Hydrodynamic processes, nutrient availability, phytoplankton, zooplankton and larval fish abundance and distribution have been investigated in some areas of Mozambique coastal waters such as the Sofala Bank during the “Dr. Fridtjof Nansen” Survey, September to December 2007.



The results showed that zooplankton horizontal distribution was greater at the region where estuarine influence is dominant. In this region, phytoplankton biomass was concomitantly lower due to high grazing pressure (Leal et al. 2009). 

Previous studies have also shown that maximum plankton abundance occurs over the continental shelf slope. This is a transition zone between the south-flowing Mozambique current and shelf counter current. During the night, plankton is more or less evenly distributed in the whole water column in the shelf area. The lowest plankton abundance occurred during the southern summer and the maximum values were observed in September–October period. Preliminary results from the ASCLME Project, during the Dr. Fridtjof Nansen survey 2008 in the North of Mozambique.

The issues related to secondary production are linked to conservation of biodiversity and fisheries production. There are therefore related to ecosystem health and productivity. Healthier and diverse ecosystems lead to higher fisheries production. Gaps There are few studies on plankton in the Mozambique Channel. These are focussed on Sofala Bank and North Mozambique coast (Lutjeharms 2006, Barlow 2008, Leal et al. 2009).  There is a need to study the role of the currents and eddies on the transport and retention of the plankton. In addition, there is a need to conduct surveys of species composition in order to determine the biodiversity of the plankton in the Mozambique Channel.


Coastal zone and continental shelf

Description and extent of coastal and marine habitats Mozambique possess the third longest coast line in the Western Indian Ocean (2,700 km). The continental shelf averages 15 to 25 km in width. However, it can be as narrow as 100 m in some places such as in Pemba in northern Mozambique. It can also be as wide as 145 km as in the case of Sofala bank. Total continental shelf area is about 104,300 km2 (Hoguane and Pereira 2003).

The Mozambique coast has been conveniently divided into three major natural ecoregions. These are: the coralline coast, the swamp coast and the parabolic dune coast. A fourth type, the delta coast, is very restricted and only occurs at the mouth of the Zambezi and Save rivers. Two highly productive areas are recognized, being the Sofala Bank and Maputo Bay. The contribution of the two areas through their rich fisheries to the economy of Mozambique is enormous. The northern coast is renowned for holding most of the marine protected areas rich in biodiversity. 


Coral Reefs The coral reefs of Mozambique are the southern continuation of the well-developed fringing reefs that occur along major sections of the fairly narrow continental shelf of the East African coast of Somalia, Kenya and Tanzania and around the offshore islands between latitude 5°N and 15°S. The reefs are broken by large river outflows and are most extensive where the shelf broadens around islands. 

Fringing reefs are confined to the northern coast and extend south to Mocambo Bay (15°09’S). North of Angoche, reefs are common close to the mainland and become more extensive and shallower towards the north. From Pemba northwards, the islands are much more common almost continuous, some reaching substantial sizes. Rich reefs are found at Pinda off the peninsula south of the Lurio River, and between Pemba and Mecufi.

Islands are also much more common along this northern stretch. The barrier shoal from Moma to Angoche has two strings of small islands - the southern string known as the Primeiras and the northern one known as the Segundas. From Moma southwards to the South African border, rocky reefs with scattered coral are extensive but at only  few places are they attached to islands or the mainland. Most of them occur off shore at 3-30 m depth. South of Pebane, there are few islands -those that exist such as in the Bazaruto Archipelago and Inhaca Island are relatively large and were once part of the mainland. 




Inhaca Island is reported to be the southernmost coral reef of the African mainland, although coral communities extend southwards into South Africa. Mozambique corals are vulnerable to the effects of the El Niño. The 1997-1998 El Niño southern oscillation (ENSO) phenomenon caused extensive coral bleaching due to an increase in temperature beyond tolerable level (Schleyer et al. 1999, Motta et al. 2002).

The regeneration of corals after the El Niño in some cases did not occur. In areas where corals are under intense fishing pressure and where human interference is high, no improvement has been observed (Schleyer et al. 1999). The other threats to reefs include sedimentation, flooding, beach seining, fishing nets and trampling.