Marine & Coastal Habitats & Vegetation
Jinack Island in The Gambia offers diverse marine and coastal habitats that attract a wide range of bird species, making it a great destination for birdwatching. In addition to birdwatching, the island’s geographical diversity and unspoiled beauty provide unique opportunities for studying and researching other wildlife, flora, and fauna.
Permanent Shallow Marine Waters
The coastal profile between Barra Point and Buniada Point features a gently shelving sand embayment with a predominant northerly current. The depth of water at high tide is approximately 5 meters up to 2 kilometers offshore. The movement of sediments in the area, particularly around Buniada Point, has resulted in the formation of sand bars extending up to 2 kilometers to the west. Erosion along the shoreline of Jinack Island has contributed to the deposition of sand.
There is limited sub-tidal vegetation, but occasional presence of eelgrass (Cymodocea nodosa) along the shoreline suggests the presence of beds within the confines of the Niumi National Park.
The northern tip of Jinack Island forms an estuary for the outflow of several bolongs (tidal creeks), some of which originate from the Delta du Saloum. The Masarinko bolong is the main water body within Niumi National Park, rising as two streams 1 kilometer inland. During the dry season, the freshwater flow in these bolongs is minimal, resulting in brackish to saline conditions throughout the year. The habitats associated with these water bodies include mangrove forests, intertidal mudflats, and salt marshes. Freshwater pools persist in the upper reaches of the bolongs into the dry season but eventually dry completely. Rice cultivation takes place on the upper flood plains of the rivers under the canopy of relict gallery forest.
A single coastal lagoon exists at Buniadu Point on the north shore of Jinack Island, covering an area of approximately 2 hectares. The lagoon is maintained by sediment accumulation from the outflow of the Masarinko Bolon and the northerly currents from the mouth of the River Gambia. The sediments form a spit that extends north-west from Buniada Point for about 1 kilometer. The lagoon is periodically inundated by the sea during spring tides through a channel on the northeast side. However, tidal surges have caused breaches in the western bank, posing a potential risk. The fringe of the lagoon is vegetated with a pioneer community of plants such as Ipomea pes-caprae, Sesuvium portulacastrum, Cenchrus biflorus, and Cyperus spp. Occasional Avicennia shrubs are found on the southern edge, transitioning into Dichrostachys thickets with emergent Adansonia digitata.
Niumi National Park encompasses two main creek systems. The Niji bolon connects to the ocean immediately north of Barra Point and merges with the Mansarinko Bolon at the Senegalese border, forming Jinack Island. This bolong experiences regular diurnal tidal cycles, with relatively little seasonal variation in salinity due to its small catchment area.
The Mansarinko bolon divides north of Mbamkam, giving rise to the Ker Jatta and Duniajoes bolongs. These bolongs have a combined catchment area of approximately 100 square kilometers, resulting in marked seasonal variation in salinity. During the dry season, hyper-saline conditions occur in the upper reaches due to limited tidal flushing and high evaporation rates. With the onset of rains, dilution occurs, gradually reducing salinity levels. Mangrove vegetation dominates the banks of these bolongs, with woodland and grassland occurring in other areas. Aquatic vegetation is generally absent, except within the mangrove complex.
The upper reaches of Ker Jatta and Duniajoe bolongs have seasonal freshwater flow. Other small bolongs on Jinack Island and the mainland are rain-fed but prone to rapid salinization due to a combination of evaporation and intrusion. These bolongs feature floating/emergent freshwater vegetation dominated by species such as Nymphaea lotus, N. micrantha, Typha spp., and Cyperus spp. Relic gallery forests fringe the bolongs, although some areas have been cleared for rice cultivation and seasonal vegetable gardening.
The inclusion of the freshwater stretches of these bolongs within the proposed Niumi Biosphere Reserve is under negotiation with neighboring communities.
Gambia Bird Watching Holidays, Trips & Tours
For a brief outline of the birding and birdwatching opportunities available throughout the year, follow the provided link.