Survival Strategies in Estuarine Nereids

Abstract

Nereid polychaetes are among the most abundant worms in the estuaries of north-western Europe. Like most other estuarine macrofauna, they have their origins in marine conditions and the colonisation of estuaries has presented special challenges, both physiological and ecological. This paper considers some of the special strategies which appear to have accompanied the penetration and colonisation of estuaries by nereids.

Reproductive Cycle of Marphysa sanguinea (Montagu, 1815) (Polychaeta: Eunicidae) in the Lagoon of Tunis

“…According to Prevedelli et al [15], the disappearance of the epitokal phase in species that colonize brackish habitats seems to be generalized. The suppression of epitoky is a common trend in estuarial species [9–11] and is probably related to a reduction in the dispersal phase [7]; species living in unpredictable habitats such as brackish environments tend to limit spatially the gametes emission.…”

“…Later, Wilson [4] described a two-factor classification system for types of reproductive modes within the Polychaeta based on the type of larval development and the fate of the female gametes (free spawned or brooded in a variety of ways). Mettam [9], Olive [10], and Prevedelli and Cassai [11] related this diversity of reproductive traits to the importance of variation in life history traits related to the characteristics of brackish environments, presence or absence of epitoky, and reduction or disappearance of the dispersal phase.…”

Comparison of the life cycles of two sympatric estuarine polychaetes, Hediste diadroma and H. atoka (Polychaeta: Nereididae), in the Nanakita River estuary, northeastern Japan

“…Ecological significance of different life cycles of H. diadroma and H. atoka in the Nanakita River estuary Most marine and estuarine benthic invertebrates have a dispersal phase in their life cycle (Mettam 1981;Scheltema 1986). The benefits of dispersing to reach new territories must balance the benefits of remaining safely within a preferred habitat.…”

“…All nereidid polychaetes have a semelparous life cycle; they reproduce once in a lifetime and die soon after spawning (Mettam 1981;Olive and Garwood 1981;Fong and Pearse 1992). In estuaries in the northern temperate zone, five Hediste species are common nereidids.…”

“…Nereidid polychaetes are among the most abundant worms in estuaries (Mettam 1981). All nereidid polychaetes have a semelparous life cycle; they reproduce once in a lifetime and die soon after spawning (Mettam 1981;Olive and Garwood 1981;Fong and Pearse 1992).…”