Population structure and reproduction of the carrageenophyte Chondracanthus pectinatus in the Gulf of California

Abstract

Population structure and dynamics of the carrageenophyte Chondracanthus pectinatus (Dawson) L. Aguilar and R. Aguilar, an endemic species from the Gulf of California, were studied from November 1994 to December 1995. Plant maximum size and weight were reached in May (80 cm, 480 g dry wt), when new recruits were approximately 0.6 mm in length. In April, the first plants that washed ashore were observed at densities of 25 g dry wt m-1) of shore line. In summer (June-July), plants in the water became fragmented into small pieces. Gametophytes were always more numerous than tetrasporophytes (7:3). Male plants were not observed in situ. Reproduction was observed as early as December in small plants (6 cm long), with a low cystocarp and tetrasporangia density. However, the density of reproductive tissue increased exponentially in spring (384 000 cystocarps, 111 000 tetrasporangia per plant). Although reproduction by spores is significant, vegetative tissue remaining submerged is capable of re-attaching and generating new plants.