the average weight was 0.06 kg. The com- 

 pany, working with the National Marine Fisheries 

 Service, will begin test marketing the 0.2-0.34 kg fish 

 shortly after the beginning of the year. Current ef- 

 forts also include an evaluation of the potential en- 

 vironmental effects of a large-scale operation of this 

 type. 



In northern California, at Humboldt State College, 

 fisheries biologists are in the early stages of testing 

 the efficacy of enriching brackish water and saltwa- 

 ter rearing ponds with sewage etTluents for the rear- 

 ing of salmon and trout. The fish are released as fry 

 and fingerlings into two ponds, one a control sea- 

 water pond and the other contains a seawater and 

 sewage effluent mixture. The scientists hope to deter- 

 mine if it is possible to rear fish to migrant size more 

 cheaply by this method than with standard fish cul- 

 ture techniques. Harvest for human use would occur 

 after the fish had been released and continued their 

 growth in the natural environment. 



At the present time there are 40,000 coho salmon 

 (10,000 of them marked) and 2,500 steelhead trout 

 divided between the two ponds. Growth and mortal- 

 ity studies are being conducted to evaluate the suc- 

 cess of this technique. 



Scientists at the University of Rhode Island are 

 attempting to develop a new form of aquaculture, 

 based on a closed cycle, controlled environment 

 system, which will have almost no environmental 

 impact and be compatible with other demands on 

 coastal resources. Salmonids; Atlantic salmon, 

 Salmo scihir: pink salmon, Uncorhynclus goibiischa; 

 rainbow trout, bluefish, Pomatomus saltatrix; and 

 striped bass, Moronc suxcililis. are being grown in 

 the project. The work is intended to provide infor- 

 mation which will increase the operating efficiency 

 and capacity of present day salmon hatchery and 

 smolt production facilities as well as improve diets 

 for fish in culture. Nutritional and physiological 

 studies are underway, with one study the effect of the 

 level of dietary protein and different lipids on the 

 nutrition of rainbow trout adapted to an intermediary 

 salinity (16"/(mi) just completed. 



Studies are being conducted to determine the re- 

 quirements for rapid activation of biological filters in 

 both marine and freshwater systems. Also, alterna- 

 tives to biological filters for water purification in the 

 closed circuit system are being evaluated. 



One key part of this work is aimed at solving the 

 problems resulting from the accumulation of ni- 

 trogen waste products in the closed system. Another 

 part of this program is an analysis of the economic 



feasibility of commercial salmonid culture for food 

 fish markets. A projection of production costs for a 

 model salmonid aquaculture facility has Just been 

 completed. 



Striped Mullet 



In an effort to develop a controlled culture system 

 for striped mullet, Miigil cephaliis. scientists at the 

 Oceanic Institute in Hawaii have devoted consider- 

 able effort, with success, to the induction of spawn- 

 ing. Successful breeding of wild, adult fish has been 

 accomplished with injections of salmon pituitary in 

 conjuction with Synahorin. or with low doses of a 

 partially purified Pacific salmon gonadotrophin. 

 Spawning was also induced in captive animals using 

 a controlled photoperiod regime followed by injec- 

 tions. Larval rearing studies are also underway using 

 copepod adults and nauplii and gastropod veliger 

 larvae as food. The veliger larvae appear to be pre- 

 ferred by the striped mullet larvae and are produced 

 in the laboratory. 



In a companion project, the problems associated 

 with rearing the striped mullet in coastal ponds are 

 being studied. Artificial seaweeds ("X" sheets of 

 plastic) are anchored in the ponds. Algae grow on 

 this plastic "grass" and are eaten by the fish, thus 

 providing a cheap source of food for the fish in cul- 

 ture. 



Young striped mullet have been studied at Texas 

 A&M University to determine high temperature re- 

 sistance and acclimation rates in laboratory tests. 

 Salinities of 1 and lO'Von were more suitable than 20 

 and 30"/oo for temperature acclimation and heat resis- 

 tance of young mullet. These findings may be useful 

 in the development of pond stocking guidelines. A 

 two-factor laboratory study on the effects of salinity 

 and temperature on survival and growth of striped 

 mullet has recently been completed. Statistical 

 analysis of the results has not been completed, but 

 the data suggest that striped mullet are tolerant to 

 broad ranges of both factors. 



Dolphin 



Work is underway by North Carolina State Uni- 

 versity biologists to determine the feasibility of 

 commercial propagation of the do\ph\n. C orypluicna 

 hippiinis. Successful efforts, being conducted at 

 Hatteras. N.C., and Bimini, Bahamas, have been 

 directed toward developing artificial spaw ning tech- 

 niques by use of sex hormones. Capturing and trans- 

 porting techniques have been developed, and growth 



48 



