by Rich Ross | May 28, 2014 | Fish, Invertebrates, Science
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 by Admin | May 22, 2014 | Conservation, Fish, Industry, Science
Figure. Photos of Colurella adriatica;a potential new live feed for bothmarine and freshwater fish larvae.This post is in response to requests for more information about Colurella adriatica. As previously stated, we’ve examined salinity and found that although they tolerate a wide range, optimal performance is at 15-20 g/L (ppt). For feeding marine fish larvae this is likely going to be the culture salinity as acute acclimation to full strength seawater is good and this will save on salt. Colurella also grows well at 5 g/L and therefore when growing them for freshwater fish, this is the recommended salinity. Thus far, attempts to grow Colurella in 0 g/L freshwater have yielded poor results. The only other culture parameter tested so far has been diet. An industry partner works as a microbiologist and isolates bacteria. He had some freeze-dried bacteria that he wanted us to test. When solely fed freeze-dried bacteria the Colurella populations survived. When compared to those Colurella fed algae paste (Nanno 3600™; Reed Mariculture), the ones fed freeze-dried bacteria initially grew better than those fed paste. However, after 4 days the Colurella fed paste had significantly greater growth. The results of this trial are still being evaluated, as is optimal diet, but Colurella’s ability to be fed, and survive on, freeze-dried bacteria seems feasible. Other culture parameters haven’t been tested yet, but we keep our populations at ~78° F with gentle aeration and can reach ~500 rotifers per mL with a population growth rate half of what is achieved with Brachionus sp. rotifers. Hopefully, once we know more about this species we can increase the population density and growth rate. As stated in a previous post, Colurella has been fed to and consumed by a number of marine fish larvae. In fact, it is easier to mention the one that has not consumed it: green chromis. Digestibility has been an issue for us when using Colurella as prey for marine fish larvae. We've actually seen live, undigested Colurella being passed through the gut of marine fish larvae. After talking with Patrick Sorgeloos, his suggestion was to feed less and increase the residence time in the gut. We'd always fed high densities. One of the unique attributes of Pacific blue tang larvae is their ability to survive heavy water movement (usually in the form of aeration), even to the point of being unable to feed (more on this in a future post). One of the tests we’ve run to increase digestion was to feed them Colurella followed by periods of heavy aeration so they couldn’t feed. What we found were digested Colurella in the gut of Pacific blue tang larvae. The results were encouraging and recent tests have focused on ways to increase residence time of Colurella in the gut of marine fish larvae. Digestibility of Colurella is not a problem for freshwater fish larvae. To date, we've fed them to bala shark, dwarf gourami, lemon tetra, and red-eye tetra larvae and they've all survived. Recently a population of Colurella was supplied to a freshwater fish farmer in the hopes of more advantageous results during larval rearing. Perhaps the most exciting information is that in the next few weeks we’ll be awarded a grant to look at the culture conditions and larval feeding of Colurella (and Oithona colcarva; our marine cyclopoid copepod). Whether this will be in the form of hiring someone or promoting someone at our facility remains to be seen, but having someone focused solely on answering these questions will help us obtain valid information quickly. The Rising Tide team at the Tropical Aquaculture Laboratory by AquaNerd | May 22, 2014 | Fish, Science
Interzoo is the largest international aquarium-based trade show on the planet, and it just so happens to be right around the corner. With the date quickly approaching, we’re starting to hear rumblings of new products that will be announced at the massive event, leading off with a new item from Vertex Aquaristik. In a move that shouldn’t even remotely come as a surprise, Vertex looks as though they will be announcing a larger model to their popular Omega protein skimmer line. While we don’t have any specifics about the products, as Vertex wouldn’t immediately address our questions, we do know that it will be the Omega 180 based on the engraving on what is very likely the skimmer’s lid. We assume the Omega 180 will utilize the same wine glass body, Sicce Syncra pump, bubble diffuser plate, vibration dampening pads, and other features found in the rest of the lineup, only beefed up to handle a heavier bioload. We did notice that large red fish, part of the Vertex branding, on the skimmer lid, which is absent in the original design of the Omega. Perhaps this is the only subtle change, but perhaps there is more. We’ll know more about the Omega 180 as the show draws closer. by Rich Ross | May 21, 2014 | Fish, Invertebrates, Science
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 by AquaNerd | May 19, 2014 | Fish, Science
There are several species of angelfish that many in the aquarium trade would label as THE “holy grail” angel. The short list includes the masked angelfish (Genicanthus personatus), peppermint angelfish (Paracentropyge boylei), Abe’s angelfish (Centropyge abei), and a few more. And while each of those species is supremely rare and insanely beautiful in their own right, but they all fall short of the absolute king of the angelfish, the tiger angelfish (Apolemichthys kingi). Named for its tiger-like stripes that only get more elaborate with age, A. kingi is one of those fish that virtually never gets collected in the wild and therefore is almost never seen in the aquarium trade. I think one or two of them have ever made it into captivity, putting its rarity right up there with the most elusive of aquarium fish. Thankfully, De Jong Marinelife has somehow gotten their mitts on a beautiful juvenile tiger, as well as a peppermint angelfish, and they’ve been oh so generous with the news.
