Potential for sustainable floodplain fisheries development: a case study of Tatabu floodplain

This study presents evidence from a case study of an ecological appraisal of Tatabu flood plain aimed at formulation management approaches for the enhancement of the fishing communities social economic and cultural realities. Tabtabu flood plain is located north of Jebba and at high water the ecosystems cover about 700 hectares. Fishing constitutes the principal economic activity of natural fish food and flora (especially phytoplankton and zooplankton) which support and favour the growth of over 26 fish species that belong to 15 families. Among the commercially important species in terms of dominance on percentage weight basis are Mochokidae, Cichlidae, Claridae and Characidae with an overall average standing crop of 88.24kg/ha based on gill net experiment. The study based on the intrinsic ecological attributes and local people willingness for sustained contribution of fisheries to food supply indicates that with adequate management Tatabu flood plain ecosystems have tremendous fishery potentials that would enhance the economic well being of the communities. Several management options that are applicable to similar plain are discussed

Radiocarbon record of solar variability and Holocene climatic change in coastal southern California

EXTRACT (SEE PDF FOR FULL ABSTRACT): Pollen analysis and 5 radiocarbon dates for a 687-cm core provide a detailed chronology of environmental change for San Joaquin Marsh at the head of Newport Bay, Orange County, California. Sediment deposition kept pace with sea level rise during the mid-Holocene, but after 4500 years BP, sea water regularly reached the coring site, and salt marsh was the local vegetation. Brief periods of dominance by fresh-water vegetation 3800, 2800, 2300 and after 560 years BP correlate global cooling events and (except the 3800-year BP event) with carbon-14 production anomalies. The coincidence of climate change and carbon-14 anomalies support a causal connection with solar variability, but regardless of the causal mechanism(s) the delta-carbon-14 curves provide a chronology for global, high-frequency climatic change comparable to that of Milankovitch cyclicity for longer time scales.

Diversity indices of selected macrobenthos in Karanja Creek (District-Raigad), Maharashtra, west coast of India

The diversity indices can be used as a good measure for studying the effect of industrial pollution because industrial wastes and sewage almost always reduce the diversity of natural systems into which they are discharged. A measurement of diversity often provides a better index of pollution than a direct measurement of pollutants. The assessment of macrobenthos diversity with respect to diversity indices reflects the marine population and habitat disturbance, and also serves as an important indicator of environmental conditions. The present study was designed to investigate the diversity indices of selected macrobenthos at two ecologically distinct locations on the Karanja creek (District - Raigad), Maharashtra, west coast of India. Results on various diversity indices like Index of Frequency (F) or Importance Probability (Pi), Index of Dominance (c), Rarity Index (R), Shannon's Index of General Diversity (H¹) Margaf’s Richness Index (R sub(1)) and Evenness Index (e) did not vary significantly. This demonstrates that at present, Karanja creek harbours varied forms of macrobenthic community showing no effect of human disturbance, but in future, measures must be taken for the protection and conservation of macrobenthic community of the creek.