27
5.13. Shoreline and intertidal rocky
shore invertebrate species
Shrimps and crabs of estuaries and deltas are also included
here. Only 3 (
Penaeus notialis
,
Penaeus atlantica
and
Penaeus kerathurus
) out of 6 species of shrimps are found
in the coastal waters of Sierra Leone. There may be post
larval stages and juveniles found in plankton. The species
of crabs of commercial importance found in the Sierra
Leone River estuary are the entire genus
Callinectes
and are
Callinectes pallidus
,
C. amnicola
and
C. maginatus
.
Two of the six shrimp species of commercial importance
Penaeus notialis
and
Penaeus kerathurtus
inhabit the
mangrove swamps, estuaries and inner continental shelf to
a depth of 55m.
As in the case above, these fisheries are in good condition.
5.14. Benthic filter feeders of soft and
hard substrata
Several benthic fauna species occur in the estuaries of
Sierra Leone (Tab. 5.1). Longhurst (1958) has identified the
following assemblages of benthic organisms in the Sierra
Leone River Estuary:
Venus community,
Amphioplus
sub-community,
Venus/
Amphioplus
transition, P
achymelania
sub-community and
Estuarine gravel community.
The Venus community is found near the mouth of the
estuary and in the deep channel on shelly-sand and fine
lateritic gravel. It is dominated by poriferans, nemerteans,
small crustaceans, brachyuran, pagurids, procellanids,
lamellibranches, asteroids, echinoderms and ascidians. The
most important members include:
Brachiostoma leonense
,
Aloidis sulcate
,
Astroecten michaelseni
,
Tris carbonorea
,
Polychaeta
Clymene monilis
Glycera convoluta
Diopatra neapolitana
Pectinaria souriei
Gephyrea (Sipunculidae)
Ochetostoma Mercator
Branchiopoda
Lingula parva
Echinodermata
Rotula orbiculus
Holothuroidea
Amphioplus congensis
Mollusca
Iphigenia truncata
Tellina nymphalis
Donax owenii
Mactra
sp.
Glycimeris
sp.
Aloidis dauzenbergi
Cephalochordata
Branchiostoma leonense
Crustacea
Squilla africana
Callianassa balssi
Alpheus pontederiae
Penaeus notialis
Parapenaeus atlantica
Bigelowina septemspinosa
Upogebia furcata
Latreutes parvulus
Table 5.1:
Dominant benthic fauna of Sierra Leone’s
estuaries
Lumbrineris impatiens
Goniada multidentata
Terebellida
Sipunculus titubens
Acrocnida semisquamata
Ophiuroidea
Astropecten michaelseni
Surcula coerulea
Pachymelania aurita
Neritina oweniana
Neritina rubricata
Neeritina glabrata
Aloidis trigona
Polyonyx
sp.
Diogenes pugilator
Paguristes
sp.
Uca tangeri
Heteropanope caparti
Menippe nodifrons
Porcellana longicornis
Clibanarius cooki
Modiolus stutorum
, Astrangia sp.,
Oliva accuminata
and
Rotula orbiculus
.
The
Amphioplus
sub-community occurs on mud, shelly-
mud and sandy mud in the lower reaches. It is a much more
diverse group and may consist of poriferans, brachyurans,
crustaceans, gastropods, bivalves, polychaetes and
ophuiroids. The representative members may include:
Upogebia furcata
,
Callianassa balssi
,
Clymene monilis
,
Pectinoria sourei
,
Goniada multidentata
,
Glycera convolute
,
Deopatia neapolitanea
,
Nereis senegalensis
,
Notomastus