This project is seeking to measure the domestic trade that occurs in this beautiful species of shell. It is a well known predator of the crown-of-thorns starfish and it is hoped that this species will eventually be listed in Appendix II of the Convention in Trade of Endangered Species (CITES) Treaty. Such a listing will ensure that this species continues its natural role as a starfish predator throughout it’s extremely wide geographic range. If you are a school group and wish to participate by gathering trade information from shell shops in your local area we will coordinate your results and compile the necessary data to facilitate the adequate protection of this species. For further details about how you can be involved in this project please email and state your details together with any particular areas of interest or concern.
While the triton is a well known predator of starfish, little is known of its general biology. In the study of this extremely interesting outbreak phenomenon, future crown-of-thorns starfish research must surely include the basic study of its most well known predator.
What is the aim of the CITES Project?
To get some idea of the number of these shells that are being collected annually we need to at least monitor the domestic trade that is occurring in this species. In addition, we need to know the basic biology of this species. To ensure its international protection the Giant Triton needs to be listed in Appendix II of the CITES Treaty.
To clarify the role of natural predators in this outbreak phenomenon, we need to:
- Estimate the density of tritons on many different reefs to see if a relationship exists between triton and starfish abundances
- Establish the feeding rate and prey preference of the triton to see if a relationship exists between prey preference and relative starfish abundance
- Examine the early life history of the triton, including settlement, to see if the triton commences its benthic life as a starfish parasite
- Explain why some reefs have low triton density while on others it appears to be more abundant
- Determine whether starfish egg fertilisation depends on the spatial pattern of the starfish population
- Determine whether the foraging activities of the triton can effect starfish spatial pattern
How to conduct a triton survey.
- First identify a coral reef that has undergone a large starfish outbreak a few years ago. The outbreak must be in the rapidly declining phase. Most of the coral on the reef should be dead.
- Find the last remaining starfish aggregation of a hundred or so in about one hectare of reef. This area should contain live coral but be surrounded by a large area of predominantly dead coral. Other areas of this reef will contain elevated numbers of other starfish species but most of the Acanthaster should be aggregated in this small region of residual outbreak.
- Once this area of about a hectare is identified, it is a matter of repeatedly searching every small cave and crevice in detail using scuba. Don’t be surprised if ten tritons are concealed in this small area only occasionally emerging to feed on the starfish. Look out for starfish with missing arms.
- Don’t advertisethe location of triton specimens that you have located or else they will be stolen by shell collectors. Remember that certain governments have actively opposed the CITES listing of this species. International trade in the Giant Triton is lucrative and widespread.
Surveying populations of the Giant Triton (Charonia tritonis) is not as simple as 14 days of manta towing over hectares of beautiful coral reef in clear tropical waters. If it was this simple, we would already have estimated the average abundance of this animal in many different locations and would probably have mounted a major research and mariculture effort given what little we know of the biology of this shell. Unfortunately, most attempts to locate specimens of Charonia have met with failure.
Most observations and probably most specimens collected for sale are simply stumbled upon by divers with snorkeling gear. For every one brightly patterned shell, there are ten that are completely covered with calcareous encrustations. For every one shell out in the open, there are ten hidden in small crevices within the coral. For every one specimen located, a hundred were passed over without even being noticed. Before you can study an animal, first you must find enough specimens. Then while they are being studied, you must hide them from collectors so that they are not stolen for sale in shell shops. There is nothing worse than mounting a two week expedition with thirty divers and having the precious specimens stolen from cages out on the Great Barrier Reef.
The most successful method of locating Charonia is by detailed scuba searches in regions of residual Acanthaster outbreak. Unfortunately this means that at any time, there are only a few reefs in a suitable state for surveying. When the Charonia are dispersed on a reef, the chance of locating even one specimen is quite remote but you can be lucky. When they are aggregated on the few remaining Acanthaster (their preferred prey) at the end of an outbreak, then they are much more easily located.
If you have any observations of Charonia or can suggest good locations for further survey, particularly if they are reasonably accessible, then please email Charonia Research.