Category Archives: sites

Mostly fish watching sites in Hawaii

Diving Dog Pee Beach

Marla and I have been feeling that our scuba skills were getting a bit rusty. Neither of us had dived for almost  year, so the other day we booked a single tank dive with the friendly folks at Jack’s Diving Locker.

We went to a dive site I’d been wanting to visit for a long time. It was a very short boat ride—just a few hundred yards outside Honokohau Harbor where Jack’s keeps their boats. The site has a lot of different names, including Alula Beach, Crescent Beach, Manta Cove, and Dog Beach. The last of these comes from its popularity with dog walkers. So popular that the beach can smell of dog urine. Which is why we, in our typical coarse fashion, call it Dog Pee Beach. The site can be accessed from shore, but that involves a rather long walk over lava to reach the beach, so doing it by boat, while a bit costly, was our preferred option.

We had a great dive. The site had lots of fish, and lots of variety. Here are a few highlights:

The numerous large Yellowfin Surgeonfish at the site seemed very interested in us, sometimes to the extent of interfering with my attempts to photograph other types of fish. I often see these guys while snorkeling at Hapuna Beach, where they’re much harder to approach. I wonder if someone’s been feeding them here.

Another large surgeonfish, the Eyebstripe, or Dussumier’s. These did not seem as interested in us as the Yellowfins. I think these are the handsomest of Hawaiian surgeonfish.

For me, the best fish of the dive was this gorgeous Bicolor Anthias—only the second I’d ever seen. This solitary male was skittish and difficult to photograph.

Lots of Gilded Triggerfish at this site. This one’s a female.

And here’s a male, so you can tell how this species got its name.

I wish I could say I took this photo, but I can’t. It was taken by our most excellent divemaster, Keller. He blew this bubble ring and shot through it to capture one of the numerous spinner dolphins that swam above us during the dive. I gotta learn how to blow those rings.

A Twospot Wrasse, probably not very interesting except to us geeks. The wedge-shaped tail and (I think) red and black triangle at the front of the dorsal fin indicate that this attractive little fellow is a male. This species is one of several small, nervous, deep water wrasses I’m always trying to get a decent photo of. 

And, oh yeah, I almost forgot to mention, Marla and I were attacked by a large shark. Luckily, we escaped.

 

Look what drifted in at Hapuna

Most reef fish begin their lives as planktonic larvae, drifting in the open ocean. Most perish before settling down to adult life on the reef. Some are undoubtedly scooped up into the cavernous mouths of passing mantas, many are consumed by smaller predators, and many more are probably just lost at sea. Research has shown that a surprising number are somehow able to return to their natal reefs*. How they accomplish this, along with most other aspects of the planktonic lives of reef fish, is a mystery. But return they do.

Last week we saw several groups of small juvenile Oval Chromis, an endemic damselfish, at the north end of Hapuna Beach. They weren’t there a couple of weeks earlier, so it was clear they’d just settled in from their open ocean journey. Welcome back, little guys!

A school of newly-recruited Oval Chromis. The little fish, none over an inch long, huddle in a recess in the reef, which they are very reluctant to leave. This allows fairly good photo opportunities despite the fact that the fish are in constant motion. The vivid yellow and iridescent blue color scheme is quite common among Indopacific damselfish, but this is the only Hawaiian species with these showy colors. As is the case with many reef fish, the adults are much duller. (See April 13, 2018 post.)

Members of another school. The fish on the right is clearly younger than the other two, indicating that it’s joined the school more recently. How did this one find the others?

*https://www.cell.com/current-biology/comments/S0960-9822(05)00712-8 https://www.pnas.org/content/104/3/858/

Kahalu’u’s friendly fish

Kahalu’u Beach Park in Kona has always been one of my favorite snorkeling spots. It’s got a lot of fish, it’s uniformly shallow, and it’s often calm and clear. One thing it’s usually not is uncrowded. The park is widely touted in books and web sites as one of the best sites in Hawaii, so sometimes it seems like every tourist in Kona is there, chasing fish, walking all over the reef, and crashing into one another. The fish don’t seem to mind the human crowds. In fact the fish here are more approachable than at most other sites I’ve snorkeled, owing largely to the fact that spearfishing is prohibited.

Due to the State’s coronavirus lockdown the park has been closed for a while, but has recently reopened. You have to walk in though. No loitering or socializing—just swim, shower if desired, dry off, and scram. Between the loitering restrictions and the current lack of tourists, the reef here is now very uncrowded. Surf was calm yesterday and weather was fine, so Jeff and I decided to take advantage of the conditions with a nice long morning snorkel. We were well-rewarded.

This pair of Lined Butterflyfish trailed me for the entire hour and a half I was in the water. The stately beauties approached very closely, apparently looking for a handout. This behavior contrasts sharply with this species’ shy behavior at Mahukona and every other site I’ve seen them. Someone has clearly been feeding them here.

The Lined Butterflies followed us like dogs. They seemed to be particularly interested when I dove to the bottom. Maybe whoever’s been feeding them was doing so by diving and breaking open urchins’ hard, spiny shells. Broken urchins, as I’ve noted in earlier posts, attract all sorts of fish, eager to cash in on the newly-exposed, soft insides. That’s Jeff in the background, trying to get a shot of a little hermit crab.

A mature female Yellowtail Coris boldly approaches the camera. Look at those snaggly teeth! These fish feed largely on hard-shelled invertebrates, breaking a lot of teeth in the process. Luckily for them, lost teeth are regrown.

Threadfin Butterflyfish were abundant and easy to approach. That’s Mound Coral (Porites lutea) in the background—the area is full of large, healthy heads of this species.

Jeff spotted this pair of large Yellowmargin Morays being groomed by a juvenile Hawaiian Cleaner Wrasse. I didn’t manage to get a photo of the shy little wrasse, so settled for this eel portrait. Morays tend to be solitary creatures, so it was quite unusual to see this pair. My guess is that the pairing is coincidental—”hey, what are you doing in my coral head?”

Social distancing at Kawaihae

We’re lucky here in Hawaii. The Governor is encouraging outdoor water activities, and a few of our favorite swimming holes remain open. Last week Marla, Hai, and I were snorkeling off the Kawaihae breakwater when one of the local mantas stopped by.  She graced us with her presence for about twenty minutes and then wandered off.

Our friend Hai positions himself for a photo.

 

Where’s the fish?

Yesterday Hai and I spent the morning poking around under the main loading dock at Kawaihae Harbor. The dock, which is idle most Sundays, is supported by an array of hundreds of concrete pilings. Each piling hosts a miniature ecosystem of encrusting sponges, coral, and miscellaneous small, sessile, so-called fouling organisms. A wide variety of fish are attracted to this jungle, many sheltering among the corals and sponges.

Hai noticed something unusual as we passed one of the pilings: he thought he saw one of the corals move. Looking closer, we discovered that it wasn’t a coral, but a large frogfish. More precisely, a Giant Frogfish, also known as Commerson’s Frogfish. These cryptic ambush predators are sublimely adept at blending into their surroundings. Sometimes they assume a solid color and texture similar to that of a nearby sponge or coral, but sometimes they take on a patchwork appearance to mimic the fish’s background substrate. As you can see below, this individual has chosen the latter option. The effect is enhanced by a partial coat of some sort of grayish organisms that the frogfish has apparently recruited. How can these fish be so good at camouflage? Eons of natural selection can work wonders.

You can kind of make out the shape of a frogfish here. The primary giveaway is the hand-like pectoral fin on the lower right. Frogfish use these and their pelvic fins (hidden here) like limbs to clamber around the reef. The anal fin (to the left of the pectoral fin) and the caudal (tail) fin are also fairly apparent. What is not apparent, or even visible, is the fish’s eye, which is hidden by all the fuzzy growth on the fish’s head. As the name suggests, Giant Frogfish are the largest members of their family. According to Hoover they can reach a foot in length—this one is about eight inches.

Another view of the Giant Frogfish’s left side. This time the eye is visible, but I wouldn’t exactly call it obvious. Can you find it? (Colors here are a bit different from the first photo because the first photo did not use flash, while this one did.)

This is the fish’s right side. Harder to recognize as a fish, but the eye is a little more obvious. Still can’t find it? It’s a third of the way down from the top edge of the photo and a third of the way right from the left edge.

A closeup of the above photo. The eye is the small, round, spoked structure at the dead center. Amazing, huh?

At the other end of the size spectrum is this Reticulated Frogfish. Hai found this little guy—a little over an inch long—hiding in a cauliflower coral on a Kawaihae breakwater a few weeks ago. With those clownish eyes and big, grim, downturned mouth it looks like something out of a horror movie. And that’s what it is to any fish small enough to fit into that mouth that wanders by.

 

An obscure world record—we think

Last week Hai and I did a little snorkeling at Kawaihae Harbor. As usual, we started out at the big concrete platforms at the south end of the main harbor where the military ties up its landing craft. There was nothing much to see at the first platform so we moved on. It only took a minute or two at the second platform for Hai to zero in on the biggest Gloomy Nudibranch either of us had ever seen. It was just a few feet below the surface on one of the platform’s support pilings, and we guessed it was about five inches long. We marveled at it for a while, took some photos, and continued on to inspect the rest of the pilings. Soon Hai spotted another similar sized Gloomy, again just a few feet deep on a piling. (I don’t know how he does it—he seems to have a sixth sense  for finding invertebrates. He’s an architect, but he’d have made a great field biologist.) Both Gloomies were actively crawling around, apparently feeding on bryozoans. We took some more pictures, and this time Hai placed his dive scissors next to the nudi in order to establish a size scale.

After we got back to our respective homes we exchanged texts and photos and speculated about the size of these nudibranchs. We also did some research. Hoover, in Hawaii’s Sea Creatures, says that Gloomy Nudibranchs reach about three inches in length. The authoritative and amazingly comprehensive web site, seaslugsofhawaii.com said 76 millimeters (come on, you figure it out). And Keoki Stender’s marinelifephotography.com says four inches. It was obvious to us that the specimens we saw that day were larger than four inches, so Hai took a picture of his dive scissors next to a tape measure so we could use it and his earlier photo to compare tape to scissors to nudibranch. He sent both photos to Dr. Cory Pittman, head honcho of seaslugsofhawaii.com. Cory looked at the photos and proclaimed that our specimen was 121 mm long, a number now reflected on his web site. So we’re calling it a world record.

Here’s the first Gloomy Nudibranch we found that day. Notice the blue-green color of the highlights on the inside of the branchial plume (the gill tuft on the middle of the back).

This is the second Gloomy. Its inner branchial highlights are distinctly more blueish than those of the first individual. Seaslugsofhawaii.com notes that this species is quite variable in coloration, and that the relative abundance of blue versus blue-green specimens has varied quite a lot over the last couple of decades.

Here’s Hai’s photo of the same individual as shown above, with dive scissors for comparison. (The body color here looks a bit different from my photo because I shot without flash—my camera batteries were dying—while Hai used flash.)

Hai got this fantastic closeup of the Gloomy’s “face.” It’s dining on a blue bryozoan, which seaslugsofhawaii.com says constitutes its sole, or at least primary, food source.

My Fivestripe hypothesis

John Hoover calls Fivestripe Wrasses uncommon in Hawaii, John Randall says rare, and Keoki Stender even says they’re “very rare.”  When I first moved to the Big Island in 2009 I tended to agree with at least the first of these assessments. I’d see an individual at Mahukona now and then, but more often than not they were absent from any of the North Kohala sites where I snorkeled. This started changing a few years ago, about when the first warm water coral-bleaching event occurred in Hawaii. Fivestripes have become more common each year since. Now I see them every time I snorkel at Mahukona, and often see them at several other Kohala sites like Hapuna, Pauoa Bay, and Makaiwa Bay. There are almost always a few sub-adults present at Mahukona’s “First Point.”

So, my hypothesis is that the higher water temperatures Hawaii has been experiencing in recent years have conferred a competitive advantage to the Fivestripe over the closely-related Saddle Wrasse. While the Fivestripe Wrasse ranges widely through the tropical and subtropical Indopacific, the Saddle Wrasse is endemic to Hawaii. Within its range the Saddle Wrasse is much more common and lives in a wider variety of habitats than the Fivestripe, which in Hawaii is pretty much restricted to the shallow surge zone. It seems not unreasonable to assume that the two species compete in shared habitats, and that this competition may limit Fivestripe abundance in Hawaii. Maybe warming water favors the Fivestripe, since this species thrives in very warm waters outside Hawaii, while the Saddle Wrasse is restricted to cooler Hawaiian waters. Of course I have no real evidence for this hypothesis, but, as the greatly-missed Tom and Ray Magliozzi would say, post hoc, propter hoc, right?

One of a handful of sub-adult Fivestripe Wrasses that you can find at Mahukona’s “First Point” on any given day.

A handsome initial stage adult at Mahukona. This one may have a few Saddle Wrasse genes—the two species often interbreed.

Here’s a sub-adult photographed in 2018 in Bali, where they’re quite common.

Some little guys at Mahukona

We recently returned from a long trip to the mainland and headed straight to Mahukona. The water’s been very clear and the fish have been abundant and cooperative.

Marla spotted this Dwarf Moray swimming out in the open near the “Second Point.” By time I swam over for a look it had retreated into a hole, but it couldn’t resist poking its head out to watch us, and doubtless to check if these giant human ogres had departed. These pretty little eels are fairly common at Mahukona.

There’ve been a lot of Scarface Blennies among the rocks right in front of the Mahukona dock lately. They’re pretty shy, but you can sometimes get a good look at one hunkered in a crevice looking back at you. It’s kind of dark down there, but the flash on my little TG-6 camera did a pretty good job of illuminating this handsome little fellow.

A young Wedgetail Triggerfish, AKA Picasso Triggerfish, AKA Humuhumunukunukuapuaa. These intermediate sized juveniles have been quite common this year. The little ones tend to be a little bolder than the camera-shy adults. Hoover informs us that “nukunukuapuaa” means pig-snout.

A Whitetip checks me out

Yesterday I took advantage of unusually calm conditions to take a long swim from Mahukona to Nishimura Bay, a little-known spot about a half mile to the north. Just short of Nishimura a Whitetip Reef Shark cruised by going in the opposite direction. I turned to follow it and, contrary to to my usual experience with this species, the shark turned toward me and did a circle around me at a distance of maybe fifteen feet. I’ve got to admit that this made me just a bit nervous, but I was confident in my book-learnin’ that unprovoked attacks by Whitetips are vanishingly rare. So I grabbed the little camera out of my pocket and took a few shots—what else would I do? The shark quickly lost interest and swam away in that oh-so-calm manner characteristic of largish sharks, leaving me stoked.

The Whitetip giving me the eye. A lot of spearfishing goes on in this area, and it could be that this fellow, about five feet long, was wondering if I happened to have a stringer of recently speared fish that it could snatch. I’ve read that the pattern of dark spots on the flanks can be used to identify individual sharks.

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.