Spatial variation in the reproductive biology of Paralvinella palmiformis (Polychaeta: Alvinellidae) from a vent field on the Juan de Fuca Ridge

Abstract

The microdistribution and dynamics of deep-sea hydrothermal vent communities often reflect the extreme heterogeneity of their environment. Here we present an assessment of spatial variation in the reproductive development of the alvinellid polychaete Paralvinella palmiformis at the High Rise vent field (Endeavour Segment, Juan de Fuca Ridge, NE Pacific). Samples collected from different locations across the vent field suggest patchy reproductive development for this species. Males and females from several locations contained few or no developing gametes, while gametes were abundant in samples collected at the same time from other locations. Samples lacking gametes were distinguished by body size-frequency distributions with peaks at smaller sizes and the presence or absence of other fauna consistent with early stage assemblages in a successional mosaic model previously proposed for Endeavour Segment communities. Where gametes were present, synchrony of reproductive development between females within samples and between samples was evident. Reproductive synchrony between pairs of samples initially declined over a 7 d interval between samples, suggesting a rapid rate of reproductive development for P. palmiformis. Samples collected 1 mo apart, however, displayed similar frequency distributions of developing gametes. A peak of mature male and female gametes appeared to develop and disappear within the limited temporal resolution of the samples, consistent with possible simultaneous maturation of gametes despite pseudocopulation and sperm storage in this species.