Biology of the deep-water shrimp Plesiopenaeus edwardsianus in French Guiana

In spite of the commercial interest of the deep-water shrimp plesiopenaeus edwardsianus (Decapoda, Aristeidae) on the continental slope of French Guiana, the biology of the species has as yet been poorly studied. Four scientific surveys were conducted in 1990 and 1991 on the Guianese slope at bottom depths ranging from 200 to 900 m and samples from commercial fisheries were also regularly observed from 1988 to 1933, in order to establish the bathymetric distribution, the abundance, the growth and the reproduction of the species. P. edwardsianus is widely distributed from 447 to 855 m, but the species has a peak abundance near 700 m (temperature: 5 degrees C) where better yields reach 10 kg/h/net. Samples show a constant predominance of females. The females have a single main season of sexual maturation, from March through September. Mean sizes of captures increase with depth. The size frequency distributions indicate the existence of two age-classes for females, probably atributed to two annual cohorts, and it seems that sexual maturity of females is reached at the end of the first pear of life and that the duration of life of the species is about 2 years. (C) Academie des sciences/Elsevier, Paris.