Page 109 - Bulletin 20 2016

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OF FISH TRAPS AND TIDAL POOLS

Graham Avery

Introduction

Systems using the tidal range to allow fish to enter pre-built enclosures and be trapped at low
tide are widespread globally and South Africa is no exception (Goodwin 1946; Avery 1975;

Hine et al. 2010). They vary in shape, size and spatial complexity and historic and on-going

use has undoubtedly led to their preservation. (Figs 2.1 & 2.2).

Distribution

Tidal fish traps (visvywers) are found along the South African coast from St. Helena Bay to

Mossel Bay, with an apparent gap in the Eastern Cape Province (Fig. 2.3). They extend from
Kwa Zulu-Natal (Kosi Bay) into east Africa at least, where wooden poles or reeds form

enclosures in sandy areas in mangrove channels and the Kosi Bay lakes.

That none are reported from the Eastern Cape, may reflect the non-fish eating tradition of
some Nguni peoples. But E Cape and KZN people collect shellfish. (Bigalke 1973; Bigalke

and Voigt 1973).

Stone walling was not confined to the coast; inland, in addition to the use of basket traps with
stone walling, stone-barriers have been recorded along rivers, such as the Orange and its

tributaries (Lichtenstein 1815; Smits 1967).

Construction and Fishing Method

The visvywers exhibit simple but clever engineering which required a ready source of suitable

rocks (boulders) on a gently-sloping substrate with an off-shore break to minimize wave

energy; open shores and gullies were enclosed and free-standing walls were built to create
enclosures. To minimize wave energy seaward sides were sloped with steep internal sides of

the walls, which, together with level tops, minimized the rough water that might alert