A pilot-scale unit for suspended cultivation of Gracilaria gracilis in Izmir Bay, Aegean Sea-Turkey

Abstract

A metal frame with dimensions of 1 x 1 x 1 m for the suspended cultivation of Gracilaria gracilis (Stackhouse) Steentoft, Irvine and Farnham was settled in shallow water in Inciralti in Izmir Bay. The alga was tied by sixteen ropes just below the surface of the water (0.1-0.2 m), at mid depths (0.6-0.7 m) and near the bottom (1.1-1.2 m). The total of 16 plants were measured weekly from July 28th to October 20th 2002. Water temperature, dissolved oxygen, nitrate, nitrite, ammonia, orthophosphate and silica were also analysed. The healthy growth of algae was observed only at mid depth. The plants near to the surface died because of waves, water level fluctuations or direct sunlight. Gracilaria suspended near to bottom was lost, consumed by fish or bleached and died after two weeks. Relative growth rates varied from 8.2 to 0.96% day-1. At the end of the experiment, mean individual weight of plants reached to 9.3 g. © 2006 Asian Network for Scientific Information.