Review of the projected impacts of climate change on coastal fishes in southern Africa

The coastal zone represents one of the most economically and ecologically important ecosystems on the planet, none more so than in southern Africa. This manuscript examines the potential impacts of climate change on the coastal fishes in southern Africa and provides some of the first information for the Southern Hemisphere, outside of Australasia. It begins by describing the coastal zone in terms of its physical characteristics, climate, fish biodiversity and fisheries. The region is divided into seven biogeographical zones based on previous descriptions and interpretations by the authors. A global review of the impacts of climate change on coastal zones is then applied to make qualitative predictions on the likely impacts of climate change on migratory, resident, estuarine-dependent and catadromous fishes in each of these biogeographical zones. In many respects the southern African region represents a microcosm of climate change variability and of coastal habitats. Based on the broad range of climate change impacts and life history styles of coastal fishes, the predicted impacts on fishes will be diverse. If anything, this review reveals our lack of fundamental knowledge in this field, in particular in southern Africa. Several research priorities, including the need for process-based fundamental research programs are highlighted

The Changing Global Climate and its Implication on Sea Level Trends in Tanzania and the Western Indian Ocean Region

Global mean sea levels show a general rising trend that has been accelerated by the recent changes in world climate. This is ascertained through geological and historical records, measurements from in situ tide gauges around the globe and since 1992, through satellite altimetry. About 60% of the 34 tide gauge stations in the Western Indian Ocean region with at least four years of data portray rising trends of relative sea levels, while the remaining 40% show falling trends. Sea level records in 14 other stations in the region were not considered in this investigation due to short data spans. Relative sea levels in Tanzania show falling trends in Tanga (1962-1966), Dar es Salaam (1986- 1990) and Zanzibar (1984-2004), but portray a rising trend in Mtwara (1959-1962). Published results from satellite altimetry (1993-2003) also concur with the national and regional tide gauge observations, and are similar to those observed in the Eastern Pacific. However, these patterns likely reflect inter-annual and decadal fluctuations rather than long-term trends. Available literature on model reconstructions of long-term sea level trends (1955-2003) show a general rising trend in Tanzania (0.4 to 2.0 mm/yr) and the Western Indian Ocean (-0.4 to 2.4 mm/yr). The global average within this period (-0.4 to 3.6 mm/yr) is basically higher than these national and regional trend