Category Archives: sites

Mostly fish watching sites in Hawaii

Opportunists

Butterflyfish, with their tiny mouths, subsist mostly on tiny prey—coral polyps, small polychaete worms, amphipods, etc. But given the right opportunity, many (but not all) butterflyfish species will dine on all sorts of other things. Dead fish or larger invertebrates on the reef attract the attention of butterflies and many other fish. There’s often quite the crowd of opportunistic feeders gathered around the corpse, all so fixated on a chance for an easy meal that intruding photographers are largely ignored. We’ve seen a handful of these events at Mahukona recently.

Lined Butterflyfish are known to be difficult to approach and photograph. Attracted by the floating body of a half-eaten Hawaiian Whitespotted Toby* (below the butterflyfish on the left), these two allowed me to get quite close. Other species enjoying the free meal include the ubiquitous, highly opportunistic Saddle Wrasse, as well as Black Durgons, Pinktail Triggerfish, and a Yellow Tang.

These Fourspot Butterflyfish (you’ve got to count the spots on both sides of the fish) have found a broken-open sea urchin. Saddle Wrasses have joined in. Both this and the previous photo were taken at Mahukona.

We were snorkeling at Manase in Samoa in 2017 when we spotted a melee of fish swirling around a head of Acropora coral. We couldn’t identify what was attracting them—it was hidden deep in the coral—but it was apparently a dead something. Most of the crowd consisted of Sixbar Wrasses (a close relative of Hawaii’s Saddle Wrasse), Convict Tangs, and Orange-lined Triggerfish. While we were watching, this huge Longface Emperor and its companion showed up out of nowhere to see if they could get in on the bonanza. The emperors were apparently attracted by smell or by the frenzied activity of the smaller fish, or?

A closer look at the Longface Emperor. This thing was almost three feet long—big enough to startle us when it showed up. The species eats a wide variety of invertebrates and fish.

*Kind of strange to see a dead toby being fed upon by such a wide variety of fish. The bodies of these, like all puffers, contain a potent toxin to deter predation. Either these fish are immune or they know how to avoid the most toxic parts of the body, like the Japanese fugu chefs who prepare puffers for human consumption.

More tiny blennies

In September I posted a photo of a little Gosline’s Fang Blenny poking its head out from a hole in the reef. It’s easy to spot the fang blennies because they spend most of their time swimming conspicuously above the reef, only retreating to their hidey-holes when they feel threatened. There are other types of blennies that occupy these holes, but, while supposedly quite common, they’re a lot harder to spot. That’s because when not in their holes they tend to lie motionless on the reef, blending in with their cryptic coloration. I’ve been seeing them a lot more often recently—maybe because I’m getting better at finding them. Here are a couple from recent snorkel outings:

A Bullethead Blenny peering out from its hole in about three feet of surgey water at Mahukona. It lay motionless—and quite hard to spot—on the reef until I approached, when it shot unbelievably quickly into its hole, tail-first. This one was about three inches long—they reach about four inches. There’s a photo of this species lying exposed on the reef here: https://onebreathkohala.wordpress.com/2015/11/11/hapuna-beach-its-not-just-for-boogie-boarding/

A Strasburg’s Blenny at Hapuna Beach. Like the Bulletheads, the Strasburg’s lives mostly in shallow, surgey water. The surge on this day made it difficult to get much of a photo of this little guy. The fact that its head was just a few millimeters across didn’t help. These endemics are among Hawaii’s smallest blennies, maxing out at only two inches.

 

Our friend the cleaner wrasse

I’ve been spending a lot of time near the cleaning station just off the corner of the Mahukona dock. Two Hawaiian Cleaner Wrasses have occupied this station for many months. All sorts of reef fish come by and pose to be groomed by the little wrasses. It’s a great place to just linger and watch as the fish queue up for cleaning, sometimes chasing each other around, and doing other interesting stuff.

A Goldring Surgeonfish (kole in Hawaiian) poses for cleaning at Mahukona.

An Orangespine Unicornfish queued up along with a Yellow Tang and a Goldring Surgeonfish. Shortly before I took this photo I watched this unicornfish chase off another individual of its species that was also lined up for cleaning. After it had chased its rival at least 20 feet away it hurried back the lineup.

The Hawaiian Cleaner Wrasse is endemic to Hawaii, but three other members of its genus are distributed through the Indo-Pacific. Cleaner wrasses have been getting a lot of press lately. A 2018 National Geographic article describes research showing that Bluestreak Cleaner Wrasses are capable of recognizing their own image in a mirror—the only fish known to be able to do this. https://www.nationalgeographic.com/animals/2018/09/fish-cleaner-wrasse-self-aware-mirror-test-intelligence-news/ Another 2018 article in The Atlantic describes research suggesting that not only do cleaner wrasses benefit the physical health of the fish they service by removing energy-sapping parasites, but they also boost the intelligence of the other fish, again, by removing parasites. https://www.theatlantic.com/science/archive/2018/03/the-fish-that-makes-other-fish-smarter/554924/ If you’re reading this post you should definitely check out both of these fascinating articles.

Here’s a Bleeker’s Parrotfish posing for a Bluestreak Cleaner Wrasse in Bali. I could not have gotten this shot were the parrotfish not holding still for the wrasse.

A Bluestreak getting into the gills of a Doublebar Rabbitfish, again in Bali.

A big Emperor Angelfish posing for a Bluestreak; Bali.

Even the hyperactive Scissortail Fusiliers stop occasionally for a cleaning; Bali.

The appropriately named Bicolor Cleaner Wrasse, a slightly larger, somewhat less common species; Bali.

Kawaihae’s hung over gobies

Marla, Hai, and I spent a relaxed Sunday morning snorkeling around the landing craft platforms in Kawaihae Harbor. We were hoping to see the black frogfish that Hai had been seeing on one of the pilings, or maybe the lionfish that he’d seen there a time or two, but we pretty much just saw the usual suspects: a handful of nudibranch species, Gorgonian Gobies, featherduster worms, Hawaiian Dascyllus, etc.

A thick wire hanging into the water from the second landing craft platform is home to several Gorgonian Gobies. It’s amusing to watch as they periodically dart out from their stations on the wire to to snatch  passing particles of plankton, but these fish are so small—just over an inch long— that it’s hard for my and Marla’s old eyes to make out much detail. (Hai sees everything with his seeming supervision.) Examining photos after we got home we noticed that the gobies have bloodshot-looking eyes—a lot like mine would look after a long night of drinking back in the day. Like this:

One of several Gorgonian Gobies under the second platform. Look at that bloodshot eye! Gorgonian Gobies, also known as Sea Whip Gobies, are easily confused with the similar Wire Coral Goby. The latter are a bit smaller, have a less pointed snout, and are less reddish in color. Wire Coral Gobies are found pretty much exclusively on wire coral, while Gorgonian Gobies will live on anything shaped more or less like a wire or thin stick.

More of the usual suspects—a handsome family of Hawaiian Dascyllus.

Hawaiian Whitespotted Tobies among the Halameda on the rubble at the base of the breakwater. These cute little endemic puffers are very common throughout the Islands. So is Halameda, a pantropical genus of green macroalgae.

A nice sized Painted Nudibranch on the march on one of the pilings. These, Trembling, and Gloomy Nudibranchs can almost always be found at this site lately.

“Big” nudibranchs and search images

I mean bigger than one inch.

Most of the nudis in recent posts have been less than an inch in length—some less than half an inch. This one from last week at Kawaihae Harbor is all of an inch and a half. It’s Dendrodoris krusensternii, a relatively rare species in Hawaii with no common name. Hai, that preternaturally skilled critter finder, found it crawling on a piling a couple of weeks ago and brought Marla, Sandra, Jeff, and me out to see it last week. We swam out to the pilings where Hai’d spotted the nudi, but at first none of us could find it. Luckily, I’d studied a photo of this thing that Hai had previously posted and I’d developed a pretty good search image*. A good search image—a visual idea of just what one is looking for—is really useful for spotting nudibranchs. Pretty soon I located this one on a partially dead Cauliflower Coral growing on a piling a few feet below the surface.

A Blue Dragon nudibranch from a dive earlier this month at a North Kohala site called Ulua. It’s about three inches long. We saw much larger specimens at Backside Molokini last year. These relatively active nudibranchs are supposedly quite common in Hawaii.

*Funny, if you Google “search Image” in 2019 you get a bunch of links telling you how to search for images on line. In this old guy’s world, the term means as described in this fascinating link: https://evolution.berkeley.edu/evolibrary/article/0_0_0/happyface_11

A rare (-ish) morph of a common fish

Whitemouth Morays are pretty much everywhere on Hawaiian reefs. We see at least one poking its head out of the coral on most of our snorkel outings. Most are brownish with a dense pattern of small white spots, the size and density of spots varying quite a bit. On some individuals the spots almost merge, resulting in the appearance of a white background with brown reticulations. We ran into this morph the other day at Mahukona.

All Whitemouths are handsome fish, but the reticulated morph really stands out. This form is uncommon enough that there are no photos of it in either Hoover’s or Randall’s* books. (Hoover does mention this morph though.)

This is a more typical Whitemouth. The spots can often be larger and the background less reddish. In general, the larger the individual the smaller and less dense the spots. (At least that’s my impression.) This specimen is somewhat larger than the one in the top photo.

Another photo of the first eel, just for anyone who doubts that this is a Whitemouth. The white inside of the mouth (as well as a white tail tip) is a definitive identifier of this species.

*See the “About” page of this blog for Hoover’s and Randall’s books.

Cute eels

Morays are common and conspicuous on Hawaiian reefs—considerably more so than other places we’ve snorkeled or dived, such as Samoa and Bali. John Randall in Reef and Shore Fishes of the Hawaiian Islands attributes this difference to Hawaii’s geographic isolation. Since the Hawaiian Islands rose from the ocean quite recently, geologically speaking, everything that lives here has to have colonized the Islands from somewhere else.  In the case of reef fish this somewhere else is the South Indopacific and East Asia. Morays have a prolonged planktonic larval stage, allowing them to drift far enough in the open ocean from their ancestral homes to become established in Hawaii. In contrast, fish groups that compete with morays—specifically snappers and groupers—have shorter larval stages and hence have not become established here. (Hawaii therefore has few native shallow-water snappers and no groupers, although some have been introduced).  Morays then occupy ecological niches that are held by snappers and groupers in the much less geographically isolated South Pacific islands.

Most morays eat fish. To accomplish this their mouths are full of sharp teeth, giving them a nasty, dangerous appearance. A few morays are crab eaters though. These species have blunt rather than sharp teeth—the better to crush their prey’s shells. So they lack the sinister look of their toothier brethren, actually appearing quite benign, even kind of cute. Here are a couple examples we’ve seen recently:

We see Zebra Morays often, but they are usually nestled deep in the rocks with only isolated portions of their body visible. Even when the head is exposed these slow-moving eels seem pretty much oblivious to the presence of humans. This one, at Puako, bears a particularly innocent, almost puppy-like countenance.

Another blunt-toothed species, the Snowflake Moray is to me Hawaii’s handsomest eel. These guys are often seen swimming in the open, completely unfazed by—but clearly aware of—the close presence of a snorkeler or diver with camera. This one was near the dock at (where else?) Mahukona.