CLIMATE AND THE DISTRIBUTION OF MARINE ANIMALS 



327 



16 



1.4 



<n 1.2 

 o 



z 



g..O 



o .8 



1 en 



i .6 



2 •4 

 .2 



-\ 



-1 I I I I \ r 



-1 — I — I — I — r 



\- 



I I I I I I I I 1 I I I L. 



1918 1922 



1930 1938 



YEAR 



1946 



1954 



Figure 21. — Landings of lobsters in the Middle Atlantic 

 States, 1921 to 1950. 



4.0 



35 — 



S 10 



\ 



V 



I 918 1922 

 Figure 22. — 



1930 



1938 

 YEAR 



1946 



1954 



Landings of lobsters in 

 1919 to 1950. 



Massachusetts 



Consideration of tliesc data, together witli tlic 

 Canadian trends, suggests that there are optimum 

 conditions for lobsters and that these optimum 

 conditions ceased to e.xist in the area south of 

 Cape Cod about the middle of the 1920's. This 

 hypothesis also implies that conditions began im- 

 proving in the area north of Cape Cod about 1940 

 and that this improvement lias contiiuu'd to the 

 present time. 



Monthly landings of lobster have been reported 

 in Maine since January 19.'}9. The availability of 

 montlily surface water temperatures at Boothbay 



Harbor over the greater part of this period affords 

 a means of further investigation of the relation of 

 water temperatures to lobster catches. 



Figure 24 shows monthly lobster catches in 

 Maine, plotted against the corresponding mean 

 surface water temperatures, for tlie months of Oc- 



32 



28 



-1 — I — I — I I I 1 1 1 \ I I 1 I 1 I r 



I I I I I I I I u 



_] I I I i_ 



1918 1922 1930 1938 1946 1954 



YEAR 

 FiouRE 23. — Landings of lobsters in Maine, 1919 to 1951. 



40 50 



DEGREES FAHRENHEIT 



FiGCKE 24. — Monthly catches of lobster in Maine plotted 

 against corresponding mean surface water temperatures 

 at Boothbay Harbor for the months of October through 

 April, 1939 to 1949. 



