Peptone 10.0 g, Beef extract 10.0 g, Agar 20.0 g, Distilled water 250.0 ml, Filtered, aged seawater 750.0 ml. Dissolve yeast extract and peptone by heating in tap water, adjust pH to 7.8 and boil for 10 min. Readjust pH to 7.3. Add agar and autoclave at 121°C for 20 min. Cool to 50°C and add warm (50°C) sterile sea water. Liquid medium without agar should be combined when cooled to room temperature.