The Queen Conch (Strombus gigas)
The queen conch is the largest of the family Strombidae. It is found from Florida to Brazil. It is most commonly found in the islands of the West Indies. This large conch grows up to 30 cm, and is an edible conch. When alive they are white, although often covered with thin brown plasticlike periostracum. When alive, the outer lip is a bright pink.
Although it is most prominent in the islands of the West Indies, it is uncommon to find them on the more populated islands. The queen conch is harvested for its meat by the natives and is ignorantly collected by tourists. On the Bahamas, the queen conch shells are exported for cutting into cameos.
It is illegal to import the queen conch into Canada, alive or dead. The queen conch is listed as an endangered species; the Canadian Ministry of Agriculture in conjunction with the governments of those nations, where the queen conch inhabits, are trying to save it from extinction. For educational and research purposes, such as this study, papers may be attained in advance of a trip, allowing for the collection and importation of the queen conch. In this study, all queen conch shells, which were collected, were dead at the time of collection. We discovered many conch shells that were inhabited by the either the conch organism themselves or by the red hermit crab, these shells were released immediately back to their natural habitat.
The queen conch shell is a very
sturdy and robust shell. It forms thick walls within the shell, which makes
for an excellent defence. This feature also makes them an excellent study
specimen, as they can endure years of degradation and have little to no
affect upon the whole of the shell. But rather the outer shell becomes
a landscape of history of what has happened to that shell since it died.
Location of Discovery of Each Sample
On Shore: Moderate Queen Conch
Lagoon: Queen Conch, Small Conch, Immature Queen Conch A
Patch Reef: Immature Queen Conch, Immature Queen Conch B
Back Reef: Broken Queen Conch
The queen conch inhabits all areas of the reef. A variety of sizes were found in different environments of the reef, suggesting that the queen conch has adapted to the entire reef.
The degree of degradation of the conch shell depended upon several factors. How long the conch had been dead; whether the conch was completely buried, or only partially buried; the ability for bioturbators to feed upon the shell; the ability for encrusting organisms to attach themselves to the shell; and the amount of erosion, either chemically or mechanically.
The length of time is the most critical factor of the degree to which the conch shells were affected. The longer the conch was exposed to the other factors, the more they were able to affect the shell.
A shell buried in the sediment of the ocean floor, was somewhat protected from bioturbators, but was more exposed to encrusting organisms. Those shells that were exposed to the sea water, may have undergone chemical erosion, and or mechanical erosion from bioturbators feeding upon the shell or the physical movement and damage as the shell was moved about.
Encrusting organisms such as the red foraminifera Homatrema rubrum, as well as the serpulid worms and gastropods are common on most of the shells. These are particular to this region, and attach to all shells and other organisms, not just the queen conch shells.
There is a recurrence of a weak point within each shell. This weak point occurs between the last and 2nd last whorl of the shell. All the shells that have been exposed to some type of erosion display this weakness trait. The weakness is displayed as a hole into the shell. This hole is likely due to erosion or bioturbation at that point where the shell is weakest and gives way.