Litter fall varied significantly between species, R. 5.10 ± 1.36 g DW m −2 day −1) and lower rates in the cool and wet South Easterly Monsoon (SEM) season, June-October (ca. Litter fall was seasonal in both content and quantity, with high rates occurring in the dry North Easterly Monsoon (NEM) season, January-April (ca. The mean annual litter fall was estimated at 12.16 ± 2.89 t ha −1yr −1. (Avicenniaceae) were monitored over a period of two years. (Sonneratiaceae), and Avicennia marina (Forssk.) Vierh. Litter from three common mangrove species, Rhizophora mucronata Lam. The productivity of an over-exploited and sewage polluted peri-urban mangrove was assessed through litter fall studies to establish vulnerability to human actions and climate change. Implementation of the present shrimp fishery management plan, and continued monitoring of fish trawl bycatches will be crucial for the effective management of fisheries resources of the estuaries in the bay. Significantly smaller-sized individuals of these seven species occurred in trawl bycatches than in artisanal catches attributed to differences in gear selectivity. This similarity was attributed mainly to seven common and most abundant fish species targeted in artisanal fishery as well as these species made the highest bycatch proportion in the shrimp bottom trawls. Similarity in catch composition was evident between the artisanal catches and bottom trawl bycatches in the inshore areas. On the other hand, trawl bycatch rates were significantly higher in inshore than offshore areas and distinct in composition but less differing between the seasons. Shrimp total biomass and catch rates were significantly higher during the wet Southeast Monsoon (SEM) season than the dry Northeast Monsoon (NEM) season, and decreased as depth increased. Bottom trawl fish bycatch species diversity was higher than for artisanal fish catches with a total of 223 and 177 species respectively. indicus in the Tana estuary, and more abundant P. Distinct shrimp species composition existed between the two estuaries characterised by more abundant F. Five shrimp species: Fenneropenaeus indicus, Penaeus monodon, Metapenaeus monoceros, Penaeus semisulcatus and Penaeus japonicus were recorded. These aimed to determine species composition, relative abundance and distribution patterns of the penaeid shrimps and associated trawl fish bycatches, and fish catches from the artisanal fishers. We describe the present status of the fisheries resources of the estuaries in the bay following shore-based catch assessments between 20, and shallow-water bottom trawl surveys in early 2011. These sectors have exerted pressure on the fisheries resources of the bay and will continue to do so due to the increasing artisanal fishing effort. Currently these estuaries in the bay support over 3 000 artisanal fishers and a maximum acceptable fleet of four medium-sized trawlers. This chapter provides an overview of the key ecological and physical characteristics of the region, setting the background for the deeper analyses presented in the following chapters.įor over 30 decades, the Sabaki and Tana estuaries of the Malindi-Ungwana Bay, Kenya have supported both the artisanal fishery and semi-industrial bottom trawl sectors. At the crossroad between land and sea, the estuarine ecosystems of the region are the gathering point of a number of large river basins, many of which transboundary of nature, and bringing in influence from far away inland. The ecosystem services provided by this rich marine environment are estimated at over 25 billion US$ per year. It is estimated that about 22 per cent of the species found in the WIO region are unique to this region. The region furthermore boasts the longest unfragmented fringing reef in the world, with over 350 species of corals, and a diverse assemblage of coastal forests, mangrove forests and sea grass beds. The region is a hot spot of biodiversity hosting over 2,200 species of fish, five species of marine turtles, more than thirty-five marine mammal species, including humpback whales, dolphins, whale sharks and the highly endangered dugong, and the enigmatic coelacanth a prehistoric fish once thought to be extinct. The coastal and marine environment of the Western Indian Ocean (WIO) region is one of the least ecologically disturbed in the world.
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