(3) Length-Weight Data. — Sampling of the catch in- 

 dicates in Table 1 the relation of total live weight to 

 carapace length for selected carapace sizes. 



Measurement of lobsters for length-weight distribu- 

 tion from 1949 to 1956 indicated that growth averaged 

 about 14 percent in carapace length and 50 percent in 

 weight with an average moulting frequency of approx- 

 imately 12 mo or less. Actual gross samples with a 

 total of 282,057 lobsters ranged in weight increase 

 from 44.7 percent to 53.6 percent with an average for 

 all samples of 49.4 percent (Table 2). 



Table 1. — Length-weight relation of American lobsters. 



Carapace length 

 (mm) 



Number of lobsters 

 in sample 



Average weight 

 (f;rams) 



Table 2. — Lobster weight increase by moult; gross samples. 



Moult 



Percent increase 



First 



Second 



Third 



Fourth 



Fifth 



Sixth 



Mean 



53.6 

 51.9 

 50.1 

 48.8 

 47.5 

 44.7 

 49.4 



'Gross sample weights derived from length frequency distribution 

 measurements of 288.601 lobsters made from 1949 to 1957. show 

 differences in weight by moult classes. 



(4) Soft-Shell Lobsters. — As a result of increased 

 meat tissue, the lobster's body becomes too large for 

 its shell. This is the primary cause of mouhing, al- 

 though not necessarily the mechanism which deter- 

 mines the time of moulting. The process of moulting 

 takes from 15 to 20 min. The new shell is soft and 

 rubbery and does not provide the lobster with any pro- 

 tection from enemies. For a short time after moulting 

 the lobster has to remain inactive. 



By the time the shell has reached the latter half of 

 the second intermoult stage described by Donahue 

 (1954), the lobster is ready to forage and is easily 



trapped. Approximately 60 percent of the annual catch 

 consists of soft-shell lobsters. In addition to having a 

 thin soft shell, lobsters of this class have a compara- 

 tively low ratio of meat to shell and shell liquor. Com- 

 mercial shucked meat ratio to live weight at this stage 

 is approximately one to eight, whereas at the max- 

 imum yield (just before moulting) the ratio is approxi- 

 mately one to four. During this period meat yield is 

 small and the problem of holding and shipping live 

 lobsters to market is great. 



The excellent summer demand for lobster by 

 tourists absorbs a large part of the July- August shed- 

 der catch. Approximately 25 to 30 percent of the an- 

 nual catch is marketed in the Northeast during this 

 period to tourists. The catch in excess of this amount 

 and that made during the early fall at the end of the 

 tourist season is generally held in tidal pound storage 

 for shell hardening and meat quantity and quality im- 

 provement for later marketing when the catch is low. 



(5) Hard-Shell Lobsters. — Hard-shell lobsters are 

 defined by the industry as those whose shells have 

 developed and hardened so that they are quite resis- 

 tant to digital compression. When the shell is firm the 

 lobster is able to survive handling by the producer, the 

 buyer, the dealer, and the retailer much better than 

 can the soft-shell lobster. In addition to having a 

 stronger shell, the hard-shell lobster has eaten suffi- 

 ciently in most instances so that the percentage of 

 meat tissue to live weight has increased. This increase 

 in meat density will continue provided the lobster is 

 able to feed regularly until he is ready to moult again. 

 The hard-shell lobster commands a premium market 

 price for obvious reasons. He is more viable and can 

 better withstand the rigors of handling. Meat yield is 

 greater — approximately 25 percent as compared with 

 about 12.5 percent for soft-shell lobsters. 



F. Growth and Mortality Rates . 



Stratified sampling of the catch supports the as- 

 sumption that the resource is intensively exploited 

 (see discussion in III below). 



Between 1939 and 1957 measurements were made of 

 the catch to determine the size of individual lobsters 

 and the number of lobsters in various carapace size 

 classes. Table 3 shows the size of the sample in num- 

 bers and weight in relation to catch. During the period, 

 348.645 lobsters (weighing 182.5 metric tons) were 

 measured by Fish and Wildlife biologists and Depart- 

 ment of Sea and Shore Fisheries wardens and 

 biologists. 



Between 1949 and 1957 the Department of Sea and 

 Shore Fisheries measured 286,244 lobsters weighing 

 150 tons, representing one-fifth of 1 percent of the 

 catch during the 9-yr period, for the purpose of deter- 

 mining: (1) the size of individual lobsters, and (2) the 

 number of lobsters in various size classes (Table 4). It 

 was assumed that size distribution data would produce 

 information on: (a) the approximate percentage of 



