settled mussels upon the filamentous substrata. The
tanks were not opened during this procedure, and all
counts were made through a clear see-through lid and
side windows fitted in each tank. A large hand lens
provided some assistance to visualize individual
mussels. At the end of 24 h, the tanks were opened,
and an accurate count of settled mussels within the
filamentous substrata and the tank rims at the water
surface were recorded. At this point, a mussel was
considered attached if it was not dislodged when a
vigorous stream of water was forced from a pipette
(Eyster and Pechenik, 1987). Then, all mussels were
removed from each tank, counted, and the number of
live and dead mussels was recorded under the
microscope.