Trophic TRAnsfer eFFICiency in the Benguela Current
The Benguela Upwelling System, off southern Africa, belongs to the most productive marine ecosystems on earth and supports many important fisheries. In TRAFFIC, scientists from Germany, Namibia and the Republic of South Africa investigate the efficiency of its food chains.
Coastal upwelling systems produce a major portion of global fisheries resources, and the Benguela Upwelling System ranges among the largest. However, considerable differences currently exist between the fish stocks and the populations of their prey in the southern and the northern sections of the Benguela Upwelling System. Environmental conditions as well as the intensity of fishing activities have contributed to this divergent development.
In TRAFFIC, German scientists investigate, together with partners from southern Africa, the mechanisms behind the difference in transfer efficiency and productivity of the food webs in both regions. Researchers of the Thünen Institute of Sea Fisheries and the South African fisheries research institution DAFF, jointly lead a subproject focusing on mesopelagic fishes. These widely distributed fish species conduct extensive diel vertical migrations and thereby contribute significantly to the flux of matter between different depth zones of the ocean. Nevertheless, their role in the productivity of the food chains supplying commercially exploited fish species has received only limited attention, thus far.
Fisheries managers, scientists, general public
During two sea-going expeditions, the international team will investigate the distribution patterns and the vertical migration behavior of mesopelagic fishes. Hydro-acoustic measurements as well as net hauls will be taken with a research vessel. Closing nets allow for targeted sampling of fish from different depth zones, and various methods will be applied to obtain insight into the feeding behavior of the fishes.
Investigations at sea involve hydro-acoustic documentation of the distribution patterns of the fishes with direct net sampling. Methods of onboard analyses and investigations in the laboratory ashore include:
7.2018 - 6.2021
Project funding number: 03F0797D
Project status: ongoing