Optimización del cultivo de las macroalgas Ulva rigida, Hypnea spinella y Gracilaria cornea en aguas efluentes de cultivos marinos

Abstract

The aim of this research was to evaluate the optimal rearing conditions for the culture of the macroalgae Gracilaria cornea J. Agardh, Hypnea spinella (C. Agardh) Kützing and Ulva rigida J.Agardh within the aquaculture research facility of the Instituto Canario de Ciencias Marinas (ICCM). Macroalgae species were chosen according to their suitability as feed for the Canarian abalone H. tuberculata coccinea which had been determined in previous studies. Four trials were carried out during 10, 6, 6 and 3 weeks evaluating the biological inde-xes (growth rate and biomass yield) of the seaweeds under: initial stocking densities (low: 1, 3 and 4 g.l-1 and high: 4, 4 and 6g.l-1) and water exchange rates (24, 8 and 4 vol.d-1). Presence of epiphytes as well as environmental factors: water temperature, irradiation, oxy-gen and pH were also measured and are discussed. In the experimental tanks used for the assays, maximum growth rate (5.08, 6.01 and 8.63 %d-1) and yield (37.02, 31.80 and 36.60 g DWm-2d-1) were obtained at a low initial stocking density and high water exchange for G. cornea, H. spinella and U. rigida respectively. Yield was significantly higher in G. cornea whereas U. rigida showed the highest growth ra-te. Results indicate that to maximize growth performance in this experimental system, density of U. rigida, H. spinella and G. cornea should be adjusted to 1, 3 and 4 g FW l-1 respectively and water exchange rate should be as high as possible.