Zonation by size in the Armandia sp. (Polychaeta: Opheliidae) population on an intertidal sand flat

Abstract

Spatial and temporal changes in the body-size composition of a population of Armandia sp. (Opheliidae), a burrowing polychaete species with a planktonic larval phase, are described for an intertidal sand flat in west Kyushu, Japan. From spring to summer 1980, the recruitment of Armandia was by discrete settlement of larvae (every spring tide), which allowed the fate of a particular cohort to be followed easily. At the end of June, when the largest recruitment in the year occurred, the larvae settled exclusively in 2 particular zones. A part of the population emigrated from the settlement zones mainly in an offshore direction with growth of body size generating a size zonation, and the densities of Arrnandia adults became spatially uniform through July and August. The significance of following migration processes of mobile benthos for understanding the structure of soft-sediment benthic communities is discussed.

Population dynamics and secondary production of Euzonus furciferus Ehlers (Polychaeta, Opheliidae) in an exposed sandy beach of Southern Brazil

“…Euzonus heterocirrus Rozbaczylo & Zamorano, 1985 deposit feeder of intertidal sandy beaches in Japan, were also found in a well defined zone parallel to coast line (TAMAKI 1985). Euzonus furciferus is the only deposit feeder species in the upper and middle intertidal of South Brazilian sandy beaches.…”

Comparison of resistivity to transport by wave action in several polychaete species on an intertidal sand flat

“…At the end of June, Armandia larvae settled almost exclusively in the Solen zone and in the neighborhood of the Prionospio zone. A part of the population had emigrated from the settlement zones mainly in an offshore direction with concurrent growth of body size by July 14 (Tamaki 1985). The distribution pattern of juveniles and adults in November was similar to that in summer, i.e.…”

“…Spatial and temporal changes in the densities of the macrobenthos were examined along a transect situated 120 m southeast of the northwestern edge of the sampling area (the white line in Fig. 1 in Tamaki 1985). Sampling was conducted at every or every other spring tide from March 1980 to March 1981.…”

“…A rectangular area delimited by 2 lines perpendicular to the coastline, 300 m wide, was selected for routine sampling (the black-colored area in Fig. 1 in Tamaki 1985). A preliminary survey revealed that the macrobenthic community on the sand flat was subdivided into 4 zonal assemblages parallel to the coast line (Tamaki & Kkuchi 1983).…”

“…Two facts suggest that the low density of adults in the Prionospio zone on 14 Jul 1980 was due to sampling error: (1) on 29 Jun, juvenile density in the Prionospio zone was as high as that in the uppermost Calhanassa zone; (2) on 28 Jul 1980, adult density in the Prionospio zone was higher than that in the uppermost Cahanassa zone (see Fig. 4 in Tamaki 1985) adults along the fixed transect during the end of June to mid-July 1980, and during November 1980 to March 1981, are shown in Fig. 1.…”