Population dynamics of the symbiotic crab Djssodactylus mellitae Rathbun were studied by monthly collections from their sand dollar host Mellita quinquiesperforata (Leske) in North Inlet, South Carolina, USA. Size frequency analysis of carapace widths indicated a 12 to 15 mo life cycle for D. mellitae. Larvae were released during summer, grew to produce one or more clutches of eggs the next summer, and died shortly thereafter. Sex ratio was 1:l throughout the year; females attained a slightly larger maximum size. Fecundity did not vary over the reproductive season (April through September) and mean egg number was 206 ? 62 (S. d.) eggs per clutch. Most recruitment occurred from May through September. D, mellitae differs from other species in the family Plnnotheridae in that males and females are more similar in size and longevity, there are no soft carapace stages, clutch size is relatively small and the entire clutch is completely covered by the abdomen. Accessibility of sand dollars to settling D. mellitae and protection provided to post-metamorphic individuals may decrease mortality enough to balance the small clutches produced by this crab.

Feeding activity and prey selection of adult bay anchovies Anchoa mitchilli in the highsalinity North Inlet Estuary, South Carollna (USA), were examined during 2 summer days and nights in 1985. Stomach contents were compared to 2 size fractions of zooplankton (153 and 365 pm mesh) collected at the same time (every 2 h) and place (near the bottom) in a tidal creek. Adult bay anchovies (40 to 60 mm) consumed a wide variety of zooplankton, but selected items according to prey size, density, and type. Most prey items were between about 0.4 and 3.25 mm in length, although some copepods (less than 0.3 mm) and decapod shrimps (up to about 12 mm) were eaten. Among the available potential prey taxa, crab (primarily Uca) megalopae were by far the most important. Uca megalopae comprised almost 60 O/O of the diet based on numbers and volume and were favored even when their densities were much lower than other s~milar sized animals. First stage pinnothend crabs and hydromedusae were completely avoided. There were hstinct tidal and diel rhythms in feeding patterns and prey selection. Generally, large prey (e.g. Uca megalopae, shrimp zoeae, amphipods) dominated the &et around high tide especially at night, and small items (e.g. copepods, Uca zoeae, barnacle cyprids) were most important around daytime low tide when larger prey items were less abundant in the water column. Rapid changes in feeding were observed when preferred prey became avadable, especially around dusk. Adult anchovies fed throughout the night and immedately responded to the sudden avallabihty of crustacean larvae originating from nocturnal hatching events.A l l evidence suggests that adult anchovies are selective parhcle feeders which probably rely on more than vision alone to determme prey suitability. As a widely distributed and abundant planktivore, A. rmtchilli represents a major link in estuarine food webs and probably plays a significant role both in the survival patterns of benthic invertebrate larvae and in the dynamics of estuarine zooplankton communities.

ABSTRACT. A 5 yr record (1981 to 1985) of polychaete and bivalve abundance in North Inlet. South Carolina. USA, was examined to estimate whether the timing of peaks in abundance of planktonic larvae was a reliable predictor of settlement timing and abundance of meiobenthic and macrobenthic recruits. Biweekly collections of zooplanktonic larvae, meiobenthos, and macrobenthos were made in close proximity to each other. Both smoothing and regression techniques were used to characterize the recruitment patterns of each life-history category. Despite year-to-year variability in both estimated peak abundance and the time of the peak's appearance, an annual cycle in the pattern for these major taxa was apparent. The interval between appearance of planktonic larval peaks and subsequent peaks in abundance of meiobenthos and macrobenthos varied greatly during 5 years. We conclude that, despite variability in the timing of settlement and recruitment of soft-bottom benthos, the temporal windows during which recruitment activity is highest are very predictable for polychaetes and bivalves in North Inlet. This will allow more efficient investigation of these fundamental events with higher frequency samplings in the future. The stock-recruitment problem, a lack of predictable correspondence between planktonic larval and adult abundances, is no less complex in benthic ecology than in fishenes ecology.

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