Tag Archives: Hawkfish

Cauliflower coral not spawning

Cauliflower coral and arc-eye hawkfish

Cauliflower coral

Cauliflower coral was once a mainstay of reefs along the west coast of the Big Island, but has been in decline for a while. Then, in late 2015, high water temperatures caused a huge coral bleaching event, which resulted in a die-off of more than 90% of the area’s cauliflower coral. In some places, nothing was left. Because of this, the reproduction of surviving corals has become of increased importance.

Different corals have different methods of reproduction. Cauliflower coral reproduces in a synchronized spawning event. During this event, the corals release gametes (eggs and sperm) into the water, creating a milky cloud. For many corals, the spawning event takes place at night, but research indicates that cauliflower corals spawn shortly after sunrise, two or three days after the May full moon. At least, that’s what I was told.

Consequently, twice last week, I got up at an early hour in order to be in the water before 7 a.m. in the hope of witnessing a cauliflower coral spawning. Yes, that’s the kind of life-on-the-edge that I lead.

The first priority was to find some live cauliflower coral, easier said than done. There were a few patches in deeper water, but since visibility was not great, it would be almost impossible to tell if and when they spawned. After some finning around, I found a shallow spot with three small clumps and decided to pin my hopes on them. The live coral was part of a larger mass, part of which had died, as can be seen in the photos. Also to be seen in the photos are an arc-eye hawkfish (above), and two four-spot butterflyfish (second photo) among others. Corals are very important to fish stocks because many small fish, and the young of bigger fish, use the coral for protection, a place to hide when threatened.

What’s not to be seen in the photos is any evidence of spawning, because I didn’t see any. It was unlikely that I would. Conditions might not have been right for the coral or my timing could have been off. The May full moon is actually on the 29th so it might be that the spawning will be at the end of the month, not the beginning. I’ll try again then.

Posted in response to this week’s WordPress Photo Challenge ‘Unlikely.’

Stocky hawkfish

A stocky hawkfish in the waters off the Big Island of Hawaii.

A lot of fish use camouflage, either for defense or for ambushing prey. From a photographic point of view, the nice thing about these kinds of fish are that they’ll remain stationary, relying on blending in, even when I get quite close. The downside, of course, is that it’s really hard to spot them unless they move.

Lately, I’ve been on a bit of a run of noticing some of these fish, moving or not. This stocky hawkfish remained glued to this spot even as I floated a foot or two away. It’s fun to see them on the move because they swim quite fast and then plunk down on a bit of rock or coral and are instantly still.

Arc-eye hawkfish

An arc-eye hawfish rests in a head of coral
It’s a common sight to see an arc-eye hawkfish perched in a head of coral, well assuming you’re in the water that is. If a predator comes along, they slip deeper into the coral for protection.

There are two patterns to these fish. Sometimes they’re paler than this one and have a distinctive white stripe on the side. One study has shown that the lighter fish tend to inhabit slightly deeper water where the coral is spread farther apart. Both patterns have the arc behind the eyes and the blue and red bars on the gill covers.