Yesterday I took advantage of unusually calm conditions to take along swim from Mahukona to Nishimura Bay, a little-know 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.
I’ve been spending more and more time at the close-in Cleaner Wrasse station at Mahukona. It’s great fun watching the complex interactions between cleaners and cleanees, as well as among the cleanees. There’s a lot of jockeying for position and chasing. The posing fish are clearly eager for the wrasses’ attention, expecting to have a parasite or excess bit of mucus removed. But the little cleaners often double-cross the cleanees by taking a bite of living skin, to the subject’s obvious annoyance. From earlier this month:
When snorkeling or diving we routinely look deep down among the branches of any cauliflower or antler coral we pass. You never know what you’ll find in there—these corals (what’s left of them after the 2014-2015 bleaching event) provide shelter to a wide variety of fish and invertebrates. I posted a photo of a guard crab hiding in an antler coral back in June. Here’s what we saw yesterday in a cauliflower coral at Mahukona:
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.
*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.
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:
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.
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.
There’s a bit of sadness attached to snorkeling or diving the Hawaiian reefs these days. The reefs have just not been the same since the coral bleaching event of 2014-2015. There’s a lot less coral around and considerably fewer fish. Sadder yet, we appear to be headed into more bleaching this year. But there are still a lot of fish around. The other day Marla and I swam through this enormous school of Barred Jacks at Hapuna Beach. Seeing this abundance, similar to that still often encountered in Bali and other South Pacific locations, lifted our spirits. A little, anyway.