Long-term trends in the competitive shore fishery along the KwaZulu-Natal coast,South Africa

Twenty-four years (1977–2000) of competitive shore angling catch and effort data from the KwaZulu-Natal Coastal Anglers Union for the province of KwaZulu-Natal were analysed. Of a minimum of 117 species recorded, the most commonly caught species were dusky shark (Carcharhinus obscurus) (26%), milk shark (Rhizoprionodon acutus) (18%) and shad (Pomatomus saltatrix) (10%). By weight, the top species were dusky shark (34%) and diamond ray (Gymnura natalensis) (19%). All the above species showed considerable inter-annual variation in their respective contributions to annual catch. Probably as a result of changes in fishing patterns, dusky shark and milk shark showed a general decline in percentage contribution to catch over the period, while contributions of lesser guitarfish (Rhinobatos annulatus), giant guitarfish (Rhynchobatus djiddensis), diamond ray (Gymnura natalensis) and brown ray (Himantura gerrardi) increased. Mean overall annual cpue by number and weight showed a non-significant increase over the period, while each of the investigated species showed a constant trend in mean annual weight. There were high proportions of juveniles in the catches of dusky shark (100%), dusky kob (92%) and giant guitarfish (78%). Improvements made to the structure of shore angling competitions and the overall contribution of competition angling to resource management in South Africa is discussed.     

A Contribution Towards a Revision of the Aquatic Oligochaeta of Africa

Gene products of nine loci were examined by horizontal starch-gel electrophoresis in five samples of black mussels, Choromytilus meridionalis, from the south-western Cape coast. Allelic frequency variation for four polymorphic proteins suggests no racial differences between west and south coast populations. Mean heterozygosity (H) showed a non-significant increase from south to west coast populations. The duration of the pelagic larval stage and currents may both contribute to long-distance larval recruitment, although gene flow between neighbouring populations may be more important.     

Causes of admissions to a raptor rehabilitation centre in KwaZulu-Natal,South Africa

With many species of southern African raptors becoming increasingly threatened, records from rehabilitation centres can give an indication of the threats faced by birds of prey in particular areas and to particular species. Thus, admissions records from a raptor rehabilitation centre in KwaZulu-Natal, South Africa, were analysed for trends. Over eight years (2004–2011), 547 birds from 39 raptor species were admitted to the centre. The majority of individuals were spotted eagle-owls (16.6%), western barn owls (15.2%) and yellow-billed kites (9.7%). The most frequent known causes of injury to raptors were motor vehicle accidents and injuries caused when birds flew into buildings. There was no significant difference in admissions of motor vehicle collision cases between seasons. People generally waited 3.8 days before bringing injured raptors in to the centre, and approximately half of the birds admitted were fed within that time, highlighting a need for public education regarding the general diets of raptors and the benefits of prompt medical attention.     

Predictive modelling of the potential future distribution of Vachellia nilotica within the KwaZulu-Natal province of South Africa

Many regions of South Africa are prone to woody plant thickening. This can have an ecologically detrimental effect on the open savannas and grasslands. KwaZulu-Natal, a province on the east coast of South Africa, is currently experiencing an increase in both the density and distribution of Vachellia nilotica. This research aims to gain better insight into the potential distribution of this plant and to determine some of the main environmental conditions that promote its thickening. Using the Maxent programme to determine the potential distribution, a map was developed to illustrate the possible extent of V. nilotica within KwaZulu-Natal. It is estimated that a possible 800 968 ha (8.5%) of the province has a greater than 50% distribution probability, whereas in 26.9% of the province there is 25%–50% probability of V. nilotica inhabiting these areas. Using Maxent, it was determined that geology and altitude were key determinants for V. nilotica habitat selection. This model-based map will be particularly useful for conservation and rangeland planning for future management and control of the plant through being able to predict which areas of the province are more likely to be high potential regions for the thickening of V. nilotica.