Articles by Keyword: Population Dynamics

Search results for Population Dynamics

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  1. POPULATION DYNAMICS AND DEMOGRAPHY OF AN ESTUARINE COPEPOD (<em>PSEUDODIAPTOMUS EESSEI</em>) IN LAKE SIBAYA, A SUBTROPICAL FRESHWATER COASTAL LAKE

    POPULATION DYNAMICS AND DEMOGRAPHY OF AN ESTUARINE COPEPOD (<em>PSEUDODIAPTOMUS EESSEI</em>) IN LAKE SIBAYA, A SUBTROPICAL FRESHWATER COASTAL LAKE

    Item type: Journal Article • Journal: Journal of the Limnological Society of Southern Africa
    Population size and stage structure of Pseudodiaptomus hessei (Mrázek) was studied over 27 months at a single site in subtropical Lake Sibaya. Population density varied seasonally from about 1 to 4 individuals per litre, but a fairly stable population structure...
  2. RELATIVE FISH POPULATION DENSITY CHANGES IN THE P.K. LE ROUX DAM DURING THE FIRST THREE YEARS AFTER INUNDATION

    RELATIVE FISH POPULATION DENSITY CHANGES IN THE P.K. LE ROUX DAM DURING THE FIRST THREE YEARS AFTER INUNDATION

    Item type: Journal Article • Journal: Journal of the Limnological Society of Southern Africa
    Before inundation in September 1976 Barbus holubi and Labeo capensis were the dominant species each making up 46% of the total catch. Immediately after impoundment the relative density of B. holubi increased to 75% while that of L. capensis dropped...
  3. PRODUCTION OF THE AFRICAN CATFISH <em>(CLARIAS GARIEPINUS)</em> I. GROWTH, MORTALITY AND YIELD SOUTH OF THE ZAMBEZI

    PRODUCTION OF THE AFRICAN CATFISH <em>(CLARIAS GARIEPINUS)</em> I. GROWTH, MORTALITY AND YIELD SOUTH OF THE ZAMBEZI

    Item type: Journal Article • Journal: Journal of the Limnological Society of Southern Africa
    Clarias gariepinus were sampled from eight water bodies in southern Africa between 1973 and 1975. Aging results indicate a similar growth pattern for most areas with a near linear age-length relationship. Between year growth compensation was found to be present...
  4. EFFECT OF PROGRAMMED CIRCADIAN TEMPERATURE FLUCTUATIONS ON POPULATION DYNAMICS OF <em>BULINUS TROPICUS</em> (KRAUSS) AND <em>LYMNAEA NATALENSIS</em> KRAUSS (GASTROPODA: MOLLUSCA)

    EFFECT OF PROGRAMMED CIRCADIAN TEMPERATURE FLUCTUATIONS ON POPULATION DYNAMICS OF <em>BULINUS TROPICUS</em> (KRAUSS) AND <em>LYMNAEA NATALENSIS</em> KRAUSS (GASTROPODA: MOLLUSCA)

    Item type: Journal Article • Journal: Journal of the Limnological Society of Southern Africa
    Until now all life-table studies on Bulinus tropicus (Krauss) and Lymnaea natalensis Krauss involving temperature as the variable factor have been conducted at constant temperatures. This study evaluates the effect of programmed, circadian temperature fluctuations, ranging from 18 to 28...
  5. EFFECT OF CONSTANT TEMPERATURE ON POPULATION DYNAMICS OF <em>BULINUS TROPICUS</em> (KRAUSS) AND <em>LYMNAEA NATALENSIS</em> KRAUSS

    EFFECT OF CONSTANT TEMPERATURE ON POPULATION DYNAMICS OF <em>BULINUS TROPICUS</em> (KRAUSS) AND <em>LYMNAEA NATALENSIS</em> KRAUSS

    Item type: Journal Article • Journal: Journal of the Limnological Society of Southern Africa
    Life-tables were compiled for cohorts of the two freshwater snail species Bulinus tropicus (Krauss) and Lymnaea natalensis Krauss at six different constant temperatures from 17 to 32 °C under identical conditions of crowding, feeding and chemical composition of the water...
  6. SUITABILITY OF TROPICAL FISH FOODS FOR LABORATORY CULTURE OF FOUR SPECIES OF FRESHWATER SNAILS ACTING AS INTERMEDIATE HOSTS FOR ECONOMICALLY IMPORTANT HELMINTH PARASITES IN SOUTH AFRICA

    SUITABILITY OF TROPICAL FISH FOODS FOR LABORATORY CULTURE OF FOUR SPECIES OF FRESHWATER SNAILS ACTING AS INTERMEDIATE HOSTS FOR ECONOMICALLY IMPORTANT HELMINTH PARASITES IN SOUTH AFRICA

    Item type: Journal Article • Journal: Southern African Journal of Aquatic Sciences
    Four different kinds of tropical fish food from Tetra Werke, West Germany, as well as a mixture of two of these, were evaluated as possible nutrients for the laboratory culture and maintenance of four freshwater snail species of economic importance...
  7. Transformation of a savanna grassland by drought and grazing

    Transformation of a savanna grassland by drought and grazing

    Item type: Journal Article • Journal: African Journal of Range & Forage Science
    The relative effects of drought and heavy grazing on the floristic composition, population size and structure, and basal cover of an African savanna grassland were differentiated by comparing changes over eight years, which included a severe drought year, across a...
  8. Phytoplankton responses to changes in macrophyte density in a tropical artificial pond in Zaria, Nigeria

    Phytoplankton responses to changes in macrophyte density in a tropical artificial pond in Zaria, Nigeria

    Item type: Journal Article • Journal: African Journal of Aquatic Science
    The response of phytoplankton population dynamics to changes in densities of Nymphaea lotus L. and Polygonum limbatum Meisn. was studied in an artificial pond in Zaria, Nigeria, from June to November 2007. Antagonistic effects of these macrophytes on Netrium sp.,...
  9. Population Dynamics of the Wandering Albatross <em>Diomedea Exulans</em> at Marion Island: Longline Fishing and Environmental Influences

    Population Dynamics of the Wandering Albatross <em>Diomedea Exulans</em> at Marion Island: Longline Fishing and Environmental Influences

    Item type: Journal Article • Journal: African Journal of Marine Science
    The subantarctic Prince Edward Islands (Marion and Prince Edward) support the largest breeding population of the Vulnerable wandering albatross Diomedea exulans. The number of birds breeding at Marion Island has fluctuated over the past three decades apparently as a result...
  10. Temporal and spatial variability in the characteristics of <em>Alexandrium fundyense</em> blooms in the coastal zone of the Bay of Fundy, eastern Canada

    Temporal and spatial variability in the characteristics of <em>Alexandrium fundyense</em> blooms in the coastal zone of the Bay of Fundy, eastern Canada

    Item type: Journal Article • Journal: African Journal of Marine Science
    The abundance of the dinoglagellate Alexandrium fundyense has been monitored at four locations in the Bay of Fundy, eastern Canada, at weekly to monthly intervals since 1988. The date of first appearance of A. fundyense varied each year from Day...