that the coral bleaching event of 2015 had wrought upon the entire West Hawaii coast.  About the greatly reduced coral density and the consequently* reduced fish abundance and diversity.  I was lamenting to myself how fish species that had appeared with some regularity at Mahukona prior to 2015 were now absent or nearly so.  (Heller’s barracuda and scrawled filefish come to mind, but there are several others.)  I was thinking that Mahukona seemed to be offering little new and different for fish watchers these days.

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A small portion of the opelu school.

The week proved me wrong about that.  About an hour into my snorkel, in about thirty feet of water, I ran into an enormous school of opelu, or mackerel scad.  While we often see these fish at Mahukona and elsewhere, I had never seen a school this large—easily several hundred fish.  Their frenzied swimming, sometimes as a highly coordinated group and sometimes in what appeared to be random chaos, was mesmerizing and irresistibly spirit-lifting.

Later, up close to the dock in just a few feet of water, I spotted what appeared be a piece of leaf among the rocks on the bottom.  Something about it seemed odd, so I stuck my head down for a closer look.  It was a leaf scorpionfish, a new species for me.  (A couple of months ago Marla and I had tried to see one of these with Jeff and Sandra Hill.  They’d found a leaf scorpion at Kahaluu Beach that had stuck around in the same location for several weeks, but by the time we got down there for a look it had disappeared.  If you’re reading this you should check out Jeff’s highly amusing—not to mention informative—blog: konafishwatching.blogspot.com.)

A couple of days later Marla and I went back to where I’d seen the leaf scorpionfish to see if it was still there.  We couldn’t find it, but Marla spotted a small fish wedged motionless between two large rocks.  We couldn’t figure out what it was, but I took the best photo of it that I could and went home to consult the books.  It turned out to be a speckled scorpionfish, also a new species to us.  So it ended up a good week, with two new fish species observed.  Maybe Mahukona isn’t so boring after all.

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With its camouflage coloration, leaf scorpionfish, like many scorpionfish, can be hard to identify as fish. The eye is perhaps the best giveaway. John Hoover writes that looking into these strangely vacant eyes is “like peering into another universe.”  I agree.

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Another view of the leaf scorpion. These ambush predators are supposedly fairly common in Hawaii, but they usually stay well hidden during the day.

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A speckled scorpionfish wedged head first between the rocks. These fish are allegedly very common.  They’re usually hidden among the branches of antler coral by day, moving to more exposed spots at night. Antler corals are almost absent in waters less than thirty feet deep at Mahukona, but we find them in shallower water at other sites. I intend to start checking these corals for speckled scorpions when I encounter them in the future.

*I’m speculating to some degree here.  I’m pretty sure that the coral beaching is at least partially responsible for the fish decline, but there may be other unrelated causes.  Unexplained fluctuations in fish populations are not uncommon.  A striking example is the 2014 surgeonfish explosion along the West Hawaii coast, described in an August 2014 post.

Return to paradise

No, not the 1953 movie (filmed in Samoa), and certainly not the unrelated 1998 movie of the same name.  I’m talking about returning to North Kohala after almost a month away in Samoa and the mainland.  We’ve been back for a couple of days now, and while we’re always happy to come home, this time we’re especially appreciative of the peace and natural beauty of the place.  I’ve spent a lot of time in the water at Mahukona with my little point-and-shoot camera since we’ve been back.  As always, the reefs yielded ample objects of interest:

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I spotted this giant porcupinefish suspended midwater about fifteen feet down. When I dove for a better look it approached me quite closely, making me a bit nervous—these fish can really bite. Giant porcupines are sometimes quite tame and other times very skittish.

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A “leucistic” yellow tang and a manybar goatfish keep wary watch on me.

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Check out the chin barbels on these marauding blue goatfish.

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Juvenile yellowtail corises and ornate wrasses are fast-moving, elusive photographic subjects—hence the poor focus. The coris is transitioning from the clownfish-ish younger juvenile phase to adult coloration. The ornate wrasse is transitioning too.  Those black spots (ocelli) on the dorsal fin are more conspicuous on younger specimens.

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This ambon toby appears to be taunting the stout moray below it. This sort of behavior is common among many reef fish species.

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A closer look at the stout moray. I don’t often spot one of these smallish eels, but they are supposed to be quite common—just shy and retiring.