AGAR YIELD AND QUALITY OF GRACILARIA-CHILENSIS (GIGARTINALES, RHODOPHYTA) IN TANK CULTURE USING FISH EFFLUENTS

Tank cultivation of Guacilaria using fish effluents has permitted a pr oduction of 48 kg m(-2) yr(-1) and can reduce the dissolved nitrogen l oads in the seawater. We report the yield, gel strength, gelling and m elting point of agar from Gracilaria cultivated in tanks with seawater previously utilized in intensive, land-based salmon cultures and comp ared to a control using directly pumped seawater, over a study period of 22 months. The results show that the highest agar yield (20 to 22%) was obtained when Gracilaria was cultivated with pure seawater as com pared to the fish effluents. The gel strength, gelling and melting poi nt were higher in the agar obtained from algae cultured with fish effl uents. During the spring, the gel strength, gelling and melting point increased in tanks with fish effluents and decreased in tanks with a s upply of pure seawater.