Pantar, Indonesia (May 2014) ~ I just saw a blenny that I don’t recognize and you have to go back to see it. Ned nodded in assent, barely looking up from his laptop. Our liveaboard dive boat, the Dewi Nusantara, was scheduled to remain in this bay for one more day, so I had the evening to pursuade Ned to return to the dive site the next morning instead of exploring another spot. And we had to go back - because I found the blenny at the end of my dive, when everyone else had surfaced and boarded the tender. There were actually a half dozen of these blennies and they were so animated and distinctly patterned and big – oh blenny!
A male Midas Blenny (Ecsenius midas) in its nuptial (courting) colors
A female Midas Blenny (Ecsenius midas) in a typical color pattern
I love blennies, but I am by no means an expert and there are many blenny species that I have never seen, so announcing that I saw one I don’t recognize isn’t necessarily an earth shattering proclamation. But this was a site that we have dived a half dozen times over the past eight years so it was hard to believe we’d missed such a charismatic fish. What was going on? I downloaded the little bit of footage I managed to get and showed it to Ned – we both agreed it looked like a Midas Blenny, but was much larger than the little yellow ones we usually see mixed in and feeding with Anthias in the water column. But Ned did not share my enthusiasm for a return dive and did not tell me why until after we returned the next morning. He said that after he saw my video and the crazy way the fish were swimming he really thought there was no way in hell that he’d get a decent shot.
Male Midas Blenny trying to entice a female into laying eggs in his hole
We confirmed my mystery blenny was indeed a Midas Blenny, Ecsenius midas – a male – in its nuptial colors. There was no doubt once we spent an hour watching them – the males did their best to entice females back to their holes in the reef to lay eggs that the males would guard. And Ned got the shots. I’ve loaded a short video on our YouTube Blennywatcher channel or you can watch it by clicking below:
In May 2012, Ned returned from a dive in Lembeh, Indonesia, with images of this tiny, clear Melibe nudibranch. He had been working the very shallow black sand shelf with our guide, while I was below them at 60 feet, taking video of another, much larger species of Melibe. I was pretty satisfied with my Melibe -until I saw the image of his, which happened to be a species neither of us had ever seen before. I managed to talk them into going back to the dive site the next day on the off chance that we might find it again. Ned and our guide valiantly hunted for about 15 minutes before they abandoned me to my hopeless quest but I stayed with it for 90 minutes with no luck. Ned sent his photo off to Dr. Terry Gosliner who identified it as Melibe megaceras, a species he had described in 1987.
Video frame capture – you can see the size next to our guide’s 1/4-inch wide pointer.
May 2014 found us back in Lembeh Strait and on this particular dive, over on the opposite side of the bay at a famed site called Hairball. Our goal was a pair of Ambon Scorpionfish known to be in the area but another boat was positioned where we wanted to drop, so we opted for a fairly bare patch of shallow black sand nearby. Almost within a minute, our guide Man, motioned me over, pointing to the black sand, where I saw absolutely nothing. It took several iterations of the point-shrug-can’t see-show me again-pantomime before I realized that he had found another Melibe megaceras! It was so tiny (see in the video frame capture above how it sizes up to Man’s pointer) and clear but this time I could add one more Melibe to my life list! Video below:
Recently, during a get-together of diver friends, the subject of parrotfish cocoons came up – I don’t remember why – and surprisingly, several said they had never seen a parrotfish sleeping in a mucous cocoon. After thinking about it, Ned and I realized that in all the hundreds of night dives we’d made, we had only seen it maybe a half dozen times. We encountered it for the first time in the mid-90s off Key Largo while waiting for the coral to spawn. We didn’t see the coral spawn that night, but the parrotfish cocoon made our dive. Mucus, secreted from a gland below the operculum, enveloped the sleeping fish in a protective bubble. And until about four years ago, all I knew about this phenomenon was what was taught when I first started night diving: that the mucous cocoon prevented attacks from nighttime predators like moray eels, by masking the scent of the sleeping fish. That theory was proposed in the 1950s by the scientist (H.E. Winn) who originally described the mucous cocoon of parrotfishes.
In November 2010, marine researchers from the University of Queensland published their findings that proposed another theory behind the mystery of the fishy cocoons: the nighttime covering provides protections from blood-sucking parasites. In tests, when exposed to parasites, 95% of the fish not protected by cocoons were attacked while only 10% of those in cocoons were. They point out that this theory doesn’t have to be mutually exclusive with the moray eel predator theory.
Parrotfishes and some species in the related wrasse family sleep at night by bedding down directly on the sand or in holes in the reef, making them ideal targets for parasites that would have a more difficult time attaching to a swimming fish. Although we’ve only seen parrotfishes in cocoons, wrasses like the Bluestreak Cleaner Wrasse (Labroidesdimidiatus) and some in the genus Pseudocheilinus have been observed sleeping in mucous cocoons both in the wild and in aquariums.
I have posted a short video on our Blennywatcher YouTube channel or you can watch it below. (Note: We originally wrote about this in our June 2011 Critter Hunt column in Scuba Diving Magazine).
Lembeh Strait Indonesia, May 2014 ~ What if you carried your home around with you – one that you built yourself – what shape would it be? If you were a worm, then I guess a tube would make sense. I watched the tiny, one-and-a-half-inch, onuphid worm in its clear tube, struggling to negotiate the [...]