Effect of salinity on survival and growth of Marphysa sanguinea Montagu (1813) juveniles

In order to develop rearing techniques for Marphysa sanguinea Montagu (1813), the influence of salinity on survival and growth rates of juveniles has been investigated under controlled laboratory conditions. For this purpose, 720 worms were produced in the laboratory. After rearing up to 6-9 setigerous segments, the worms were subjected to an experimental set-up for 2 months, in which they were exposed to salinities ranging from 15 to 40. For each salinity set-up, two sediment groups were used: an unmodified natural sediment and the same supplemented with Ulva lattuca, an assumed important natural dietary item. The results obtained showed the following: (1) Salinity changes produce an immediate and significant effect on growth; (2) no significant differences were noted between the two groups subjected to different diets, but a significant interaction was noted between each of the two factors. Results of this study can have significant implications for M. sanguinea aquaculture, concerning farm site selection and salinity maintenance in order to maximize commercial productivity.