Red Data Book

2.5 Lepidochelys kempii, Kemp's Ridley Sea Turtle

There are no records of Kemp's ridleys in St. Lucia, nor would the species be expected to occur. The diminutive Kemp's ridley is gray in colour as an immature and primarily olive green as an adult (Pritchard et al., 1983). The carapace is round, often as wide as it is long, and carapace scutes do not overlap one another. According to Ross et al. (1989), adults weigh 60-90 lb (27-41 kg) and have a shell length of 23-30 inches (58-76 cm). The species is carnivorous and eats mostly crabs, but also preys upon other crustaceans, shellfish, jellyfish, sea urchins, starfish, and fish. With the exception of a single recapture from Caribbean Nicaragua of a "head-started" individual (Manzella et al., 1991), which may have displayed altered behaviour due to being held captive during its first year (Woody, 1991), Kemp's ridleys are confined to the Gulf of Mexico and temperate northern Atlantic. The total adult population is thought to number no more than 900 females and an unknown number of males (Ross et al. 1989), making it the world's most endangered sea turtle. The species nests in Tamaulipas, Mexico.

2.6 Lepidochelys olivacea, Olive Ridley Sea Turtle

There are no records of this species from the waters of St. Lucia, nor would it be expected to occur. Olive ridleys are similar in appearance to Kemp's ridleys (section 2.5), having a nearly round carapace (width about 90% of the length) and an adult colour of olive green or brown dorsally and yellow-white ventrally. The turtle rarely exceeds 100 lb (45 kg) (Pritchard et al., 1983). Each front flipper bears a single claw, the horny beak may be finely serrated, and carapace scutes do not overlap one another. The lateral scutes (those to either side of the median on the shell) are divided into 5-9 pairs, considerably more than other sea turtles which typically have 4-5 pairs. The only significant nesting colony in the Western Atlantic is in Suriname, primarily at Eilanti Beach (Schulz, 1975). Olive ridleys nesting in Suriname have declined considerably in recent years, from about 3,000 nests per year in the late 1960's to fewer than 500 nests per year today (Reichart and Fretey, 1993). Diffuse nesting occurs in northwestern Guyana and in French Guiana (Reichart, 1989).

III. STRESSES ON SEA TURTLES IN ST. LUCIA

3.1 Destruction or Modification of Habitat

St. Lucia's population has soared from 42,220 in 1891 (CCA/IRF, 1991) to 135,975 in 1991 (Government of St. Lucia, 1991). Today St. Lucia has a balanced economy with a sophisticated manufacturing structure and a well-developed tourism sector. In hand with economic development and an increasing human population, commercial and recreational activity along the coastline has noticeably affected the habitat of sea turtles. One of the major factors has been and continues to be sand mining (section 4.131). The construction industry relies on beach sand as a source of fine building aggregate. In recent years, some sandy beaches (e.g., Soufrière) have been reduced to cobble by the mining. At the present time at least six turtle nesting beaches are heavily exploited, legally or otherwise. Of these, at least two have become unsuitable for nesting. Grand Anse beach, the largest in St. Lucia and a regionally important nesting site for endangered leatherback sea turtles, is experiencing severe structural instability. Grand Anse is now characterised by an unnaturally shallow profile, which means that in many cases leatherbacks are forced to abandon the nesting sequence after digging into the water table.

In addition to sand mining, sea turtles face additional threats to their survival as a direct result of coastal development and industry (see section 4.13 for details). For example, the emphasis on tourism (an industry which contributed 22% of the total GDP in 1986: CCA/IRF, 1991) has seen the establishment of hotels on some nesting beaches. As a consequence, vegetation has been removed and beach footage above high water has been lost. Beach-front lighting is also a problem in that it disorients emerging hatchlings and may dissuade gravid females from coming ashore. Not all coastal development has been associated with tourism, however. Dennery and other long-established communities are clustered along once prominent turtle nesting beaches. These shorelines are densely populated and characterised by modest homes, fishing and market facilities, roads, and subsistence fishing vessels. Some beaches are affected by tar globules from ocean-going vessels and by debris such as plastic bags and bottles. This problem is greater on the windward east coast. In addition, domestic garbage is carried to the sea by rivers and storms and ultimately washes ashore on sandy beaches.
Some of the reefs around the island have been damaged or destroyed by the use of dynamite, in contravention of the Fisheries Act of 1984 (see section 4.141). Other reefs have been completely obliterated by dredging during coastal projects, such as land reclamation. There is also the serious problem of reef destruction which results when yachts, dive boats, and fishing vessels anchor on living coral and when fish pots are dropped on coral reefs. This is especially serious along the west coast (in general, the east coast is too rough to provide good anchorage). Finally, it is believed that marine habitats are being affected by siltation due to the erosion of upland regions, agricultural run-off, and indiscriminate waste disposal. These problems are discussed in greater detail, and some solutions proposed, in later sections (especially section 4.14).

3.2 Disease or Predation

No studies have been carried out on local sea turtle populations to determine the incidence of disease or predation. To date, no cases of green turtle fibropapilloma, a debilitating and sometimes fatal tumor disease reported elsewhere in the Caribbean (Jacobson, 1990), have been reported in St. Lucia. Ghost crabs (Ocypode quadratus) and night herons (Nyctanassa violacea) prey on emerging hatchlings. Pigs sometimes dig up nests, such as at Anse Sable. Consumption of eggs and hatchlings by domestic dogs is reported from Vigie Beach, Castries (P. James, pers. comm., 1993). The extent of nest loss to these predators is unquantified. Predation by mongooses (Herpestes auropunctatus) has not been documented. On a few occasions nesting female leatherbacks have been observed with bitten-off flippers, suggesting attacks by sharks at sea. Some years ago, leatherback remains were found in the stomachs of three killer whales captured off St. Vincent (Caldwell and Caldwell, 1969). In the absence of evidence to the contrary, the level of predation is assumed to be within normal and natural limits.