World Status, Exploitation and Trade - WIDECAST

MEXICOUntil the 1950s tortoiseshell from Hawlcsbills was traded in: fishermen onthe east coast of Baja California would capture Hawlcsbills and sell thetortoiseshell to local prisons where it was crafted into combs, pendants,rings and other ornaments for sale. At present Hawlcsbills when captured arereportedly cleaned and stuffed to be kept as curios or sold to Mexican orNorth American tourists; the meat is eaten (Cliffton et al , 1981).Hunting intensity Hunting intensity in general appears very high,although stocks are severely depleted.In Michoacan, Alvarado and Figueroa (1986) estimated that some 350-500 adultC. mydas (mostly males) were taken, illegally, in the winter of 1985/86despite efforts to prevent such poaching. This was a considerable increaseover 1984/85, when an estimated 240 (again mostly males) were taken, thisrepresenting c. 60 each month of the breeding season (September-December)(Alvarado and Figueroa, 1986). Until the initiation of protective measuresin the early 1980s, the egg harvest at Michoac&n was extremely heavy (see"Historical trends" below).There are few very recent data on harvests in the northern feeding grounds,although it is evident that hunting pressure is severe. Cliffton et al.(1981) noted that by the late 1970s, the Seri Indians of the Sonoran coastin the Gulf of California had "virtually extirpated" the remaining seaturtles from their region; as an indication of hunting efficiency they notethat, of 13 adult and subadult C. mydas tagged in the Infiernillo Channel inMarch 1977, seven had been captured by the Seri by May 1977.Intensive hunting of overwintering turtles in the Infiernillo Channel andadjacent areas by Mexican fishermen of the Kino Bay region began in 1975.In that year five turtle boats (pangas) were landing 4-5 tonnes ofturtles/week (c. 160 turtles, mean weight 29 kg/turtle) from late Novemberto early March. Overwintering sites were successively depleted and by theend of 1979 Kino Bay divers reportedly travelled three times the distanceand invested many times the hunting effort to obtain far smaller catches,although the greatly increased value of turtle meat still made huntingprofitable (Cliffton et al . 1981).Hunting methods Sea turtles are principally hunted with nets, by harpoonand by direct capture while swimming and, in the past at least, by "turning"females on nesting beaches.Nets are used principally in the Caribbean, the Gulf of California, thesouth-west coast of Baja California and, recently, in Jalisco andMichoacan. Nets are usually of monofilament nylon, though sometimes ofcotton. They are of variable size, generally over 50 m long, with a widemesh (70-90 cm internode distance) and supported by buoys at c. 2 mdistance; the depth of the net varies from 4 to 12 m. The base of the netis weighed down with small stones or lead weights, these being sufficientlylight that turtles, once trapped, can still swim relatively easily to thesurface to breathe (Marquez, 1976a).Nets may be set parallel or perpendicular to the shore, depending on localconditions; they are generally placed no further than 4 miles (6.4 km) offshore and in areas with little current, as their lightness makes them proneto drifting. Nets are usually set in the evening and checked each morning,as trapped turtles are vulnerable to attack from sharks. Simple harpoonsmay be used to facilitate loading of the turtles onto the boats (M&rquez,1976a)359