A possible economic impact of libellulid larvae on production of freshwater shrimps in Guadeloupe, French West Indies (Anisoptera: Libellulidae)

Guadeloupe has relatively few permanent aquatic habitats. Annual precipitation is on average four times higher in the wettest month as compared to the driest season and varies from 1000 mm in the East of Grande Terre to more than 11000 mm at the top of the Soufrere. In addition, aquatic habitats suffer by serious agricultural, industrial and domestic pollution, impacting the odonate biodiversity. In this context, the rise of aquaculture (particularly freshwater shrimps, locally called “ouassous”) is of importance since it has a favourable effect on dragonflies. In 2000, there were in Guadeloupe 13 shrimp farming sites, with a total basin surface of ca 20 ha. The basins represent permanent odonate breeding habitats, their physicochemical properties are regularly monitored and controlled, and they are providing an abundant and regular food resource throughout the year. On 1 and 5 May 2003, we surveyed the odonate communities in two Macrobrachium rosenbergi (Man, 1879) farming sites at Basse Terre (Petite Plaine at Pointe Noire and Vauchelet), and counted 12 breeding odonate species, some of which are rare (e.g. Tramea binotata [Rarab.]) or not very common (e.g. Ischnura hastata [Say]).