MAINE SARDINE INDUSTRY. 



33 



Table 11.— Temperature changes in loads of fish during transit — Continued. 



DRY-SALTED 150 POUNDS OF SALT PER HOGSHEAD; FISH 2\ FEET DEEP IN BOAT; 

 ' 47 PER CENT OF FEED PRESENT. 



Temperature. 



Time 

 observed. 



Of air. 



Of fish. 



Warmest 

 day. 



Mean for 

 month. 



a. m. 

 9.30 

 10.36 

 11.30 



p. m. 

 12.30 



°C. 



17.2 



"C. 



9.6 



• C. 

 11 

 14 

 18 



23.5 







20.0 



11.9 



DRY-SALTED; 90 PER CENT OF FEED PRESENT. 



a. m. 

 5.56 

 6.24 

 9.23 

 10.36 

 11.30 

 /). m. 

 12.30 

 2.00 

 4.20 



"C. 



11.7 



■c. 



6.7 



° a 



11 

 12 



IS. 5 

 22 

 24.5 



27 















20.0 

 22.8 

 20.0 



11.9 

 12.4 

 11.1 



37.5 



The changes of temperature in the outside air were not sufficient to 

 account for the changes in temperature which occurred in the loads 

 of fish. It is evident that fish heat when carried in bulk, as is now 

 the custom, the temperature increasing in proportion to the amount 

 of feed present. The temperature of fish which contained but" a 

 small amount of feed and were carried in pickle rose 4° during one 

 and one-half hours. That of dry-salted fish, estimated to be 47 per 

 cent feedy, rose 12.5° during three hours. A boatload of fish in dry 

 salt, 90 per cent of which were estimated to contain feed, rose 11° 

 in temperature during a run of four and one-half hours. Just before 

 the fish on this boat were unloaded, practically 10J hours after they 

 had been taken from the water, the temperature of the mass, taken 

 midway between the top and bottom, showed an increase of 26.5°. 



The rise in temperature of masses of fish in bulk is caused by 

 decomposition changes due to bacterial growth, by far the greater 

 part of which takes place in the viscera and contents. As the tem- 

 perature of the mass of fish rises and approaches the optimum 

 temperature favorable to bacterial growth, it is evident why the 

 decomposition of feedy fish proceeds, at times, so rapidly. It is also 

 evident why keeping the fish in smaller bulk and at a low temperature 

 markedly retards this decomposition. 



Conclusions. 



It is not necessary to salt excessively fish which are to be in transit 

 for a reasonable length of time only. Since excessive salting does 

 5890°— 20— Bull. 908 3 



