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 RV "Dr. Fritjof Nansen"
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Northwest Africa Ecosystem survey

20.10.2011 R/V Nansen started its 62 days long survey along the coast of Northwest Africa, from Conakry in Guinea up to the Gibraltar strait in north. The survey is an ecosystem survey and different survey techniques will be used to provide a holistic overview of the ecosystem. In addition to the Norwegian staff, 32 persons from 8 different countries will participate on this cruise.

The Canary Current Large Marine Ecosystem (CCLME) is a vital food and economic resource not only for coastal populations bordering the Large Marine Ecosystem (LME), but also for much of Western Africa. Sustainable stewardship of the CCLME is essential for achievement of the Millennium Development Goals in Africa.

The CCLME is one of the world’s major cold water upwelling boundary current LME. It ranks third in the world in terms of primary productivity and it has one of the highest fisheries production of any African large marine ecosystem with an annual production ranging from 2-3 million tonnes.
The fisheries in the Canary Current LME are of major economic and social importance in that they provide sustainable livelihoods, fish-protein supplies and revenue for the coastal populations and states of the region.

Figure 1. Course track during the survey.

Figure 1. Course track during the survey

The CCLME coastal zone also provides important goods and services to coastal states including provision of critical fish habitat, wood from mangroves and provision of coastal and marine space for agriculture, aquaculture, urban development, tourism and transport.
However, fisheries in the Canary Current are on the decline and many resources are now classified as overexploited. Some of the underlying causes of the declining fisheries include the over-capacity of fishing fleets (both industrial and artisanal); ecosystem complexity and variability; weak management and monitoring, control and surveillance; lack of scientific and technical capacity for management; and poor stakeholders’ participation in magement decision's.

In addition, the region is experiencing degradation of several important habitats including estuaries, wetlands (particularly mangroves) and benthic habitats. The causes for the degradation include over-harvesting of wood, trawling, sedimentation, upstream hydro-electric and irrigation schemes and the absence of any systematic policy for conservation of these critical habitats. Habitats are also affected by changing water quality such as salinity changes (mainly due to river dams), oil pollution and eutrophication.

During the 2 months long survey, demersal fish resources will be covered with a swept area trawl survey within predefined depth regions on transects spaced 20 NM apart. This will be combined with acoustic registration of pelagic fish and plankton en route. Each trawl station will be accompanied with a CTD to collect physical oceanographic parameters.

In addition dedicated environmental transects has been designed with spacing 60 NM apart (every third transect). During these transects additional CTDs will be taken (7 stations per env. Transect). Sampling stations for zooplankton and benthos biodiversity (tree stations per env. Transect) will be conducted at fixed bottom depths. Sampling of plankton will be conducted with hydrobios multinet and sampling of benthos biodiversity will be collected with a benthos sledge, or with a grab at stations >100 m bottom depth. Specific sampling protocols have been developed for the sampling of various parameters during the survey.

The survey will produce a cruise diary. This diary will be posted on the IMR web pages once a week.

Weekly reports

Here you can read the crewmembers weekly reports from the survey.