What We Found

To say that this study was enlightening would be an understatement. While the results of the transects were presented to some degree at MACNA XIII (Baltimore) by Dr. Bruckner, and will be covered in an upcoming paper we will produce as soon as all the data is amassed and studied, my purpose in writing here is to provide the fascinating accounts of where many of our most popular aquarium corals are found. This is some of the first information ever provided regarding their location and habitat, and it is my hope that finally aquarists will have some idea of the conditions that may be most appropriate for these corals in aquariums, ensuring their success and survival.

I can only hope that our future surveys and the guidelines being developed will provide even more information, and that information promised to be gathered by the Marine Aquarium Council (MAC) and the exporting nations/collectors can provide more information to help benefit aquarist efforts in coral care.

Trachyphyllia geoffroyi (Open Brain Coral)

(Table 8). There are two major collection habitats for Trachyphyllia. The coral known as Wellsophyllia is also reported on Indonesia quotas, but Wellsophyllia is actually synonymous with (or possibly a separate species/subspecies of) Trachyphyllia. Trachyphyllia were found mostly as unattached, free-living colonies, although in one habitat they were frequently found attached to reef substrate along with unattached colonies.

Habitat 1: Trachyphyllia, such as those most commonly seen in US markets as the brilliant green, red, or pink morphs, are collected far offshore in deep waters from 30-40m in depth. They are found on extensive soft bottom areas between islands (often with no land in sight), spaced sporadically across the seafloor. The sediments are fine sands and silt, and the area is covered with cyanobacterial mats. Macroalgae is common, rooted in the substrate. There is no coral reef present, but other solitary or free-living corals are found here. Because of the habitat and ease of collection Goniopora, Cynarina, Catalaphyllia, Sinularia, Herpolitha, small Euphyllia, and a few other genera can be gathered here. However, this does not appear to be a primary collection area for any corals except Catalaphyllia, Cynarina and Trachyphyllia. The current at the bottom is very slow, but present, and probably reflects tides more than any other source. The water in the archipelago is not crystal clear, and at this depth, the water was quite dark and light levels were very low. I wouldn't expect many zoooxanthellate corals to be able to survive with such low irradiance.

Habitat 2: The other area where Trachyphyllia are collected is quite different and consisting of shallow areas from 3-4m in depth. Here, Trachyphyllia are quite abundant, but rare any deeper. It is an area that is very near shore, and runoff and river flow leaves the water with a visibility of 2-5m maximum. The reef has high levels of sediment, and Trachyphyllia are found in both attached and unattached forms, nearly buried in silt. The coral coverage of these reefs was the highest we recorded, and was nearly 100% covered by stony corals, with Galaxea and Montipora being by far the most abundant taxa present. The area is also very extensive, and it does not appear that there is any likelihood of over collection in these areas On several dives, I could not see the bottom until my mask was nearly pressed into the sand and silt. Catalaphyllia is also reported to be collected here, and is supposedly one of their primary collection areas (see below). Currents were low and light levels reduced because of the amount of suspended silt in the water column. However, this may vary depending on the season or conditions over time. Nonetheless, it is somewhat irrelevant; the Trachyphyllia that are found here are not the morph most popular in the trade. They are drab in color; brownish pink or brownish green and somewhat mottled or striped. We did see these morphs in the exporting facility, but they were not common, and they were rarely seen being held at the collection facility. I have also seen these morphs in US aquarium stores, but again, they are not common.

Euphyllia spp. (Anchor, Frogspawn, Hammer and Torch corals)

Euphyllia spp. have been listed by leading coral scientists as being uncommon (Veron 1986, 2000). This designation was considered in the EU's temporary ban of selected species. We were quite surprised to find that, at least in the Spermonde Archipelago, this was not the case. Euphyllia species were found at all reef sites, and at some sites in high abundance. Although most of the colonies were small, there were occasions when we saw very large colonies. We also saw most, if not all of the species known, including E. glabrescens, E paraglabrescens, E. cristata, E. yaeyaemaensis, E. ancora, E. parancora, E. divisa, and E. paradivisa. Only E. cristata was uncommon in our transect. The primary collection areas for Euphyllia are patch and fringing reefs from 4-25m in depth. These are mostly clear water sites, although clear water in the Spermonde is still somewhat turbid and greenish. Currents vary with conditions, but were quite calm during our dives. Surprisingly, I would estimate that half or more of the colonies were of branching species, considering they are less common in the trade. Deepwater sites varied in their abundance of Euphyllia, but deeper sites (>30m) contained almost exclusively small colonies of the branching species. Their skeletons are subject to much bioerosion, and I don't think colonies can get very large as a result. Furthermore, at a few deepwater sites, there is no hard substrate for them to form secure attachments above the sediment surface, resulting in smallish colonies. Unfortunately, there were no other consistent morphological or skeletal differences to distinguish colonies between the habitats, and therefore specimens of Euphyllia found in an aquarium stores may be from very different habitats and subject to very different conditions (Table 9).

These Euphyllia are just some of the species photographed across a range of habitats in the Spermonde Archipelago

Catalaphyllia jardinei (Elegance coral)

Habitat 1: Perhaps one of the bigger surprises came from our attempts to locate Catalaphyllia. We were assured that Catalaphyllia would be very common and collected from several sites. In fact, it was quite uncommon at all sites and the locations given by coral collectors seemed to vastly overstate its abundance. Fortunately, we did find examples at several different locations and, like Euphyllia, in very different habitats. Unlike Euphyllia, we found them to adopt quite distinct morphotypes, depending on the area of collection. The deepwater sites where Trachyphyllia were collected were also the area where we saw the most harvest of Catalaphyllia. To repeat, this is a very low-light sand and silt seafloor with no hard substrate and colonized by sparsely populated free-living corals, macroalgae, and cyanobacterial mats. Here, Catalaphyllia were found as small, free-living colonies that are generally the size and shape of the vast majority seen in aquarium stores. However, every coral seen - and every Catalaphyllia collected - from this area had purple tentacle tips. None of the Catalaphyllia at any other site had this characteristic.

Habitat 2: In contrast, the Catalaphyllia we found (rarely) at fringing, patch, and shallow submerged sites were mostly medium to large attached colonies. These colonies grew on the hard reef substrate and seemed to be able to grow much larger, adopting significantly developed flabello-meandroid growth forms. Furthermore, their skeleton, being attached, would be broken off for collection, rather than having the cone-shaped or unbroken bases typical of free-living colonies at all other sites. The colonies had the typically seen color patterns of bright green to brown with radiating stripes on the oral-disk, and brownish tentacles. Furthermore, the skeletons were well cleaned and whitish from grazing, and coralline algae and other typical invertebrates were found colonizing the skeleton. This is notable, given the next habitat description.

Habitat 3: The same general near shore, silty, shallow area where the dull colored Trachyphyllia were collected is also reported to be a prime area of Catalaphyllia collection. We did find a few specimens using searching and manta-tow techniques, but none ever appeared on any transects of the area. Therefore, we must assume a sporadic occurrence of low density. Like the deepwater habitat, Catalaphyllia collected here were free-living and never attached. They were found nearly buried in deep fine silts and were, also like the deepwater colonies, small and apparently size-limited by the substrate. More notably, the thick brown silt had discolored their skeletons from white to a dingy brown. The only notable growth on the skeleton was from the calcified tubes of polychaete worms. Their coloration was drabber, being brownish with muted green-brown oral disks and tentacles.

Cynarina lacrymalis (Button or Meat coral)

Even the coral collectors admitted, that Cynarina were significantly difficult to find .In fact, they couldn't point out any areas where one could just go and find them readily; searching an area - and subsequent collection wherever one was found - seemed to be the norm for them. We also found this to be true in our many dives, and transects showed the coral to be extremely rare to absent at all sites. However, they were present at patch, fringing and submerged reef habitats, and in the deepwater habitat as free-living colonies. Most were very small juveniles, but there was one very large specimen and several of average collected size. Like Euphyllia, it is hard to generalize on the preferred habitat. If anywhere, the density was highest (found by searching but not by transect) in the 30-40m algal flat deepwater habitats. On the reef, Cynarina was found occasionally; always attached and never free-living. Once again, the skeleton will provide clues as to whether the coral was attached or free-living, and may therefore be used to approximate the likely collection habitat. Attached Cynarina were always found lodged into nooks and crannies of the reef, under overhangs, and under corals. They appear to prefer or dwell almost exclusively in extremely protected areas receiving very low light levels. There were no other determining morphological characters we found that could be used in assessing habitat.

<- PREVIOUS | NEXT ->

Copyright 2002 Advanced Aquarist's Online Magazine