SPC/ 9/WP.21 14 January 1977

ORIGINAL : ENGLISH

SOUTH PACIFIC COMMISSION

NINTH REGIONAL TECHNICAL MEETING ON FISHERIES (Noumea, New Caledonia, 24-28 January 1977)

TURTLE FARMING PROGRESS REPORT ON THE SOUTH PACIFIC COMMISSION FARMING PROJECT IN THE COOK ISLANDS

by

D.J. Brandon Volunteer South Pacific Commission

I. INTRODUCTION

1. In September 1974, the South Pacific Commission initiated a turtle farming project in the Cook Islands. This project was proposed to investigate the viability of raising hatchling , in captivity, from the egg to a size suitable for the market as an alternative source of protein for the Pacific Island territories. Included within the scope of the Turtle Project was a small-scale population study of the marine turtles in the Cook Islands, the establishment of a demonstration turtle hatchery and farm, and also an attempt was to be made to have a breeding stock in captivity.

2. It would be worthwhile to emphasize at this point that the difference between a TURTLE FARM and a TURTLE RANCHING operation is that a turtle farm is completely independent of wild turtle populations. At the present time it is believed that there does not exist a turtle farm in the true sense although the large Anglo-American venture on Grand Cayman Island has had some success with rearing Green Turtles in captivity.

3. The project in the Cook Islands has a well-established turtle hatchery on the main island of Rarotonga. The major problem that faces this project is the acquisition of a regular food supply and it seems at this stage that a great deal of work will have to be done in this area before turtle farming can be assimilated within the economic structure of the Cook Islands and similar territories. In the early stages the young turtles require fish as the staple food for at least eight months,at which time the turtles can then be weaned onto a herbivorous diet. However, a high level of protein in the turtle feed must be maintained to produce a satisfactory growth rate. In the Cook Islands there is no supply of turtle food which is both cheap and in regular supply.

LIBRARY SOUTH PACIFIC COMMISSION SPC/Fisheries 9/WP.21 Page 2> ••'•,.,

4. A draft of turtle legislation has been submitted to the Cook Island Government with recommendations on the designation of certain uninhabited islands as Turtle Sancturies (see; .Appendix,;1) , and suitable size limits restricting the capture of turtles from 45 cm to 90 cm in length. A closed season has also been recommended to protect the turtles during the nesting season.; , v i , ,..-, ,.•: ,.

5. At the present time, 58 two year old turtles are being held in the hatchery on Rarotonga, and these are the remainder of an original complement of 450 hatchlings received from Palmerston Island in December of 1974. The figures above represent an 87% mdrtiality rate. Apart from the normal high mortality ;rate> sexperijenced, amongstvthe ,hatchlings during the first two months, ma^y;%^ytlksir^a^-r^e:ti,~X

6. It has been decided to seek the,advice of an expert in turtle farming so that the future of the, SPC Turtle Farming Project may be decided. The expert, who should arrive early in 1977, will ascertain whether the Cook Islands' situation is suitable for the further development of turtle farming as a viable economic proposition.

II. BACKGROUND

7. The Cook Islands, consist of fifteen islands scattered over 751,000 square miles of ocean.from 9 degrees south of the equator to 22 degrees south (see Appendix 1). The islands of the southern group are volcanic, whilst those of the' northern group are atolls. As far as turtle conservation is concerned, it would be expected that the,northernand southern groups would have turtle populations, which are; as different, from each other as each is different from those in say, French Polynesia, because of the great distance involved.

8. All of the islands are visited by the Green Turtle (Chelonia mydas) and less frequently by Ha,wksbill (Eretmpchelys imbxicata) . It has been reported that the leather-back {Dermochelys) and Loggerhead (Carretta) turtles have been sighted. However, it is only the Green Turtle which appears to nest to any great extent in these islands, with Rarotonga and Aitutaki excluded because of over-exploitation. The exploitation of the Green Turtle for its shell is increasing in the northern islands as the shells are a valuable source of money or trading power., especially with foreign vessels entering the ports illegally. It,is hoped that the, draft legislation put to the Cook Islands Government w;ili be enacted and enforced to prevent further depletion of the turtle resource within the Cook Islands.

9. The islands of the Cook group are generally small and therefore do not have extensive coastlines that; are found in other territories. In conjunction with the. above feature is the limited shelf area around the islands which are generally the tops of very steep pinnacles rising from the ocean floor. Hence the potential area for seaweed or turtle grass production is very limited. In fact very little marine vegetation can be found around these islands, although there is a certain amount of growth found within the lagoons but this would not be an unlimited resource. Consequently, a turtle farmer must find alternative food sources for his turtles. It is possible to utilize the relatively abundant fish resource as turtle feed but, SPC/Fisheries 9/WP.21 Page 3 in an area where there is a large market for all species of fish, it would be both energetically and economically unwise to exploit a fish resource in this manner.

10. To be more specific on the type of food that should be fed to turtles in the farming situation it is important that any form of culture should utilize the lowest trophic level applicable to that particular animal in order to make the best use of the world's declining food and energy resources. Therefore, the turtles,which are basically herbivores, should be fed on plant protein.

11. In the Cook Islands there is very little surplus food available as the small amount of agricultural waste is in big demand for pig production and there are no processing plants from which wastes can be obtained. The cost of obtaining any food which is palatable for turtles is extremely uneconomical.

12. During the past two years, several projects under the auspices of UNDP and SPC have been attempting to develop the Cook Islands fisheries industry. The major problem appears to be the lack of suitable storage and transport facilities,with the inherent difficulties of maintaining the machinery after it has been installed. It is envisaged by the Cook Islands Government that the fisheries potential is large enough to warrant the establishment of fishmeal plants some time in the future. In the first stages of fisheries development it would be expedient to utilise any fish trash directly as stock food rather than go to the expense of converting the waste to fishmeal. The second alternative would be to make a fish silage which is also far cheaper to produce. In any event, the development of fisheries in the Cook Islands may lead to the production of an economical source of turtle feed, although, according to the rule of energetics, such a supply should be fed to a carnivore.

13. The point is, that in the Cook Islands,and in similar territories, the major factor prohibiting the introduction of turtle farming or any other livestock programme for that matter, is the inadequate supply of good quality stock food which can be obtained at an economical price. It is hoped that an institution capable of delving into the question of stock food can be approached to augment a research programme in this area in order that a food which is cheap to manufacture and contains local ingredients can be produced.

14. Another important aspect of the Cook Islands background relates to the cultural implications of introducing intensive culture into the socio­ economic structure of these islands. The Polynesian people have been living at a subsistence level where it is not expected that a daily routine be maintained. However, for an aquacultural system where the captive animals must receive daily attention, then the people must be made aware that turtle farming is a work-intensive enterprise where neglect will jeopardise all previous efforts put into raising the animals. Through having a large number of turtles together in close proximity,cannibalism due to lack of food, and disease are factors which are both sudden and possibly devastating.

III. PRESENT STATUS OF TURTLE FARMING

15. Since the inception of the turtle farming venture on Grand Cayman Island in the Caribbean , established some seven years ago, there has been a great deal of interest focused on the possibility of the marine turtle becoming the aquatic equivalent to the domestic cattle, sheep or pig. There have been a number of interesting articles published which expound the virtues of turtle farming (1, 2, 3, 4, 5). SPC/Fisheries 9/WP.2L Page 4

16. The farm on Grand Cayman Island is an extremely capital- ] intensive venture which has not yet'proved to be art1 economical''prop'ositioh. Perhaps the most valuable contribution made by this farm is the success in breeding turtles, in captivity.(A, 5). After introducing a number of wild male turtles into the artificial pond holding the breeding stocky iira'ting and subsequent nesting by the 'females readily occurred1., ; This; is1 a major*' ' step forward in alleviating the dependence of turtle farms on natural populations, for turtle eggs to provide the basic stock. It txsty bepossible:' in the future that a method of hormone treatment can be introduced,1 so that the females will breed on a more regular cycle. In the Pacific region where the supply of food is limited, a breeding stock of females which only nest every two or, three years would probably be unsuppqrtable. ''•"'•

17. It has been suggested that'a farm mairitajiriirig; a s't&ck of around 6,000 turtles/yr. rather than the 60,000/yr. aimed for by the Gfarid Cayman venture would be a more realistic figure(1). Even at the suggested stock regime above, approximately 1,500 mature turtles would be required to provide sufficient eggs to maintain the farm.1 In the Pacific region, unless a central breeding stock was established, the figure of 1 ,'500 would seem astronomical. ''•"•-,• i

18. Looking at turtle farming from the village level where the capital outlay must be minimal arid the farms of a size that can be operated by only a few people, the systkm of a'"few pigs in the back yard" would have to prevail. Each island could operate their own breeding colony and each individual look after about 20b turtles/yr., provided the food is available.

IV. PROGRESS RESULTS (a) Material

19. The turtle hatchery on Rarotonga consists of a large building which has an iron1 roof and is. enclosed•'• with wirer-netting around, the walls for security reasons: The turtles are held in two concrete tanks (12' long, 6' wide and"3' deep: the second is 24' long, 6' wide and 3' deep). Initially, the hatchlings were placed in aluminium trays (12' by 2' by 6'') and these have since been replaced with concrete tanks of similar dimensions. Fresh sea-water is supplied by a two-inch pump through P.V.C. piping to the building to completely change the water twice daily.

20. This 'facility was reconstructed from the) remains of, a defunct venture which was terminated in the early part of this decade. There aire several outside ponds available for further expansion of the turtle project on this site or for any other* culture experiments.

21. If the project is to continue, then it will be necessary to move the turtles into enclosures within the' lagoon; to -reduce .the amount of labour involved with changing the water and keeping the tanks clean. A constant tidal flow of clean water will reduce the occurrence of bqth fungal and Pseudomonas infections which are the two most prolific diseases encountered.

(b) Methods

22. Each day the water is changed in the morning and afternoon prior to feeding the turtles. Twice a week Gentian Violet is applied to fungal infected areas and the tanks are cleaned periodically to control green and brown algal growths on the concrete walls. SPC/flsheries 9"/WPT21 Page 5

23. Growth rate measurements are taken monthly and all measurements are straight line rather than following the curve of the carapace. Head, carapace and plastron measurements are recorded with the weight of the turtle.

24. Food is collected from a number of sources, and the main constituents are fruit, cabbage leaves, bread and fish when obtainable. Many other types of food have been tried without very much success as the condition of the turtles deteriorates rapidly when the food given is not palatable.

(c) Results

25. From the growth rate curve (Appendix 2) it can be seen that the results obtained have not been encouraging when compared to data from other sources. For instance, the farming venture on Grand Cayman Island records a weight of 25 lb for two year old, farm raised turtles. The two year olds that are held at the hatchery have an average weight of about 5 lb, an 80% drop in growth rate. The main contributing factors to this discrepancy would be the different quality of food used in the Grand Cayman which is a pelletised food of high nutrient value supplemented with turtle grass to provide the essential elements to produce healthy, thriving turtles. In the Cook Islands the food is limited to terrestrial vegetation which is not assimilated very efficiently by the turtle,possibly because of the high cellulose content, and an irregular supply of fish.

26. During this past 6 months when fish has been very difficult to obtain, very little fish has been fed to the turtles. The turtles become rather cannibalistic when they are fed with fish and it has proven necessary to feed them with a quantity that will satiate the appetite, or else eliminate fish from the diet altogether, to alleviate the problem of the turtles eating each other.

27. At times when the temperatures drop to around 20-23°C(in the tanks) the turtles greatly reduce their food intake. If they are already in poor condition, death by starvation is relatively common. However, if fish is fed at times of low temperature, then the turtles will eat voraciously. It seems therefore, that if a cake or meal could be produced containing a certain amount of fish or shark meat plus a variety of other ingredients then it may be possible to improve the growth rates. The possible sources of food which could be formed into a cake are the high protein land vegetations that have no commercial value (Mimosa varieties), sea cucumbers, coconuts and shark meat.

28. Although bread was fed in limited amounts, it has been found that too much bread will cause bloating In the manner that Pseudomonas infections affect the turtles. Possibly, the bread forms an ideal substrate for the proliferation of the bacterium.

29. Of the 450 hatchlings received from Palmerston Island in January 1975, only 58 have survived to the age of two years. Apart from the occasional outbreak of Pseudomonas bacteria and theft , the major cause of the high mortality experienced has been the persistent shortage of sufficient high quality food. Consequently, the turtles are generally in a state of poor condition, making them far more susceptible to fungus and Pseudomonas diseases. A Pseudomonas outbreak can be readily controlled through the oral administration of Penicillin or Chloromycetin (approximately 50-100 mg depending on the size). SPC/Fisheries 9/WP.21 Page 6

30. During' the/voyage from Palmerston to;1 Rardtoriga, many of the first complement of turtles died due to physical1 damage in the" drums in which the •' ; ' fisheries vessel RAVAKAI'transported them. It was decided therefore to obtain; the ,1975/1976 season turtles as eggs and transport them in polystyrene containers* Unfortunately the. irregular'shipping1 services^prevented1 a trip ! being: made during the ,peak"' of trie seasbn, and^ so only 260 dggs were received in Penrhyn. Before "'the' inter-island vessel M.V. MNUAI left Penrhyn 110 eggs hatched out. From the boxes containing 150 eggs, lib' natchlirigs emerged giving a hatching success of 73.3%. The majority of unhatched eggs were contained in one box which became wet en route. If this latter box is disregarded, then the hatching success becomes 95%, which seems to prove that polystyrene containers are very effective for transporting turtle eggs.

31. One of the experiments carried out on the 1975/76 hatchlings was to condition them to respond to a stimulus at feeding time. After one week all the hatchlings responded immediately to the stimulus (banging a stick on tin). If the project is to continue as a turtle farming venture, then this approach to feeding turtles must take an important part in the programme because it may be possible to have free-ranging conditioned turtles which not only find a certain amount of their own food but also would not require any kind of elaborate enclosures. Unfortunately, all these hatchlings died during the 6-10th weeks in Rarotonga as a result of an early spell of unusually cold weather and, as already mentioned, the turtles Will not eat if the temperatures fall to the low 20s. as they are cold-blooded and tend to go into a state of torpor,. The above response of . the hatchlings leads to starvation and reduced resistance to disease.

32. The turtle population in the Cook Islands may h'otr be as extensive as was first thought, and consequently an increase in manpower involved in the turtle population work may be necessary. The exploitation of turtles for the shell and the possible demand to be created by the rapidly developing tourist industry for turtle meat would cause further decline in the Cook Islands turtle resources. Information received from Palmerstbn during the 1975/6 nesting season and.personal observations by the project manager at Suwarrow, indicated that very few turtles nested on these islands during the season. However, it was encouraging to note that many small 2^3 year old turtles have turned up at Palmerstoh early in the 1976/77 season, most probably the result of the hatchling release programme that was initiated in Palmerston some years ago. A small-scale tagging programme of adult turtles will be undertaken this season by the Palmerston people. It is hoped that the Cook Islands Government will adopt the proposed Turtle Conservation Legislation in the near future.

V. DISCUSSION

33. The future of turtle farming in the Cook Islands, and in other Pacific territories, will depend largely on further research into two main areas, which are: (a) BREEDING BIOLOGY (hV FOOD SUPPLY It is fortunate that the scientists stationed on Grand Cayman Island are making very good progress in the field of breeding Green Sea Turtles in captivity and will inevitably supply the necessary data for use in the Pacific region. However, the problem of investigating possible sources of food will be,in the main, an area of research to be dealt with by each territory separately. SPC/Fisheries 9/WP.21 Page 7/8

It is believed that CNEXO in Tahiti has an extensive research programme under way in the field of animal food technology, and therefore the assistance of such organisations as CNEXO should be sought.

34. Another area of importance as regards marine turtles in the SPC region relates to the dearth in our knowledge of the extent of the turtle resource. It is imperative, therefore, that further work on the population biology and conservation of sea turtles should be initiated. Already a small- scale tagging programme has been started in Palmerston Island of the Cook group and, shipping service permitting, turtles from some of the other islands will be tagged this season. In conjunction with any conservation measures, and especially with tagging programmes, an education programme must also be introduced to inform the people of the reason for conserving the populations. Naturally, any conservation programme dealing with a migratory species must be a unilateral effort between all territories frequented by the sea turtles.

35. The conclusion to be drawn from the two years that the SPC Turtle Project has been in operation in the Cook Islands is that, for a group of islands which do not have any readily available food supplies for live stock, in-depth surveys for possible sources of food must precede any turtle farming development. It is hoped that the imminent visit by an expert seconded by the South Pacific Commission to the Cook Islands will be able to provide the necessary answers.

VI. REFERENCES

1. Clayton,D. (1975). Farming Green Turtles, 'keep it small and simple'.

Fish Farming International Vol.2 No.3

2. Marine Turtle News Letter. No.l August 1976.

3. Grey, Anthony, (1975). Turtle Farming in The Caymans. London Magazine October 1975. 4. Simon, Martin H, Glenn F. Ulrich and Alan S. Parkes, (1975) The (Chelonia mydas) : Mating, Nesting and Hatching on a Farm. J. Zool., Lond. (1975)117,411-23.

5. Simon, Martin H (1975). The Green Sea Turtle (Chelonia mydas) Collection, Incubation and Hatching of eggs from Natural Rookeries. J. Zool., Lond. (1975)176, 39-48.

6. Carr A.F. and Main A.R., (1973). Turtle Farming Project in Northern Australia. .Report on an Enquiry into Ecological Implications of a Turtle Farming Project. SPC/Fisheries 9/WP.21 Page 9/10 COOK ISLANDS APPENDIX 1

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