ABOUT LOBSTERS 33 



The disease develops rather slowly, at least three 

 months being required for it to reach advanced stages. Ob- 

 servations on lobsters held at the Boothbay Harbor station 

 indicate that the disease is relatively dormant at tempera- 

 tures below 35°F., but becomes increasingly active as the 

 water temperature approaches and exceeds 40° F. 



Observations up to the present indicate that the disease 

 is spread only through physical contact with diseased lob- 

 sters, but experiments are now in progress to determine if it 

 may be carried by water. Horn-decomposing bacteria are 

 known to be widely distributed in nature, and it is possible 

 that the disease may be spread through contact with the 

 mud of infected pounds. 



It has been shown that lobsters free from previous con- 

 tact with the disease will develop it when held in tanks with 

 diseased lobsters. In one experiment, 36 per cent of the 

 healthy lobsters put in tanks with diseased lobsters de- 

 veloped visible lesions in forty days. A mortality of 71 per 

 cent has been observed among diseased lobsters held in 

 tanks for a period of eighty-eight days. 



The bacteria in shell disease attack only the external 

 parts of the lobster and exhaust their food supply before 

 ever reaching edible flesh. Although lobsters in the ad- 

 vanced stages of the disease are very unsightly, it has never 

 been reported that the presence of the disease in a shipment 

 impairs the value or marketability of the lobsters. 



In order to prevent the spread of shell disease to native 

 lobsters, dealers who handle imported lobsters must be very 

 careful to avoid dumping dead lobsters or parts of dead lob- 

 sters from an infected lot into the ocean where native lob- 

 sters can come in contact with them. Since it is customary 

 to dispose of dead lobsters by dumping them in the sea, 

 great care must be taken to see that every person handling 

 an infected lot is clearly instructed. 



The recommended means of disposing of lobsters with 

 shell disease is to burn them. This is readily accomplished 

 if a coal fire is available. When burning is impractical, boil- 

 ing for thirty minutes and dumping on a garbage dump is a 



