December 8, 1916] 



SCIENCE 



829 



However, an experiment that was at first 

 supposed to be a very minor one compared with 

 lobster rearing turned out to be the major one. 

 It was this. About the middle of June, 47 

 females and 15 males (all known as " commer- 

 cial lobsters," because the females when caught 

 in fishermen's traps have no " berries " on 

 them) were placed in a wooden pound en- 

 closing an area of 10 feet by 20 feet. The 

 slats of which the pound was built were about 

 4J feet long, 3 inches wide and 1 inch thick. 

 It was intended to retain the animals over 

 winter for the purpose of elucidating the old 

 question of whether or not adult females moult 

 one year and extrude eggs the next, or whether 

 they extrude eggs every year (when mating 

 conditions are favorable) and only moult occa- 

 sionally as they grow older. 



On the 12th of August the whole of the 62 

 lobsters were dipped up to see what condition 

 they were in. They all appeared healthy, and 

 36 per cent, of the females carried eggs. 

 Dr. Herrick in his well-known book on the 

 American lobster quotes from "Vinal Edwards 

 to the effect that the percentage of berried 

 lobsters caught by fishermen off the Massa- 

 chusetts coast was 12 per cent, for the autumn 

 of 1893 to June 30, of 1894. Careful inquiries 

 among both canners and fishermen of the St. 

 Mary's area elicited the information that only 

 about 1 per cent, of the females caught in 

 fishermen's traps carried eggs. And then the 

 question arose: How is it that in fishermen's 

 traps only one female in every hundred carries 

 eggs, whereas in our mating pen thirty-six 

 out of every hundred carry eggs? The prob- 

 lem did not grow any simpler when it was 

 found that by the end of September the per- 

 centage in our pen had risen to 64 per cent. 

 The 17 females which did not extrude eggs 

 were removed from the latticed pen and the 

 30 which bore eggs, representing the 64 per 

 cent., were kept over winter in a compart- 

 ment by themselves. On April 7, 1915, the 30 

 were all found to have the full complement of 

 eggs upon them. Subsequently, in June and 

 early July, they all hatched out their eggs, and 

 being kept in compartments by themselves 9 

 of them were found to have extruded eggs in 



late July and August. These 9 were removed 

 from the pen, the remaining 21 being retained, 

 but unfortunately one corner of the enclosure 

 gave way, allowing most of the 21 to escape 

 and mingle with others, so that it was impos- 

 sible to know how many more of them did ex- 

 trude eggs. 



Mating experiments were resumed during 

 the summer of 1915, but were not so success- 

 ful as those of 1914. Only 40 per cent, of the 

 females extruded eggs, and the eggs were most 

 of them unfertilized. Probably the sole reason 

 for this was lack of males. During the early 

 part of the summer we had only one male to 

 mate with 51 females. Later on, we were for- 

 tunate enough to secure 25 more males, but 

 half of these died from accidental poisoning 

 by paint on the inside of our mating pens. 

 Moreover, many of the remaining males were 

 decidedly undersized — 9J to 10 inches in 

 length. But perhaps the most fundamental 

 reason for the poor showing of 1915 lay in the 

 fact that the large majority of the females had 

 been retained in the pound over winter, and 

 as a consequence had suffered considerably in 

 general health. Few of them had moulted and 

 their " shells " were covered with dark brown 

 algal growths that I have always seen upon 

 lobsters when in lengthened confinement, but 

 never upon those which were taken directly 

 from the open sea. 



In 1916 the Biological Board authorized an 

 extension of the mating experiments to two 

 other places on the maritime coast, namely, 

 St. Andrew's, New Brunswick, and Pictou, on 

 Northumberland Straits. The results to date 

 are 25 " berried " out of 105 in St. Mary's Bay, 

 8 out of 22 at St. Andrews and 14 out of 21 at 

 Pictou, or, expressed in percentages, 25 per 

 cent., 36 per cent, and 66 per cent., respec- 

 tively. 



How do these percentages compare with the 

 percentages of females caught in lobster traps 

 in these same areas? Fortunately, through 

 the courtesy of the Department of Naval Serv- 

 ice, Ottawa, we were able to make a close ap- 

 proximation to an answer to this question. At 

 the request of the Biological Board, the nat- 

 uralist of the Fisheries Branch, Mr. Andrew 



