Reef Threads Podcast #263


Compliments of Matthew Proudfoot’s sister, Reef Threads has now reached all seven continents.

It’s podcastin’ time again and the big news is we’ve reached our seventh continent, compliments of Australian listener Matthew Proudfoot and his sister. Thanks Matt and Matt’s sister. This week we also talk about food protein content, two-part dosing, and Gary’s tank plans. Download the podcast here, or subscribe to our podcasts at iTunes. Also, follow us on Twitter at reefthreads.—Gary and Christine

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If you get lost in Antarctica, Reef Threads will be there to help.

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Amazing Sea Hares from Anilao Pier

Anilao Pier, home to the notorious bobbit worm, is my favorite site in the Philippines for night diving. I first dove here in 2012, during my graduate studies at San Francisco State University and the California Academy of Sciences. The diversity of marine invertebrates here is astounding, especially with respect to sea slugs, snails, and anemones. I’m particularly interested in sea hares, a group of sea slugs in the order Anapsidea. They’re called sea hares thanks to the horn-like structures on their head, known as rhinophores, which allow them to sense their environment—and which happen to resemble rabbit ears. Like the nudibranchs they’re related to (same phylum, different order), sea slugs have evolved potent chemical defenses to deter predation, since they’re soft-bodied and possess either a reduced shell or no shell at all. On one of my night dives during the expedition, I came across two beautiful, large, lime-green sea hares crawling through the sand and sea grass about 3 meters down. Overwhelmed with excitement upon spotting them, I actually squealed through my scuba regulator! I picked one up and let it go, watching it swim gracefully with its wing-like dorsal appendages (called parapodia), and later collected both for the Academy’s sea slug collection. This was my first encounter with a species I later learned was Syphonota geographica, the only species within the genus Syphonota. Despite it being circumtropical (distributed throughout the tropics) and an invasive species in the Mediterranean, the Academy’s Senior Curator of Invertebrate Zoology, Terry Gosliner, had only encountered this species once before in the Philippines. I’m thinking about investigating its taxonomy and chemical composition for my PhD, since it may actually represent more than one species and contain variable chemical composition, depending on where it’s found and what it eats. Syphonota geographica in the Indo-Pacific have been reported as feeding on brown algae, while those from the Mediterranean are considered specialists, feeding instead on the invasive seagrass Halophila stipulacea. Representatives from Greece have been studied chemically, but specimens from the Philippines haven’t been researched—offering a great chance to add another chapter to our understanding of the area’s biodiversity. —Carissa Shipman, PhD student at University of the Philippines Diliman

Return from Lubang

Well, we’ve just returned from Lubang Island, and I’ve never been to a more remote, more rustic place in the world. The boat ride we were told would take three hours ended up taking five, but the sea was calm and we had a beautiful ride out. We saw dolphins, jellies, and tons of flying fish. When we first pulled up at the port, there were probably 50 people who came out to look at us. I have no doubt we were the first Americans many of them had seen—kids were yelling, “Power boat! Look, a power boat!” and running over to check out our relatively modest, 15-foot whaler-type boat. As soon as we arrived, four of us took off in the power boat to scout for the dive locations for the next two days. We looked for rocky outcrops on the end of the island facing the drop-off into the South China Sea, and we used side-scan sonar to find rocky areas in the 200- to 350-foot-deep range. After a few stops, we found a spot to dive, so Elliott and I suited up and dropped into a dive site we named “The End of the World.” We did a (relatively) quick pass on the site—buzzing down to 300 feet on scooters and then taking our time coming back up—the total length of dive was 71 minutes, which is about as quick as you can do a dive like that. We saw all kinds of interesting fish and invertebrates even in that short time, so we knew this was the spot we’d be diving over the next two days. What’s really amazing is that I have no doubt Elliott and I were the first people ever to see this reef. It’s mind-boggling to realize that more people have been in space than have been to this spot on the Earth! We spent the next two days revisiting the site and collecting animals (both live and preserved) to bring back with us. It was a series of really long days, as it took close to three hours to motor from our hotel at the port to this site on the other end of the island. We’d do a dive, then try to motor back in time to beat the sunset so that we could actually see the channel back to the port! We did two big dives there, including my own longest (290 minutes) and deepest (354 feet) dive to date. The surface water was 90 degrees, but the deep reef was 73 degrees, so we really felt that temperature drop on the way down. Brrrrr! We collected an undescribed species of damselfish—a cute little orange-and-white fish—to bring back to the aquarium as well as a bunch of other rare fish. The two guys we’re diving with from Hawaii are really good at catching fish underwater—they got ten fish for every one that I could catch! This morning, we packed up the ferry and came back to Mabini. (We’ve got the fish we collected swimming in two kiddie pools here at the resort where we’re staying—pretty cool that we can build a temporary, portable aquarium wherever we go!) The sea was fairly rough, so we had a pretty bumpy ride for the six hours it took us to get “home.” I’m feeling the rocking right now, and will definitely be rocked to sleep soon! All in all it was an amazing adventure. I was really shocked by the isolation and simplicity of the lives that the people there are living, and the reefs were very healthy, with loads of fish—including some really big and rare species. A few folks on our team saw a manta ray, and we saw several napoleon wrasses, which have been really fished out in most areas. —Bart Shepherd, Director of Steinhart Aquarium