anemic at the conclusion of the feeding trial. Because of the ex- 

 cellent growth response attained from hake-fed salmon, further ex- 

 perimentation is proposed to determine a combination of foods which 

 will produce optimum results. 



Rockfish 



Rockfish, a term used to define several species of the genus 

 Sebastodes , are abundant in the trawl fishery of the Pacific Coast. 

 The market for these fish is not well developed and a cheap source 

 of fish food is available . Both the whole rockfish and the offal 

 from filleting operations were tested at the 100 per cent level to 

 evaluate the potentialities of these food sources in the diet of 

 blueback salmon (Table U, Diets 15> and 16). Although the whole 

 rockfish produced a greater gain in weight in the fish than did the 

 offal, neither trial indicated that these products had a growth fac- 

 tor sufficient to warrant their inclusion in the diet of blueback 

 salmon. At the end of eight weeks of feeding the fish were acutely 

 anemic and the experiments were terminated. 



Of the various fish products tested only hake and salmon viscera 

 offer sufficient promise to warrant further experimentation. Numerous 

 fishery products remain to be explored, however, which, as time per- 

 mits, will be included in the feeding trials. 



Dry Meal Supplements 



In the J-<eavenworth feeding trials, dry meals were used both as 

 absorbing agents to improve the feeding consistency and as nutritional 

 supplements. In these evaluations it was found that the type of meal 

 used, the source from which it was derived, the method by which it 

 was prepared, and the water temperature at which it was fed, all were 

 factors which affected the utilization of dry meal supplements by 

 blueback salmon. 



Certain types of mineral, vegetable, and animal meals were in- 

 corporated into the Experimental diets. The mineral and vegetable 

 meals were used primarily as absorbing agents to improve the feeding 

 consistency and secondarily as vitamin and mineral supplements. The 

 animal meals which were derived exclusively from fish products were 

 used as protein supplements . 



If the addition of either mineral or vegetable meals were to 

 compensate for a vitamin or mineral deficiency in the diet, an ac- 

 celeration in growth rate such as was reported by Donaldson and 

 Foster (191+7) for the addition of kelp meal .Tight be expected. No 

 such results were noted when apple pomace, tomato pomace, kelp meal, 



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