RSS Where have the large coral colonies gone?

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  1. MASA Admin

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    8 May 2007
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    Recently I came across a box of slides and began looking at the shots of the many tanks I had seen over the years and several things stood out. I have been fortunate to see a lot of tanks and take photographs of them, so I have a good way to chronicle and compare how tanks have changed.

    I noticed how much more colorful our tanks are now compared to the past. Due to better lighting, husbandry and selecting for the most colorful corals, our tanks are virtual rainbows of color, especially when compared with tanks of the past when many of the corals were brown, which is probably why so many hobbyists love our sticks.

    An almost 1 meter across colony of Acropora millepora, not on a reef but in the tank at State College

    I also noticed how many larger tanks there are compared with the past. Up until relatively recently, a big reef tank was thought to be anything around 150-gallons or larger, now that seems to be the average size tank I see, and I have had the opportunity to see many tanks over 1000-gallons, which was almost unheard of until recently.

    On the down side though one thing was very apparent, most of the colonies I now see in tanks are significantly smaller than what I saw in the tanks in the past. This got me wondering as to why that is, especially since now the technology and husbandry we use is far superior. I have talked about this with several of my friends and fellow speakers/travelers and we came up with several possible reasons.

    The first reason we thought of was that many of the tanks we see are being kept by people who have been in the hobby for a relatively short time. Since a significant segment of hobbyists are relatively new to keeping corals it makes sense that many of the tanks we see have not been set up for very long and hence the corals have not been growing in them for very long.

    Yes there can be too much of a good thing. Here a Sinularia was allowed to overgrow a tank, which it filled, killing off the other corals in the tank

    Also, when you are just starting out the likelihood that you will lose corals is greater so rather than investing in large corals you start off with smaller corals to begin with. The husbandry used on these tanks has not been totally refined so the growth rates of the corals is probably not as high as it is for hobbyists who have been doing this for a while. While this hypothesis may have some validity in the new tanks we saw, we also saw many tanks 5 years and older that also did not contain many or any large colonies of even soft corals.

    This led us to our second hypothesis as to why we were seeing so few large colonies: unlike in the past where “wild” colonies were the norm, most tanks we now see are stocked with either frags or maricultured or aquacultured corals. Since stocking a tank with both of these types of corals starts a tank with much smaller corals from the start it makes sense that even after 3-4 years the colonies would be much smaller than when the tank had been stocked with wild colonies.

    Even a large gorgonian colony, though beige in color, can be impressive when grown to a large size

    From the early 1990’s to the mid 2000’s the majority of corals used to stock our tanks were wild colonies that were usually in the 4-6” diameter range from the start. So even though our lighting, water conditions and general husbandry were not as good as they are today, these corals still often doubled in size in a year or so. So if you started out with a 4” colony and you did not kill it, you could expect to have at least 12” colony after less than 2 years. Compare that with what many people are starting out with today.

    I frequently see tanks stocked with numerous ½” or ¼” designer frags with the owners patiently waiting for these to grow into the full sized colonies they have seen pictures of. If we do the math and give the corals a growth rate of doubling every 6 months instead of a year, that ¼” frag will be a 1” colony in a year a 4” colony at 2 years and a 16” colony at 3 years.

    Here in the tank of Marcus Resch it is easy to see what allowing a few colonies to grow out and house only a few species of fish can produce when given time and space

    However it should be noted that as the colony gets bigger the growth rate usually tends to slow down some, so a more realistic size for these colonies is probably around 8”, which is still impressive to see. However for most of me and my friends when we discussed how often we saw colonies even this big we all agreed that it was still relatively rare.

    So again this got us thinking what was making us see so few coral colonies even 8” in size. The next thing we came up with is that because there are now so many amazing corals available, many hobbyists, myself included, try to keep as many beautiful corals as possible and as a result no one wants to have one or two huge colonies take up a significant amount of space in their tanks as it denies them space for keeping other rare colorful corals.

    This kind of makes sense in that when I compare European tanks and American tanks, there are a couple of notable differences that stand out. First the European tanks typically do not house as many different species of fish and corals as our tanks do. To my eye, their tanks look more like what you would see in a small section of a reef where typically only a few species of coral dominate.

    A stand of large coral colonies also at State College

    Rarely did I see 30 or 40 different species of coral in a tank along with 25 different species of fish like we seem to do here. Also the corals they house were given a lot of space from the start and were allowed to grow into nice full colonies that caught your eye as soon as you walked into the room. Rarely did I have to look for a small frag or a tiny colony that was hidden in the rock somewhere.

    Granted, most of the tanks I saw had been up for a significant period of time and the corals had been given both time and space to reach their full potential. In speaking with their owners, they also had a different mindset when they set up their tanks they had an idea of what they wanted it to look like over time – so many reefers put their corals in place, added their fish, and then pretty much let it grow into a “mini-reef”.

    Very few of the hobbyists I spoke with were constantly adding, removing or cutting their corals. They pretty much set it up right from the start with a goal in mind and then let it grow. Sadly I have tried to do this in many of the tanks I have set up, but I always come across that ‘one more’ coral that I just need to have, and as a result my tanks are constantly moved around or things are cut or something is done which disrupts the tank.

    The large colonies in Sanjay’s tank, note the size of the lights above the tank for comparison

    In my opinion, every time I disrupt a coral, either by moving it, cutting it, or somehow changing the environment, it sets back the growth by 2-3 months. I am assuming it is the same for others, so maybe the frequent changing and manipulating of our tanks is at least in part keeping many hobbyists from having large colonies.

    One other thing that I also noted is that European hobbyists still seem to be much more willing to share rather than sell frags to one another. As a result I noticed a kind of regional bias to which corals were being kept. That is, the tanks in one area all had a lot of the same corals in them due to the hobbyists sharing frags. Then I would see the same thing in the next region or country I went to in terms of coral diversity in the tanks. This is also much different than what we have observed here.

    And this brings us to what some of us now believe is one of the biggest reasons why we no longer see large colonies: corals now get fragged far more frequently than they used to. Many of the tanks we see for the most part house mostly named, expensive corals. It is our theory that since many of the owners of these corals paid significant amounts for these corals at least some of them try to recoup their investment by fragging them and selling the frags as soon as the branches are of fraggable (yes that’s a new word) size.

    One of the author’s tanks where small corals predominate. It just does not have the impact of a few large colonies

    Since many of these corals are in high demand and there is limited supply, this makes sense. Otherwise we could not come up with any other explanation as to why so many of the nicer colonies we saw were never any bigger than a golf ball. So while I understand this, it does make me feel bad that so many hobbyists whose tanks I’ve seen are missing out on seeing the beauty of what a big colony looks like.

    To me even a big colony of a green Bali slimmer or a common tricolor Acro is far more appealing to look at than a tiny frag of some designer coral. It is also my opinion that a big colony is better to frag than a small colony and causes less trauma to the coral so that it bounces back much faster. It makes more sense to let a colony grow out before fragging it so that I can not only enjoy the impact that a big colony has, but also so that I can frag it without worrying that in doing so I will wipeout the whole colony.

    I once took 30 1” frags off a single colony from the Bali slimmer that was in my 1200-gallon tank for a science project my cousin was doing on the effect temperature and water motion has on coral bleaching and within 2 months you could not tell that any frags had been taken. And yes, the slimmer lived up to its name and produced a tremendous amount of mucous from being fragged, with small colonies this would not have been possible.

    Large colonies grown over the years at the Aquarium of the Pacific

    Some great examples of how impressive large colonies of coral can be in a captive environment t best are the many huge colonies grown from frags in Joe Yaiullo’s 20,000-gallon tank at Atlantis Aquarium, the massive Pocillopora and Turbinaria and Montipora colonies at the Aquarium of the Pacific and the numerous colonies also grown from frags in Sanjay’s 500-gallon plus tank. In these tanks, once the corals were set in place they were simply allowed to grow with for the most part little interference until they had to be fragged to keep them from over growing one another.

    Even though for the most part these tanks are not stocked with named designer corals it is my opinion that these tanks are the best examples of how impressive large colonies can be in captive systems. I realize that there is great temptation to constantly frag our tanks, but I think once you see how impressive even a common coral can be when allowed to reach a large size it will offset the desire to constantly frag it when it is small.

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