154 U.S. BUREAU OF FISHERIES 



high iron, low copper, and low manganese; and (3) Gulf, with high 

 iron, low copper, and liigh manganese. These oysters from different 

 localities were fed to anemic animals and all induced regeneration of 

 hemoglobin, thus giving further evidence of the importance of oysters 

 as a source of iron in addition to their other food factors. 



-KELP MEAL EXPERIMENTS 



Cooperative work with a producer of kelp meal was continued by 

 Dr. H. P. Morris, research associate of our teclmological staff, in the 

 Washington laboratory to determine the nutritive value of kelp meal. 

 The work completed with laboratory animals to wliich diets com- 

 posed of plant substances, with and without the addition of kelp 

 meal were fed, indicates that kelp meal has a beneficial effect on 

 growth. With some diets the addition of kelp meal definitely stimu- 

 lated appetite. However, with the diet in which linseed oil meal sup- 

 plied the protein tliis was not the case. The greater growth of the 

 rats in tliis experiment can probably be ascribed to the mineral con- 

 tent of the kelp meal. The increased growth was not due to sodium 

 or potassium chloride, as the control diets were corrected for these 

 salts. 



At the conclusion of the experiments with laboratory animals 

 arrangements were made with the Poultry Office, Bureau of Animal 

 Industry, United States Department of Agriculture, for a coopera- 

 tive study to determine the value of kelp meal when fed to poultrj^ 

 However, due to the withdrawal of financial support by the kelp-meal 

 producer, this work was discontinued December 31, 1932, before 

 enough data had been accumulated to draw definite conclusions. 



PRESERVATION OF FISHERY PRODUCTS FOR FOOD 

 IMPROVED METHODS FOR HANDLING FRESH AND FROZEN FISH 



Studies dealing with the relative freshness of fish were continued 

 during the year at the Gloucester technological laboratory under the 

 direction of James M. Lemon with the assistance of Maurice E. 

 Stansby. Several methods for packing fresh fish were stu-died and 

 the rate of spoilage under each was determined. It is expected that 

 final results of this research will indicate methods for packing which 

 are the least injurious to fish and which will yield the highest grade of 

 product. 



Efforts also were made to determine the temperature at which 

 frozen fish suffer the least deterioration during storage. It is known 

 that certain of the enzymes found in the flesh of fish continue to func- 

 tion even at low temperatures. The study of this problem deals with 

 these changes, and efforts are being made to effect a method which 

 will retard this enzymic action. 



The technique of freezing and storing several varieties of shellfish 

 is being given consideration for the reason that more efficient methods 

 for this would be of great aid to the oyster, crab, and shrimp indus- 

 tries. Thus far very little is known of the effects of freezing and long 

 storage upon these products. These studies are aimed to determine 

 the proper temperature for freezing, the most efficient temperature 

 for storage, the effect of defrosting and refreezing, and the rate of 

 spoilage after defrosting. 



