The Christmas double star, the solstice, and the music of the spheres

The winter solstice coinciding with the conjunction of Jupiter and Saturn has had me thinking about the music of the spheres*—the sublime harmony of celestial motion. Jupiter completes its path around the sun—perceived by us as a march through the Zodiac—every twelve years. It takes Saturn 29 years to complete the same circuit. Which means that Jupiter catches up with and passes Saturn about every seventeen (~12x[1+12/29) years. Because the orbits of the two planets are tilted with respect to one another they don’t usually get all that close when Jupiter overtakes Saturn. But this year the overtaking occurs when their respective orbital planes cross, so they get really close. As you’ve probably read, they last got this close around 800 years ago. Or was it 400? No matter—long before any of us was born.

And then there’s the winter solstice. As everyone knows, Northern Hemisphere days get shorter as we approach the solstice and start to get longer after the solstice—December 21 this year (and most years). Less obviously, sunsets get later over the couple of weeks prior to the solstice even though the days are getting shorter. This is because of Earth’s elliptical orbit and the fact that the solstices occur at the long ends of the ellipse. The laws of motion dictate that the earth moves faster on an angular basis relative to the Sun when it’s at either end of the ellipse. This effect is stronger for the winter solstice than the summer solstice because the former happens to occur when the earth is at the end of the ellipse that’s closest to the sun—”perihelion.” The earth is getting ahead of the sun, so both sunrise and sunset get later each day before the solstice even though the days are getting shorter. All this stuff is kind of hard one’s head around, unless you’re Newton or Keppler, but that’s okay. Just as you don’t need to know a D-minor from an arioso to appreciate Beethoven you don’t need to know physics to appreciate the music of the spheres**. (But it helps.)

A photo of this year’s Christmas double star—bright Jupiter and dimmer Saturn—taken on my iPhone from Kappa’a Beach Park. Click if you can’t see the pair of planets on the middle left.

*Wikipedia describes musica universalis, also called music of the spheres, as “an ancient philosophical concept that regards proportions in the movements of celestial bodies—the Sun, Moon, and planets—as a form of music.” It further says that the term “music” is not literal, but rather a “harmonic, mathematical, or religious concept.” Check out the Wikipedia entry for “musica universalis.”

**There’s a medium-technical explanation of all this here: https://earthsky.org/earth/winter-solstice-and-late-sunrise

Lapakahi’s magic coral patch and an alien urchin

The other day Marla, Wendy, and I snorkeled north from Mahukona to the southern end of Lapakahi Marine Life Conservation District—about a three-quarter mile swim. As the name suggests, Lapakahi is a protected area where “the taking of any type of living material (fishes, eggs, shells, corals, algae, etc.) and non-living habitat material (sand, rocks, coral skeletons, etc.) is generally restricted.” This means, in contrast to Mahukona, no spearfishing or aquarium collecting* is allowed. The results of this protection are quite apparent—the fish at Lapakahi are significantly less wary than at heavily-spearfished Mahukona, and fish diversity is better too.

During our swim we stumbled into one particularly rich patch of coral. It was only a few meters in diameter and about five meters deep. Marla quickly spotted a Flame Angelfish—uncommon for such shallow water, and considered a nice find even at scuba depths. It turned out there were at least two Flame Angels, and the patch was crawling with Hawaiian Squirrelfish, Saber Squirrelfish, Iridescent Cardinalfish, and many other species.

It dawned on me that I’d been to this same coral patch with Hai and Lottie a couple of years ago. It was similarly rich in fish back then. Hai visited the site at least one other time back then, and reported that he’d counted forty species of fish there—a very impressive number. These days we’re calling it the Magic Coral Patch. It’s kind of a long swim, and not very easy to find, but we plan to return soon.

One of the Flame Angelfish poses with a Goldring Surgeonfish. These little angels, like most Hawaiian angelfish, are quite shy, but their vivid coloration makes them easy to spot. No other Hawaiian reef fish shows such a highly-saturated red.

An Iridescent Cardinalfish and a Hawaiian Squirrelfish hunker in a dark recess.

On the swim back eagle-eyed Marla spotted something unusual in about eight meters of water. Her first thought was that someone had discarded a hubcap out there. Turns out it was a Blue-Spotted Urchin.

This splendid Blue-Spotted Urchin was about eight inches in diameter. Hoover says the species is uncommon in Hawaii and usually found below fifty feet. Those spines are screaming look but don’t touch.

This closeup shows why it’s called Blue-Spot Urchin. See those tiny blue spots arranged along the arms? Hoover says the spots can expand or contract, I guess according to the urchin’s mood. Maybe this one’s depressed on account of being in such shallow water.

*Thankfully, a recent court ruling has effectively ended commercial aquarium collecting in West Hawaii.

Caught in the act

Predatory fish are everywhere you look on Hawaiian reefs. Morays, groupers, snappers, Trumpetfish, Ringtail Wrasses, just to name a few. The funny thing is, you almost never see any of them actually eating another fish. In the many hundreds of hours I’ve spent snorkeling and diving in Hawaii I’ve only seen it a handful of times. Here’s an event I caught the other day at Mahukona:

I came upon this Crocodile Needlefish as it was half way through swallowing what looks like an Acute Halfbeak. (The fish in the background look like Keeltail Needlefish.) Needlefish—both Crocodile and Keeltail—are pretty common year-round, while the halfbeaks seem to be much more abundant in the winter months. There’ve been hoards of them this month.

This is the same Crocodile Needlefish a few minutes after finishing its meal.

A better shot of an Acute Halfbeak. They’ve been amazingly abundant for the last few weeks.

A furtive moray

There’s a rock near the Mahukona lighthouse that intermittently houses a Yellowhead Moray. Our snorkel buddy Wendy turned us on to this spot several months ago, and since then we’ve swung by occasionally to see if the moray is there. More often than not the eel is absent, but sometimes…

Yellowhead Morays are supposedly fairly uncommon—this is the only one we’ve ever seen—as well as nocturnal, and usually found at scuba depths. This one has stuffed itself into what seems like an impossibly small hole only a few feet below the surface.

One of the voices in my head urged me to stick my finger into this hole, but better sense prevailed. (Come on, don’t you sometimes want to do something like that? No? Hmm, go figure.)

A castaway

We’ve been seeing a solitary, shy, yellow butterflyfish at Kawaihae Harbor for the past several months. It’s a Speckled (or Citron) Butterfly, a common species in many parts of the tropical Pacific, but quite rare here in Hawaii. Hoover and Randall* say rare in Hawaii, while Stender says “very rare.”

Good old reliable Jeff** (who does not run a floating crap game as far as I know) has recorded his Speckled Butterflyfish encounters since the eighties. Over countless hours of snorkeling the Big Island he’s seen this species roughly seven times—three pairs and four solitary individuals. This is a species that, like many butterflyfish, has a strong tendency to form mated pairs when given the opportunity, so Jeff’s ratio of four singles to three pairs is rather odd. I think this has got to be due to the species’ rarity in Hawaii. Like most reef fish, the Speckled Butterfly goes through a planktonic larval stage that drifts freely in the open ocean until settling in on a random reef. In the case of fairly common species, numerous larvae will settle onto any given reef and transform into adults, providing individuals the opportunity to find others of their kind and establish mated pairs. But, alas, for the Speckled Butterflyfish low numbers mean that some larvae will be the only members of their species to settle on a given reef. Of course the adults are free to wander the coast in search of mates if they choose (I believe in fish free will—not sure about humans), but for this rare species the nearest potential mate may be very distant. So, based on Jeff’s and my observations, I figure that Kawaihae’s single Speckled Butterflyfish is doomed to the lonely life of a castaway.

Kawaihae’s lonely Speckled Butterflyfish. It seems to be a home body, attached to a quite small portion of the reef. We don’t see it every time we visit the harbor, but when we do see it it’s always in the same area.

A Milletseed Butterflyfish. This much more common, endemic species is similar enough to the Speckled that it’s easy to overlook a solitary Speckled among the multitude of Milletseeds. In fact, that’s what I did until Jeff pointed the Speckled out to me months ago.

* Links to the three fish experts listed here can be found in the “About” section of this blog.

**Jeff on the other hand, while very knowledgeable, would not profess to be an expert. He’s my snorkel buddy and papier-mache fish modeler extraordinaire though.

Coral condominiums

On Saturday we snorkeled at Kauna’oa Beach in front of the Mauna Kea resort. Hai has spent a lot of time snorkeling there, and on this day he took us on a tour of some of the highlights. Most impressive were a handful of isolated antler coral and cauliflower coral heads a hundred yards or so off the beach in ten to twenty feet of water. (They were much more common, and less isolated, prior to the 2015 coral bleaching event.) The corals bustled with life—several species of fish as well as assorted crabs and other invertebrates sheltered among the coral’s branches. But you had to look pretty closely to find them.

A Spotted Coral Blenny, also known as Shortbodied Blenny. This is the species featured on my home page. I used to see these guys fairly frequently, usually perched on a lobe coral. These days I see them less often, and they’re usually hiding inside a branching (i.e., antler or cauliflower) coral.

Another Spotted Coral Blenny, this time sharing its spot with a Yellow-spotted Guard Crab.

A Hawaiian Coral Croucher. This endemic is fairly common, but kind of hard to find, much less photograph, as it’s almost always found hiding deep in a branching coral. An alternate common name is Hawaiian Orbicular Velvetfish—much cooler if you ask me. You can just make out another croucher hiding below this one. Like I said, these places are crowded.

Hawaiian Swimming Crab—another fairly common species, found in crevices as well as in branching coral. How many other species do you know that have electric-blue striped eyes? Despite its common name (and its scientific name, Charybdis hawaiensis) this crab is not endemic, but it’s got a pretty limited distribution within the central Pacific.

Hai got this fine photo of an Arceye Hawkfish. These are among the most conspicuous fish inhabiting branching corals in Hawaii.

A toby pushes the envelope

Tobies are a group of cute, diminutive puffers belonging to the genus Canthigaster. Four species occur in Hawaii and several more are found throughout the Indo-Pacific. I’ve posted about different tobies a handful of times before—search this blog for “toby” if you’re interested.

Anyway, a few days before leaving on our recent California trip Marla and I spotted a solitary Crowned Toby while we snorkeled at Mahukona. We’d seen this species a handful of times before, but never while snorkeling—only on scuba. It turns out that, according to both John Hoover and Keoki Stender, these fish prefer depths of twenty feet or greater. Hoover goes further, saying the species is “seldom seen by snorkelers.” This one was at about nineteen feet—pushing the depth envelope.

The Crowned Toby warily eying me. My camera recorded a depth of 5.6 meters—18.4 feet—for this shot. Besides being unusually shallow, the little fish was alone as far as we could tell. The species (endemic, by the way) usually occurs in pairs. I bet it returned to deeper waters, and its brethren, pretty soon after we saw it.

Jockeying for photo ops at Black Point

Yesterday Marla and I joined our friend Wendy for a two-tank dive trip with Kohala Divers. As usual, the KD staff was excellent and the dive sites were great. The only trouble was that there were too many passengers with cameras. Due to the virtual absence of tourists on the island these days there were only nine paying divers on the boat, but at least six of them, including Wendy and me, were toting cameras.  With that many photographers in the water, sighting of an interesting fish can result in something resembling a rugby scrum—everyone muscling in for a good shot before the poor, terrified fish bolts. It seems like the people with the biggest, most expensive photo rigs are the worst. I guess they figure that we peons with smaller, less expensive setups will never be able to take a good photo anyway, so what the heck. Wendy and I, with our modest cameras, and our senses of civility, tended to hang back. (Marla is wise enough to not mar the experience of enjoying the fish by carrying a camera at all.)

Kohala Divers, like most West Hawaii operators, tries to mitigate this situation by sending divers down in small groups—in this case one group of four and one of five divers. This helps, but sometimes, especially if an unusually uncommon fish is sighted, the groups will converge.

That said, it was a great couple of dives, with lots of interesting fish at both dive sites. And don’t mind my kvetching—we all had a great time.

Almost immediately on our descent at the first site (Black Point) we spotted this Bandit Angelfish. This endemic species is uncommon to rare here on the Big Island, and neither Marla, Wendy, nor I had ever seen one before. By time I waited out the initial scrum the fish had had enough of us and started moving off. I got this parting shot.

We came across a handful of Ewa Fang Blennies—also endemic. Not particularly uncommon, but so pretty. This one is joined by one of the ubiquitous Gold-ring Surgeonfish.

We came across this Tiger Snake Moray on the second dive at a site called Black Point Caves. Marla and I had only seen this species once before—sans camera. John Hoover calls it secretive and nocturnal rather than particularly uncommon. He also informs us that the species preys primarily on other eels.

A Potter’s Angelfish popped its head out while I was trying to photograph the snake moray. We also saw, but did not photograph, a Flame Angel, and I briefly spotted a Fisher’s Angel. That makes all four of the angelfish species one has any likelihood of running into in the main Hawaiian Islands.

This one was a heartbreaker for me. I’d been wanting to see and photograph a Longnose Hawkfish—a fish that Hoover calls “an unusual find in the Islands”— for several years, but have never encountered one until yesterday’s dive. Once again I was late to the show—the fish bolted right after my arrival and this was the only shot I managed. Oh well, better luck next time. (Don’t you love that plaid pattern?)

So, yeah, a really great trip. I was buzzed for the rest of the day. Maybe I should be more like Marla and just enjoy the dive instead of getting so wrapped up in the goal of acquiring photos. Maybe one day, but for now it’s a fun (okay, a bit expensive, too) way to exercise my inner hunter-gatherer.

Optimism pays off

The plan was to go for a snorkel inside the harbor at Kawaihae. Marla and I entered the water while Hai was still suiting up. We found the water full of gunk. More precisely, it was full of larvacea tests—tiny, clear, gelatinous blobs that are the used-up remnants of the feeding apparatus of free-floating tunicates (more on that in a later post). They were so thick that it looked like an underwater snowstorm. While they’re harmless—don’t sting like some of the blobby stuff you often run into in Hawaiian waters—they’re kind of disgusting, so we decided to scratch the harbor swim.

Marla and I suggested an alternative plan: snorkeling in the less disgusting water outside the breakwater. Hai was unenthusiastic—fish diversity outside the harbor is low, and coral is mostly dead—but for the sake of camaraderie he agreed to come along. As we walked to the alternate entry point I talked him up on the idea, emphasizing that you never know what you’ll encounter on any ocean outing. That’s one of the best things about saltwater snorkeling and diving: the ocean is big, and anything can show up. Hai agreed and in we went.

I was first in the water, and low and behold, within 30 feet I spotted a brown, camouflaged fish scuttling along the bottom in about eight feet of water. It was an Oriental Flying Gurnard. It was only the second time any of us had seen one of these very odd, very uncommon fish. We spent quite a long time excitedly following the fish around getting photos. It turns out there was another gurnard nearby—we’d presumedly found a mated pair.

It’s the promise of encounters like this that keep us fish geeks going out day after day. Any day you find a fish as uncommon and interesting as these is a great day.

Here’s the larger of the two Oriental Flying Gurnards. It was only about seven inches long, small for a species that, according to Hoover, reaches fifteen inches. (Its presumed mate—no photos—was more like five inches.) The “wings” are enormous pectoral fins.  The fish uses the fingerlike spines at the front these fins, along with its pelvic fins, to scuttle around the bottom. If you look closely you can see a small part of the pelvic fin inside the front of the pectoral fin. We watched the fish use those pelvic fins to scratch around in the sand, presumably to dig up tiny prey.

These bizarre-looking fish are sometimes called helmet gurnards. The species ranges widely throughout the Indo-Pacific.

Hai got this photo of the gurnard with its wings spread. The fish swims on these spread pectoral fins when mildly alarmed. When fully alarmed it’s capable of swimming off with surprising speed.

 

The crustacean hour

We’ve been snorkeling at Mahukona in the late afternoon—just before sunset. It’s a good time to see crustaceans as they start to stir from their dark recesses in preparation for their nocturnal activities.

This is about the biggest Banded Coral Shrimp we’ve ever seen. These shrimp are not strictly nocturnal, but, like most marine invertebrates, they’re much more active, and more likely to be out in the open like this one, at night. They’re usually found in pairs or small groups, but this one appeared to be solitary.

Flat Rock Crabs like this one are abundant on boulders in shallow water. Like the shrimp, they’re not strictly nocturnal, but as sundown approaches the rocks come alive with these pretty, extremely active little guys.

An aptly named Blue-Eyed Rock Crab. These are much less common than their flat cousins, and almost never emerge from hiding when the sun is high. I think the hairy-looking stuff on the crab’s arm may be some kind of algal growth.