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The main survey is completed

R/V Dr. Fridtjof Nansen arrived Pemba Friday afternoon and the main survey of the marine ecosystem in Mozambique is now completed! Since the start of the survey in Maputo 27 September we have covered the whole coast between the borders to South Africa and Tanzania, and sailed near 6000 nautical miles. Despite a delay of two days of waiting for permission to enter the port of Beira due to bad weather, we have fulfilled the cruise according to the survey plan.

R/V Dr. Fridtjof Nansen arrived Pemba Friday afternoon and the main survey of the marine ecosystem in Mozambique is now completed! Since the start of the survey in Maputo 27 September we have covered the whole coast between the borders to South Africa and Tanzania, and sailed near 6000 nautical miles.

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Despite a delay of two days of waiting for permission to enter the port of Beira due to bad weather, we have fulfilled the cruise according to the survey plan. The areas south of Angoche (~17°S) was adequately sampled with bottom trawl, however, the steep and rocky bottom in the northern part of the coast prevented a proper trawl sampling of this area.

A main objective of the survey has been to map and estimate the biomass abundance of important fish and shrimp species in Mozambique, and the combination of acoustic and bottom trawl techniques enabled us to measure the distribution and abundance of both pelagic and bottom dwelling species. The preliminary results show that the pelagic species such as carangids, barracudas and clupeids are distributed in shallow coastal waters, which in depths shallower than 20 m are unavailable for larger offshore research vessels.

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Acoustic densities of pelagic fish (carangids, scombrids, barracudas and hairtail) in the southern region.

The highest catches of shrimps were in shallow waters on the Sofala Bank, and on the slope (200-800 m) in the regions south of Angoche. The demersal fish groups; Sciaenidae (croakers), Sparidae (Seabreams), Ariidae (catfish), Serranidae (groupers), Lutjanidae (snappers) and Pomadasyidae (grunts) were distributed on the shelf in relatively low densities, while the Ophidiidae (cusk eels) were caught in deep waters. Several of the fish species caught in the trawl have never before been recorded in Mozambiquan waters, and the extensive sampling and identification of species has provided valuable new insight into the species composition and diversity on the shelf and slope.

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In addition to the important study of the fish and shrimp resources, we have also carried out an intensive sampling of the environmental and oceanographic data. These data will improve the knowledge of the ecosystem, currents and upwelling systems in the region.

We are grateful to the crew on RV “Dr Fridtjof Nansen”, who always provides excellent assistance and is the fundament for all scientific work on board. 

Espen Johnsen