DISTRIBUTION Mainly in tropical and subtropical waters in all major oceans, although a few species are found in shallow waters in temperate regions (7). The distributions of individual species are little known at present. Some appear to have wide distributions: Antipathes dichotoma occurs throughout the Indo-pacific in deep waters and in the Red Sea (7); A. japonica is common at about 10 m depth from Taiwan to central Japan; Cirrhipathes spiralis and C. anguina (whip corals) occur from 30-500 m throughout the Indo-west Pacific (1317 Others have localized and restricted distributions: A. aperta is found in all fiords of the west coast of southern New Zealand (30). A. panamensis is known from Panama, Colombia, Ecuador and the Galapagos Is; A. galapagensis is endemic to the Galapagos Is. (33). POPULATION Unknown, and as for all colonial species is very difficult to estimate. HABITAT AND ECOLOGY Found in deep water, usually between 30-110 m although some have been recorded from depths of 2000-3000 fathoms CFOOO-OOO m) (12); in the Caribbean the greatest density is between 40-200 m (8); in Hawaii adult colonies were found to tolerate depths of 1-146 m (9). Colonies are frequently associated with terraces and undercut notches, which suggests that abundance is related to habitat space (10). In New Zealand, A. aperta is found in shallow, cold waters, on the steep rock walls of fiords (30). Light and water turbulence play important roles in the distribution of A. grandis off the coast of Hawaii. Adult colonies can withstand light intensities of up to 60 per cent of the surface incident light, but it appears that larvae cannot settle and survive under a light intensity greater than 25 per cent of the surface light. This would account for the greatest densities being found below 35 m. Colonies were found at shallower depths only in turbid water or in shaded areas (9). Off Curasao, Black Corals are found as shallow as 10 m and in the shade of rocks occasionally shallower; the greatest density of colonies is found between 15 and 50 m (15). In the Galapagos, A. panamensis and A. galapagensis are found throughout the archipelago where there are steep vertical rocky walls (34). They occur at depths from 3-50 m; the unusually shallow depths at which they occur may be due to the cool waters surrounding the Galapagos. It appears that A. panamensis like most black corals, settles preferentially in dark areas (caves, underhangs) from which the colony grows outward into the current. A. galapagensis appears to tolerate a wider range of substrates, often more exposed. A. panamensis is rarer compared with A. galapagensis (33). Black Corals may be scarce where sediment covers terraces (10). Only animal material has been observed to be ingested by A. grandis (9). The normal method of feeding is probably trapping of animal plankton by the nematocysts (21). Polyps are either male or female but colonies may be hermaphroditic (7). Reproductive maturity in A. dichotoma is probably reached between 10 and 125 years and the reproductive cycle may be annual (10). Asexual reproduction occurs naturally by fragmentation of branch ends. Colonies may have a life span of 70 years (10). SCIENTIFIC INTEREST AND POTENTIAL VALUE Antipatharians are of interest for their unusual body structure compared with other anthozoans, and they are important in providing a habitat for many other small invertebrates of systematic value (13,16). In the Middle and Far East Black Coral has long been accredited with medicinal and magical properties (26). It was once abundant in the Persian Gulf from where it was exported to India (25). It has recently become a popular material for souvenir jewellery and is sold to tourists in many tropical countries, providing income to local people (3,4,6,10). Synthetic 'Black Coral' is often sold to unsuspecting tourists (28). An unknown but probably fairly large amount is involved in international trade. For example, in June 1982 the U.S.A. imported 24,000 pieces of Black Coral jewellery from Taiwan and 359 pieces from the Philippines (27). In 1981, prices for A. dichotoma on the international market were 20-50 U.S. kg (28). 48


ornamental articles. The most valuable mother-of-pearl is obtained from four species; Pinctada maxima P. margaritifera Trochus niloticus and Turbo marmoratus although a number of others ( Pinctada sp, Haliotis sp. and some freshwater mussels) are also used. The mother-of-pearl trade declined with the development of plastics, but recently it has been undergoing a revival; 3apan, Taiwan and South Korea are the centres of the carving industry. Currently there is an annual demand of about 6000 tonnes of unprocessed Trochus shell alone (13). The Philippines and Indonesia export large quantities of Pinctada sp, and Indonesia, the Solomon Islands and other Pacific islands export Trochus niloticus and Turbo marmoratus (14). In the South Pacific the export of mother-of-pearl may be the only source of cash income for people on some of the remoter islands (13) and the button industry is being revived in some areas (45). 3apan is the main producer of pearls, techniques for culturing these valuable molluscan products having been developed in this country first. It is thought that there is potential for pearl culture industries in other countries (18). Shell collecting has been a popular hobby for centuries. The ornamental shell trade is now a major industry, centred in the Philippines which exported about 3500 tonnes of ornamental shells in 1979. The main consumer is the U.S.A, whose imports rose from just over 1000 tonnes in 1969 to about 4400 tonnes in 1978. There are currently an estimated 1000 shell dealers in the U.S.A, and in Florida alone there are probably between 5000 and 10 000 retail outlets such as gift shops, hotels and department stores (33). Other major consumers are Japan and many European countries. The species most in demand are the big colourful gastropods from the Indo-pacif ic and Caribbean, such as the Queen Conch Strombus gigas the Tiger Cowry Cypraea tigris, the Pearly or Chambered Nautilus Nautilus pompilius and helmet shells, cones and volutes (33). The jewellery industry has made use of shells for many centuries. Naples in Italy has long been important for cameos, carved from the shell of the Indo-pacific gastropod Cassis Recently shell jewellery and other shellcraft articles have undergone a revival in popularity. Small cowries, dove shells and a variety of other shells are used in large quantities to make necklaces, lampshades, decorated boxes and figurines. The Philippines is the main supplier and is also the centre of the capiz shell (Placuna placenta ) industry. Nearly three and half million capiz shell articles were exported in 1979 (14). THREATS TO SURVIVAL As for many marine invertebrates there are few examples of molluscs that are threatened with extinction. The Giant Clams (see data sheet) are possible exceptions, but even they may still occur in large numbers on some of the remoter Pacific atolls. There are, however, many examples of commercially important species which have been locally over-exploited; some examples are given below. Less information is available on the effects of pollution and habitat disturbance, but in some cases these factors could have serious effects. 1. Exploitation Abalone has been overfished in many countries including Japan, China, South Africa, New Zealand, south Australia and Mexico (43). Haliotis tuberculatus has practically disappeared from the English Channel (16), and the Pacific species were heavily overfished on the coast of California, U.S.A. earlier this century (22). Oysters were once the food of poor people but are now considered a luxury in most countries. Natural oyster grounds have been destroyed through coastal development, domestic and industrial pollution, poor management and over-exploitation. In some cases, where pollution has not harmed the bivalves themselves, they have been rendered unfit for human consumption. By 1964, 12 per cent of the total active shellfish-producing area in the U.S.A. had been closed for health reasons and oyster production on the Atlantic coast had been reduced from 43 million kg in 1920 to less than half that amount. Oyster fisheries have also been lost in the Philippines, Australia, Great Britain and on the Pacific coast of the U.S.A. (21,39,40,43). Scallops were fished to virtual commercial extinction 71


off Tasmania earlier this century (39). In Chile the giant mussel Choromytilus chorus and the gastropod Concholepas concholepas have both been overfished (23). Even cephalopods, a resource under-utilized in many regions, have been overfished in some areas. Catches of cuttlefish in the eastern central Atlantic have declined drastically and the north-west Pacific catches, which still represent 60 per cent of the total world production, have been declining steadily since 1968 (9). Commercial mother-of-pearl species have been over-collected in many areas (18). In Papua New Guinea catches of Trochus niloticus decreased progressively during the first half of this century, until 1956 when regulations were introduced (26). In the Andaman and Nicobar Islands, the introduction of new diving techniques by the Japanese in the 1930s caused rapid depletion of T. niloticus ; whereas in 1933 over 20 shells could be collected in an hour, by 1935 only two or three were found in the same length of time (27). In New Caledonia, populations have been periodically over-collected (13) and by the 1950s there was evidence of serious overfishing in Palau (15). Intensive exploitation has led to the disappearance of the pearl oyster Pinctada margaritifera from some Polynesian atolls (2). There is evidence that the ornamental shell trade is causing depletion of local populations of some of the more popular shells, although it is unlikely to cause the biological extinction of any species (If). Shells have been heavily collected on the Kenyan coast for many years by amateur shell collectors, tourists and commercial operators. This has resulted in the extreme scarcity of large colourful species on the more accessible parts of the coastal reef (1,30). Similar situations are to be found in Guam, Florida, the Seychelles and other regions where tourism has recently become a major industry (31,32,33). In the Philippines certain species are becoming rare (29), particularly the giant clams Tridacna spp. and the Giant Triton Charonia tritonis (see data sheets). Marine species with restricted ranges are particularly susceptible to over -collection. Easter Island and Mauritius have several endemic cowries such as Cypraea cribellum and C. esontropia ; with the growth of tourism, these species could be over-collected (1 1). Cymbiola rossiniana a volute endemic to the south-west coast of New Caledonia, is highly sought after, fetching high prices on the international market and there are fears that it could be over-collected (28). The rapid growth of SCUBA diving as a hobby and the development of new fishing techniques could pose a threat to some species since previously inaccessible populations can now be reached. Certain deep-sea molluscs have always been rare and have fetched high prices on the shell market; for example the Glory-of-the-sea Cone Conus gloriamaris fetched U.S2000 in 196 but it is now being found in comparatively large numbers, particularly in the Philippines, and sells for U.S200-300 (29). Harpa costata is a very valuable, apparently rare species, endemic to Mauritius. Specimens have been collected in considerable numbers in the past (11) but the impact of exploitation on this and similar species is unknown since nothing is known of their ecology and population dynamics. 2. Pollution Very little is known about the effects of pollution on marine molluscs. Oil on the shore and in the intertidal zone can kill molluscs by smothering or poisoning them, and filter feeders and deposit feeders may ingest and accumulate dispersed or segmented oil. Moderate and chronic exposure of bivalves to low concentrations can have an important commercial impact. It has been recognized that there is a need to control pollution from oil and chemicals discharged from ships in Dongonab Bay in the Sudan to prevent damage to Pinctada margaritifera which is cultured in the area (25). Bivalves filter a large volume of water, and ingest hydrocarbons which accumulate, particularly in the fatty tissues, at a faster rate than they are eliminated. However, following the cessation of pollution it is usual for hydrocarbons in the tissues to be reduced to low levels within 30 days. Like many other marine invertebrates, molluscs may be 72


TRITONS TRUMPET or GIANT TRITON Charonia tritonis (Linnaeus, 1758) Phylum MOLLUSCA Class GASTROPODA RARE Order MESOGASTROPODA Family CYMATIIDAE SUMMARY Charonia tritonis has a large attractive shell which is popular with shell collectors and has had a long history of use in the Indo-pacific as a trumpet. It is found on coral reefs and appears to be rare throughout much of its range. In some places this may be a result of overcouection. DESCRIPTION Charonia tritonis has a large, very attractive shell reaching 40 cm or more in length. It has a high pointed spire, and is creamy white with purple and brown markings and an orange interior to the aperture (1). mm DISTRIBUTION Indo-west Pacific (1) to the Red Sea (19), including the Great Barrier Reef, Australia (t), the Philippines (6), Indonesia, Seychelles, Mozambique (22), Guam (lj), the Marshall Islands, Hawaii (23) and Fiji. POPULATION Unknown, but densities appear to be naturally low in many areas. In a three month study in part of the Sudanese Red Sea only two specimens were found; over the same period local shell collectors had taken five and they reported that specimens were only found occasionally (19). Reported to be uncommon in Guam (If) and on the Great Barrier Reef where in a study of 81 reefs, only 2f specimens were found (20). In a survey of 133 sites on 92 reefs in Indonesia only two specimens were recorded (22). Population densities may actually be higher as specimens are difficult to find on account of their nocturnal habits and camouflaged shell (19). HABITAT AND ECOLOGY No detailed ecological study has been carried out on 91


the Giant Triton. It is usually found among corals on coral reefs. On the Great Barrier Reef it tends to occur on seaward slopes or on coral pinnacles in lagoons (20). It is usually nocturnal (19) but in Indonesia has been recorded from sand near coral in broad daylight (22). It feeds principally on starfish including Culcita novaeguinea the blue starfish Linckia laevigata and the Crown-of-thorns, Acanthaster planci but also occasionally on holothurians (2,15,20,21). When preying on A. planci it takes mainly large juveniles and adults on which it may feed whole (4,5,15). It may take up to six years to reach its maximum size (3). It has been reported that the female lays clumps of sausage-shaped egg capsules under protective rocks. The larvae are long lived and have considerable dispersal abilities (3,23,2f). SCIENTIFIC INTEREST AND POTENTIAL VALUE The shells of this species have been used as a trumpet in the South Sea islands, Indonesia, Hawaii and the Seychelles for centuries (3). More recently it has become one of the more sought-after shells in the ornamental shell trade and is collected in large numbers in the Philippines and other countries (6,17). It has been collected extensively in Queensland waters since World War II and available evidence indicates that thousands of specimens were collected on the Great Barrier Reef during the 1950s and sold to tourists and to the shell trade via the commercial trochus shell dealers on Thursday Island in the Torres Straits (7). Shells were collected intensively at several islands in the Marianas and Carolines in the 1960s (18). In 1970 a thousand specimens were seen on sale in Suva market, Fiji said to have come from remote islands (10) and in 1971 specimens were seen on sale at several localities on Manus Island, Papua New Guinea (7). Heavy collection was reported in this area in the 1970s. In Hawaii in 1971, shells were on sale for U.S65 each. The value in 1978 was put at U.S7-30 depending on size and quality (16). In 1981 specimens in the Philippines sold for U.S5-20 (17). It has been suggested that C. tritonis may be a key species in the coral reef community. As a predator of the Crown-of-thorns Starfish it was thought to be important in keeping this species in check (7). Its role in this context was hotly disputed at the peak of the Acanthaster outbreaks in the Indo-west Pacific, and no final conclusion has been reached, as several other factors are almost certainly involved. Specimens of C. tritonis do not appear to be sufficiently common to exert any control over A. planci populations, and starfish attacked by the mollusc have been found to survive (7,15). Furthermore, C. tritonis may prefer other species of starfish (21). However, areas with particularly low numbers of C. tritonis have been found to correlate with infestations of the Crown-of-thorns (f5,7,20). THREATS TO SURVIVAL Over-collection may have been responsible for reports of depletion of this species in some areas. Furthermore, the large numbers taken strongly suggest that populations may have declined. Populations have been severely decimated by over-collecting in Guam waters (8) and the species is said to be vulnerable to collecting in southern Japanese waters (9). Some shell dealers in the Philippines reported Giant Tritons to have become scarce in 1981 (17). At the end of the 1960s C. tritonis was reported to be common in Palau and Rota in the Pacific, areas which were seldom visited by collectors (15). In the Caribbean, a similar species, the Variegated Triton C. variegata has also been depleted through over-collection (13). However, despite these reports, this species, although certainly rare, may not be threatened at present. Its wide distribution and prolific long-lived larvae would suggest that it may be able to support current collecting pressure (2f). Like many other species C. tritonis populations could have been reduced as a result of the accumulation of toxic residues from pesticides and other pollutants in the tissues of specimens, particularly since this species is a predator of high trophic status (f7) but there is no data to substantiate this. 92


T. squamosa has an elongate shell with about five strong, low, rounded radial ridges, each carrying fluted scales growing large towards the edge of the valve. The valves are white, tinged with lemon yellow towards the margin, and may reach 35-0 cm in length (22). In the southern Philippines and Indonesia some individuals are found with deep orange and yellow shells 2ti-6). x: ; i A" ' '■ J -' -A J. -v-, Viii i; V: AIB. Jy-riv Mantle colour in most species varies geographically and ranges through brilliant blue, green, purple and brown depending on incident light. The vivid pigmentation is caused by iridophores and may help to protect the tissues against the effects of the intense light to which they are continually exposed 3U). It may also serve to confuse potential predators or to warn them of potential danger (16). When the mantle is fully expanded, the shell margins are entirely obscured by the scalloped, coloured siphonal tissues. The exhalant aperture, at the end of a tubular extension, is in the middle of the upper surface. The mantle tissues are briefly withdrawn when a shadow falls on them and only withdraw permanently during periods when animals are left exposed at the extreme low water of spring tides (33). The basic biological features of tridacnids are reviewed in (8). DISTRIBUTION Restricted to limited areas of the Indo-pacific; their ecological requirements (shallow waters of coral reefs) and short larval life (preventing long range dispersal) may confine there to their present ranges (22). Hippopus hippopus occurs from the Malay Peninsula to eastern Melanesia. There are records for at least the following countries: Singapore, Ryukyu Islands, Philippines, Indonesia, North Borneo, Western Australia and Queensland, Papua New Guinea, Solomon Islands, Vanuatu, (New Hebrides), Fiji, New Caledonia, Caroline Islands, Marshall Islands, Gilbert Islands, Tonga (22). H. porcellanus appears to have a more restricted range than H. hippopus but overlaps with it. It is known from the Sulu Archipelago in the southern Philippines, one specimen has been recorded off Masbate Island, central Philippines it5), and specimens have been recorded recently from Indonesia (16). 98


Tridacna crocea ranges from the western coast of the Malay Peninsula east to Micronesia and north to the Ryukyu Islands, Japan, including Thailand, Singapore, Philippines, Indonesia, North Borneo, Papua New Guinea, the Solomon Islands, the Caroline Islands (22). It is reported to be common on the Great Barrier Reef, Australia (19) and in 1969 was the most abundant giant clam in Palau in the Caroline Islands (10). T. derasa is known from the Philippines, Indonesia (Irian Jaya), Guam, Cocos-keeling Islands, Australia, Papua New Guinea, New Caledonia, Caroline Islands (22). T. gigas occurs from the Philippines to Micronesia. Records exist for the Ryukyu Islands, Philippines, Indonesia, western Australia and Queensland, Papua New Guinea, Solomon Islands, Vanuatu, (New Hebrides), Caroline Islands, Marshall Islands, Gilbert Islands (22). T. maxima and T. squamosa are the most widespread, extending from the Red Sea and the East African coast to the Tuamotu Archipelago and Pitcairn Island, and from southern Japan to the coast of New South Wales, Australia (16,22). Both species have been recorded from Mozambique, Kenya, Madagascar, Saudi Arabia, Egypt, Seychelles, Mauritius, Maldives, Chagos, Thailand, Malaysia, Japan, Philippines, Indonesia, North Borneo, Australia, Papua New Guinea, New Caledonia, Fiji, Marianas, Caroline Islands, Marshall Islands, Gilbert Islands, Tuvalu (Ellice Islands), Samoa, Tonga, Tuamotu. T. maxima has also been recorded from South Africa, Sri Lanka, Andaman Islands, China, Taiwan, Solomon Islands, Vanuatu (New Hebrides), Lord Howe Island, Wake Island, Line Islands and Henderson Island (22). POPULATION Unknown. The smaller species are still found abundantly in many areas. In certain areas of the Great Barrier Reef T. crocea density regularly exceeds 100 animals per m2 (30). In closed lagoons at Tuamotu, T. maxima has been found at densities of 63 per m, that is up to 90 000 individuals per hectare (31). In Indonesia near Vogelkop as many as 30-50 large specimens of T. derasa and T. gigas have been found on certain reefs (29). In many areas populations are now much reduced (see below), although in shallow reef areas Tridacnidae are often the commonest bivalves, if not in actual numbers, nearly always in biomass (33). HABITAT AND ECOLOGY Restricted to shallow waters of coral reefs. T. gigas is found on sand and among corals on reefs from about 1 to 20 m in depth. Some or all of the shell may be exposed at low tides (22). T. derasa generally occurs on the outer edges of reefs at about 'f-lo m (22); it appears to be restricted to oceanic environments and is not found on reefs adjacent to large land masses (itj). H. hippopus is found on sandy substrates on coral reefs down to 6 m in depth and on sea grass beds near the reef (22). T. maxima is essentially a reef-top inhabitant living on the surfaces of the reef or sand, or partly embedded in coral (16). T. crocea burrows by mechanical, and possibly chemical, means into coral boulders on the reef-top and lives with only the valve margins visible; it is found most often on top of small, detached coral boulders on the interior reef flat (30). T. squamosa usually occurs on coral reef surfaces in depths less than 15 m, most often in protected environments such as reef canyons and fissures, sheltered lagoons and marine lakes (19). It is uncommon in atoll environments (17). Juveniles of all six species are attached to the reef by a gelatinous byssus. This is retained in small species but is gradually lost in T. gigas T. derasa and H. hippopus (33). Giant clams feed by filtering plankton from the sea with their gills. A supplementary source of food is provided by zooxanthellae of the species Symbiodinum (= Gymnodinum ) microadriaticum which are specialised dinoflagellates that live symbiotically in the mantle tissues and produce glycerol, 99


SCIENTIFIC INTEREST AND POTENTIAL VALUE Land snails have long been favourite subjects of study for biologists, as they are slow moving and easy to catch, are easily marked and are generally tolerant of laboratory conditions. They have been used extensively for research into the basis of natural selection, on account of the high degree of diversity found both within and between populations. Some of the strongest evidence that natural selection acts on genetically determined visible characters has been produced from studies on land snails such as Partula (see review)f5). Land snails are also important subjects of study for biogeographers, providing evidence for theories on the distribution of land masses and species (16). Terrestrial molluscs play an important ecological role. They dispose of large quantities of dead plant matter and provide food for a wide variety of animals (25). Compared with marine molluscs, their use as food by man is fairly small, but in several countries snails are considered a gastronomic delicacy. Helix pomatia is famous for its role in French cooking (see review) but other species such as Helix aspersa and increasingly Achatina fulica the Giant African Snail, are also eaten in large quantities. Taiwan is now a major exporter of the latter (34). Shell collectors have recently become interested in land snails, particularly the colourful tree species. Liguus virgineus from Haiti, L. fasciatus from Florida, Polymita from Cuba and a wide variety of species from the Philippines and Papua New Guinea are involved in the international shell trade (26,27,28). THREATS TO SURVIVAL Land snails include some of the most vulnerable terrestrial invertebrates, and many species have become extinct over the last century. This is particularly apparent on Pacific islands. The unbalanced nature of the original fauna arriving on such islands and the subsequent lack of immediate competition often results in the development of very delicately balanced communities which can be easily disturbed. The degree of land snail extinction in the outer islands of Polynesia (Rapa Island, Marquesas, Mangareva, the Hawaiian Chain and the Austral Group) has been described as catastrophic (15). By 193f, the land snail fauna of Mangareva was reduced to a single forest patch; Rapa Island probably lost 50 per cent of its endemic species between 193 and the mid-1960s; and very few endemic species were found in the Marquesas or on Kauai in the 1970s. In the Society and Samoan Islands ground-dwelling taxa are fast becoming extinct (15). In Hawaii, of approximately 1061 endemic snail species, about 600 have probably become extinct recently and another 200-t00 are probably endangered (10). Many species in the family Achatinellidae are seriously endangered. The subfamily Achatinellinae of approximately 100 species is endemic to Hawaii and provides a good example of the rapid decline of this group. Recent searches have failed to find many species in the four genera, Achatinella (see review), Partulina Perdicella and Newcombia No trace of Hawaii Island's three Partulina species have been found recently; Oahu's only Partulina has not been found for decades; on Molokai only five of the eight species have been found recently, most of which were very rare and local; and Lanai has only two or three Partulina species in the small amount of remnant native forest. On Molokai only one living individual of the island's sole Perdicella species has been found recently (8,56). All members of the Partulidae are probably threatened (see review for Moorean species) and the Short Samoan Tree Snail Samoana abbreviata may now be extinct. In 1926 this species was abundant and widely distributed on Tutuila but despite strenuous efforts it was not collected in 1975 (16). In the Pacific, more than 100 species in the family Endodontidae have become extinct within the last 50 years (35). In the 1830s, 13 species were collected on Rarotonga in the Cook Islands but in 1965 only two were found. In the 18tos living endodontoids were recorded from Mangareva in the Gambler Islands but in 193> only the dead remains 158


the range of several species (25). Loss of finland is responsible for the decline of many species in the genus Vertigo such as V. angustior V. geyeri V. genesis and V. moulinsiana which are widespread but very local and found only in calcareous fens and marshes. Woodland species and relic species with small ranges are particularly vulnerable, including Elona quimperiana Catinella arenaria Truncatellidae arcyensis Vallonia sp, Trichia sp. and Trochoidea geyeri (39). Elona quimperiana for example, is found only in the west of Brittany, France and in north eastern Atlantic coastal areas of Spain in deciduous forest and damp headlands. Its biology and ecology are poorly known and there is concern that it could become endangered through habitat loss moil). In the U.S. A. surveys have revealed many species threatened through habitat loss. In the eastern U.S.A, 22 species are considered to be potentially endangered on account of their limited ranges or because they are found in areas undergoing rapid development (tf-s). For example, most forms of the well-known Florida Tree Snail ( Liguus sp) are now extinct in the Keys, eliminated by the growth of holiday homes and tourist resorts. Fortunately several have been transplanted into the Everglades National Park where they stand a good chance of survival. The Painted Snake Coiled Forest Snail Anguispira picta is threatened by lumbering in its limited area of distribution in Tennessee. Succinea ovalis chittenangoensis the Chittenango Amber Snail is known only from the spray zone talus under the waterfall after which it is named, and is vulnerable on account of its small ranee (33). Little information is available for Africa and many species have only been recorded from their type localities. In South Africa, where the terrestrial molluscan fauna is comparatively well-studied the number of endemic species is high; for example, the proportion of endemics reaches 90 per cent in the genus Gulella Many species are forest dwellers, and the area of coastal bush and forest along the east coast is particularly vulnerable. Other areas important for molluscs include the Chirinda Forest (Mt Selinda) and the Victoria Falls Rain Forest, both in Zimbabwe Ct). Terrestrial snails are even less well-studied in Asia, where many species may become extinct before they are known to science. In the Philippines, deforestation and fire had eliminated much of the endemic snail fauna by 1957, and even in Palawan, probably the least accessible and developed island in the country, much of the original fauna has probably gone (10). 2. Introduced species The introduction of carnivorous snails to many Pacific islands in an attempt to control the Giant African Snail Achatina fulica has caused enormous damage to endemic snail populations. A. fulica was confined to the African mainland and Madagascar until the beginning of the 19th century when it was introduced to Reunion Island in the Indian Ocean, purportedly for making soup for the Governor's mistress. Within a few years populations had reached pest proportions, the snail showing a preference for cultivated plants. It subsequently spread to India and colonized large areas of the Asiatic mainland, and has since spread eastwards across the Pacific, becoming established in Tahiti, the Hawaiian chain, Vanuatu and New Caledonia (12). Attempts at biological control of A. fulica were made with the carnivorous snails, Gonads quadrilateralis from Africa and Euglandina rosea from Florida (10,19). Studies carried out to investigate the effectiveness of these species have produced no satisfactory results, although one study cited decreases in the abundance of A. fulica at several Oahu sites. However, no attempt was made to determine whether this was due to predation or to disease and other factors (7,11). Results from a second study suggested that the carnivorous snails preyed selectively on juvenile A. fulica (1) but this study did not consider reproductive seasonality as a factor determining presence or absence of young A. fulica, and at least one study 160


the inclusion of grass as part of crop rotation, may have a beneficial effect. Grassland has been shown to have a higher density of earthworms than arable land, probably because more organic matter is available for food in the former. Adding organic manure may improve populations, and the effect of healthy earthworm populations on crop yields is such that worms are being bred commercially for this purpose (2). Research is being carried out into a number of other uses for earthworms. Experiments are in progress to determine ways in which they can be most efficiently used for disposal of organic waste, either producing a useful fertilizer, or the worm crop itself being used as a source of protein. Worm meal has a high protein content (58-71 per cent on a dry-weight basis), competing well with meat or fish meal in experimental trials, and there is good reason to believe that it will become an important component in commercial feeds for intensive livestock industries and fish culture (8). The bait market is another major consumer of earthworms. For example, huge quantities (all introduced species) are exported from Canada to the U.S.A. each year for this purpose, the worms having been collected at night from golf courses and sports fields (30). Vermiculture is big business in several countries. The Japanese are currently the foremost earthworm producers with the U.S.A. second and the Philippines third (8). Farms in the U.S.A produce as many as 05 million worms per day (2). Lumbricids are cultured in the more northerly states of the U.S.A. and the peregrine African earthworm Eudrilus eugeniae (Eudrilidae), the African Night-crawler, is cultured in the southern states. The potential of worms as human food is also being investigated (some people, such as the Australian aborigines (28) and the Paris in New Zealand, have traditionally made use of earthworms in this way) but worms are unlikely to become important in this way for many years (8). By contrast the Palolo Worm has long been important in Samoa. The spawning period is awaited with great expectancy, and as the epitome rise to the ocean surface they are scooped up in armfuls. The epitome also provide food for fish, birds and other predators (1). Many annelids contain compounds of value to man. Earthworms could prove to be a source of new drugs and new species should be studied with this in mind. Folk medicine in several countries has prescribed earthworms for a variety of ailments including jaundice, smallpox, haemorrhoids and rheumatism. More recently earthworm extracts have been shown to have an antipyretic activity that could be made use of in medicine. Some earthworms have a bioluminescence reaction which is dependent on peroxide and can be used as a clinical test for this substance (26). However, as yet there is no substantial evidence to suggest that earthworms could make any significant contribution to human or animal medicine, although the supposed rheumatism curing properties may be worth investigating (8). The use of the leech in medicine is well known, and current work on the Medicinal Leech Hirudo medicinalis is discussed in the data sheet. Haementeria ghilianii from French Guiana, the largest leech in the world, may prove to be the most important species in research on account of its easily dissected and simple nervous system, the extracts that can be obtained from it which have potential medicinal applications, and its large eggs which permit embryological studies, unlike those of the Medicinal Leech. It is now bred in large numbers in Berkeley, California (17). The polychaete Lumbrineris brevicirra produces a toxin in its integument which has been used in the development of an insectide, effective against pests such ais Colorado Beetle, Mexican Bean Beetle and insect strains resistant to organophosphates and organochlorides. It is also reported to be essentially nontoxic to warm-blooded animals and decomposes fairly rapidly in biological tissues and the natural environment (29). Aquatic oligochaetes play a major role in the retrieval of organic matter from the sediments of lakes and rivers. Leeches and aquatic oligochaetes have been considered as potential indicators of pollution, but many species that are an obvious feature of polluted waters also occur in clean habitats and there appears 199


' & ) Limulus polyphemus T. tridentatus has been reported from western and southern Japan, Taiwan, Philippines, North Borneo, Vietnam and Sumatra, Indonesia (15,33). T. gigas and C. rotundicauda have been reported from the coast of India, Thailand, Malaysia, Singapore, Indonesia, the Philippines and Borneo and have essentially the same ranges (15,33). All three Asian species are found sympatrically at Kota Kinabalu on the north-west coast of Borneo and throughout much of Indonesia and T. tridentatus and C. rotundicauda are found sympatrically along the south-west coast of the Philippines including Palawan (33,3f). POPULATION In general horseshoe crabs are abundant in the areas where they occur. In 1956 there were thought to be more than one hundred thousand adults in the Cape Cod Bay area (30) and currently L. polyphemus is often brought up in trawls and dredges off the east coast of the U.S.A. (32). The population in waters off Massachusetts, north of Cape Ann, is also probably large as 16to crabs have been tagged there (32). The largest of the populations along the east coast of the U.S.A. is centred on Delaware Bay (13,32); in 1977 and 1979 peak spawning activity was estimated to involve 305 500 adult animals (13). In coastal waters off New Jersey, crabs are abundant in the inshore 3 miles (5 km) from Cape May to Atlantic City, but much less common further north (14). HABITAT AND ECOLOGY Horseshoe crabs are marine bottom dwellers living in sandy and muddy bays and estuaries. Limulus polyphemus has been well studied and most of this account deals with this species. In Florida, Gulf of Mexico, adults are found to a depth of 30 m, but major concentrations are found at about 5-6 m, and the animals only return to the beach to breed (25,31). Limuli have been dredged from depths to 2t6 m and at distances as far as 56 km off the Atlantic coast (26,32). C. rotundicauda differs from the other species in that it is often 236


freshwater and terrestrial isopods have evolved directly from marine ancestors and their current distributions provide useful data on early geological events. The suborder Phreatoicidea, for example, is a very ancient group, fossil phreatoicids from Middle Pennsylvanian deposits in Illinois dating back some 120 million years (5). The phreatoicid fauna of Great Lake in Tasmania is also of interest with two endemic genera ( Mesacanthotelson and Onchotelson ) and nine endemic species (f). The Ostracoda have the most extensive fossil record of any crustacean group, stretching back over 300 million years. Certain oil-bearing strata are rich in certain ostracod fossils which can be used as indicator species when searching for new oilfields (1). The main value of crustaceans to man is as a food resource and they are a major element in both commercial and subsistence fisheries. Of greatest economic importance are the prawn and shrimp fisheries, the world catch of which totalled over 15 million tonnes in 1980 (12,13). FAO has produced a catalogue of almost 350 species of shrimps and prawns that are used by man or are considered to be of potential commercial value throughout the world (58). Over 20 major types of crab fisheries are listed by FAO, and the 1980 world production totalled over 800 000 tonnes (12). The lobster is probably the most valuable and popular crustacean and the world lobster catch (including both clawed and spiny lobsters) totalled over 150 000 tonnes in 1980 (12). Spiny lobsters of the family Palinuridae are found in all major tropical and temperate oceans and support subsistence, large-scale commercial or recreational fisheries in most areas. The 1980 catch totalled nearly 70 000 tonnes, 70 per cent coming from the Caribbean, eastern Indian Ocean and south-east Atlantic (12,15). The recreational harvest of spiny lobster used to be insignificant but, with the growth in popularity of SCUBA and skin diving, has become important in several areas (17). Although lobsters are now considered a luxury food in most countries, in the past 'they were taken for use as fertilizer, bait and as a subsistence food (16). The clawed lobsters, Homarus americanus in the west Atlantic and H. gammarus and Nephrops norvegicus from the eastern Atlantic and Mediterranean, have been exploited intensively for centuries (16). A wide range of other marine crustaceans are used as food by man, including barnacles which are eaten in some countries including the Philippines k9) and Spain (50). The potential value of the krill stocks of the Southern Oceans has recently become a major issue. Krill fishing is still considered a pilot-scale activity, but the swarms that appear regularly in the Antarctic summer make this species easy to catch. Krill catches in 1980 totalled over it20 000 tonnes, of which the U.S.S.R. was responsible for 388 000 tonnes (12). Estimates of sustainable yield are extremely variable, ranging from a few million to tens of millions of tonnes. Krill is now considered unlikely to have any major value as a human food resource, but krill protein concentrate could have potential as animal feedstock although other species currently provide a more economical source of fish meal (10,13,67). Freshwater crustaceans accounted for 82 787 tonnes of the 1980 world crustacean catch (12). In Europe crayfish have been consumed in large quantities since Roman times. They are now considered a luxury food in most of the western world but in regions such as New Guinea and Madagascar they are an important source of quality protein (2). The U.S.A. is probably the major crayfish producer. The industry is centred on southern Louisiana where in recent years 30-60 million pounds (13-27 thousand tonnes) of Procambarus spp. (mainly P. clarkii) have been taken annually from natural swamps and marshes and about 50 000 acres (20 235 ha) of culture ponds. The wild harvest accounts for about 60 per cent of the total, and varies with the amount of sustained spring flooding (2,18,19). Pacifastacus leniusculus is exploited commercially in California, Oregon and Washington and Orconectes rusticus and O. virilis in Wisconsin. Sport fisheries for food crayfish 263


DISTRIBUTION Birgus latro is widely distributed throughout the Western Pacific and eastern Indian Oceans, occurring almost exclusively on oceanic islands or on small offshore islets adjacent to large continental islands (2). However, although it has a wide geographic spread, it probably does not occur on all atolls since those that are dry do not provide enough food (31). In the Indian Ocean, it is found on islands south of the equator (21). Still occurs abundantly on Aldabra (f3) but is extinct on almost all the islands in the Seychelles group (23); occurs on some of the numerous small islands off the Tanzanian coast (5); in the Andaman and Nicobar Islands now found only on South Sentinel Island (21,22) and at Galathea Bay where it was said to be common in 1967 (350); formerly occurred on Mauritius but exterminated in the second half of the 19th century; in 1939 almost exterminated in the Keeling Islands (except for uninhabited North Keeling I) (21); in the Chagos Archipelago, found on both of the northern atolls and on most of the islands of the Great Chagos Bank (25); widely distributed on Christmas Island f). Has not been recorded from the East African mainland coast, the Maldives and Laccadives, the islands near Peninsula Malaysia and Sumatra, the western part of the Malay Archipelago nor the islands in the South China Sea (21). In 1981, found on Sipadan Island, about 30 miles (48 km) off the east coast of Sabah, Malaysia (33). In 1939 was still present in parts of Indonesia, the Philippines and Taiwan (21). Currently is found on Olango Island, off Mactan (Cebu) in the Philippines (28). In Indonesia it has recently been reported from the Togian Islands, Central Sulawesi (24) and in 1963 from the north coast of Irian Jaya (15). A detailed account of its distribution in the 1950s on the small islands off the north coast of Irian Jaya is given in (46). In Papua New Guinea has been reported from Rantan and Sae Islands (32) and Los Negros Island (30) in Manus Province. In the Pacific found in Fiji and the Marshall Islands but not in the Hawaiian group. Wake or Midway (13,31). Recorded from Gardner Island in the Phoenix Islands (7), the Juice Islands and Tuamotus (31), Fanning Island (14), the Marianas (2) and Vanuatu (36,37). POPULATION Unknown. HABITAT AND ECOLOGY Almost entirely terrestrial and drowns in water (1 1,44), although the female has to return to the sea to release her eggs and crabs may go to the beach and drink seawater to maintain their salt balance (2,26). On Guam they are most typically found in coastal limestone forests where they establish burrows within the porous, solution-pitted limestone substrate. On some islands in the northern Marianas they occupy burrows dug in the soil or in the interstices of the boulder-cobble shorelines (2). On Olango Island in the Philippines, they live in burrows in coral rock in thick undergrowth. These are 05-1 m in diameter and 1-2 m deep, and may extend 4-6 m in a horizontal direction (28). On barrier reef islands crabs have been found to live in shallow burrows in the substrate or hidden among Pandanus roots and fallen coconut fronds. On such islands Coconut Crabs may occur throughout the island, but on larger high islands, such as Guam, they are rarely found in the interior (2). On Aldabra the species is most abundant in the sandy coconut grove at Anse Mais and in damp Pandanus thickets on South Island, but is also found in the barren coastal champignon and throughout the plain. Normally the crabs inhabit rock crevices, although they can burrow in sand (42). On Christmas Island, the Coconut Crab occurs from the beach through the shore terrace to the highest parts of the plateau. Its distribution is uneven and some areas are apparently avoided. Crabs frequently collect together in groups of a dozen or more (10). Larger crabs may inhabit the best areas of an island, with sandy soil for burrowing and abundant coconut palms (13). 3t0


PYGMY HOG SUCKING LOUSE ENDANGERED Haematopinus oliveri Mishra and Singh, 1978 Phylum ARTHROPODA Order ANOPLURA Class INSECTA Family HAEMATOPINIDAE SUMMARY The Pygmy Hog Sucking Louse is a blood-sucking ectoparasite known only from the Pygmy Hog ( Sus salvanius), an endangered species probably restricted to north-west Assam in northern India. Both the hog and its attendant louse are threatened by destruction of thatch-scrub savanna. DESCRIPTION The Anoplura are blood-sucking ectoparasites of mammals; they are wingless and cannot live independently of the host at any stage of the life-cycle. The eyes are reduced or absent, and the mouthparts highly modified for piercing and sucking. The body is dorsoventrally flattened with a leathery integument, and the legs are strongly developed with powerful claws for attachment to the host's hairs (12). Haematoplnus oliveri is a parasite of the Pygmy Hog ( Sus salvanius . The female louse is 39 to tt2 mm in total length; the male is unknown. The species has been described in some detail and differs from the other six species of Haematoplnus by a combination of the absence of paratergite II, the shape of the thoracic sternal plate and the relatively short head (6,15,16). DISTRIBUTION The seven species in the genus Haematoplnus infest wild pigs from Africa and Europe right across the Orient to the Philippines (15,16). The Pygmy Hog was formerly found in southern Nepal, Sikkim, north-west Assam, the foothills of Meghalaya, northern Bangladesh and south-east Assam. It is now extinct in most of this range and probably restricted to small, endangered populations in north-west Assam, India Cf, 8,9, 10, 1 1). POPULATION Unknown. The only specimens collected are three females (holotype and two paratypes) and one associated nymph, all taken from a Pygmy Hog in Darrang, north-west Assam in 1977 (6). In louse populations, as in many other parasites, most individuals are on a few animals, whilst most hosts have few or no parasites. Elimination of very few hosts from a population may, therefore, lead to virtual or complete elimination of lice from that host population (3). The Pygmy Hog was at one time feared extinct but reappeared in 1971 near Barnadi. That hog population is now virtually extirpated and the only certainly known surviving population is in Manas National Park and certain of its buffer Reserve Forests (8,9,10,11). The population there is believed to be only a few hundred individuals, but may be considerably less. HABITAT AND ECOLOGY Anoplurans are generally very host-specific. Close physiological relationships between the parasite and the host's blood characters are important (1), but this is only one of a variety of interacting components, including host hair type, skin microclimate and host ecology (3,5). The majority of Anoplura carry symbiotic bacteria which are essential in providing B group vitamins (13,17). The lethal effect of abnormal host-blood on Anoplura may result from the death of these bacteria (1,12), or from the accumulation of crystalline blood chemicals which rupture the midgut (2,7). Details of the biology of the louse are not known, but in common with other Anoplura it certainly feeds solely on blood and cannot survive without the host (17). Mating occurs on the host, and the eggs are cemented to host hairs, probably hatching within two weeks (12). The habitat of the Pygmy Hog is primarily unburnt thatch-scrub savanna, composed of mixed scrub and tall grasses (f8,9,10ll). 365


members of the cryptic brachiopod-coralline sponge community in the Caribbean (Jamaica, Curasao), Red Sea and Pacific. High densities are found on the undersides of foliaceous corals or overhangs and in the interiors of crevices or caves (6). A variety of rarer forms are known from depths of between 500 m and 6000 m (3). Examples are the relict species Sphenarina ezogremena and Septicollarina hemichinata known only from single specimens collected at a depth of 2W m in the Bali Sea (27). Probably the richest brachiopod area in the northern hemisphere are in Puget Sound, around the San Juan Islands (Washington State, U.S.A) and off the southern coast of British Columbia, Canada (30). Brachiopods are rarely found washed up on the sea shore since the shell breaks easily once the animal dies (2). In the inarticulate brachiopods the Lingulidae and Discinidae occur in tropical and subtropical regions. The two genera in the family Lingulidae are geographically disjunct: Lingula is found in shallow inshore waters in the east Atlantic and Indo-west Pacific regions, while Glottidia is confined to both coasts of the Americas. Representatives of the Discinidae are restricted to shelf waters in all oceans, except for a single cosmopolitan deep-sea species. The Craniidae occur worldwide, but mainly in temperate shelf waters. All groups may be exceedingly abundant, and can be found at densities of up to 1000 per m (17,18). Most articulate brachiopods live permanently attached to hard material on the sea floor either by a fleshy stalk or by cementing the ventral valve directly to the surface, but a few species are able to attach to aggregated sediment grains and other soft substrates (9,31). They feed mainly on plankton and other organic material collected by the filaments on the lophophore, which create a current of water through the mantle cavity; they may also feed directly on dissolved nutrients (2,5). They are not found in areas of soft, fine sediment with a high rate of sedimention, since such conditions would clog the lophophore, but they can survive strong water currents. They do not generally tolerate salinities deviating more than a few per cent from that of normal sea water (2). Sexes are normally separate although there are a few hermaphroditic species. Eggs and sperm are usually shed into the water, where fertilization occurs, but a few warm-water species brood their eggs. The fertilized egg develops into a free-swimming larva which, after a short planktonic existence, sinks to the bottom and develops into the adult form (5). In the Inarticulata, lingulids live in semi-permanent vertical burrows in sandy sediments (19). They occur in areas that may be subjected to lowered salinities for relatively prolonged periods. Craniids require a hard substratum for attachment, as do the discinids, which are often found in clumps attached to each other. Little is known of the salinity tolerance of these two families. Larval development patterns appear to enhance wide dispersal of lingulids and discinids (lf15) but crinoids have a short larval life and only limited potential for dispersal (20). SCIENTIFIC INTEREST AND POTENTIAL VALUE The phylum is particularly important in the study of evolutionary history, as brachiopod remains are often abundant in fossil-bearing rocks of almost every geological age. Brachiopods have one of the longest observable evolutionary histories, having existed for at least 550 million years (2); the continuity of their fossil record is extremely good (9). The genus Lingula is the classic 'living fossil, remaining unaltered in external appearance and probably in life habit for about 500 million years. It is the most studied of all brachiopod genera. Lingula has been utilized as a food item in Japan (26), the Philippines, Burma, Thailand and by Australian aborigines. Some discinids have been recorded as fouling ships' hulls (12), but they are likely to be of only minor significance in this regard. No other species of commercial importance is known. 534


biology such as the structure of the larvae and development of the egg provide strong evidence that echinoderms may be closely related to the group which gave rise to the vertebrates. The eggs of sea urchins have been used as subjects for fundamental research on cell structure, fertilization and experimental embryology (16,17). In recent years sea-urchin eggs have even been shot into space in rockets to find out whether cosmic rays or other such phenomena have an effect on living organisms. Their relatively short development period allows researchers to observe the teratological effects of drugs, since adverse reactions can be noted in a matter of days instead of weeks or months (7), and there is potential for the use of sea urchin larvae in bioassay techniques (1). Interest has been shown recently in the large spines of the Slate-pencil Urchin, Heterocentrotus mammillatus since the structure of the material of which they are composed may provide a template for the synthesis of artificial bone (13). Several echinoderms have been found to contain active compounds that may be of use medicinally. Holothurin, a steroid saponin isolated from the Bahamian sea cucumber Actinopyga agassizi suppresses the growth of tumours in mice, and holothurin-like substances from other sea cucumbers and sea stars elicit a variety of effects on a number of biological systems. Crude extracts of the sea stars Asterias forbesi Acanthaster planci and Asterina pectinifera are effective against influenza B virus in embryonated chicks, and the sea cucumber Stichopus japonicus is the source of two extracts, one of which shows antitumour activity, the other exhibiting high antifungal activity (20). Echinoderms have been used for food since before the time of Aristotle (16). Currently 50 000 tonnes of echinoderms are harvested annually, most of which are sea urchins, although in the South Pacific holothurians have a greater relative importance (19). Sea urchins of various species are marketed in a number of countries, largely as a luxury food. Paracentrotus lividus is collected in Ireland, the Mediterranean and Brittany (see data sheet), Tripneustes ventricosus in Barbados and Loxochinus albus in Chile (9,12). Strongylocentrotus franciscanus is collected on the west coasts of the U.S.A. and Canada and S. droebachiensis on the east coasts. The gonads are sold fresh or frozen, and are particularly popular with Italians and other immigrants (16). In Japan S. intermedius Heliocidaris and Hemicentrotus are fished commercially, the former being the most important. In Australia surveys are in progress and a fishery for Heliocidaris erythrogramma Tripneustes sp, Centrostephanus and Phyllacanthus is being considered (31). Dried sea cucumbers, known as trepang or beche-de-mer, were among the earliest products of the South Pacific to enter international commerce. In the Far East they are highly regarded as an aphrodisiac, a tonic and as a cure for various illnesses, particularly high blood pressure. However, their most important use is as a food, their protein content being as high as 3 per cent. The main consumers are the Chinese, both in China and in countries throughout South East Asia. Hong Kong and Singapore (the main trading countries) both import more than 'f50 000 kg annually; imports into Japan, Taiwan, the U.S.A. and France have increased recently and Australia also has a small market. The trade has always been run on a cottage-industry scale, and local processing on coral cays and in coastal towns has been found to be more economically feasible than large central processing factories. Sources of supply are scattered from the east coast of Africa to the South Pacific, the main exporters being Fiji, the Solomon Islands, Papua New Guinea, Palau, Sri Lanka, Indonesia and the Philippines. Only a few species are commercially valuable, the most important being Microthele nobilis and Actinopyga miliaris and the best quality coming from the South Pacific. Sea cucumbers are easy to catch; in the Solomon Islands, over a period of nine days, 7122 specimens of H. nobilis were caught by local fishermen, an average of 11 specimens per man per hour (19,25,27,28,29,30). In the U.K. sea urchins are collected for the curio trade (see Echinus esculentus data sheet), and dried starfish and sand dollars are collected in other parts of the world for ornamental purposes. 540


The spines of the Slate-pencil Urchin are used in the sheilcraft trade in large quantities particularly in the Philippines (18). Sea urchins are the main grazing element in shallow waters and play an important role in controlling algal growth. Off Plymouth, U.K, at least one third of the rock is cleared of its seaweeds and encrusting algae each year by Echinus esculentus (see data sheet). Under certain conditions, urchin populations may reach pest proportions and cause overgrazing of kelp beds. This has occurred in some areas of Canada, possibly as a result of the decline in abundance of the lobster, Homarus americanus which is a known predator of the urchin Strongylocentrotus droebachiensis (32). The starfish Asterias of northern temperate seas may be a pest of commercial shellfish beds. The Crown-of-thorns Starfish Acanthaster planci of the Indo-west Pacific has gained a certain notoriety on account of the damage it can cause to coral reefs. It feeds on living corals, and in some areas where major population outbreaks have occurred up to 95 per cent destruction has been recorded. There has been considerable controversy over the causes of such plagues. It is not clear to what extent this species may have a natural fluctuating population, or whether the current outbreaks are due to human activities (see section on Cnidaria). No satisfactory methods have been found to control the outbreaks (22). THREATS TO SURVIVAL 1. Pollution Echinoderms are nearly all sensitive indicators of clean water and may be killed in large numbers by toxic oil. It has been found that a 001 per cent oil emulsion inactivated the tube-feet of urchins and was lethal within one hour of exposure (2). The developing eggs of Strongylocentrotus purpuratus have been found to be very sensitive to oil pollutants, particularly crude and heavy bunker oils (3). In a study of urchins on the coast of Italy it was found that there was a much lower density of Paracentrotus lividus and Arbacia lixula near Naples than further south in unpolluted areas, and that these two species were absent at Sorrento and Naples wherever the sewage loads were very high. Furthermore, the dry weight of urchins was found to be much smaller in the Bay of Naples than further south (). However, a study on the French coast near Marseilles revealed that domestic pollution could lead to huge population oscillations in sea urchins with densities as high as 'FOO per 10 m being reached (5). The same study illustrated the sensitivity of three species ( Paracentrotus lividus Arbacia lixula Sphaerechinus granularis ) to industrial pollution, which caused a reduction in the size of individuals as well as a decrease in numbers. The sea cucumbers Holothuria tubulosa and H. forskali were found to be even more sensitive and disappeared in areas of highpollution. This is probably due to their feeding method since they ingest sediment and pollutants tend to become concentrated in this part of the benthos (5). Two populations of highly deformed sea urchins of the species Tripneustes cf. gratilla were found in the vicinity of a combined power and desalination plant in the Gulf of Eilat (Aqaba), Red Sea, an area which is highly polluted by thermohaline and heavy metal ion effluents. More than 60 per cent of the urchins showed irregular bulging of the aboral half of the test and under unpolluted conditions in aquaria the growth rate of such urchins was very slow (14). A large concentration of Lytechinus variegatus urchins were found in Cartagena Bay, Colombia with skeletal deformations which were probably caused by oil and waste water pollution (15). Studies following the wrecking of the 'Torrey Canyon' tanker showed that oil had affected a number of echinoderms including the starfish Marthasterias glacialis the burrowing heart urchin Echinocardium cordatum and Echinus esculentus although some species (eg. the starfish Asterias rubens and the brittle star Acrocnida brachiata ) appeared to be little affected (23). The effects of pollution could be particularly serious in places such as the Red Sea where echinoderm endemicity has been estimated at as high as 12 per cent (2). 2. Exploitation Although small scale artisan fisheries probably have little effect 541


DELFINADO: LAELAPTOID MITES OF THE PHILIPPINES 99 MALE: Unknown, though four males were found on the same host and are so labeled. Holotype. Female, ex Rattus everetti. Mindanao: Mount Apo, 6400 ft. elevation, Davao, November 8, 1946 (H. Hoogstraal). In the Chicago Natural History Museum collection. Paratypes. Three females, same data as holotype. One in the United States National Museum collection. WPM Fig. 31. Echinolaelaps echidninus, female: A, anterior portion of dorsal plate; B, posterior portion of dorsal plate; C, venter. Genus ECHINOLAELAPS Ewing, 1929 Echinolaelaps echidninus (Berlese). Figure 31, A-C. Laelaps (Iphis) echidninus Berlese, 1887, Acari Myriapoda et Scorpiones, fasc. 39, nr. 1, t. 50, figs. 1-4. Laelaps (Laelaps) echidninus Berlese, 1887, Vitzthum, 1926, Treubia, 8: 56 (female, ex Paradoxurus hermaphroditus; Java; illus). The female of this species is characterized by the lightly sculptured dorsum, the greatly expanded epigynial plate between setae II and III, and the shallow emargination of the posterior margin of the sternal projection. The anal plate is about as long as wide, sculptured as figured, and rounded anteriorly, fitting closely into the


Nat, H isl. duifye. 7 DELFINADO: LAELAPTOID MITES OF THE PHILIPPINES 95 sternal plate is nearly straight, and the anal plate almost touches the epigynial plate. FEMALE Gnathosomal setae stronger than hypostomal setae; chelae toothed; pilus den tills slender with bent, knobbed apex. Dorsal plate 504 n long, 307 n wide; two pairs of short, subequal vertical setae; strong and long, subequal medial and B t t Fig. 27. Laelaps spinigera, female: A, anterior portion of dorsal plate; B, posterior portion of dorsal plate; C, venter. marginal setae, and a pair of much reduced submarginal setae. Sternal plate wider than long, posterior margin nearly straight; sternal and metasternal setae short, subequal in length. Epigynial plate drop-shaped, posterior margin rounded; the distance between setae IV greater than the distance between setae I. Anal plate about as long as wide, almost touching the epigynial plate; adanal setae located on midline of anal opening, not longer than anal opening; postanal seta twice as long as adanal setae. Metapodal plates elongate oval, about twice as long as wide. Venter with 6 pairs of moderately strong, short setae adjacent to epigynial and anal plates. Peritreme reaching posterior margin of coxa I. Leg I with strong, recurved spines on femur, tibia and tarsus. Distal setae on coxa I thumblike, the proximal ones strong, spinehke; proximal setae on coxae II and III spinelike. MALE: Unknown.


58 COMMERCIAL FISHERIES REVIEW Vol. 18. No. 5 Republic of the Philippines SHRIMP FISHERIES The catch of shrimp in the Philippines amounted to 2,641 metric tons (valued at US20 million) in 1954, compared with 1,618 tons in 1953, and 1,311 tons in 1952. Exports are confined to small salted shrimp (rangoon ala-mang) and varied in quantity between 1,300 pounds in 1952 and 16,700 pounds in 1954; in 1955 exports totaled 13,100 pounds. Salted shrimp are considered a delicacy by the Filipino residents in Guam and Hawaii. The shrimp fishery in the Philippines is not specialized as in the United States. Shrimp are caught along with other varieties of fish by beam or otter trawls fished by motorized sampan-type wooden vessels, a United States dispatch dated January 11 from Manila states. The principal fishing grounds, with yields of 50 metric tons or over, are located in Carigara Bay, Guimaras Strait, Manila Bay, Magueda Bay, Samar Sea, San Miguel Bay, Sulu Sea, and Visayan Sea. There are no shrimp canneries and there is only one commercial freezer, located in Manila. The principal species of shrimp are as follows: Peneaus indicus (Milne-edwards); P. canaliculatus (Olivier); P. affinis (Milne -Edwards); P. incisipes (Spence-bate); and P. monodon (Fabricius. The sizes (heads-on) vary between 4 and over 100 to the pound. The shrimp fisheries do not receive governmental assistance and there are no foreign vessels engaged in this fishery. Licenses to operate fishing vessels, subject to taxation, are issued to United States citizens on the same basis as to citizens of the Philippines The greatest potentialities for expansion of the shrimp catch is the cultivation of shrimp in fishponds. The shrimp, P. monodon is now being cultivated in Philippine estuarine fishponds together with small varieties of shrimp and milkfish ( Chanos chanos) P. monodon is considered to be a delicacy and commands the highest prices in the markets. The abundant supply of immature P. monodon found all over the Philippines where milkfish fry are caught makes the development of pond rearing of shrimp a promising enterprise. Portugal CANNED FISH PACK, JANUARY AUGUST 1955: The pack of canned sardines in oil or sauce for January-august 1955 amounted to 13,417 metric tons (net weight). The August 1955 pack was 4, 105 tons as compared with 5,592 tons in August 1954, CANNED FISH EXPORTS, JANU ARY OCTOBER 1955 . Portuguese canned fish exports totaled 7,931 metric tons (417,400 cases), valued at US36 million, during October 1955; and 50,702 tons, valued at US253 million, during January-october 1955.


30 COMIFFIECIAL FISHERIES REVIEW Vol. I3, No. 12 Republic of the Philippines IMPORT CONTROL LAW ALFFINDMENT AFFECTS FISHERY PRODUCTS IMPORTS An amendment to the Philippine Import Control Law (Republic Act 650) was issued by the President of the Philippines on August 24, I95I (Executive Order No. 471 • Imports of certain fishery and related products are affected by this action. The amenftnent revised Appendix "A" of Republic Act 65O, the Import Control Law which became effective July 1, I95I; banned the importation of certain commodities; and provided the procedure for importing goods under EGA authorizations. A new Annex "A" listed items completely decontrolled, together with essential items of import. Fishery products listed as completely decontrolled were canned salmon and sardines. Listed as essential items of import under this same list were canned mackerel, herring, and squid; cod liver oil; hydrogenated animal products and fish oils; fish meal; and fishery gear: specifically fish hooks and fishing rods and tackles-Annex "B" indicates items the importation of vftiich was immediately banned. Included among the items listed are all fresh fish, canned anchovies, mother-of-pearl, canned moss and seaweeds, and dried moss and seaweeds. Annex "C" listed items which will be banned beginning July 1, 1952, but there were no items listed under this category of interest to the fishing and allied industries. The amendment also establishes that goods to be imported under ECA procurement authorizations shall not be licensed by the Import Control Commission. United Kingdom FISH-HANDLING METHODS ABOARD VESSELS BEING TESTED Survey and experimental work by the Torry Research Station at sea under commercial conditions is now in progress to test the effectiveness of the present practice in cooling fish as quickly as possible and maintaining them at 32° F-from catching to landing. A small observation cabin has been fitted on a commercial trawler, according to an article which appeared in the November I95I issue of The Food Trade Review This article summarizes the work carried out by the Research Station on fish under the Government's Food Investigation Organization. "A study of the influence of exposure of the fish on deck showed that unguttea Lin, if left on tae deck. in warm weather, could reach temperatures which accelerate action by enzymes and bacteria so much that the fish deteriorated badly before landing even though chilling and storage in ice had been efficient. "An analysis of the figures for fish condemned at one of the Dinner ports during the year suggests that handling and stowage on many of the distant-water fishing vessels could be improved a good deal even with present equipment" according to a November 9 American Embassy dispatch which quoted parts of the article. or