Usage Route for Seedlings 

 Characteristics of Naturol 

 Larvae and Seedlings 



Acclimation 

 including 

 Noturalizotion 

 Adaptation 

 C onditioning 



and or 

 Hardening 



Biological 

 Characteristics 

 of 

 Natural Larvae 



\ 



Optimal Conditions 

 for Natural Larvae 



Optimal Conditions 

 for Artificial 

 Seedlings 



Biological 

 Charocteristics 



of 

 Artif iciol 

 Seedlings 



J 



Figure 4. — Some differences in the biological 

 characteristics between natural larvae and seed- 

 lings and artificial seedlings. 



lings to find natural foods orto avoid predators. Con- 

 ditioning and training, based on biological require- 

 ments to achieve the intended purpose, should be 

 tried in the acclimation facility; otherwise, success- 

 ful acclimation cannot be expected. 



The greatest problem connected with the future of 

 fish farming is the pollution of natural waters. Al- 

 though water pollution is a matter of concern among 

 the people and plans for pollution control are being 

 developed, the adverse effect on fish farming is not 

 fully recognized. 



Some aspects of this biological problem have been 

 investigated to find ways to reduce the effects of 

 pollutants on fisheries, and water quality criteria and 

 water quality standards have been described for 

 some aquatic organisms. However, most of the re- 

 search data are on adult organisms. 



In fish farming, the situation is more severe. For 

 example, the period of larval development is the 

 weakest stage of the life history of organisms, and 

 even seedlings have lower resistance to pollution 

 than adults. Brood stocks require a high quality of 

 water to maintain healthy adults v\hich will produce 

 active larvae. 



As the mass production of seedlings is possible, a 

 limited number of hatcheries can supply the demand 

 for seedlings. Places chosen for hatching facilities 

 should have the best environmental conditions in 

 unpolluted regions. Farming, especially of the stock 

 recruitment type, requires extensive areas of unpol- 

 luted water for the production of large amounts of 

 fish or shellfish. Complete water pollution control 

 will be needed to keep released organisms safe. For 

 this purpose, the cooperative research will have to 

 be carried out by fishery biologists and specialists on 

 pollution control. Without this cooperation the ad- 

 vancement and expansion of fish farming will be 

 hopeless. 



CONCLUSION 



The history of aquaculture in Japan is quite long. 

 Mariculture of oysters and algae was started some- 

 time before the beginning of science. Procedures 

 were established by fishermen, and the techniques 

 have been developed and reformed year by year 

 based on their experiences. 



Since the beginning of fisheries science about a 



31 



