Impacto de la cosecha y recuperación de la biomasa del alga Gelidium sesquipedale sometida a dos formas de explotación en el País Vasco (España)

Abstract

Two commercial harvests of Gelidium sesquipedale by plucking and cutting, were carried out in July 1989 and July 1990. The recovery rate was studied in order to obtain data to manage the exploitation. After the harvest, biomass reduction of Ca. 80% could be observed; the density of the fronds did not Vary and the mean length of the population was reduced by 48% by cutting and by 31% by plucking.The most important period of biomass recovery extends over 3 to 4 months after the harvest. Therefore, in October there were no significant differences between biomass mean values in the control and the harvest areas. During this period growth rates were very little in the control area, while in harvest areas were approximately 1.3% day−1. From March to July growth rates were approximately 0.9% day−1 in both areas.Production was 1.4 times higher in harvested areas (ca. 1 100 g.m−2.yr−1) and the turnover rate 2.5 times higher (ca. 6.8 yr−1).Epiphytes disappear after harvesting and recover their biomass along the next month, although neverincreasing significantly in relation to the control area. © 1994 IFREMER-Gauthier-Villars.