Tag Archives: process
Humbug Damselfish (Dascyllus aruanus)There’s a reason I chose to spotlight Dascyllus aruanus, the humbug or three-striped damselfish, in this profile. “Caribbean” Chris and I will soon be matching wits with four representatives of this species that have laid claim to a large marine aquarium situated in one of our local coffee shops. Steve, the shop’s owner, is at wits’ end with these four humbugs, which won’t abide most new tankmates, and would like to see them captured and relocated by any means necessary, short of (or possibly including) dynamiting the tank. Chris and I figure that between the two of us, we should have the mental prowess to outsmart these little devils, so we’re currently brainstorming the capture techniques we’d like to experiment with over the next week or so (suggestions from fellow salties are most welcome). We plan to document the process on video, so stay tuned for updates. For the time being, though, let’s take a closer look at our future quarry: Physical traits D.
Dissolved nutrients. Sounds like a good thing, right? After all, every organism needs nutrients in one form or another in order to grow and stay in good health. So why are marine aquarium hobbyists—particularly reefkeepers—seemingly so fixated on keeping the level of dissolved nutrients in their systems as low as possible? To understand this fixation, you have to keep in mind that the waters surrounding coral reefs are naturally nutrient-poor environments. Unless a reef is subject to agricultural runoff, sewage discharge, etc., the levels of dissolved nutrients around it never approximate what can accumulate in the closed system of a marine aquarium. Elevated dissolved-nutrient levels lead to problems with nuisance algae and declining water quality, which is stressful or even deadly to marine livestock. That’s why hobbyists must implement different measures to export dissolved nutrients from their systems. Here’s a sampling of basic nutrient-export techniques: The routine water change I’ve listed the water change first because it’s the most straightforward technique and provides many additional benefits beyond exporting dissolved nutrients. You should be changing a minimum of 10 percent every week or 20 percent biweekly (more if testing shows that nitrate, and/or phosphate is exceeding the acceptable level), siphoning out as much accumulated particulate waste as possible in the process.
I would always like to think the aquarium owners are the ideal feeders and give every organism the proper nutrition. Chances are though that you, like everybody else, have forgotten to feed your fish for a few days. We are human and feeding a sun coral multiple times a day is not something every aquarium owner wants to do. It is a hassle for some people to feed there corals once a week!… SO… Well when I discovered I had a dying anemone I knew that I would have to feed it every day. For about a month I followed through with this but then eventually it becomes annoying to go through the process of pulling the food out, preparing it, feeding it, and cleaning up. So I started doing once every other day, and that turned into once every three days. My point is that I started feeding for the results but over time what mattered to me was the convenience
Butterflyfishes on the west coast of the Big Island of Hawaii where aquarium collectors are active. Image by Eric Sorensen, WSU. An Aquarist’s Notes: Turbulence in Hawaii I first went to Hawaii on assignment for CORAL Magazine in 2010, and for the better part of four years I have covered that state’s aquarium fishery. I expected to find a fishery full of complicated regulations and even more complicated conflict. I found the latter in spades, but the former, to my surprise, didn’t really exist. Regulations were relatively few and far between—no total allowable catches (TACs), no quotas, no bag limits, no limited entry. I was, quite frankly, shocked that a commercial fishery in U.S. waters would be so unregulated. The fishers I interviewed, especially on Big Island, didn’t view it that way. Many felt they were being unfairly targeted and that veils of regulation were being drawn around them like the barrier nets they use to catch aquarium fishes. Some felt they had consistently given ground, made concessions in the face of anti-trade activism. Some were ready to make a stand, saying they couldn’t—wouldn’t—give any more. Some of these fishers opposed the rules package just signed by the governor. A few of them still oppose it, although they are not willing to say so on the record. Those fishers who stand in opposition to the new rules have some strange bedfellows. There are the anti-trade activists who say the rules don’t go far enough; the most extreme will not be satisfied with anything short of a fishery closure. Then there are mainland aquarists who are lukewarm on the new rules. They worry that a White List will make it more difficult to acquire some species with which they want to work in the short term. They anticipate a slippery slope that will lead to fewer and fewer species remaining available to trade in the long run. Personally, I was pleased to see the governor sign the rules package. I’m pleased because I see it as a step forward for aquarium fisheries in general. I see an opportunity to manage the fishery based on real data. The data really does matter, and rather than less, we need more. This rules package takes a relatively small swath of ocean—a shoreline of less than 150 miles—and says we’re going to manage it based on something more than anecdote and emotion. I look forward to reporting on the progress and talking about how this may be a model viable for export to other aquarium fisheries in far worse shape than Hawaii’s. Hawaii is on a path of good, data-based, adaptive management of its aquarium fishery. This type of management can protect the fishery in terms of both environmental sustainability and economic value. It replaces a messy form of conflict resolution with a multi-stakeholder, community-based approach, and now that the new rules are law, I think we all owe it to the people, the process, and the potential to get behind them.
Fish are Pets: Take care of them as such! A lot of times you hear about aquariums as “display pieces” and are talked about like you would a painting or sculpture. In some cases, the aquarium has replaced some peoples televisions all together. One thing that may become lost in the process is the fact that no matter what your tank actually looks like you still have living animals that have individual personalities. Ok, maybe your snail is a boring pet, but your clownfish, tangs, puffers, and even damsels are uniquely varied in attitudes and needs. Sounds like a dog or a cat to me, right? en.wikipedia.org When you go to the LFS to buy your critters there is usually the same vibe you get from going to rescue dogs from the pound
LIVE ROCK ACID BATH Sometimes you get to the point where your rock is not working out for you. Maybe you had a stagnant tank and everything died? Maybe you have an insane algae problem? Maybe you just got the rock for free from some fishy character on Craigslist and just don’t trust it? Even aiptasia, hydroids, or dinoflagellates can make every other option impossible. Either way you are at your wits end and need a fresh start. Time to bust out the heavy artillery
Whelks, Anemones, and Sea Urchins I am back to continue with my posting after an unexpected absence due to bodily self-decomposition. A word to the wise, don’t get old. Or if you do, don’t let your body know. It might just not like the process. Anyway, on with my tales from the slimy lagoon… In an earlier discussion, I mentioned that aeons ago I saw large female whelks depositing egg capsule masses on one of my research sorties to “my” intertidal study site near Homer, Alaska. I found this to be very interesting, at the time I was casting around for some research to do, and here a potential easily-done project dropped into my lap. Normally I don’t trust to luck, but I wasn’t about to overtly examine the buccal anatomy of this presentation equine. I was able to identify the animals, but, at that time, there was no record of them depositing egg capsules in a mass or otherwise. In point of fact, virtually nothing was known about the natural history of these beautiful whelks, an artifact of being found in an out-of-the-way place where the accumulated knowledge of such critters was minimal. In fact the only reason I knew the whelks were at this area was that I had taken some students down to the site the previous autumn on a class field trip. Neptunea pribiloffensis whelks on the study beach. The substrate is sandstone, and the “fuzzy” clumps are masses of a feather duster worm which is one of the common prey of the whelks. Figuring that the presence of essentially unknown animals that I was interested in learning about would lead to an easy publication, the following spring I decided to do a little bit of basic research on the snails, and went down to the site to make some field observations as well as to collect a few animals for gut analyses. Having examined some other Neptunea, including some specimens for this species, I knew I had to look at the gut contents to determine what they were eating rather than simply examining their feces, which was a technique I had perfected for some other snails for my doctoral research. Fecal analysis is a much preferred technique when compared to gut analysis, as the animal is not harmed in the process. However, fecal analyses require that the animal’s foods leave some indigestible and identifiable trace in all the feces, and that was not the case with these animals. They could eat a wide variety of things, including carrion and animals possessing no hard parts at all, as well as some polychaete worms having chaetae, which would be passed through the gut undigested. It was during a trip for the collection of some specimens for the dietary study, that I noticed the ovipositing females. Several female Neptunea pribiloffensis depositing egg capsule masses near a large sea anemone. Obviously, this was an immediate serendipitous chance for some more and different research. As with every other aspect of Neptunea pribiloffensis life, virtually no aspects of their reproduction were known. I had budgeted a couple of days of “research” time on the beach. I figured I would need about fifteen minutes to collect all the animals I needed for the gut content work, but the site was beautiful and in the spring the weather was often gorgeous. I had been told that when the Russians owned Alaska, their anecdotal name for the Homer region was “летом земля or Summer land” for the nice climate- a distinct contrast to effectively everywhere else in the region. Consequently, I truly considered it a terrible hardship to have to make the four or five hour drive to Homer to do field work. Given how low the tides needed to be for my research, the field work time each day didn’t amount to much time being spent, which meant my assistants and I had plenty of time to work up our samples in the motel we stayed in while working there. After wandering around the study area on the couple of days I had budgeted for that research, for a total of maybe five hours of field work time. I came away from the site with some facts in hand. First, there were a number of old egg capsule masses in the area. Second, the new egg capsule masses were being deposited near the old ones. Third, most egg capsule masses were being deposited near individuals of large sea anemone, Urticina grebelnyi, referred to at the time as Tealia crassicornis. Egg capsule masses near a large sea anemone. Note the whelk to the upper right. And my experimental marker is indicated by the arrow. A couple of fundamental questions immediately presented themselves. Is there any benefit for the whelk to place its egg capsule masses near the anemones? Likewise, is there any benefit for the anemone to have a whelk egg capsule mass near it? Today, it seems obvious that the answer to either or both of these questions would almost certainly be yes, but in the late 1970s very little was known about boreal marine symbioses, in general, and specifically interactions between spawning whelks and anything, let alone anemones. At the time, there were no hard data either supporting or rejecting a hypothesis of benefit to either party for such an interaction. And here I was, standing plumb in the middle of a wonderful opportunity in a beautiful area with the chance to address this question. So!!! Boy-Scientist, at the ready! I grabbed some buckets, my camera, my voice-activated tape recorder, a meter-stick, and kazango! I was research bound! Obviously, I didn’t go into this situation as a naïve biologist. I had just spent several years working at a laboratory where many researchers were studying a wide variety of marine research topics. As one might expect, there was a lot of cross-pollination of information and ideas. For example, one of my acquaintances during that time was completing the scientific description of one of the larger, previously unknown, sea anemones from that region. He told me that it would be called “Tealia piscivora”, a name meaning “the fish-eating Tealia”, an apt name because specimens had been found with their gut cavity full of fish; herring, as a matter of fact. Those data told me that the nematocysts of a sea anemone closely related to the one I was seeing in Alaska could pack a really potent sting. And, therefore, the anemones might well be able to protect the snails’ developing progeny. Two egg capsules (white arrows) near a protective anemone are intact. The green arrow indicates my experimental marker. Also, I knew from other researchers that individuals of the sea urchin species, Strongylocentrotus franciscanus, would eat the egg capsules of other whelks, and that those whelks protected their spawn by attacking any urchins that approached their egg capsules. Given that the “green sea urchin” Strongylocentrotus droebachiensis was common in this Alaskan intertidal habitat, not only was it was possible, indeed, it was likely, that it would eat the egg capsules and the eggs they contained if given the opportunity. An egg mass that is about a year old. The top has been eaten off by sea urchins. My working hypothesis was that the snail obtained some benefit from depositing its egg capsules near the sea anemone. I anticipated that I would find that the sea anemone protected the egg capsules from predation by the sea urchin, and perhaps other predators as well. I thought it was also likely that the sea anemone would obtain some benefit from the situation; potentially it could benefit by eating sea urchins that would be attracted to or eating the snail eggs. I immediately set about collecting some animals and egg capsule masses, and setting up some experiments both in the laboratory and in the field. Some of the experiments were long-term, running about a year in the field and lab, others were of shorter duration. When I was finished with all of the work, I thought would be able to answer many of the questions necessary to be able to assess the hypotheses. An experimental egg capsular mass is completely gone after the anemone’s removal. All that is left is my marking washer. This Snail Has Babysitters!! I found a series of statistically significant results. First, the snails were more likely to deposit their egg capsular masses near the sea anemones. It takes about a year before the snails hatch from the capsular masses. At hatching times the capsular masses near sea anemones were bigger, had more capsules remaining in them, and fledged more juveniles than those capsular masses a short distance away from the anemones. The anemones could deter predation on the egg capsule masses in the laboratory experiments and certainly appeared to do so in the field. My lab tests showed that the anemones can protect the capsular masses from the sea urchin. Finally, the sea anemones can eat the sea urchins. In the lab tests and field observations indicate the major cause of capsular mortality is urchin predation. Lab and field experiments and observations support the hypothesis that the anemone babysitter protects the capsular masses from predation by urchins by eating the approaching urchins. Newly hatched whelks fresh out of the capsule. All six came from one capsule. And each “corncob” like mass would average about 50 capsules. The scale is mm. This neat little series of interactions started me down the road investigating a number of significantly more interesting anemone interactions that just happen to have some of the most beautiful animals in the world as the actors in the various plays. More on that in the near future. Reference: Shimek, R. L. 1981. Neptunea pribiloffensis (Dall, 1919) and Tealia crassicornis (Müller, 1776), On a snail’s use of babysitters. The Veliger. 24:62-66.