Sierra Leone - State of the Marine Environment 2015

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.

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