GROWTH, PRODUCTION AND ECOLOGICAL SIGNIFICANCE OF OPHIURA-ALBIDA AND O-OPHIURA (ECHINODERMATA, OPHIUROIDEA) IN THE GERMAN BIGHT

Growth and production of the shallow-water ophiuroids Ophiura albida and O. ophiura were investigated at two stations in the German Bight from 1988 to 1991. Growth rings visible on the vertebral ossicles of the ophiuroid arms were interpreted as annual age markers. A correction for overgrown first rings allows for more exact estimations of growth and age. In both species growth could be described by Von Bertalanffy growth functions with the asymptotic disc diameter D(infinity) = 10.1 mm, K = 0.229 and t(o) = - 0.192 in O. albida and D(infinity) = 27.7 mm, K = 0.084 and t(o) = 0.042 in O. ophiura. Somatic production was calculated from mass specific growth rates. Annual production:biomass (P:B) ratios were estimated at 0.32 for O. albida and 0.43 for O. ophiura.