Sponsored in Part by
The Velvet
Corals
(Finger coral, Branching coral)
Subclass: Zoantharia Order: Scleractinia Family: Acroporidae Genus: Montipora
Species: digitata, spongodes, and over eighty others
In the Beginning.
I just returned from MACNA VIII in Kansas City, where Dr. Charles Veron, arguably to world's foremost authority on coral taxonomy, gave a fascinating and surprising speech that threw a curve into every reefkeeper's life. The subject? Well, it seems as though attempts at classification of the stony corals is best left to his estimates, because few of us have any chance of an exact identification of coral species. Few corals present a more pronounced proof of these findings than members of the genus, Montipora.
Several years have passed since the reefkeeper's bible, The Reef Aquarium, has been published. In that book, Julian Sprung and Charles Delbeek stated that Montipora is an infrequently imported species to the aquarium trade. In fact, there is little mention of this coral in their book at all. Yet, the past few years have seen many importers regularly offering this small polyped stony coral for sale. In fact, I believe it to be one of the most frequently offered SPS types. While this may be due, in part, to an increased shifting of primary sites of coral collection to the Solomon Islands, Bali/Jakarta, and especially Fiji, I feel that the successful experiences of hobbyists have been instrumental in the increased importation. It has now been conclusively shown that this coral is especially well suited to the home aquarium.
A little
background
Montipora consists of eighty or more established species found throughout the Red Sea, Indian Ocean and Southern Pacific areas. While this is indeed a wide area with a number of species that is very large, perhaps only surpassed by Acropora sp. and Porites sp., a more interesting fact is the diversity of reef areas in which Montipora is found. Members of the same species are often found in shallow water and at great depth in excess of 100 feet. They are found in areas of low water movement and in areas of high turbidity.
They are equally common in high nutrient lagoons and in low nutrient reef slopes. This diversity would likely suggest that Montipora is quite tolerant of differing water conditions and should therefore prove hardy in our own closed systems. In fact, this is what has been observed as increased numbers of hobbyists are keeping these wonderful corals in their homes.
Appearance and upkeep.
Montipora, to the inexperienced, may not be considered the most "flashy" of corals. Although it appears in many colors, including brown, purple, and green, the shades are quite subdued. Any coloration may disappear in the aquarium, depending on the type of lighting used. I have yet to see a shocking color morph of Montipora offered for sale that would be appealing to someone who is not mesmerised by subtleties of the different species.
Despite having several colonial formations, skeletal cues are (fortunately)quite
specific. Many species may, at first glance, strongly resemble members of
the genus Porites. Colors and shapes are also similar between these two genera.
However, Montipora has generally smaller corallites which do not appear
"jewel-like" as in Porites. The skeletal teeth project inward in Montipora
and outward in Porites, accounting for the difference in appearance. Polyps
are typically very small and fuzzy, obviating its common name of Velvet coral.
The polyps are unusual in that they seem very "busy," often opening and closing
alone or in groups over the course of a day. The apparent hyperactivity of
the living polyps obviously help explain the rapid growth of colonies. The
overall shape of colonies will be discussed in detail below, as this is a
characteristic that merits special
attention.
Aquarium care is somewhat complex. Most species available for sale will require high light intensities and strong current for maximum growth and success. There is evidence to suggest that the higher temperature metal halides (with the concomitant production of small amounts of UV-a light) may be required to maintain coloration, or enhance coloration of otherwise drab colors. As with most SPS corals, all species of Montipora prefer excellent water conditions that are low in nitrates and dissolved organics. Despite articles and reports of enhanced growth of stony corals in high nutrient conditions (Carlson, Perrin, Lister, and others), I feel it is best to maintain all SPS corals in conditions of low nutrient (high quality) water since there is less chance of failure. Until further findings are established, I am afraid the view of the average hobbyist will see such findings as a green light to increase bio-load, decrease maintenance, and become poor caretakers of their aquariums. I have already heard too many people say they are not doing water changes or worrying about water quality anymore since it has been "shown that corals grow better with high nitrates." This is absolutely irresponsible, since corals must then compete with organisms, such as algae, which maybe better suited to a nutrient rich environment.
On the other hand, Montipora are found in such a wide variety of habitats in the wild that they are expectedly far more tolerant than other SPS corals in terms of water quality. Therefore, it may be a good "starter SPS," so to speak. It is important to point out, though, that most harvesting of corals occurs in very specific areas which facilitate easy collection. It is thus unlikely that specimens will come from very murky waters, areas of intense wave or current action, or great depth. It should be assumed that, barring information to the contrary, Montipora should be gradually acclimated to strong lighting and good water movement, with neither condition being extreme. Because Montipora is a very non-aggressive coral, it is highly improbable that any specimen will sting or endanger nearby corals or invertebrates. However, it is very easily stung or encroached upon by other corals, so care must be taken in this regard. Common parasites of Montipora include the gastropod, Magilopsis, and the flatworm, Prosthiostomum.
Avoidance of the usual predatory animals
of coral must also be considered, species of which include butterflyfish,
triggerfish, parrotfish, and other well known examples of polyp eating animals.
Valonia algae is also likely to encroach on this species. Often, colonies
may begin recession at the base and become covered with hair algae or
cyanobacteria as the recession proceeds toward the extremities. At this point,
a branched colony should be fragmented ahead of the recession and the living
pieces attached to rock work with underwater epoxy or cyanoacrylate glue
to prevent further algae growth at the broken ends. Fragments reattached
in this way are usually highly successful since small colonies generally
adapt better to aquarium conditions. There are several excellent articles
that have been written extolling the virtues of small colony adaptability,
and the exact reasons for their heightened success rates can be found in
these writings. Their scope is too large to be discussed here.
The Confusion Begins.
Although there are many species which comprise the genus, Montipora is found in an unsettling array of colonial formations. To one unfamiliar with skeletal anatomy of Scleractinians, the presentation of so many shapes is bewildering. Montipora forms branching (digitate), encrusting, plate-like (laminar), massive, convoluted (foliaceous), and even pillar-like (columnar) formations. It is thus found in almost all of the common colony formations that exist in the wild. To further complicate the array, Montipora shows a characteristic common to many corals, but to an even greater degree. That is, it changes its colonial form dependent on water conditions, lighting, and depth. In shallow waters, Montipora may be branching. The same coral, if left to grow in deeper waters may begin to adopt a laminar or massive shape. Heavy wave action causes branched species to become more compact. Differing light may result in coloration changes. Classification can now be encumbered by a large genus with many species, an ability to thrive in many varied areas on and near the reef itself, and a propensity to morphological change dependent on existent conditions. It couldn't be more confusing, could it?
It Gets A Lot More Confusing.
There
is something disconcerting when the world's foremost authority on corals
admits that even he can't identify many corals at a species or subspecies
level with any degree of certainty. When Dr. Charles Veron spoke at this
year's MACNA, he told a tale of larvae that drift with prevailing currents
to settle many miles away from their parent colonies. Given the millions
of years that corals have had to proliferate, this alone is daunting enough.
But he also showed how some members of the same species, separated by thousands
of years of evolution, could not produce viable colonies when cross fertilized,
and yet some members of different species could easily cross fertilize and
hybridize, forming a new subspecies. He went on to explain that various skeletal
characteristics could be found within the same colony. In his book, Corals
in Space and Time, Veron continues to describe how Montipora can even show
tissue fusion between genotypes. What this means is that two types of living
tissue can exist on the same coral! With all these variables introduced,
taxonomy of any coral, much less a Montipora, must be extraordinarily difficult.
Now what?
The Final Insult!
Dr. Veron
used a very descriptive story to illustrate the next dilemma. Apparently
there is a species of Eucalyptus near his home that changes its form as one
progresses along the coast. The point was made that members of the same species
may adopt various characteristics to mirror their environment, making
identification based on physical characteristics even more difficult, sometimes
even impossible. In other words, the famous example of Darwinian finch evolution
in the Galapagos Islands that took place in accelerated fashion, encompassing
mere tens of thousands of years (compared to millions of years) may physically
manifest in coral colonies in potentially one generation! The conclusion:
In many cases, the degree to which hybridization allows for separate subspecies
is probably not possible to ascertain at all.
The
Point
Well, the point is that members of Montipora are significant contributors to reef structure and sediments, owing to a wide variety of habitats, species, and general abundance. They are tolerant of aquarium conditions, grow quickly, and are quite beautiful. This is especially true if the hobbyist takes time to appreciate their unique subdued nature and appearance.
However, given the dramatic variances, and a natural ability to be a "poster child" to illustrate morphological change, it is best to know these corals without any attempts at speciation... unless you are a very gifted taxonomist. Who knows? After hearing Dr. Veron, I may just start calling everything my tank a "unicoral"... a fictional beast that doesn't exist.
Until next month.
Contact Eric Borneman
References:
Borneman, Eric, and Puterbaugh, Ed. A Practical Guide to Corals for
the Reef Aquarium, Crystal Graphics: Lexington, 1996.
Delbeek, Charles, and Sprung, Julian, The Reef Aquarium, Ricordea Publishing:
Coconut Grove, 1994.
Riddle, Dana, The Captive Reef, 1995.
Veron, J.E.N., Corals in Space and Time, Comstock and Cornell: London, 1995.
Veron, J.E.N., personal communications.
Veron, J.E.N., Corals of Australia and the Indo-Pacific, Angus and Robertson,
Publ., North Ryde, Australia, 1991.
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