Articles by Author: W Sauer

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  1. The Friedrichs Extension of a Pair of Operators

    The Friedrichs Extension of a Pair of Operators

    Item type: Journal Article • Journal: Quaestiones Mathematicae
    An extension of a pair of linear unbounded operators which map from a Banach space X to a Hilbert space Y is constructed and studied. The purpose of the extension is to obtain a pair of jointly closed operators which...
  2. Early post-cleavage stages and abnormalities identified in the embryonic development of chokka squid eggs <em>Loligo vulgaris reynaudii</em>

    Early post-cleavage stages and abnormalities identified in the embryonic development of chokka squid eggs <em>Loligo vulgaris reynaudii</em>

    Item type: Journal Article • Journal: South African Journal of Marine Science
    Six early, post-cleavage embryonic stages for chokka squid Loligo vulgaris reynaudii eggs that were developed in an aquarium are identified and described, expanding the embryonic stages for this species from 14 to 20. The influence of water temperature on embryonic...
  3. Recommendations for the management of subsistence fisheries in South Africa

    Recommendations for the management of subsistence fisheries in South Africa

    Item type: Journal Article • Journal: South African Journal of Marine Science
    This paper summarizes recommendations for the management of previously marginalized and neglected subsistence fisheries in South Africa. The recommendations stem from the activities and analyses of a task group appointed by Government and mandated to provide advice about management of...
  4. The process of developing a management system for subsistence fisheries in South Africa: recognizing and formalizing a marginalized fishing sector in South Africa

    The process of developing a management system for subsistence fisheries in South Africa: recognizing and formalizing a marginalized fishing sector in South Africa

    Item type: Journal Article • Journal: South African Journal of Marine Science
    Subsistence fishers were first recognized as a formal fishing sector in South Africa when new fishing legislation, aimed at redressing past inequalities, was enacted in 1998. Little information was available about these fishers, their activities, and the resources upon which...
  5. Assessment of resource availability and suitability for subsistence fishers in South Africa, with a review of resource management procedures

    Assessment of resource availability and suitability for subsistence fishers in South Africa, with a review of resource management procedures

    Item type: Journal Article • Journal: South African Journal of Marine Science
    The availability of resources and their suitability for subsistence and small-scale commercial fishers in South Africa were assessed and appropriate options for the management of resources recommended. Assessment of current resource utilization and recommendations for future subsistence and/or small-scale commercial...
  6. Histological validation of morphological stages of sexual maturity in chokker squid <em>Loligo vulgaris reynaudii</em> D'Orb (Cephalopoda: Loliginidae)

    Histological validation of morphological stages of sexual maturity in chokker squid <em>Loligo vulgaris reynaudii</em> D'Orb (Cephalopoda: Loliginidae)

    Item type: Journal Article • Journal: South African Journal of Marine Science
    Changes in the ovaries and testes during sexual maturation of Loligo vulgaris reynaudii were examined histologically. Formation and development of the spermatozoa and oocytes could be divided into four distinct stages for males and five for females, and frequencies of...
  7. Food of squid <em>Loligo vulgaris reynaudii</em> (Cephalopoda: Loliginidae) on their spawning grounds off the Eastern Cape, South Africa

    Food of squid <em>Loligo vulgaris reynaudii</em> (Cephalopoda: Loliginidae) on their spawning grounds off the Eastern Cape, South Africa

    Item type: Journal Article • Journal: South African Journal of Marine Science
    Squid on their spawning grounds feed mainly at night when they are more dispersed. In all, 28,5 per cent of squid sampled at night had food in their stomachs, whereas only 6,7 per cent of those collected by day had...
  8. A preliminary investigation of the effect of sea temperature fluctuations and wind direction on catches of chokka squid <em>Loligo vulgaris reynaudii</em> off the Eastern Cape, South Africa

    A preliminary investigation of the effect of sea temperature fluctuations and wind direction on catches of chokka squid <em>Loligo vulgaris reynaudii</em> off the Eastern Cape, South Africa

    Item type: Journal Article • Journal: South African Journal of Marine Science
    Opportunistically collected information on sea temperature and wind was used in a preliminary investigation of physical factors affecting jigged catches of chokka squid Loligo vulgaris reynaudii. Results revealed sea temperature and wind to be correlated with catches during part of...
  9. Predation patterns on the inshore spawning grounds of the squid <em>Loligo vulgaris reynaudll</em> (Cephalopoda: Loliginidae) off the south-eastern Cape, South Africa

    Predation patterns on the inshore spawning grounds of the squid <em>Loligo vulgaris reynaudll</em> (Cephalopoda: Loliginidae) off the south-eastern Cape, South Africa

    Item type: Journal Article • Journal: South African Journal of Marine Science
    The feeding patterns of fish caught on the inshore (<50 m deep) spawning grounds of chokka squid Loligo vulgaris reynaudii were investigated between November 1988 and September 1990. Fish were sampled by demersal trawl, gillnet, handline and longline. SCUBA was...
  10. Can the <em>Loligo</em> squid fishery be managed effectively? A synthesis of research on <em>Loligo vulgaris reynaudii</em>

    Can the <em>Loligo</em> squid fishery be managed effectively? A synthesis of research on <em>Loligo vulgaris reynaudii</em>

    Item type: Journal Article • Journal: South African Journal of Marine Science
    The question whether the chokka squid Loligo vulgaris reynaudii resource can be managed effectively is examined in the light of developments in the fishery and knowledge of the resource gathered in recent years. The history of the fishery since its...