Monthly Archives: December 2015

A Christmas wrasse story

No Daisy Red Ryder BB Gun, just fish.

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A particularly festive looking initial phase Christmas wrasse. Most are not this green.  These common fish belong to the genus Thalassoma, a large genus of mostly fast moving, mostly shallow water wrasses.

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Another Thalassoma, this time a terminal male saddle wrasse.  These active, entertaining endemics are among the most common and conspicuous fish on Hawaiian reefs. Photographed yesterday at Mahukona.

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Another close relative of the Christmas wrasse, but far less common, is the fivestripe wrasse.  This approximately three inch long subadult, even less common than the adults, has been at Mahukona for the last couple of weeks.  Photographed yesterday, the prominent yellow tail is unusual—I’ve not been able to find a photo of this fish showing this feature either online or in print.

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Surge wrasses look very much like Christmas wrasses, especially when young.  A distinguishing feature is the v-shaped mark above the jaw of the surge wrasse.  In larger adults like this one, the prominent, formidable looking jaw is also distinctive.  Adults also grow somewhat larger than Christmas wrasses, reaching sixteen inches in contrast to a maximum of ten to twelve inches in most members of the genus.  As the name suggests, these predators live almost exclusively in the surge zone.  They are extremely wary and hard to photograph.  I got this photo last year at (where else?) Mahukona.

 

Hoover’s Tower

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Fisher’s angelfish. This specimen is somewhat darker and less orange than most.

Our second dive last week was at Hoover’s Tower.  This site, apparently named after a voracious conger eel that lived there for over a decade, has a much more varied topography than Tako City.  There’s a coral pinnacle that rises from about thirty feet to ten feet, and there are abundant mini-caves formed from lava rubble.  Shortly after descending to the bottom we spotted a Fisher’s angelfish.  These skittish guys are less common than the Potter’s angel, with which they occasionally hybridize.  This dive was a lot of fun, although we did not see any particularly unusual fish.

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Several large sleek unicornfish were gathered in a small cave that had openings on both ends. I often see schools of smaller individuals of this species in open water at snorkeling depths. The dual scalpels near the tail —diagnostic of unicornfish—are distinct here.

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A large trumpetfish, seemingly unconcerned about my approach. Note the departing Potter’s angel behind the trumpetfish’s tail.

Tako City

On Monday, Marla and I went on a two-tank boat dive trip with Jack’s Diving Locker out of Kona’s Honokohau Harbor.  Compared to sleepy Kohala, Kona supports a bustling dive boat trade.  We saw several boats headed out as we prepared to board Jack’s boat, and I estimate that there are at least of a couple of dozen dive outfits running out of Honokohau.  Fortunately, there are many established dive sites within easy boating distance from the harbor—all with day-use moorings that allow boats to stay on site without the need to drop an anchor and potentially damage the coral bottom—so there’s no crowding.  Jack’s runs a great trip, but I’ve got to say that our local friends at Kohala Divers retain our vote for best dive shop on the island.

Our first dive was at a site called Tako City.  Despite its name (tako is Japanese for octopus) few octopus are seen at this site.  The bottom here is densely covered in coral and slopes from about thirty feet to well over a hundred feet.  Like many west Hawaii sites, the proximity to very deep waters is supposed to provide the opportunity to glimpse passing large, pelagic fish, but we didn’t see any on this or on any other dive.  However, the smaller reef fish were abundant at this site, and quite east to get close to.

Taking photos with scuba is a very different enterprise from my usual free-dive, breath-hold photography.  The most obvious difference is that scuba gives you a lot more time to linger below the surface waiting for a fish to approach or to strike a pleasing pose.  However, boat dives require you to follow the divemaster as she or he leads a small group of divers on a tour of the site.  I’ll often find a particularly interesting fish, but find myself having to move on with the group before getting a chance for a good shot.  Less obvious is that light levels are lower at scuba depths, making natural light photography (as opposed to flash) more difficult.  Color balance issues are also worse at scuba depths; the deeper you go the more of a blue cast your photos take on.  Both of these last issues can be solved by using underwater flash or video lights, but these are both expensive and cumbersome, and I’ve not (yet?) embraced that money pit.  I use a less expensive (and not as effective) way to remove the blue color cast— shooting in raw mode and using post-processing software.

Anyway, here’s some of what we saw at Tako City:

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Yellowfin goatfish are common throughout Hawaii. Individuals readily change from the the gray/yellow color of the fish in the foreground to the more reddish coloration of some of the fish in the background. Reddish is generally favored under low light conditions and at night.

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There are five species in this shot. The fish on the left, as well as the lighter colored fish on the lower right, are Thompson’s surgeonfish. These are pretty common at Mahukona and other sites where I snorkel, but at those sites they tend to hang in midwater, far from the bottom. The yellow fish is a bluestripe snapper, an introduced species. At middle right is a Thompson’s butterflyfish—not very common in my experience, but occasionally seen at Mahukona, usually in midwater. In the far background are pearly (or maybe bigscale) soldierfish, common everywhere, but generally restricted to crevices and caves by day. I was surprised to see them out in the open at this site.  And finally, upper right, is the ubiquitous goldring surgeonfish.

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A barred filefish eyes me suspiciously. Those teeth are used to eat living coral.

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Potter’s angelfish are quite common at scuba depths. These small, shy fish can occasionally be seen at depths as shallow as ten or fifteen feet at Mahukona, and they are quite common at those depths at Ho’okena, south of Kona.

Sneak attackers

In October I posted a few photos of cigar wrasses hiding among schools of surgeonfish—yellow tangs, convict tangs, and sometimes whitebar surgeons—in order to approach potential prey undetected.  We see this behavior in female cigars at Mahukona quite often, but I think we’re seeing the same individual each time.  We see the same behavior in trumpetfish much more often—numerous different individuals of differing sizes.  In both cases the yellow predators blend in well with schooling yellow tangs.  The strategies of these two species are remarkably similar.

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A yellow trumpetfish trying to hide among yellow tangs and convict tangs. Not all trumpetfish are yellow—many are grayish. Photo taken at Mahukona earlier this month at a depth of around fifteen feet.

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Female cigar wrasse, also trying to hide among tangs. Photo from October, Mahukona, 8 ft. (Photo is sharper if you click on it.)

I’ve only seen male cigar wrasses engaging in this type of behavior on two occasions—once in October and then again today (one day after Pearl Harbor anniversary—or two days GMT, which wordpress uses).  I’m sure it was the same individual both times because of a scar on the fish’s right cheek (shown in the October post, but not here).  Lacking the vivid yellow coloration of the female, the male chooses whitebar surgeons to use as camouflage.

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Male cigar wrasse hiding among whitebar surgeonfish. Photo taken yesterday, Mahukona, 6 ft.

Finescale triggerfish

We’ve been seeing finescale triggerfish at Mahukona for the last week or so.  These are by far the largest nearshore triggerfish in Hawaii, reportedly reaching thirty inches.  Until the 1990s they were not thought to breed in Hawaii, and they are still considered rare in the islands except for the west coast of the Big Island, where they still seem to be fairly uncommon.

At Mahukona I see finescales sporadically: they seem to show up for a few weeks and then disappear for several months.  There does not appear to be any seasonality to their appearances—over the last four years I’ve seen them almost every month of the year.  Most that I’ve seen have been about fifteen to twenty inches long, mostly in fifteen to forty feet of water, and most were fairly skittish and hard to photograph.  I once saw what appeared to be a pair building a nest on the sandy bottom at about thirty feet.  I returned a couple of weeks after this sighting and the finescales were gone, so either they were not nesting or the nest had been abandoned.

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Finescale triggerfish, Mahukona, January 2014, 30 ft.

More regal parrots

I posted a photo of a regal parrotfish in a June 30 post entitled “The sixth parrot.”  That fish was a terminal male, or “supermale.”  I run into more terminal males than initial stage* individuals of this species.  Yesterday at Mahukona I had close encounters with both terminal and initial phase fish.  Each was solitary, which seems to be the norm in regal parrots, in contrast to the harem or tight pairing social structure seen in most other parrotfish species.  I had my better camera with me and got a couple of photos of this handsome endemic.

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This is an initial phase regal parrotfish. Various sources describe the coloration of these fish as “pink,” “rose,” “fuschia,” “orange,” and “reddish-brown.”  Judging from other photos I’ve seen, coloration varies, perhaps with locality, or maybe among individuals.

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Here’s a terminal male regal parrot. This purplish coloration is pretty consistent among the terminal regals I see in North Kohala, in contrast to the more orangish colors I see in many photos taken elsewhere. (And, no, it’s not due to color balance issues with my camera.)

*As I described in the June 30 post, most parrotfish start their adult life in an “initial phase,” either female or in some species both female and male.  A subset of older females transform into “terminal males,” or “supermales” that cultivate female harems and dominate spawning activity.  The supermales are typically more colorful than fish in the initial phase.  Initial phase parrots are quite variable in coloration and can therefore be difficult to identify.