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NWA Ecosystem survey with R/V Dr. Fridtjof Nansen

Then we are well underway with this year's ecosystem cruise along the northwest African coast. Last year, the cruise was carried out at the end of the year (October to December), while this year we conduct the survey from May until the end of July. In this way we hope to capture seasonal variations in species distribution and ecosystem dynamics.

We have a total of 70 days to identify an area from Conakry in Guinea in the south, and up to the Gibraltar Strait in the north. During this time 54 scientists and technicians from 15 countries working to identify the ecosystem known as the Canary Current Large Marine Ecosystem (CCLME).

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

Every third transect is termed an “Ecosystem transect” with a more elaborate sampling program. These transects extends to 1000 m depth. CTD’s are taken at 1000 m, 500 m, 200 m, 100 m, 50 m and 30 m at the coastal margin of the transect. Additionally, three stations for sampling of nutrients, chlorophyll, phyto and zooplankton, and soft-sediment invertebrates are conducted at 500 m, 100 m and 30 m depth. Trawling is undertaken within the same depth regions as for all other transects. Samples of the fish and sediments are collected for further analysis of pollution.

When 2/3 of the cruise is over, we have taken more than 200 bottom trawl stations, 161 CTD stations, in addition to over hundred horizontal and vertical plankton net hauls, sledge and grab samples. From the catches of the bottom trawl, we have registered over 480 different fish species, belonging to over 120 different families. In addition, we identified about 1000 different invertebrate species, belonging to almost all phyla: sponges, cnidarians, mollusks, crustaceans and echinoderms. Species identification is a tedious process, in which details are essential. Although we have a Spanish professor on board who specializes in hydroids and bryozoans, some of the individuals are given the name "alien" in a few days before the correct species has been identified. The biggest challenges are trawling between 500 -700 m then we can get many strange "being" on board, but we have been fortunate to have several very talented local researchers on board. They have been working hard, despite of bad weather (storm) and seasickness. 

In the following some of the participants of the cruise will tell about their experiences on board. Many thanks to the crew on board who should have their share of the credit for the Nansen program is a success story. Then we just cross our fingers and hope that we get a new boat and that Nansen program can continue for a while.
 

Follow the boat's position:

"Dr. Fridtjof Nansen"

Facta box:

  • 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 Canary Current Large Marine Ecosystem (CCLME) project is executed by the Food and Agriculture Organization of the United Nations (FAO) and the United Nations Environment Programme (UNEP) in a combined effort to reverse the degradation of the Canary Current large marine ecosystem caused by over-fishing, habitat modification and changes in water quality by adoption of an ecosystem-based management approach.
  • The current phase of the CCLME project will be operational for five years (2010-2015) in the seven participating countries Cape Verde, Guinea, Guinea Bissau, Mauritania, Morocco, Senegal and The Gambia.
  • The project is funded by the Global Environment Facility (GEF) and co-financed by participating countries and other partners. The Nansen program is selected as one out of the 10 most successful bilateral programmes in FAO 

Contact

Kathrine Michalsen
454 29 971