Last week Hai and I did a little snorkeling at Kawaihae Harbor. As usual, we started out at the big concrete platforms at the south end of the main harbor where the military ties up its landing craft. There was nothing much to see at the first platform so we moved on. It only took a minute or two at the second platform for Hai to zero in on the biggest Gloomy Nudibranch either of us had ever seen. It was just a few feet below the surface on one of the platform’s support pilings, and we guessed it was about five inches long. We marveled at it for a while, took some photos, and continued on to inspect the rest of the pilings. Soon Hai spotted another similar sized Gloomy, again just a few feet deep on a piling. (I don’t know how he does it—e seems to have a sixth sense for finding invertebrates. He’s an architect, but he’d have made a great field biologist.) Both Gloomies were actively crawling around, apparently feeding on bryozoans. We took some more pictures, and this time Hai placed his dive scissors next to the nudi in order to establish a size scale.
After we got back to our respective homes we exchanged texts and photos and speculated about the size of these nudibranchs. We also did some research. Hoover, in Hawaii’s Sea Creatures, says that Gloomy Nudibranchs reach about three inches in length. The authoritative and amazingly comprehensive web site, seaslugsofhawaii.com said 76 millimeters (come on, you figure it out). And Keoki Stender’s marinelifephotography.com says four inches. It was obvious to us that the specimens we saw that day were larger than four inches, so Hai took a picture of his dive scissors next to a tape measure so we could use it and his earlier photo to compare tape to scissors to nudibranch. He sent both photos to Dr. Cory Pittman, head honcho of seaslugsofhawaii.com. Cory looked at the photos and proclaimed that our specimen was 121 mm long, a number now reflected on his web site. So we’re calling it a world record.