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SPC/lnshore . Res./WP2 29 February 1988

ORIGINAL: ENGLISH

SWTH PACIFIC COMMISSION,

WORKSHOP ON PACIFIC INSHORE RESOURCES (Noumea, New Caledonia, H-25 March 1988)

MISCELLANEOUS MOLLUSC RESOURCES OF PACIFIC ISLANDS

By

DrA.D. Lewis

Introduction

1. Molluscs (Phylum ) are a diverse array of "", which Include bivalves (, cockles, , - Pelecypoda), gastropods (, , seahares- Class ) and (, , cuttlefish - Class Cephalopoda). These support large marine , world landings of molluscs exceeding 6 millions tonnes in 1985 (Anon, 1987) and dominated by cephalopods (1.67 million ml), clams, cockles and arkshells (1.61 million mt.) and oysters (1.03 million mt).

2. Previous sessions at the workshop have considered in detail the molluscs of major commercial Importance to Pacific Islands. This Include molluscs harvested primarily for industrial purposes (eg. trochus, green and pearl shell, for their nacreous shell interiors) as well as those harvested primarily for human consumption (giant clams).

3. There is In addition, however a wide range of molluscs harvested throughout the Pacific Islands for subsistence purposes and in some cases small scale commercial exploitation. Many are gleaned from a variety of inshore , Including mud flats, mangrove roots, sandy beaches, reef flats and rubble areas. These molluscs are commonly collected by women, and have traditionally served as important reserve food sources during times of bad weather or poor line . In densely populated atolls, they may become a primary foodsource, Zann (1985) noting that in South Tarawa (Kiribati), landings of three lagoon bivalves exceed that of all finfish combined.

4. Other more active molluscs are taken with lures or baits (cephalopods), whilst others are trawled (). Some additionally offer potential for mariculture (Pinoiato, Crassostres. AjMdata, etc). Table 1 lists the main genera of molluscs exploited for food throughout the Pacific Islands. This does not include molluscs harvested for other traditional uses, eg. artefact manufacture (Pernetta and Hill, 1983) or as collectors items (Parkinson, 1982). SPC/lnshore Fish. Res./WP2 Page 2

5. Richard (1983) provides estimates of mollusc productivity in French Polynesian high volcanic islands and atolls of 230 kg/ha/yr and 50 kg/ha/yr, respectively. Mollusc productivity on larger islands further to the west is likely to be even higher, underlining the potential importance of these resources to island ecosystems. This paper reviews available information on Pacific Island miscellaneous mollusc fisheries and their management requirements.

Noatnal catches of Miscellaneous aolluscs

6. Data on inshore mollusc fisheries is not readily available for most Pacific Islands, a situation which extends to artisans) and subsistence fisheries generally. Six countries record miscellaneous mollusc production for 1985 (Anon, 1987), as follows: The reliability of these figures is however uncertain.

Cook Islands 236 mt (includes trochus) Fiji 2770 mt (includes estimated subsistence) Kiribati 3286 mt New Caledonia 40 mt Western Samoa 48 mt

7. FIJI, where some relatively detailed data are available, provides a signal example of the importance of an inshore mollusc fishery in the lower river fishery for kai (Batissaviolacea) throughout the two main islands. This has provided commercial sales of approximately 1400 mt p.a. since 1983 (Lewis, 1985). Table 2 also lists sales volumes of other molluscs in Fiji which amounted to 144 tonnes, with an estimated value of Ft 112,000 in 1986. 8. Notwithstanding the general lack of data on miscellaneous mollusc catches, the following sections consider the present status of mollusc fisheries, and their potential for further development.

Bivalves (Class Pelecypoda)

9. In terms of current production, bivalves are the single most important group of molluscs, and a very wide variety of is harvested (Table 1). Anadara.aaenus generally restricted to mud/sandy mud is pre-eminent amongst these, and there is evidence of depletion in some areas due to its heavy harvest, in some cases over centuries of exploitation (Swadlfng, 1982- Papua Const; Zann, 1975- Tarawa).

10. The Tarawa lagoon fishery for "te bun" (Anadara maculosa) provides a staple protein source for the rapidly increasing population of South Tarawa, particularly for those families outside the cash economy, and the annual harvest has been estimated to be as high as 18001. per year (Bolton, 1982). The resource appears to be in need of some management input and this issue is now being addressed (Mees, pers. comm.). SPC/lnshore Fish. Res./WP2 Page 3

11. In Fiji also, Anadara (A. cornea-kaikoso) provides the largest marine mollusc sales volume (approx. 1001- Table 2) and the genus Is also harvested in Tonga. Techniques for the culture of Anadara have been wel) developed In South East Asia (Broom, 1985) and Malaysia exported 40,000 t. of Anadara oranosa in 1982, based on coastal mudflat cultivation of collected natural seed (Wong and Urn, 1985). This species apparently occurs in Papua New Guinea (Swadling andChowning, 1983) where it Is harvested for subsistence, ami may occur elsewhere in Melanesia. A. antlquata is also harvested in Papua New Guinea.

12. In the coral sand lagoons of Polynesia, Anadara generally becomes of less Importance, with Area and Asaphls more commonly harvested.

13. The Fijian kai (Batissa) fishery has been mentioned earlier. This species Is found In rivers throughout Melanesia, in fresh water under tidal influence, but appears to be of only minor importance elsewhere. The relatively low price (approx. 20c/kg whole ), ready availability and non-perishable nature of the product (It is sold live and can be kept for up to a week) establish it as possibly the cheapest available protein source in Fiji. Approximately 1400 tonnes are now marketed annually (this does not include a sizeable subsistence catch) and although production has essentially stabilised since 1983 (Lewis, 1985), there are concerns that the resource may be harvested at close to Its maximum sustainable level. Yield estimates are required with some urgency.

14. The saucer (Amusium iaoonicum baltoti). with the smaller A. oleuronectes. supports a scallop fishery off the coast of central Queensland (22*-26' S) (Dredge, I.P.I. this workshop). Annual catches (meat weight) have been in the range 600-1200 mt p.a. Recent trawl surveys In the north of New Caledonia at In a similar latitudinal range (19*-20* S) have revealed the presence of scallop beds there (Clavier and Laboute, 1987) and it is possible a small commercial fishery for A. 1. ballot! may develop. The standing biomass in an area of approximately 700 km2 was estimated at 3000 mt. Quantities of Aoleuronectes are taken incidentally In the Gulf of Papua trawl fishery, some of which is marketed. Scallop fisheries are vulnerable to over-exploitation because of the high product value and erratic recruitment Dredge (LP. 1) argues that recruitment over fishing may already be occurring In the Central Queensland fishery.

15. With the exception of the examples mentioned, It is unlikely that bivalve resources on most Pacific Islands are being exploited at even moderate levels. Their Importance to subsistence consumption should however be borne in mind, as well as their subsceptibility to depletion and to unfitness for human consumption through pollution or environmental degradation.

Gastropods (Class Gastropoda)

16. A similarly wide range of gastropods is exploited, mainly for subsistence purposes. With the exception of trochus and green snail, exploitation levels are generally believed to be low (see, for example, Table 2), and abundant bivalves are generally harvested in preference. There are however a few cases where fishing pressure on particular species is Increasing eg. Turbo setosus (arirl) on Altutaki (Cook Islands), and some assessment of the resource may be required. SPC/lnshoreF1sh.Res./WP2 Page 4

17. The generally low levels of exploitation of gastropods, other than trochus and green snail, is in marked contrast to the Caribbean, where the large queen (Sirombusaioas) Is the second most valuable fishery resource after spiny lobster, and second only to finflsh as a protein resource (Brownell andStevely, 1961). The red-lippedstromb (strnmhus luhuanus) together with the smaller S, oibberulus. is however probably the most Important gastropod taken for subsistence usage in the Pacific Islandregion.

18. Specimen or collectors shell, those taken for sale to tourists and to specialist shell collectors, provide a special case. Attractive shells, mostly gastropods of the genera Cams, Cvoraea.Cvrnatlum. Mitra. Vexillum. OHva. Terebra etc, but also bivalves (Parkinson, 1982), may have a value in the shell trade many times that as a food Item. This can lead to intensive collection of species which may already be relatively rare. Parkinson (1982) outlines a series of simple conservation measures for a collectors shell Industry, including minimising habitat damage during collection. All countries have some potential for specimen shell development.

CeplMlopods (Class Cephalopoda)

19. Despite a world catch of over 1.6 million tonnes In recent years (Anon, 1987) and the potential to increase this by many times. fisheries are of minor Importance In the countries of the South Pacific.

20. Octopus, primarily Octopus cvanea. are collected in small quantities from reef flats, using lures, traps or hooks. Approx. 7mt was marketed in Fiji in 1986 (Table 2); Hawaiian landings averaged only 4.6 mt. between 1961-1979 (Kramer, 1986), and New Caledonian landings 8-17 mt pa. since 1983 (Palladln, pers. comm).

21. Lagoon (Sooloteuthis lessonlana) are captured occasionally, as are cuttlefish (Amesbury et al, 1986), and small quantities of squid are marketed as trawl by-catch in Papua New Guinea. Surveys of near-shore ommastrephid squid resources have been carried out in several countries eg. Fiji with generally disappointing results, the main species (Svmolectoteuthis oulaniensis) being of secondary market importance and used primarily as bait. This species, which Yoss (1973) speculates to have a very large potential yield from the central eastern Pacific Is often common around FAD's and In near-shore waters, and may have local potential as a bait species for individual fishermen operating vertical longllnes or Ika shlbi gear. An artlsanal fishery exists for the endemic Nototodarus hawaiiensis off Hawaii, and may have possibilities for expansion (Roper et al, 1984). The red squid (Ommmastreohes bartrami) a species of great commercial importance, occurs in waters south of 20* S, and Is usually caught In drift gill nets (Roper et as., loc. cit).

22. The chambered shell (Nautilus oompllius) has often been captured In deep- water shrimp and fish traps at depths of 100-250 m during surveys in the region. Given its value In the shell trade, It has been suggested as a possibly viable trap fishery in it own right. No organised fishery has yet developed, although there Is a specialised fishery for Nautilus in the Philippines (Roper et al., 1984). SPC/lnshoreFfsh.Res./WP2 Page 5

23. In general, there appears ample scope in the region to further develop near-shore cephalopod fisheries. Boongerd and Chitrapong (1986) provide interesting details of small scale fishing gear appropriate to the region.

Other Molluscs

24. Small quantities of and seahares (Dolabelto) are collected for subsistence use in several countries. They are nowhere considered as important food items and exploitation levels are probably low.

Cmclustons

a With the except of Amfaca *** BflUsa. K te assumed that most mollusc resources of the Pacific Islands are exploited at moderately low levels. Very little data is available however, and the countries where few alternative resources are available or where populations densities are increasing should make some effort to catalogue species harvested and ascertain levels of fishing effort. Other countries eg. Kiribati, Fiji may require detailed assessments of single species stocks.

b Several mollusc genera offer potential for increased catches, particularly cephalopods, whilst others may be amenable to stock enhancement eg Anjadjca.

c Traditional subsitsence fisheries for molluscs, as well as having a considerable market value, are often the first to be affected by coastal developments and environmental perturbation. Their importance needs to be recognised in fisheries development and coastal zone management plans. SPC/lnshore Fish. Res./WP2 Page 6

Referencts

AMESBURY, S.S; FA CUSHIN6 and R.K. SAKAMOTO (1986) Guide to the Coastal Resources of Guam. Vol. 3.. Fishing on Guam. Univ. of Guam Press, 11 Op.

ANON (1987) Year book of fishery statistics. 1985. Catches and landings. FAO, Rome. Vol. 60,462p.

BOLTON, LA (1982) Shellfish harvesting In Tarawa atoll lagoon, Kiribati. Internal Report. AtollResearch Unit, USP.

BOONGERD, S. and S. CHITRAPONG (1986) Small-scale fishing for squids and related species ASEAN/UNDP/FAO Regional Small-Scale Coastal Fisheries Development Project. RAS/84/016. Working Paper 3:44p.

BROWNELL, W.N. and J.M. STEVELY (1981) The biology fisheries and management of the queen conch, Strombusploas. Marine Fish.. Rev. 4JS( 7): 1 -12.

BROOM, M.J. (1985) The Biology and Culture of Marine Bivalve Molluscs of the genus Anadara. ICLARMSJud&fifiy. 12,37p.

CLAVIER, J. and P. LABOUTE (1987) Connalssance et mise en valeur du lagon nord de Nouvelle Caledonle: premiers resultat concernant le bivalve pectlnlde , Amusium iaoonicum balloti (6tude bibliographlaue, estimation de stock et donnees annexes). Rapp. Sclent. Techn.. ORSTOM, Noumea. 48.:73p.

KRAMER, S.H. (1986) Octopodidae: In UCHIDA, R. and J. UCHIYAMA (eds) Fishery Atlas of the Northwest Hawaiian Islands. NOAA Tech. Rept. NMFS 38, US Dept. of Commerce, p74-75.

LEWIS, A.D. (edX 1985) Fishery Resource Profiles: Information for Development Planning. Fisheries Division, MP I, Suva. 90p.

PARKINSON, B.J. (1982) The speclment shell resources of FIJI. Report prepared for SPC and the Govt, of Fiji, SPC, Noumea. 53p.

PERNETTA, J.C. and L. HILL (1983) A review of marine resources use in coastal Papua. J. de la Soclete des Oceanlstes. 5Z: 175-191.

RICHARD, G. (1983) Importance de la production malaoologlque dans les ecosystemes marlns de Polynesia Franchise. J de la Soclete des Oceanlstes. 22:77-87.

ROPER, C.F.E.. M.J. SWEENEY and C.E. NAUEN (1984) FAO Species Catalogue. Vol. 3. Cephalopods of the World. An annotated and illustrated catalogue of species of Interest to fisheries. FAO Fish. Synop. (125) 3:277p. SPC/lnshoreHsh. Res./WP2 Page 7

SWAOLING, P. (1982) Shellfish In Papua New Guinea with special reference to the Papuan Coast. In: L. MORAUTA, J. PERNETTA and W. HEANEY (eds). Traditional Conservation In Papua New Guinea: Implications for Today. Mongraph 16. IASER, Port Moresby, p307-310.

SWADLING, P. and A. CHOWNING (1983) Shellfish gathering at Nukukau Island, West New Britain Province, Papua New Guinea. J de la Soclete des 0cean1stes.3J: 159-167.

VOSS, G.L. (1973) Cephalopod resources of the world. FAD Fish Circ. (149) :75p

WONG, T.M. and T.G. LIM (1985) CocktefAnadara granosa) seed produced in the laboratory. ICLAftMNewsl.,Oct. 1985, pi 3.

ZANN, L.P. (1985) Traditional Management and conservation of fisheries in Kiribati and Tuvalu atolls. In: The Traditional Knowledge and Management of Coastal Systems in Asia and the Pacific. K. RUDDLE and R.E. JOHANNES (eds), UNESCO, Jakarta p53-77. SPC/lnshore Fish. Res./WP2 Page 8

Annex 1

Table),

List of marine mollusc genera utilised as food In the Pacific Islands, (Various sources).

CLASS PELECYPOOA

Tridacna, Hlppopus Giant clams Anadare.Arca Blood cockles, ark shells Gafrarlum, Perlglypta, Vastlcardlum Hardshell clams Pitar, Latona, Codakia, Ctena, Quadnipagus Hardshell clams Anodentla Lucira Asaph is, Atac todea , Spisula Surf clams Gelotna, Tapes Mangrove clams Sponoylus Thorny oysters Saccostrea, Rock oysters Pinctada Pearl oysters Pinna Razor Isognomon Hammer oysters Modiolus Mangrove Chama Jewelbox clam Amuslum Saucer scallop Batissa River clam

CLASS GASTROPODA

Lambis, Strombus Strombs, conchs Neritlna, Polinices, Nerita Moon snails, nerites Turbo Turban shells Cerithlum. Rhinoclavis, Littorina , periwinkles Tectus, Trochus Top shells Vasum Cypraea, Ovula Cowries Conus Cones Tonna Tun shells Chicoreus Murex Sea hares Aplysia, Dolobella

CLASS CEPHALOPODA Inshore squids Seploteuthls.Loligo Flying squids Symplectoteuthts, Notodorus, Ommastrephes Octopus Cuttlefish Nautilus CLASS AMPHINEURA

Acanthozostera Chitons SPC/lnshoreF1sh.Res./WP2 Page 9

Annex 2

Table 2, Nominal catches of miscellaneous marine molluscs In Fiji, 1985-1986 , based on Fisheries Division data. (These ftoures do not Include subsistence consumption, which Is reckoned to be considerably higher in some cases). VoluBft (at)

1985 ]9U Bivalves AD8jto(Ka1koso)« 80.7 98.1 Ml3S9(Ka1) 1286.1 1349.0 PjrjpJyjda.GjfTJ[±im(ICai(J8wa,kaitakaifih) 1.4 3.9 Alaclodea (Sigawaie) 0.5 t.O Tridacna (Katavatu. caoa) 16.6 19.1 Casselrjafi(Dlonivelttrl) 1.0 NA dflflMfi(Kuku) NA 4.4

Gastropods Strombus. Lombjs (Yoga, gero) 1.9 6.9 Tectgs(Tovu) 1.5 2.0 IfjjcJlie (SicD-meat only 4.8 3.4 Nerita. Polintces (Madrall. drevula) 0.6 3.0 OjpJJaJieJlaX Veata-seahere) 1.1 0.8

Cephalopods Octoous(Kutta) 6.7 6.8

Others AcanthtEostera (Tadruku-chlton) 1.2 1.3

* Includes some fofrartom, PeriQlvota. etc. NA - no data available; catch probably negligible.