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Sector II (Sierra Leone River estuary) and Sector IV (Yawri
Bay) in and around the port and other smaller shallow bays
and estuaries.
There is limited knowledge on adverse marine impact
or outbreaks affecting populations of birds and marine
mammals. Incidents of poisoning of marine species
affecting the trophic hierarchy of the marine food chain
have also not been reported recently.
There are visible evidences of fouling organisms such as
barnacles on ships’ hulls but these are local mollusc species
which are not known to be harmful to man or other marine
species. In fact they are edible for local residents!
The intense level of shipping activity that is associated with
the increasing traffic at the main port in Sector III has
probably made a big contribution to this minor problem.
However, no data are available on the ecological impacts of
such fouling and, for now, these effects are assumed to be
neutral in terms of ecological function.
There are occasional incidents of natural algal blooms and
the proliferation of jelly fishes (
Physalia sp
.) occurring in
some coastal areas directly connected to the ocean, like
the Peninsula, but only low levels. Blooms of
Sargassum
spp
. have been occurring in coastal waters since 2011.
Worst areas affected include the coastal water column and
beaches along the entire coastline.
In other bay areas of coastal and related development
occurred outbreaks of cholera due to poor catchment
management in these areas because of sediment and
nutrient input (such as in floods), local groundwater
contamination, urban run-off and sewage management.
No data exists on the relationship between these causes
and effects.
In the 1980s there had been reports of one pest species, the
grey triggerfish from the family Balistidae (
Balistes spp
.) Its
proliferation on the Sierra Leone shelf had been a source
of great worry because its presence was associated with the
decline in the population of some other more highly valued
species. Its occurrence however had been attributable to
hydrographic cycles when colder waters from the northern
Canary currents affected distribution patterns in the lower
latitudes until the Gulf of Guinea.
The Queen Elizabeth II Quay is an international port
and therefore exposed to many hazards including the
introduction of invasive species from ships’ ballast waters.
These questions have not been scientifically investigated
and as such no comparison or conclusion can be drawn
about such issues.
There were evidences of the proliferation of the crown-of-
thorns starfish at No. 2 River estuary acting as a ‘fouling’
organism on cultured oysters. That observation was only
in the 1980s and such population increases have not been
observed during the past two decades.
The proliferation of populations of the sea urchin is
sometimes still reported by local fishermen at fishing
grounds especially in the southern parts below the
Freetown peninsula, but these occurrences are sporadic
and do not cause alarm. There have been no reports of fish
kills over the past 5-10 years.
Little information is available on this subject and no
assessment was produced.