CLIMATE AND THE DISTRIBUTION OF MARINE ANIMALS 



323 



was 0.7° higher for February 1954 in Boston Har- 

 bor (36.6° F.) than for January (35.9°).' But 

 the following comparison (table 25) between the 

 temperatures taken February 16-18, 1954, and 

 those taken botli 10 days earlier and 10 days 

 later in the season in 1925 shows that winter chill- 

 ing was not as severe in the Bay to the southward 

 of Boston in 1954 as in 1925. The overall differ- 

 ence between the 2 years for the southern part of 

 the Bay as a whole was between 2° and 5°. More 

 striking, the temperature seems not to have fallen 

 as low as 33° anywhere in the open Bay at any 

 depth in 1954, whereas it fell there (locally) in 

 1925, almost to the freezing point of salt water as 

 it has in sundry other winters in the past (p. 303). 

 Also, readings at 2 stations in the northern side 

 of the Bay averaged 2° to 3° higher, surface to 

 bottom, on February 18, 1954, than on February 

 13, 1913, or on March 4, 1921 — which were among 

 the warmer of the winters that fell within the 

 period of our earlier surveys (table 26). The mini- 

 mum, also, seems certainly to have been no lower 

 in the Bay in 1954 than in 1953, and may have 

 been slightly higher, for while readings taken in 

 the Bay averaged about 1° lower on February 18, 

 1954, than on March 31, 1953 (table 27), a some- 

 what greater difference than this, but of the same 

 order, might have been expected between the two 

 sets of readings, on seasonal grounds. 



Table 25.^ — Maximum and minimum water temperatures 

 in Massachusetts Bay Region, southward from the offing 

 of Boston Harbor and seaward to a line from Cape Ann 

 to the tip of Cape Cod, in February, 1925 and 193 4 



[Temperatures in "F.] 



Table 27. — Water temperatures in Massachuietts Bay, 

 in 1953 and 1954 



(Temperatures In T.] 



Table 26. — Surface and bottom temperatures in northern 

 side of Massachusetts Bay in 1954 and in earlier years 



(Temperatures in °F.] 



' Information supplied by the U. S. Coast and Oeodetic Survey. 



This close correspondence between the winter 

 temperatures of Massachusetts Bay in March 1953 

 and in February 1954, added to the consistently 

 high level reached by the mean water temperature 

 for the coldest month in Boston Harbor as far back 

 as 1949 (year-to-year range, 35.9°-37.8° F.), 

 shows conclusively that we are dealing here with a 

 situation that has already persisted through 5 

 winters, not merely with 2 warm winters in succes- 

 sion, such as have been known to interrupt the 

 succession of colder winters in the past (p. 303). It 

 is of special interest that through the winter of 

 1954, as during the preceding summer, the western 

 side of the Gulf should have continued some 2° to 

 3° warmer than in earlier years, for the mean tem- 

 perature in Boston Harbor was lower for that 

 January (35.9°) than it had been for any month 

 since February 1951. This with current reports 

 of more ice than for many winters past in the 

 partially enclosed situations along the coast of 

 Maine, following severe weather in January, 

 raises the question whether the upward shift in 

 winter temperatures may have passed its climax 

 in our Gulf. 



CHANGES IN ABUNDANCE AND DISTRI- 

 BUTION OF MARINE ANIMALS 



Although valuable statistics on the landings of 

 many marine species have been collected since 

 1887, for the most part these records are not con- 

 tinuous prior to about 1930. It is not possible, 

 therefore, to show long-term trends and fluctua- 

 tions, except for a few species. Changes in fish- 

 ing methods, efficiency, and effort, as well as 

 changes in market conditions, tend to obscure the 

 relations which may exist, so that one must fre- 

 quently make general comparisons, based on 

 minor fluctuations tliat may be related to environ- 

 mental conditions when the major upward or 

 downward trends may be due to other factors. 



