Last Update : Monday 22 January, 2001 4:53 AM

Research
Survey Report Coral Reef Condition Distribution of Giant Clams Distribution of Edible Invertebrates

Survey of Distribution of Edible Invertebrates in Mu Ko Surin Marine National Park Area

Objectives

1. To study the distribution of sea cucumbers and other invertebrates usable by Sea Gypsies.
2. To study conditions and look for the ways to preserve and manage these living resources for long-lived usage of Sea Gypsies.

Survey Method

          The same method of Giant clams’ survey was used. It has been developed from Quadrat Method, which square-shaped equipment was used in certainly known area. The 4-meter-radius circle-shaped equipment was used by applying a 4-meter-long rope with one end tied to weight and the other end tied to stick tip. Survey method was done by sampling survey the area that water was not too deep. The depth of water was not more than 3 meters. Drop the weight to the sea bottom, loosen the rope, and swim in 4-meter-radius circle. While swimming, count the sea cucumbers and also identify their species. When completing the circle, record the numbers of each species. Then, repeat the same process for 20 times. From the area of circle formula, the area of circle with 4 meters radius was about 50.29 square meters. In addition, other invertebrates that could be used for food like crabs, shrimps, Mantis shrimps, cephalopods, and so on were also studied. However, snorkeling was applied to survey.

Time

          This time survey was done twice during December 12-18, 1999, and March 13-18, 2000.

Results

          As the results, 29 species from 5 phylum of edible invertebrates were found as follows:

Phylum Cnidaria

Jellyfishes
          Jellyfishes mostly found around Surin Islands area were small, only some were large but venomous. Therefore, jellyfishes were not in the potential for eating.

Phylum Annelida

Polychates

          There were so many of polychates that they could be caught to eat without making trouble to ecology system.

Phylum Arthropoda

Lobsters
          Surin Islands were suitable to be lobsters’ habitats. However, since they were caught to eat and sell in the past, their population had decreased. At present, Panurilus versicolor lobsters’ population increased, but was still regarded as low if compared to the natural condition of Andaman Sea (report from Myanmar).

Crabs
          There were a lot of crabs remaining in the coral reefs of Surin Islands, but to eat these kinds of invertebrates might harm to death. Some species could be eaten only in some certain seasons; therefore, the folk wisdom should be additional considered before eating. Though, some species could be eaten without any danger such as Ghost crabs, Swimming crabs, and Mud crabs.

Mantis Shrimps
          The large Mantis shrimps in coral reefs that could be eaten were very limited. Both species lived in deep water. Besides, the data of Mantis shrimps in coral reefs was still limited. It was recommended that some might be eaten, but the study in detail should be conducted first.

Phylum Mollusca

Bivalves
          Some bivalves like Oysters were still in large quantity. If only they were taken for foods, it would not that much affect the ecology system. However, some other bivalves, like Bonnet shells, were in small quantity, so taking large bivalves for foods should be avoided.

Gastropods
          There was small quantity of gastropods; therefore, they should not be caught not only for eating, but also for selling.

Cephalopods
          The cephalopods that lived in shallow water like cuttlefishes were still in moderate quantity, and could be caught for eating in some suitable areas (not in protected areas). Though, octopuses were in so small quantity that they should not be eaten.

Phylum Echinodermata

Sea Urchins
          Sometimes, their gonads were taken to eat; however, they were not popular among Sea Gypsies. The population of sea urchins in nature was in balance situation, so they should not be disturbed. If they are really needed to eat, study in detail should be done.

Sea Cucumbers
          There were at least 15 species of sea cucumbers in coral reefs of Surin Islands. But sea cucumbers that could be found in shallow water were only some species and their populations were rather low. Large numbers of them were caught to sell in the last 3 or 4 years was the main reason.

          Sea cucumbers are in Phylum Echinodermata, Class Holothuroidea with the characteristic of long shapes, their mouths and anuses are at different sides, their limestone sclerites were reduced to only small solid plates. They can regenerate. Sea cucumbers generally live in rocky beaches, sandy beaches, and muddy beaches. They may live on or bury in the sand floor. Some are independently swimming. Enemies of sea cucumbers are rarely found except for sea gulls and human beings.

Conclusions

          The population of sea cucumbers in Reef Flat area was very low, compared to the past report (Thon Thamrongnavasawat, 1994). The primary report showed that population of sea cucumbers was in normal situation, but nowadays, the moderate population of sea cucumbers (about 30-40 sea cucumbers per 50 square meters) was found only in Ao Kaad at the 1^st and the 2^nd survey points. In other survey points, sea cucumbers were found in very small quantities (less than 1 sea cucumber per 50 square meters). The reason why sea cucumbers were in small quantities was because a lot of them were caught to sell in the last 2-3 years. This situation was happened all over Thailand’s sea territory. From the primary study by Faculty of Fisheries, Kasetsart University (1999), it was found that sea cucumbers in Ko Tean area (Suratthani Province), and Adang-Ravi Islands (Satul Province) were also in small quantities. The reason that sea cucumbers still remained in Ao Chong Kaad area was because this area was located in front of the national park office; therefore, it could be closely inspected.

Suggestions

          At present situation, it should not make use of sea cucumbers in any forms; for example, eating, selling, and so on since the quantities of sea cucumbers are in very threatening numbers. In this situation, what should be done is to preserve sea cucumbers in any forms in order to let nature recover itself. However, Sea Gypsies could take part in studying and following up the result because this study method was designed to be easy, convenient and not complicated in preparing equipment. The study would be taken care by the national park officer and research unit. The changing of population in sea cucumbers’ data is very useful and necessary for study and conservation of coral reefs in Surin Islands in the near future. For other invertebrates that were found in normal quantities, many animals could be used for foods as in the list attached (presented in the seminar). However, to make use of those invertebrates for foods, their changing conditions have to be closely followed up. Since the survey of these invertebrates is difficult to do, expert researchers are needed. Sea Gypsies cannot do it by themselves.

Copyright © 1999-2001 TalayThai.com All right reserved.
comment to webmaster@talaythai.com