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4. Habitat

Rocky Shoreline At Cape , Freetown (Paul Lamin)

Oceanic habitats reach from the shoreline to the deep sea and include both pelagic and benthic habitats. Surface marine waters in the tropics are generally depleted in nutrients but in certain coastal regions, the nutrients are locally enhanced as a result of upwelling. The Sierra Leone coast as part of the Guinea Current coast is characterized by such an upwelling which is seasonal and occurs from Cape Palmas to Benin Republic.

Habitat quality assessment

The shallow coastal waters of the Sierra Leone have a highly diverse fish and invertebrate fauna, many of which are important in commercial fishing. Fish diversity in the coastal waters is reasonably well documented (FAO 1990). What is poorly known is the diversity of the benthic macro-fauna i.e. animals that live on the bottom or within the bottom sediment and can be retained on a 0.5 mm sieve. The situation is much worse for the meiofauna i.e. organisms smaller than 0.5 mm. Sub-tidal benthic habitats are among the least studied in the waters of the Sierra Leone Continental shelf. According to the assessment resulting from the workshop held in Freetown in February 2014, thirteen habitats were assessed (Fig. 4.1).


Habitat quality assessment

Composante Info Niveau d'évaluation Confiance
Très pauvre Pauvre Bon Très bon À niveau En tendence
estuaries and deltas Worst 10% trend: Declining Most trend: Stable Best 10% trend: Stable High Medium
small bays Worst 10% trend: Declining Most trend: Stable Best 10% trend: Stable High High
beaches (sandy beaches) Worst 10% trend: Declining Most trend: Stable Best 10% trend: Stable High High
rocky coasts, including non-coral reefs fringing coasts (intertidal and subtidal) Worst 10% trend: Declining Most trend: Stable Best 10% trend: Stable High High
seabed inner shelf (0-50m) Worst 10% trend: Improving Most trend: Improving Best 10% trend: Stable High High
water column shoreline (0-20m) Worst 10% trend: Declining Most trend: Stable Best 10% trend: Stable High High
water column inner shelf (20-50m) Worst 10% trend: Stable Most trend: Stable Best 10% trend: Stable High High
water column outer shelf (50-200m) Most trend: Stable Medium Enter confidence trend
mangroves Worst 10% trend: Declining Most trend: Stable Best 10% trend: Stable High High
mudfats Worst 10% trend: Declining Most trend: Stable Best 10% trend: Stable High High
offshore banks, shoals, islands Most trend: Stable High High
seabed outer shelf (50-200 m) Most trend: Stable Medium Medium
coastal lagoons Most trend: Stable Low Enter confidence trend
Legend
 Très pauvre  Pauvre  Bon  Très bon
Tendances récentes  Amélioration  Stable Confiance  Confiance élevée basée sur des données de haute qualité
 En déclin  Peu clair  Confiance modérée basée sur quelques preuves limitées
 Pires/meilleurs 10% des places  Faible confiance basée sur le jugement d'experts avec peu ou pas de données