are examples of some of these observations: 



1. The body temperature of skipjack 

 and yellowfin tuna immediately 

 after landing, varied from U to 

 8°F. higher than the seawater tem- 

 perature (range Th to 83°F.) . 



2. Skipjack tuna ranging from 8 to 10 

 pounds each were chilled from 8U F. 

 to 32°F. in 6 to 9 hours when 

 placed in sea water prechilled to 

 31 °F. When placed in warm sea 

 water at an initial temperature of 

 85°, skipjack required about 20 

 hours to cool to 32°, at which 

 time the sea water temperature was 

 down to 31 °F. 



3. The condition of skipjack held in 

 air on deck was influenced more by 

 initial condition of the fish and 

 environmental factors (temperature, 

 piling of fish, handling, etc.) 

 than by time on deck. For example, 

 in one case skipjack held on deck 

 for 10 hours were still in rigor 

 mortis and in excellent condition 

 whereas another lot from a dif- 

 ferent catch had passed through 

 rigor and appeared soft and in poor 

 condition after only 2 J hours on 

 deck. This difference was attrib- 

 uted partly to the greater exposure 

 and physical damage to the latter 

 fish. 



h. Fish located in the center of a 

 large brine well required an ex- 

 cessively long period to come to 

 the equilibrium temperature of the 

 well. 



5. During loading of a brine well over 

 a period of several days, the tem- 

 perature of the chilled fish already 

 in the well rose proportionately 

 with the temperature increase of 

 the brine when warm fish were added 

 to the well. 



6. Shrinkage or loss of weight of 

 skipjack and yellowfin tuna from 

 the time they were placed in the 

 well until time of unloading was 

 not of great significance under 

 the conditions aboard the vessel 

 used in the study. The average 

 loss in weight for 52 individual 



fish in k different wells was 2 

 to 3 percent of the initial 

 weight. Loss of blood and minor 

 physical damage appeared to ac- 

 count for this shrinkage. 



While these observations are of limited 

 value inasmuch as they apply only to the 

 conditions and practices aboard one vessel 

 for two trips, they do provide some indica- 

 tion as to the importance of various factors 

 in handling, chilling, freezing, and thaw- 

 ing tuna. This preliminary work indicated, 

 also, that while it was difficult to follow 

 a preconceived plan of research at sea, due 

 to conditions beyond the control of the 

 researcher, much could be learned through 

 observation of at-sea working conditions. 



62 



