Abundance and distribution patterns of three temperate marine reef fish (Teleostei: Sparidae) in exploited and unexploited areas off the Southern Cape coast

Published source details Buxton C.D. & Smale M. J. (1989) Abundance and distribution patterns of three temperate marine reef fish (Teleostei: Sparidae) in exploited and unexploited areas off the Southern Cape coast. Journal of Applied Ecology, 26, 441-451.
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Summary

As an indicator of the effectiveness of a South African marine reserve the abundance and size structure of three supra-benthic reef fish, the sparids Chrysoblephus laticeps, C.cristiceps and Petrus rupestris was determined in a marine reserve and compared with a non-protected area of similar habitat. These three species are important components of the South African recreational and commercial line fisheries.

Study sites: The study was conducted in two areas on the south-eastern Cape coast of South Africa: three unexploited sites in the Tsitsikamma Coastal National Park, a marine reserve along a 60 km stretch of coast between Nature's Valley (34º59'S, 23'34'E) and Oubosstrand (34º 04'S, 24'12'E); an exploited site (regularly fished) off Cape Recife (34º02'S, 25º42'E).

Underwater censuses (transects and point counts) were used to determine the abundance and size structure of the three sparids Chrysoblephus laticeps, C.cristiceps and Petrus rupestris (conspicuous marine reef fish species), inside the Tsitsikamma Coastal National Park and outside the reserve at Cape Recife. Data was compared to evaluate the effectiveness of the reserve as a management option for the fish.

Fish abundance:

Chrysoblephus laticeps - the 76 individual line transects at the Tsitsikamma sites gave an overall abundance of 0.025 C.laticeps/m² (c.1 fish/39 m²).

P.rupestris - overall average abundance, based on 63 point counts over high-relief areas in Tsitsikamma, was 0.0102 fish/m².

Chrysoblephus cristiceps - overall average abundance for at the Tsitsikamma sites was 0.0028 fish/m² (c.1 fish/357 m²).

In the exploited area, estimates of abundance were significantly lower than those in Tsitsikamma for C.laticeps and P.rupestris. For C.cristiceps, the estimates were not significantly different.

Fish size: Average sizes of C.laticeps and C.cristiceps in Tsiksikamma and Cape Recife were not significantly different. P.rupestris were significantly smaller at Cape Recife. For all three species the maximum recorded fish sizes in Tsitsikamma were considerably larger than those at Cape Recife.

Conclusions: The data from this South African study suggests that the Tsitsikamma Coastal National Park marine reserve is providing effective protection for fish species vulnerable to line-fishing. Sampling showed that the fish were significantly more abundant within the marine reserve, that there were more of the larger size-classes of fish and that the maximum size of fish was greater than outside the reserve.

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