No abstract

There is a general lack of information on inland commercial fisheries in South Africa. The primary objective of this study was to provide a retrospective assessment of commercial fisheries in the Free State Province based on the assessment of catch data from fisheries operating for the period 1979-2014. Permits were issued for commercial operators on 11 dams but catch data were only available for Bloemhof, Kalkfontein, Gariep, Vaal, Erfenis, Rustfontein and Koppies Dams. A total of 9 036 t of fish were harvested over the 35-year period, equating to an average (± SE) of 282 ± 185 t·yr -1. Catch composition differed between dams but comprised mainly of common carp Cyprinus carpio and the Labeos, Labeo capensis and Labeo umbratus. Based on an assessment of the available catch data, the only successful fisheries that were sustained for more than 10 years were on Bloemhof Dam (mean ± S.E.: 201 ± 25 t·yr -1 since 1981) and Kalkfontein Dam, where 127 ± 30 t·yr -1 was harvested (by an operator from Bloemhof Dam). All other fisheries appear to have failed with individual enterprises lasting between 1 and 10 years and generally yielding less than 25 t·yr -1 when operational. Success at Bloemhof Dam appears to have been dependent on the ability to harvest > 100 t·yr -1 and the long-term fisheries experience of the operators.

Recreational angling is an important form of utilisation of inland fisheries in South Africa but there is little information on this sector. The objective of this study was to provide an assessment of recreational bank angling in the Free State Province using licence sale and tournament data. During 2013 and 2014, 8 256 and 7 710 angling licences were sold, respectively. This represents a decline of 76% compared to the total licence sales in the Province in 1971. Tournament catch and effort data were obtained for 4 796 tournaments that were held on 17 dams from 1974 to 2014. Reported tournament effort decreased by 67% from 8 548 tournament days in 1998 to 2 828 days in 2014. Tournament catch composition was dominated by alien common carp Cyprinus carpio. Overall, this species comprised 81% of the weight and 77% of the number of fish landed during tournaments making it the most important angling species. The recent observed increase in subsistence angling could not be included in the analysis as participants are mostly not licensed. Alternative methods are therefore required if total catch and effort are to be estimated.

No abstract

South Africa is under increasing pressure to develop small-scale fisheries in inland waters. To inform appropriate development of this sector in the Free State Province, the catch rate of double-ended fyke nets was evaluated using survey data from 20 impoundments sampled during the 2013/2014 summer season. Fyke nets were set over night and the total sample effort was 114 fyke net nights. Overall catch per unit effort (CPUE) was 16.8 ± 28.3 kg·net-1·night-1 and catch composition was dependent on impoundment, but generally comprised of a mixture of common carp Cyprinus carpio, African sharptooth catfish Clarias gariepinus, smallmouth yellowfish Labeobarbus aeneus, Orange River mudfish Labeo capensis and moggel Labeo umbratus. The influence of temperature and the potential benefits of baiting the nets were subsequently evaluated through monthly sampling in the hyper-eutrophic Krugersdrift Dam and at the oligotrophic Gariep Dam. Baiting did not significantly influence CPUE, which was significantly higher at Krugersdrift Dam (19.97 ± 23.22 kg·net-1·night-1) than at Gariep Dam (5.02 ± 6.05 kg·net-1·night-1). Increasing temperature had a positive effect on CPUE at Krugersdrift Dam but not at Gariep Dam. Species composition also differed between impoundments and, as a result, we conclude that seasonal catch rates and species compositions will need to be evaluated prior to implementation of fyke net fisheries in specific localities.