Weight Loss of Pond-Raised Channel Catfish {Icfalurus 

 punctatus) During Holding in Processing Plant Vats 



By 



DONALD C. GREENLAND, Fishery Biologist 



and 



ROBERT L. GILL, Fishery Methods and Equipment Specialist 



National Marine Fisheries Service 



P.O. Box 711 



Rohwer, Arkansas 71666 



ABSTRACT 



Information on weight loss and mortality was obtained for samples of channel cat- 

 fish (Ictahirus punctatus) held for processing at a catfish processing plant located at 

 Dumas, Ark. Weight losses were determined for several different holding situations 

 by daily weighings of samples held in wire containers. Mortality was recorded at 24-hr 

 intervals. Test results showed peak weight loss during the test period for all holding 

 situations averaged 55 kg per metric ton (5.5 lb. per cwt), 82.0';r of which occurred 

 during the first 48 hr of holding. There was no difference in weight loss of fish held 

 at densities of 320.3 kg per cubic meter (20.0 lb. per cu ft) and 640.6 kg per cubic 

 meter (40.0 lb. per cu ft) of water ranging from 21.1° to 22.2° C (70.0° to 72.0° F). 

 However, at the heavier loading there was twice the mortality, 8.0% compared to 4.5%. 

 Fish held in a pond with temperatures from 8.9° to 15.0° C (48.0° to 59.0° F) fared the 

 best of any of the test groups. These fish had a peak weight loss of 2.0% and suffered no 

 mortality. Similar groups of fish held in vats at 21.1° C (71.0° F) aerated with agi- 

 tators and compressed air had peak weight losses of 4.2% and 6.9% and suffered mor- 

 talities of 34.0% and 15.0% respectively. 



INTRODUCTION 



Most of the catfish processing plants located 

 in Alabama, Arkansas, and Mississippi utilize 

 live fish delivered to their plants to insure a 

 high-quality finished product. These catfish 

 are held in large concrete vats at the plants. 

 As needed, fish are removed from the vats, 

 killed, and run directly onto the processing line. 

 Processors have often mentioned to us that the 

 weight of fish being held for processing 

 "shrinks" from pond-side weighings and that 

 weight deductions for scrap fish and removal 



of dead catfish account for only a portion of 

 the diflPerence. These weight discrepancies 

 have caused misunderstandings between farm- 

 ers and processors. Without accurate "shrink" 

 data, processors have been reluctant to con- 

 sider changing plant facilities to try to reduce 

 weight loss. Our assistance was requested to 

 obtain data that would be helpful to processing 

 plant managers in deciding whether fish weight 

 losses were indeed a problem. During the win- 

 ter of 1970-71, a study to determine this was 

 conducted at the Southern Catfish Processors, 

 Inc. in Dumas, Ark., by National Marine Fish- 

 eries Service personnel. 



