World Status, Exploitation and Trade - WIDECAST

MADAGASCARevidence, Europa must make a very substantial contribution to Madagascar'sforaging population. Females tagged in Tromelin have also been recoveredfrom Madagascar (also Reunion and Mauritius). See REUNION account forfurther details.POPULATION: Eretmochelys imbrlcataNesting sites Vaillant and Grandidler (1910) state that sea turtlenesting is largely restricted to the western coast, and around the northerncoast, where bays, coves and coral islands are widespread. These authorscite Megiser (1609), who stated that E. imbricata is found only in the west,notably around the scattered islets, and in the north-east, as far south aslie St Marie. Presumably the E. imbricata found on a beach a few km northof Tsimanandrafozana (Douliot, cited in Vaillant and Grandidier, 1910) wasattempting to nest. Petit (1930) reported that Nosy Chesterfield was a sitemuch favoured for hunting turtles; some of these seem likely to have beenfemales taken on the beach. Little more recent site-specific information isavailable. According to Hughes (1973a and 1974) major nesting occurs aroundthe northern third of Madagascar, with the north-east coast perhaps beingmost heavily used. Hughes (1974: Fig. 5) indicated reputed or sparsenesting at two points on the south-west coast, possibly Nosy Hao and NosyVasy, as reported in Hughes (1973a: 115). Frazier (1975) records very minornesting on Nosy Kalankarjoro, an islet in the north-west.Nesting numbers No quantitative nesting data are available. Althoughthe species has been said to be abundant around the coral islands off thewest and north-west coasts (Vaillant and Grandidier, 1910), it is not clearto what extent such estimates refer to nesting populations. Hughes (1974)suggests that nesting may be moderately aggregated in northern Madagascar,and the fact that an estimated 2500 E. imbricata were being harvestedannually in Madagascar in the early 1970s (mainly juveniles, and mainlytaken in the south-west) (Hughes, 1973a, 1974) might be taken to imply thatvery substantial numbers nest. Frazier (1975) suggested that only a dozenfemales may nest annually on Nosy Kalankarjoro.Trends in nesting numbers Writing between the First and Second WorldWars, Petit (1930) stated that sea turtles were declining in numbers aroundmainland Madagascar, but were still in evidence around the offshore islands,perhaps increasingly so. Figure 14 in Petit (1930; figure reprinted inHughes, 1973a) shows a rather steady decline in exports of E. imbricatashell from over 4000 kg in 1919 to 1440 kg in 1928 (see Table 113). It isnot clear to what extent this may be due to declining demand ratiier than todeclining numbers of turtles. Hughes (1973a) calculated that the 1919 totalrepresents some 1600 adult turtles (given a yield of around 2.5 kg perturtle). Petit regarded this decline in export volume, coupled with a sharpdecline in the size of individual E. imbricata caught, as indicating a steepdecline in the local E. imbricata population. Hughes (1973a) cited thesesame data and concluded that decline cannot be attributed to any factorother than over-exploitation.Whilst the evidence for a marked decline in E. imbricata populations overthe first three decades of the 20th century is rather persuasive, thereseems to be no clear evidence for the continuation of that trend through thepost-World War II years. Hughes's estimate of 570 adult Hawksbills killedin 1971 is almost exactly equivalent to the 576 which may have produced the1440 kg of shell Petit (1930) recorded as being exported in 1928 (given2.5 kg of shell per turtle). The available information (Petit, 1930;Hughes, 1973a) suggests that while the recorded export of raw shell has301