LOBSTER SANCTUARIES AND HATCHING PONDS 



SESSIONAL PAPER No. 38a 



49 



nncl mouth parts prevent the aiiimais from feediiiji and moulting;. The latter act 

 quite differently. They are hair-like growths which penetrate the " skin " of the 

 larvae, and not merely prevent moulting, but suck out the juices from the bodies of 

 the larvae, and inevitably produce death. 



WEATHER. 



Another difficulty which we encountered was adverse weather conditions. At first 

 sight it might appear strange that lobster larvae should be subject to slight variations 

 in weather conditions, but they arc, even more so than human beings. Every one 

 knows that when we are exposed to cold and damp and rainy weather we " catch cold," 

 which is only another way of saying that when our vitality has been lowered by cold, 

 disease germs enter the body all the more readily and make us sick. In a somewhat 

 similar way, the foggy, cloudy, and cold summer at Long Beach pond last season 

 delayed greatly the growth and moulting of the young, and gave plenty of time for 

 disease germs to attack and kill them. 



How do we know that warm water and sunlight are favourable to the growth of 

 young lobsters, and that cold water and foggj^ weather are unfavourable? Very 

 simply. We just examine the young lobsters under the microscope from day to day, 

 and see how long it takes them to moult, that is, to change their " skin." ^\Tien 

 lobsters come out of their " shells '' they are said to be in their first stage. They have 

 no little legs or swimmerets on the under surface of their abdomen. When, however, 

 they are properly fed, and when the water is warm ^nd there is fair weather, they 

 shed their skin or outside covering in from five to six days. They are then said to 

 be in their second stage. In this stage they have short little swimmerets on the 

 abdominal surface, and the presence of these is the chief mark by which we recognize 

 that they are in the second stage. In three or four days more, if all conditions are 

 favourable, :the young moult again, that is, change their skin and pass into the third 

 stage. Every time they change their skin they arq,said to moult and pass into another 

 stage, and each stage is marked by some .slight change in the size, shape, or colour 

 of different parts of the beast's body. « 



Now, remembering what moulting means, let us return to the subject of the effect 

 of warm and cold water upon the gTo^\i;h and development of lobster larvae. 



Professor Gorham has drawn vip the following table showing the results of vary- 

 ing degrees of warm and cold sea-water upon the growth and development of lobster 

 larvae at different points along the Atlantic coast : — 



Place. 



Orr's island. Maine 

 V/ood.s Hole, Mass, 

 Wickford, R. I . . 

 II I' . . . 



Annisquam, R. I. . 



Time taken from 

 1st to 3rd stage. 



25 to 26 days. 

 22 to 25 days. 

 16 days. 

 9 day.*:. 

 10 days. 



Comparing these temperatures and results with ours at Long Beach we find that 

 our temperatures ranged from 60° F. on July 17th the beginning of the hatching to 

 60°F., on August 22, the close of the plant. The highest temperature registered dur- 

 ing the period was 65-2° F., July 30. Our average for the period during which the 

 plant was in operation was GO- 8° F., and we were unable to rear any lobsters to the 

 fourth stage. The best we could accomplish was the second stage in ten days and the 



38a— 4 



