sec, 6.4), even greater yields might be realized or greater areas might 
become available for exploitation. 
Shrimp and Crab. A successful method has been developed in 
Japan to culture large prawns. It requires indoor culturing of new- 
born larvae which are fed first on diatoms and then on tiny brine 
shrimp. Ina month the larvae are almost an inch long and are ready 
to be cultivated in artificial ponds formerly used for salt production. 
Adults are produced in 1 year by being fed ground shellfish and scrap 
fish. The present complex technique is commercially profitable in 
Japan because the Japanes gourmet is willing to pay $2 to $4 per pound 
for live shrimp. For similar size shrimp, the U.S. fisherman receives 
from 50 to 80 cents per pound for the tails alone. This is the first 
commercial trial in Japan, and cheaper cultivation techniques will 
undoubtedly be found. 
The complete life cycles of several species of crabs are known in 
the United States, opening the way for artificial cultivation. Attempts 
are now underway to rear spiny lobsters in Japan. 
Squid. Squid are a delicacy for the Japanese and Mediterranean 
peoples. In Japan five species of squid are cultured in the laboratory. 
Growth in culture is faster than in nature; commercial squid weighing 
a pound or more are obtained in 3 to 5 months. Probably, more rapid 
growth can be obtained by further refinement of techniques and by 
continuous feeding. It is interesting that squid can be reared and 
maintained alive for months in captivity, whereas captured adults 
die in a few weeks. 
Phytoplankton Production. Since organic productivity rests on 
the energy-trapping ability of the plants in the sea, basic and applied 
research on the ecology of ocean pastures should be fostered. This 
research is needed if selected areas of the sea are to be farmed. 
Mass culturing of marine phytoplankton is feasible because the main 
nutritional requirements are known. It should be possible to produce 
large quantities of phytoplankton in lagoons and artificial coastal 
lakes. Algae could also be grown in floating plastic tanks or in gigantic 
submerged plastic sausages. Basic requirements for growing algae 
are ponds or large containers and relatively small amounts of nutrients 
to. add to the water. 
Phytoplankton production under controlled conditions is essential 
for development of marine aquiculture. Many economically important 
organisms feed on phytoplankton either throughout life (e.g., oysters 
and clams) or during early stages of development (newborn shrimp 
larvae eat phytoplankton and later become carnivorous). Algae are 
also needed for food for the shrimplike creatures which constitute the 
bulk of the zooplankton—the food of many economically important 
marine animals. 
14 
