Spore culture of the edible red seaweed, Gracilaria parvispora (Rhodophyta)

A hatchery was established for the inoculation of coral chips, pebbles and lines with carpospores of Gracilaria parvispora, an edible market seaweed in Hawaii. Cystocarpic thalli were placed over various substrates in tanks of aerated seawater. Carpospores attached readily to substrates and after 72 h in hatchery tanks, mean spore density on slides placed in hatch tanks was 1800 cm(-2). Inoculated coral chips and pebbles were placed out in a seawater pond. After 18-22 weeks spore density declined to 4 cm(-2) but 61% of substrates still had plants. Only 36% of inoculated lines developed good growth, but growth was more rapid on lines than on pebble or chips. Lines yielded two crops per year, each approximately 800 g m(-2) (fresh weight), whereas chips and pebbles required 50 weeks growth for an equivalent harvest. Tetrasporophytes were the dominant adult stage but cystocarpic plants accounted for approximately 10% of the culture products, demonstrating that the life cycle of this species was completed within the culture system. Spore culture of Gracilaria allowed mass production of plants on a variety of artificial substrates but the disadvantages included the long lag period and the lower reliability compared with vegetative production methods.