Regrowth after experimental harvesting of the agarophyteGelidium pristoides(Gelidiales: Rhodophyta) in the eastern Cape Province

Abstract

Rate of regrowth of Gelidium pristoides after experimental harvesting did not show significant difference between tufts cut with shears and those picked by hand. Harvested tufts grew back to the same size and biomnss as control tufts within 3–4 months after harvesting in early spring, and 4–5 months after harvesting in late autumn. Frond elongation rates showed marked seasonality, with optimum growth during the summer season. Regrowth of sheared tufts was much faster in the lower eulittoral zone. After 12 months there was no recruitment of G. pristoides in quadrats from which all visible plants had been removed, stressing the importance of vegetative regeneration in the short-term maintenance of natural populations after harvesting. The results lead to the following recommendations for commercial harvesting: (i) the period between successive harvestings should be sufficient for regrowth of individual tufts, (ii) excessive damage to the regenerative holdfast is to be avoided and (iii) harvesting should be ...