REPORT OF COMMISSIONERS OF IXLAXD FISHERIES. 201 



majority of lobsters were passing through the fifth stage. We further 

 notice in this regard that, while the average amount of increase for the 

 fourth stage lobsters was 15 per cent., the gain in length for the fifth 

 stage individuals was 20 per cent.; which again goes to show that the 

 highest percentage of increase per molt may be coupled with the 

 briefest stage-periods. 



XIV. Regarding the Probable Difference in Age of Woods 

 Hole and Wickford Lobsters at Maturity. 



It is very proljable that the lobsters in the region of Narragansett 

 Bay, and other waters of a correspondingly high temperature, attain 

 a marketable size somewhat sooner than along the coasts of Massa- 

 chusetts or Maine (the so-called "home of the lobster")- Facts 

 which would seem to warrant such a view may be obtained by ex- 

 amining the tables showing the rate of growth of Herrick's Woods 

 Hole lobsters and by inferences which can be drawn from Table No. 

 22. In Herricks Woods Hole lobsters (stages 1 to 10)the average 

 amount of increase per stage was approximately 14 per cent. We 

 already know that, as a rule, the average percentage of gain in length, 

 per stage, is never, in the later life of the lobster, greater than in the 

 first 10 stages; and that on the other hand, there is, after the eigh- 

 teenth stage, a gradual diminution in the rate of increase.* 



If we conclude, as Herrick does, that 15.3 per cent, represents ac- 

 curately the average amount of increase per stage for lobsters under 

 natural conditions at Woods Hole, and if we assume that the facts 

 stated in Table No. 18 regarding the frequency of molting are accurate, 

 then we are forced to the conclusion that the average Woods Hole 



*lt might be inferred that the percentage of increase in length of the older Woods Hole 

 lobsters would, as in the case of the early stages, be diminished as a result of the low temperature. 

 It is most probable, however, that the rate of growth of lobsters beyond the eighteenth stage 

 undergoes no great modification from the effect of water temperature. This influence is most 

 effective in the summer months and for lobsters whose stage periods is relatively brief. Since 

 we believe, as already stated, that groups of middle-aged lobsters in regions of different pre- 

 vailing water temperatures correspond rather closely with one another as regards both the 

 number and the periods of molting, and also as regards the increase in size at each molt, we may 

 stiU interpret the time of successive molts of Woods Hole lobsters of later stages in the hght of 

 the estimates presented in Table No. 18. 



