ranges from 2 to 7 or more years, depending upon species, water 

 temperature, and feeding rates. 



Hatchery techniques for clams are generally available for both 

 commercial production and for planting (enhancement) programs to 

 increase clam populations for recreational harvest. Grow out 

 systems for bay scallops in natural bodies of water using various 

 net and cage designs are approaching commercial stages. Off-bottom 

 culture techniques which eliminate most predators and enhance 

 growth, have only recently begun to be used in the U.S. 



Crustaceans 



Crawfish are reared commercially in extensive pond culture systems 

 either in conjunction with rice farming or separately. Crawfish 

 culture is rapidly expanding in Louisiana, Texas and Mississippi. 

 The States are implementing their own crawfish industries. 



Culture of the giant freshwater Malaysian prawn ( Macrobrachium 

 rosenbergii) is an emerging industry that is developing quite 

 rapidly as well, especially in Hawaii. Most operations currently 

 use extensive techniques in ponds, but some are experimenting with 

 more intensive culture systems. The Malaysian prawn reproduces 

 readily in capitivity. The larvae require brackish waters while 

 the adults grow successfully in freshwater. 



Commercial shrimp ( Penaeus sp.) culture in the United States is 

 basically at the pilot project level. However, successes in Japan 

 and Latin America indicate that shrimp have good aquaculture 

 potential. Most shrimp are cultured in large earthern ponds, but 

 raceways are showing some promise. Major constraints for shrimp 

 culture in the United States include inadequate control of 

 reproduction and a short, growing season. 



Culture Systems for Other Aquatic Organisms 



There are many aquatic organisms that lend themselves to possible 

 commercial production or cultivation. Certain seaweeds possess 

 economic value as food items or as food additives. Many Asian 

 countries have farmed kelp and other aquatic plants as food items 

 for years. Large kelp beds grow naturally and are harvested off 

 the coast of California. Studies have shown that kelp can be 

 commercially produced by planting certain regenerative portions of 

 the plant and harvesting it when mature. Other studies are 

 exploring the potential of growing marine and freshwater plants for 

 use as new material for biomass energy conversion. 



Attempts are being made to culture some threatened or endangered 

 aquatic species. For example, the state of the art has progressed 

 to the point where artificially hatched and released sea turtles 

 are now returning to beaches as adults to lay eggs. After 

 alligators were placed on the endangered species list, methods of 



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