58 



large scale there certainly seems to be considerable room for im- 

 provement, at least in my opinion. 



To give you the harvest from an actual kelp bed of about a 

 square mile or so in area at Goleta, this ranged from about 12 wet 

 tons per acre per year in 1975 to 7.5 wet tons acre per year in 1977. 

 Due to the inefficiency of the harvester and the fact that only the 

 tops of the plants are taken only about 10 percent of the material 

 present is harvested. I would guess that in a farm situation, where 

 one were growing these large plants one would design a method 

 that would allow you to harvest much more than 10 percent of the 

 biomass produced. 



The potential yields from oceanic farms, is the subject of specul- 

 tation. I think we could assume that if we were farming macro- 

 algae, as the Chinese are doing, we would be able to minimize 

 damage and loss due to wave action, sloughing, and other factors 

 that influence natural kelp beds at the present time. 



It is important to remember that in estimating production per 

 acre the acre in this case is not a land acre and it is not an acre 

 that you have to buy, so that the cost per unit area is considerably 

 less than it would be on land. A major cost would be for nutrients. 



This major point has been raised here by Mr. Hughes. I think 

 the potential yield of future ocean farms will be primarily based on 

 how efficiently nutrients can be supplied to these plants and how 

 efficiently they can be recycled in the large populations that might 

 be farmed. 



As of now, we have the deep ocean "nutrient irrigation" ap- 

 proach, being studied by the G.R.I, group. We are presently using 

 fertilizers on our Goleta Bay farm. The Chinese and Japanese both 

 have experimented with various methods of applying fertilizer 

 from containers in the sea, sprayed on the sea surface from ships, 

 and so on. 



So it doesn't seem to be the question of whether fertilization will 

 work but how to apply it most effectively that seems to be the most 

 important point. Dr. Ryther brought up the point that the Sargasso 

 Sea should be considered, which is very important since here you 

 are talking about a huge area of sea surface where much of the 

 nitrogen in the plants comes from nitrogen fixing blue-green algae 

 which grow on the surfaces of the sargassum plants. So that this is 

 yet another approach that might be used to supply nutrients to the 

 plants in an open ocean farm. 



In conclusion, it is important to note that floating macroalgae 

 occur in natural kelp forests, in the Sargasso Sea over substantial 

 areas of the sea surface, and in Japan and China, man-made farms 

 that are thousands of acres in extent. 



Thus it seems that scientific macroalgal cultivation, although it 

 is still very new, has progressed substantially in the last two dec- 

 ades. This progress has been made by a relatively few people who 

 are still alive, and kicking. You can talk to them and find out how 

 they did it in Japan and China. Apparently the task was not as 

 difficult as one might expect. 



So I think it is unduly pessimistic to contend that the develop- 

 ment of marine farms has to be a tremendously long-term project. 

 Since 20 years in Japan and China has seen considerable progress, 



