246 MARINE FISHERIES OF NORTH CAROLINA 



THE MANUFACTURING PROCESS 



Dried seaweed is thoroughly washed in a washing machine with a rotating 

 inner cylinder such as is used in laundries. Washed seaweed is conveyed to 

 a cooker to which is added about lo times as much water, by weight, as 

 weight of the dry seaweed. Cooking is done at a temperature near boiling 

 for one to two hours by means of perforated steam pipes in the bottom of 

 the tank. The resulting agar solution is drawn off the residue and pumped 

 to another tank from where it goes through a filter press, while very hot, 

 containing a diatomaceous filter aid. The clear agar solution, about 1.2 per 

 cent concentration, is then run into ice cans, allowed to cool and gel, and 

 then is frozen. The agar ice is shaved into small pieces and conveyed into 

 a tank of circulating water. As thawing occurs, the agar loses most of its 

 water, holding only about as much as dry agar would absorb if soaked in 

 warm water. Along with water lost, go most of the soluble impurities such 

 as salts and pigments. Freezing and thawing are steps in dehydration and 

 purification of agar. After thawing and washing is completed, water is 

 drained from the thawing tank and the wet agar flakes pumped to the de- 

 hydrating room where they are spread evenly on screens and dried in hot 

 air. The resulting rough sheets of dry, purified agar are hammermilled to 

 obtain a soluble, granular form, or pulverized to a fine, white powder. The 

 product is then ready for market. 



RESEARCH FOR THE FUTURE 



Volumes have been written on taxonomy and morphology of marine algae 

 but only a few papers on their physiology and ecology. Research in the 

 latter fields is badly needed and will help to expand utilization and to estab- 

 lish sound conservation measures of seaweed resources. 



Further investigations are needed on the ecology of the vegetative phase 

 of Gracilaria confervoides. Efforts should be made to cultivate it in experi- 

 mental plots and to transplant it to other parts of the State where it does 

 not grow at present. With G. foliifera and Hypnea musciformis there is 

 need for data on season of spore shedding and germination of spores that 

 results in the spring and summer growth of these species. 



Transplantation of economic seaweeds to North Carolina waters from 

 parts of the world having a similar marine environment should be tried. 

 There may be valuable seaweeds in India, Australia, South Africa, or South 

 America that will thrive in North Carolina waters. 



Seaweeds of North Carolina should be studied to determine their vitamin 

 content. Six out of seven seaweeds tested on the Pacific coast (Norris, 

 Simeon, and Williams, 1937) were found to be good sources of vitamin B, 



