The Value of the Trout Fishery at Rhodes, North Eastern Cape, South Africa, A Travel Cost Analysis Using Count Data Models

The National Environmental Management: Biodiversity Act, no.10 of 2004) makes provision for the presence of alien trout in South African waters by means of a zoning system, partly in recognition of the significant income generating potential of trout fishing in South Africa. This paper reports the first formal recreational valuation of a trout fishery in South Africa, the one in and around Rhodes village, North Eastern Cape. The valuation is carried out by applying the individual travel cost method using several count data models. The zero truncated negative binomial model yielded the most appealing results. It accounts for the non-negative integer nature of the trip data, for truncation and over-dispersion. The paper finds that in 2007 consumer surplus per day visit to the Rhodes trout fishery was R2 668, consumer surplus per trip visit was R13 072, and the total consumer surplus generated was R18 026 288.

Measuring the indirect costs associated with the establishment of a wind farm: An application of the Contingent Valuation Method

Although a green energy source, the location of electrical generating windmills may cause a disamenity effect (negative externality). The establishment of a wind farm is known as a locally undesirable land use (LULU) and leads to the not-in-my-backyard syndrome (NIMBY). In an application of the contingent valuation method, a willingness-to-accept framework was used to estimate the aggregate annual compensation required to allow the construction of a wind farm near Jeffrey’s Bay, South Africa. This compensation amounted to R490 695. A binary choice logit analysis found that retirement status, concern about climate change, concern about view-shed impacts and the offer amount are important predictors of voting for or against the project.Contingent Valuation Method, indirect cost, wind farm

The Rayleigh—Taylor problem with a vertical magnetic field, including the effects of Hall current and resistivity

The influence of resistivity and Hall current on the Rayleigh-Taylor problem involving two superposed fluids of finite density in the presence of gravitational and magnetic fields normal to the fluid interface is examined. Unlike the related problem in which the magnetic field is parallel to the interface, it appears that the dispersion relation does not exhibit singular behaviour in the zero resistivity limit. The ‘potentially stable' situation is considered throughout. The results are compared with earlier ideal and resistive theories, and an apparent anomaly regarding the existence of normal modes in such systems is resolve

TB81: Investigations on the Life History and Habits of Pityokteines sparsus (Coleoptera: Scolytidae)

The primary objectives of this study are (1) to investigate the life history of Pityokteines sparsus (LeConte) in the Oxbow area of northern Maine; (2) to study the seasonal and daily flight behavior of the insect; (3) to investigate the food energy relations of the species.https://digitalcommons.library.umaine.edu/aes_techbulletin/1110/thumbnail.jp

A SOCIAL COST-BENEFIT ANALYSIS OF A SMALL-SCALE CLAM FISHERY IN THE EASTERN CAPE, SOUTH AFRICA

When a proposal was advanced in 1991 to harvest the wedge clam Donax serra in the Eastern Cape, South Africa, for commercial gain, it elicited a huge public outcry. In order to shed light on the issue, a social costbenefit analysis (CBA), based on a biologically sustainable extraction rate of 100 ton of clams per year, was carried out on its commercial exploitation. Because fishery activities might exact a price on society in the form of negatively altering the quality of people\'s recreation experience in the area, as well as damage the aesthetic and ecological attributes of the beach system, such external effects were identified and valuated. Results from the CBA yielded positive net present values (NPVs) for project options involving live clams being sold on the export market (to Hong Kong) for R24.70 kg-1 and negative NPVs for domestic market options (Johannesburg and Cape Town), where the clam would be sold for R6.50 kg-1. Assuming a discount rate of 8&#37, the highest NPV was obtained for the scenario in which total production was sold on the foreign market and the firm rented facilities of an existing organization. The external cost was the single largest component of the cost of the fishery. The conclusion drawn is that the social benefit of the project exceeds the social cost – a conclusion which supports commercial exploitation of clam stocks along the St Francis Bay beach, but one which does not include the osts associated with policing.Afr. J. mar. Sci. 25: 159–16

TB80: Scanning Electron Microscopy of Insects: Techniques for the Novice

The scanning electron microscope (SEM) has been used to detail the morphology of small insects; however, it is often difficult for the novice to obtain acceptable results without time-consuming and costly experimentation. This brief paper outlines some of the techniques and problems encountered in an examination of the balsam bark beetle Pityokteines sparsus (Le Conte ) and the hymenopterous parasitoid Brachymeria intermedia (Nees). The information presented herein is mainly for the benefit of individuals wishing to use the SEM but having little or no experience concerning the special problems associated with the photography of insect specimens, and may form a base from which reasonable results can be obtained after limited experimentation.https://digitalcommons.library.umaine.edu/aes_techbulletin/1109/thumbnail.jp