The water at Mahukona was full of floaty stuff yesterday. This happens fairly often, when the prevailing tradewinds die and are replaced by on-shore breezes. The on-shores bring in plankton and all sorts of other things from deeper offshore waters. Sometimes they bring stinging jellyfish (as described in the December 2016 post entitled The Pink Menace), but yesterday it was primarily tiny, nearly invisible creatures, which the various species of plankton-eating reef fish rose up to dine on. (Yeah, I know, dangling participle. I’m pretty sure it’s allowed in this rapidly unravelling 2019 world. Heck, if the President can say “bullshit” at a rally, I guess I can dangle a participle.) The upper water column was loaded with feeding Hawaiian Sergeants, Indopacific Sergeants, Black Durgons, Thompson’s Surgeonfish, Milletseed Butterflies, and others.
The great thing about days like this—and ocean snorkeling in general—is that you never know what else will drift in. In this case it was a tiny creature bobbing around randomly in the upper few feet of the water column, in water about ten feet deep. It was rolled up into kind of a lumpy ball shape about half an inch across, and we initially had no idea what it was—animal, vegetable, or mineral; alive or dead. But it looked intriguing enough that I had to play with it. When I handled it, it opened up into a flatter shape, and appeared to try, slowly and not very efficiently, to swim away. With our presbyopic vision, we still couldn’t figure out what it was, so I took some pictures and we let it go on its way.
When we got home and looked at the photos we saw that the object of our interest was a Gold Lace Nudibranch. This is apparently a common endemic species, but neither of us had seen one before. It’s usually, like most nudis, found crawling on the bottom. I did a Google search and could only find one photo of a Gold Lace swimming freely. I guess this one was trying to move to a new neighborhood. Here’s what it looked like:
We often run into floating debris when the on-shores are blowing. Objects that have been in the water for any length of time accumulate marine growth, and often a collection of juvenile fish using the object for shelter. A lot of different fish species congregate around floating objects as juveniles, prior to settling out on the reefs as they get a bit older. Individual species are difficult to identify, partly because the popular books don’t typically show this stage.