Articles by Author: J C Groeneveld

Search results for J C Groeneveld

We found 22 results for you
  1. The influence of temperature and boron on pollen germination in <em>Mangifera indica</em> L.

    The influence of temperature and boron on pollen germination in <em>Mangifera indica</em> L.

    Item type: Journal Article • Journal: South African Journal of Plant and Soil
    Fruit set in the mango (Mangifera indica L.) cultivar ‘Haden’ is exceptionally low. In an effort to determine the reason for this phenomenon, the influences of temperature and application of boron on pollen germination and the effectiveness of cross- versus...
  2. Interaction between cultivar and soil fertility on grain yield, yield components and grain nitrogen content of wheat

    Interaction between cultivar and soil fertility on grain yield, yield components and grain nitrogen content of wheat

    Item type: Journal Article • Journal: South African Journal of Plant and Soil
    The effect of soil nutrient status on the performance of four wheat cultivars was studied in a long-term field experiment at the University of Pretoria. The objective was to quantify the effect of soil nutrient status on yield, yield components...
  3. Long-distance migration of the rock lobster <em>Palinurus delagoae</em> off South Africa and Moçambique

    Long-distance migration of the rock lobster <em>Palinurus delagoae</em> off South Africa and Moçambique

    Item type: Journal Article • Journal: South African Journal of Marine Science
    Long-distance migration patterns of deep-water rock lobster Palinurus delagoae were investigated using tagrecapture data obtained over a period of 6 years (1995–2000). Of 7 654 animals tagged, 363 (4.7%) were recovered from South African and seven (0.1%) from Moçambican waters...
  4. Size at onset of sexual maturity in the South Coast rock lobster <em>Palinurus gilchristi</em> (Decapoda: Palinuridae)

    Size at onset of sexual maturity in the South Coast rock lobster <em>Palinurus gilchristi</em> (Decapoda: Palinuridae)

    Item type: Journal Article • Journal: South African Journal of Marine Science
    Size at onset of sexual maturity in female Palinurus gilchristi was determined by means of two methods. Sizes using the presence of ovigerous setae as an indicator of maturity were consistently smaller than those estimated using a method based on...
  5. Breeding period and size in the South Coast rock lobster, <em>Palinurus gilchristi</em> (Decapoda: Palinuridae)

    Breeding period and size in the South Coast rock lobster, <em>Palinurus gilchristi</em> (Decapoda: Palinuridae)

    Item type: Journal Article • Journal: South African Journal of Marine Science
    The breeding period in female P. gilchristi was determined by integrating periods of higher egg-bearing proportions with the preceding ripening of ovaries. Most ovaries in the central sector ripened in June (c. 75% in Stage 4), followed by spawning in...
  6. Spatial and temporal availability in the multispecies crustacean trawl fishery along the east coast of South Africa and southern Moçambique, 1988–1993

    Spatial and temporal availability in the multispecies crustacean trawl fishery along the east coast of South Africa and southern Moçambique, 1988–1993

    Item type: Journal Article • Journal: South African Journal of Marine Science
    Catch and effort data from the crustacean trawl fishery along the east coast of South Africa and southern Moçambique are used to investigate spatial and temporal availability of several commercially important crustacean species. The abundance of shallow-water prawns, Penaeus indicus,...
  7. The influence of depth, latitude and width of the continental slope on the size distribution and availability of spiny lobster <em>Palinurus delagoae</em> off the east coast of South Africa

    The influence of depth, latitude and width of the continental slope on the size distribution and availability of spiny lobster <em>Palinurus delagoae</em> off the east coast of South Africa

    Item type: Journal Article • Journal: South African Journal of Marine Science
    The influence of depth, latitude and width of the continental slope on the size distribution and catch per unit effort of Palinurus delagoae captured in longline traps off the east coast of South Africa was examined by means of generalized...
  8. Relative abundances of spiny lobster <em>Palinurus delagoae</em> and slipper lobster <em>Scyllarides elisabethae</em> off the east coast of South Africa

    Relative abundances of spiny lobster <em>Palinurus delagoae</em> and slipper lobster <em>Scyllarides elisabethae</em> off the east coast of South Africa

    Item type: Journal Article • Journal: South African Journal of Marine Science
    Relative abundances of spiny lobster Palinurus delagoae and slipper lobster Scyllarides elisabethae were estimated during a trap-fishing survey off the east coast of South Africa. An average abundance index of 446,8 g·trap−1 was estimated for both species combined, P. delagoae...
  9. Morphometric relationships of palinurid lobsters <em>Palinurus delagoae</em> and <em>P. gilchristi</em> and a scyllarid lobster <em>Scyllarides elisabethae</em> caught in traps off the south and east coasts of South Africa

    Morphometric relationships of palinurid lobsters <em>Palinurus delagoae</em> and <em>P. gilchristi</em> and a scyllarid lobster <em>Scyllarides elisabethae</em> caught in traps off the south and east coasts of South Africa

    Item type: Journal Article • Journal: South African Journal of Marine Science
    Morphometric relationships of commercially important lobsters Palinurus delagoae, P. gilchristi and Scyllarides elisabethae were determined using standard measurements of carapace length (CL), whole mass (WM) and tail mass (TM). The relationships are important because they form the basis for assessing...
  10. Growth of spiny lobster <em>Palinurus gilchristi</em> (Decapoda: Palinuridae) off South Africa

    Growth of spiny lobster <em>Palinurus gilchristi</em> (Decapoda: Palinuridae) off South Africa

    Item type: Journal Article • Journal: South African Journal of Marine Science
    Growth of spiny lobster Palinurus gilchristi was investigated on four traditional lobster fishing grounds, Agulhas Bank, St Francis, Port Elizabeth and Port Alfred, using tagging data. Of 11 144 individuals tagged in six tagging sessions between 1988 and 1993, 1...