Summary of the Tanzanian Case Study: A tale of two upwellings

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Ocean Science in Action - Oceans of the future

9. Small Pelagic Fisheries of Pemba Channel, Tanzania

9.6 Summary of the Tanzanian Case Study: A tale of two upwellings

Video duration - 06:56

Growing evidence suggests that the ecosystem, including small pelagic fish, responds strongly to upwelling events along the Tanzanian coast, and that interannual variability in the strength of upwelling is well correlated with the catches of small pelagics.

Upwelling intensity peaks during both the south-east and north-east monsoon, although the mechanisms at play are different during these two periods. During the north-east monsoon, upwelling is driven by local alongshore winds, while during the south-east monsoon the acceleration of the strong along-shelf current results in “dynamic uplift” upwelling.

Satellite observations, ocean model outputs, and in-situ measurements can be used together to examine response of the Chlorophyll-a (as a proxy for phytoplankton) to the upwelling events. Analysis of the data shows that the yield of the small pelagics is synchronous with the available Chl-a concentrations on a year-to-year basis and responds strongly to the interannual variability in monsoonal winds.

Dr F. Jebri - NOC

Further Reading:

Jebri, F., Jacobs, Z.L., Raitsos, D.E. et al. Interannual monsoon wind variability as a key driver of East African small pelagic fisheries. Sci Rep 10, 13247 (2020).

Kämpf, J., Chapman, P. , 2016. Upwelling Systems of the World: A Scientific Journey to the Most Productive Marine Ecosystems.Springer, 433 pp.,

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