Variación estacional de la biomasa y talla de Sargassum spp. (Sargassaceae, Phaeophyta) en Bahía Concepción, B.C.S., México

Abstract

The seasonal variation of biomass and average size of Sargassum spp. was evaluated in three sites of Bahìa Concepción, B.C.S. during May 1991 to March 1992. Sargassum sinicola Setchell et Gardner, S. herporhizum Setchell et Gardner and S. lapazeanum Setchell et Gardner were found, comparising 45, 14 and 10% of the total biomass. The remaining 31% of the biomass was Sargassum not identified due to its development stage (sedlings, juvenile plants or senescent plants). We detected an anual biomass production cycle: the maximun value was registered at the end of spring (4.2 kg weigh wet/m2), it declined in summer (0.4 kg weigh wet/m2), practically disapeared in autumn and gradually increasing in winter (0.02 kg weigh wet/m2) until next spring (1.3 kg weigh wet/m2). The seasonal variation of the size shows a similar pattern of biomass: the maximun average size was registered at the end of spring (186.8cm); the size was reduce in summer (78.9cm), when the plants were senescent; in autumm the size was not registered because only Sargassum vestiges were found; in winter the size was smaller (4.8cm) because only Sargassum sedlings were found, and at the begining of spring 1992 the size was increased (86.8cm) with juvenile plants. Among the species, the size was significantly different: S. sinicola had and average size 197.4cm, S. herporhizum of 170.4cm and S. lapazeanum of 110.0cm.