Fishes In South Africa Research Articles

THE MATERIAL LAW PROTECTION OF WILD ANIMALS

The aim of this article is to consider the protection of wild animals and other living natural resources in South Africa from a material law perspective. To ensure completeness both the procedural law and problems with enforcement will be briefly considered. Possible improvements and solutions to difficulties will also be submitted. This article will focus mostly on the pre-1994 conservation ordinances which still apply in the nine new provinces. Wild animals are protected in these provincial laws on a species based approach where animals are listed in categories and each category is provided with a different degree of protection. These ordinances are the main source of law which deal with the conservation, protection and exploitation of wild animals, indigenous plants and freshwater fish in South Africa and is usually referred to as ‘wildlife law.’

First record of predation by the alien invasive freshwater fish Micropterus salmoides L. (Centrarchidae) on migrating estuarine fishes in South Africa

This study presents results from stomach content analysis of 123 largemouth bass, Micropterus salmoides, sampled at the mouth of the fishway leading into a 3 m high weir at the tidal limit of the Kowie River, Eastern Cape Province (33°32‘39“S, 26°46‘ 52.3“E). Stomach contents from small (120–240 mm fork length, FL) and large (250–440mm FL) fish were analysed separately. Fish were the dominant prey item in small bass, followed by terrestrial insects and Potamonautes sp. In large bass, Potamonautes sp. dominated the stomach contents, while fish were less dominant and other prey items were considered incidental. Estuarine fish species, Monodactylus falciformis, and two species of the family Mugilidae, Mugil cephalus and Myxus capensis, were the most common fish prey in both size classes of M. salmoides. These results are the first evidence of the alien M. salmoides preying on these three indigenous estuarine species during their migration into fresh water.

First record of predation by the alien invasive freshwater fish Micropterus salmoides L. (Centrarchidae) on migrating estuarine fishes in South Africa

This study presents results from stomach content analysis of 123 largemouth bass, Micropterus salmoides, sampled at the mouth of the fishway leading into a 3 m high weir at the tidal limit of the Kowie River, Eastern Cape Province (33°32‘39“S, 26°46‘ 52.3“E). Stomach contents from small (120–240 mm fork length, FL) and large (250–440mm FL) fish were analysed separately. Fish were the dominant prey item in small bass, followed by terrestrial insects and Potamonautes sp. In large bass, Potamonautes sp. dominated the stomach contents, while fish were less dominant and other prey items were considered incidental. Estuarine fish species, Monodactylus falciformis, and two species of the family Mugilidae, Mugil cephalus and Myxus capensis, were the most common fish prey in both size classes of M. salmoides. These results are the first evidence of the alien M. salmoides preying on these three indigenous estuarine species during their migration into fresh water.

A telemetry experiment on spotted grunter Pomadasys commersonnii in an African estuary

The feasibility of using telemetry equipment to study the movements of estuarine-associated fish in South Africa was investigated by conducting a tracking experiment on spotted grunter Pomadasys commersonnii in the East Kleinemonde Estuary. The telemetry equipment comprised two VEMCO V8 transmitters and a VEMCO VR60 receiver linked to a directional hydrophone. Field experiments demonstrated that the equipment's maximum detection range was 400m. The transmitters were tuned to different frequencies, and interference between these was found to be negligible. The accuracy of locating the transmitter equalled the previously determined Global Positioning System (Garmin GPS 12) accuracy of approximately 5m. Two fish were tracked over a seven-day period. The fish preferred the lower reaches of the estuary where they made repeated and prolonged use of some areas. A tank experiment was conducted to examine the effects of the transmitter implantation. Fish recovered quickly after the surgical procedure, and no differences in swimming behaviour and growth rates were found between these fish and the controls.

A survey of coccidian infection of freshwater fishes in South Africa, with the description of Goussia anopli n. sp. (Apicomplexa: Eimeriidae).

Seventy-seven specimens of seven freshwater fish species harvested in four sites from rivers and ponds of the Gauteng, North West and Limpopo Provinces (South Africa) were surveyed for coccidian infections. Two fish species were infected with apicomplexans belonging to Goussia Labbé, 1896. In banded tilapia Tilapia sparrmanii Smith unsporulated oöcysts of G. vanasi (Landsberg & Paperna, 1987) were found which became sporulated in tap-water within 24 hours. Another species in the gut of chubbyhead barb Barbus anoplus Weber harboured sporulated oöcysts in the faeces and in the intestinal epithelium. The latter species has been described as G. anopli n. sp.

Methodology for the assessment of human health risks associated with the consumption of chemical contaminated freshwater fish in South Africa

Studies have shown that the aquatic environment can be polluted by contaminates that are accumulated by freshwater fish and this may pose a health risk to the consumers of the contaminated fish. Developed counties like the United States of America have developed strategies and associated guidance documentation to conduct chemical contaminant surveys using fish and to use these data to reduce the heath risk to the consumers of the fish. In this paper a generic methodology is presented that will give guidance in the undertaking of fish contaminant surveys to provide information regarding the possible health risk if the fish are consumed by recreational and subsistence fishermen in South Africa. The fundamentals of the methodology are based on catchment information, socio-demographic information of consumers of fish in the catchment, bioaccumulation potential and health risks of analytes, sound sampling design, risk assessment procedures and performing monitoring at different scales and depths. These aspects are presented as 10 major steps in the methodology of which the basic requirements are discussed to focus the surveys and optimise the application of resources. Although the methodology focuses on assessing the possible health risk to the consumers of fish many of the aspects would apply to any investigation aimed at assessing the chemical contaminant levels in fish. Furthermore as these surveys identify areas in the aquatic system where fish have unacceptably high chemical contaminant levels, this information can be used in catchment management programmes to put remedial actions in place that would ensure that the fish populations of the system are fit for present and future human consumption. Water SA Vol.29(1) 2003: 69-90

Patterns of distribution and conservation status of freshwater fishes in South Africa

The combined fish collection databases of the Albany Museum and the J.L.B. Smith Institute of Ichthyology are used to identify hotspots of endemism and threatened fish distributions in South Africa. Hotspots of fish species richness occur in the north-eastern lowveld sectors of South Africa and along the ecotone between the tropical/ subtropical and temperate faunal zones. Hotspots of endemic fish richness occur within both the tropical and temperate faunal regions, notably in the Olifants River system, Western Cape and in areas of high relief such as the Cape Fold Mountains, the Amatola-Wrnterberg (Eastern Cape), and the Drakensberg Escarpment {Kwazulu/ Natal-Eastern Transvaal). Threatened taxa are concentrated in the hotspots of endemic species richness which coincide largely with areas of major river conservation concern. There is limited scope for fish conservation within the ambit of formal (or informal) declared reserves, and the survival of the fauna depends on the success of river catchment conser...

Trichodinid ectoparasites of cichlid and cyprinid fishes in South Africa and Israel

Three new and seven known species of trichodinid ectoparasites (Ciliophora: Peritricha) were identified from cichlid and cyprinid fishes collected from fish ponds, natural and man-made lakes, rivers and streams in South Africa and Israel. The new species described are: Trichodina centrostrigata n.sp., T. minuta n.sp. and Tripartiella cichlidarum n.sp. The known species, of which comparative descriptions are given and intraspecific variability discussed, are: Trichodina acuta Lom, 1961, T. heterodentata Duncan, 1977, T. mutabilis Kazubski & Migala, 1968, T. nigra Lom, 1960, T. pediculus Ehrenberg, 1838, T. reticulata Hirschmann & Partsch, 1955 and Trichodinella epizootica (Raabe, 1950). ac]19820916

The effects of land use on freshwater fish in South Africa, with particular reference to Natal

Freshwater fish live in an environment that is liable to modification by human activities. Instability of South African rivers makes them particularly vulnerable to changes brought about by settlement of the land. Indigenous species number 89, of which 47 belong to the Cyprinidae; eight exotic species are also established in South African natural fresh waters. These fish vary considerably in their tolerances, but the habitat of most species has undergone deterioration as a result of agriculture, pollution or water abstraction. Agricultural land-use effects are mainly (i) an increase in soil erosion leading to higher silt loads, which adversely affect the habitat, both for fish and for fish food and (ii) reduced low flows and higher flood-crests. Domestic and industrial pollution are liable to have disastrous effects, but fortunately serious pollution has so far been of localized occurrence and has affected mainly smaller streams. Dam building has had a major impact on fish populations. Below the dams some natural habitats have been impaired and migratory movements curtailed. The impoundments themselves on the other hand, have provided an enlarged and stable environment leading to population increases. Many of the larger impoundments carry indigenous fish, other dams have provided a habitat for exotic species. Progressive development of the land makes changes in natural waterways inevitable but conservation of mountain catchments and the building of dams are likely to prevent decimation of the more economically important species. Special steps may be needed to maintain the habitats of certain rare endemic species. Progressive development of the land makes changes in natural waterways inevitable but conservation of mountain catchments and the building of dams are likely to prevent decimation of the more economically important species. Special steps may be needed to maintain the habitats of certain rare endemic species.