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In artisanal fishery, traditional handling methods such as tossing fish onto the boat bottom or into woven mat baskets and gunny bags after capture are commonly employed. These practices accelerate fish spoilage due to cross contamination and exposure to high ambient temperature. This study aimed at investigating the effect of non-icing (onboard handling methods) on the quality of Lethrinids (Emperor fish, local name: Changu) and Siganids (Rabbitfish, local name: Tafi) landed along the Kenyan coast in comparison to iced fish. Monthly, samples were assessed by sensory methods using Quality Index Method (QIM), Total Viable Counts (TVC) and hydrogen sulphide ([H.sub.2]S) producing bacteria considered as specific spoilage organisms (SSO) counts for raw fish; Quantitative Descriptive Analysis (QDA) and Torry score for cooked fillets. Iced fish was characterised by better freshness quality attributes at landing time compared to non-iced at both landing sites. According to the QIM, iced treatment recorded better quality scores that were significantly different from non-iced groups (p Key words: Lethrinids, Siganids, Quality, Sensory, Handling, INTRODUCTION Fishing and fisheries related activities contribute greatly to the livelihoods of Kenyan coastal communities. Small-scale agriculture, mangrove harvesting, tourism, and trade also contribute substantially to the coastal economy [1]. [...]

Phytoplankton communities play a significant role in the oceanic biological pump by forming the base of the trophic structure. Increase in nutrients loading affects spatial and temporal distribution of phytoplankton. This study examined the phytoplankton community structure and ecological indices in relation to nutrients dynamics in both estuarine and oceanic areas of Ramisi-Vanga systems along the Kenyan coast. Surface water samples were collected and analysed for nutrients (PO4 3--P, NO3 --N and NH4 +-N) and phytoplankton abundance and community structure. This study reported very diverse phytoplankton community structure consisting of 88 taxa that were dominated by Chaetoceros sp., Coscinodiscus sp., Nitzschia sp., Pseudo-nitzschia sp., Alexandrium sp., Protoperidium sp. and Prorocentrum sp that are among the potentially harmful algae. Diatoms were the most abundant taxa in Ramisi-Vanga system. Phytoplankton abundance was found to be higher in the estuarine systems (1182.06±149.14 cells/L) as compared to the oceanic systems (551.99±166.70 cells/L) with high abundance observed in May for oceanic and estuarine systems. Shannon Weiner's species diversity index was greater than 2 in both oceanic and estuarine systems. Phytoplankton species' abundance, composition and diversity were found to be influenced by the availability of NH4 +-N, NO3 --N and PO4 3--P. Phytoplankton cell density was below 4000 cells/ L, thus, this study has classified Ramisi-Vanga system as an oligotrophic system implying that the current level of land based activities are not having significant impacts on the phytoplankton communities. [ABSTRACT FROM AUTHOR]

This study investigated the effects of sewage discharge on nutrient concentrations and BOD5 levels in the coastal waters and sediments ofthe City of Mombasa. The results indicated that nutrient concentrations in Tudor, Mtwapa and Makupa Creeks were elevated as compared to concentrations in Gazi Creek (mean ranges of 0.022-0.039mg/L, 0.038-0.163mg/L and 0.034-0.118mg/Lphosphates, nitrates and ammonium respectively). Sediments were found to harbour relatively higher concentrations of nutrients than water compartment (mean ranges of 0.217-1.131mg/L, 0.199-0.603mg/L and 9.394-26.73mg/L for phosphates, nitrates and ammonium respectively) thus serving as a reservoir and potential source if sediments are resuspended during heavy storms or dredging. Based on Chl-a levels, Makupa Creek could be classified as eutrophic whereas Mtwapa and Tudor Creeks could be placed at the upper limit of higher mesotrophy while Gazi Creekcould be considered as an oligotrophic system. Of the three impacted Creeks, Tudor was found to be the most polluted. [ABSTRACT FROM AUTHOR]

In situ decomposition of senescent leaves of two abundant mangrove species (Rhizophora mucronata Lamarck and Ceriops tagal (Perr) C.B. Rob), enrichment of nitrogen and activity of dinitrogen fixing bacteriaduring decomposition were investigated during both rainy and dry seasons in a tropical coastal lagoon (Gazi, Kenya). Rates of leaf decomposition were higher for R. mucronata than for C. tagal and were highest, for both species, during rainy season. Rates of decomposition, expressed as percentage dry mass loss, over a decomposition period of 50 days was: C. tagal (rainy season), 69%; C. tagal (dry season), 27%;R. mucronata (rainy season), 98%; and R. mucronata (dry season), 48%. High rainfall and diurnal tidal inundation appear to enhance the leaf decomposition process. Maximum rates of nitrogen fixation were 380nmol N2 h-1 g-1 dw for C. tagal (rainy season), 78 nmol N2 h-1 g-1 dw for C. tagal (dry season), 390 nmol N2 h-1 g-1 dw for R. mucronata (rainy season) and 189 nmol N2 h-1 g-1 dw for R. mucronata (dry season). Although N2 fixation rates were highest during rainy season,total nitrogen immobilised in the leaves was highest during the dry season. Biological nitrogen fixation can account for between 13 to 21% of the maximum nitrogen immobilised in the decaying mangrove leaves. Nitrogen fixation, as a source of allochthonous nitrogen, sustains a nitrogen input to the mangrove ecosystem, which adds significantly to the nitrogen input through leaf litterfall. [ABSTRACT FROM AUTHOR]