JUVENILE GROWTH OF NEREIS-DIVERSICOLOR (MULLER,O.F.) FEEDING ON A RANGE OF MARINE VASCULAR AND MACROALGAL PLANT SOURCES UNDER EXPERIMENTAL CONDITIONS

A laboratory experiment was conducted in 1992 (January-March) to evalu ate variation of juvenile growth (%. day(-1)) of the polychaete Nereis diversicolor (O.F. Muller) in relation to tidal flat plant species as food sources. Experimental design used plant materials (alga and vasc ular plants) found abundantly in the intertidal ecosystem along the so utheastern coast of the English Channel in which juveniles were sample d for the 3-month experiment. Juveniles (less than or equal to 1-yr-ol d) markedly increased in wet weight with the alga Enteromorpha intesti nalis (weight-specific growth rate mu: 1.9+/-0.01%. day(-1)) as food s ource. A higher value of assimilation efficiency was observed for alga l species (E. intestinalis: 86.0%) than for marine vascular plants (Sa liconia europae 61.7+/-9.5%; Halimione portulacoides 48.3+/-6.6%; Spar tina anglica 37.0+/-2.7%). The digestion of marine vascular species to ok longer (17 to 33 h) than that of algae. All these characteristics ( growth, assimilation efficiency and duration of digestive process) see m to be correlated positively with lignin and cellulose concentrations in the plant tissue.