Today’s dive was literally around the corner from our resort (five minute boat ride), compared to the 60 minute commutes we have been making searching for the great, good spots. We had turned our noses up at the prospect that such a close in spot, so near to the base of a bay, could hold much of interest for our group. Our assumptions were of course, wrong, as we found a really dynamic and healthy reef at 80-90m, below an incredibly silty and dirty steep slope. Again, clouds of deep anthias and damsels darted to avoid our lights, and caves held cardinal fish, unusual shrimp and small groupers. Richard and Brian chased a number of interesting fish, while I tried to record each species we encountered. We were joined today by Sonia, a Gorgonian / soft coral specialist, who rapidly filled her collection bags to overflowing with interesting and perhaps new species of various invertebrates.Brian was able to finally collect a specimen of the deep sand perch (Parapercis) that we have seen on several occasions deep.
It looks very similar to a super common sand perch that is very wide-ranging across the Pacific, and probably why it has been over looked in the past (if it indeed is a new species). Once collected, and before preservation, Brian and the other Ichthyologists (fish nerds) preserve a tissue sample for DNA analysis and/or stable isotopic analysis. The DNA helps figure out if the organism is a new or known species by comparing sequence data. The isotope analysis is pretty cool in that the process can determine exactly what plants or animals the specimen is feeding on to place it in the greater food chain. Pinning out and photographing the fish is the final step before fixing the specimen with a preservative before transfer at the museum to the final preservative which is usually an alcohol
mixture. The imaging is best done as soon as possible after collection, to capture the true colors of the animal. Once preserved, the fish tend to turn a drab shade of tinted brown, which can drive future researchers crazy trying to determine the coloration of the live animal.
In order to collect DNA samples, we need to have the animal in hand, and fish don’t
exactly jump into the collecting bag. I spent almost the entire decomperession of three hours, spearing our target fish with a three prong spear. I have found over these
expeditions that the skills to track a fish with a video camera, anticipating its movements serve me well with a spear. The hard part is always making sure that the fish I am about to spear is exactly the species of fish that the genetics lab needs. This involves some almost comical underwater scenarios where I stare down a little butterfly with a nine foot spear cocked to fire, deciding that it is indeed the Blackback butterflyfish (Chaetodon melannotus), not the look alike Spot-tail butterfly (Chaetodon ocellicaudus).
Unfortunately for the little fellow, I know the fish pretty well enough, and into the bag he goes in the name of science. For those who are squeamish about spearing pretty reef fish (myself included), I often quote the famous naturalist John Audubon who said “any day I don’t kill at least 100 birds is a day wasted”, and his society is now the poster child for