SET1TEJ\rlENT BEHAVIOUR OF -THE TUfE "OPl\1 "BY DR01DES r'~CRVEG~CA Gl'NNERUS IN TH~ r A~TERN HARBOl'R 07 ALEXA NDRIA By A.F.A. Ghoba~hy ar.d S.A. Selim /r1.~/ilute of Oceanography and Fisheries, AlexQmlrio, E!1ypf

SET1TEJ\rlENT BEHAVIOUR OF -THE TUfE “OPl\1 “BY DR01DES

r’~CRVEG~CA Gl’NNERUS IN TH~ r A~TERN HARBOl’R

07 ALEXA NDRIA

By
A.F.A. Ghoba~hy ar.d S.A. Selim

/r1.~/ilute of Oceanography and Fisheries, AlexQmlrio, E!1ypf

BULLETIN OP THE INS’l~1.””C’l’E OF. OCEANOGRAPHY &; FISB.L.~lES 287
ABSTRACT
Rate of settlement of Hydroides norvegica in Eastern
harbour of Alexandria was estimated for successive
15 months in 1972 and 1973 and found only significant
from April to November, reacing maximum in September.
Settlement was higher on rough sand black surfaces
This serpulid is gregarious during ettlement and surfaces
filmed with brown algae promoted its settlement. It
preferred to settle on concavities, on the lower sides of
the horizontal surfaces and at depths 1 and 1.5 m from
the surfaces.