Table 3 — Pemigwasset River runoff (in inches) Plymouth, N.H. Higher 

 vahies in late 1967 and early 1968 are typical of most New England 

 stations. 



Jan Apr INIay Jun Jul Aug Sep Oct Nov Dec 



Hachey et al. (1954) claim that an incursion 

 of warm Slope Water into the Gulf of Maine 

 would adversely affect the haddock and cod fish- 

 eries on Georges Bank. Examination of catch 

 statistics for these species could prove to be 

 interesting. 



Salinity Distnbufioji 



Gulf of Maine Basin 

 Surface Layer 



Comparison of surface salinity and tempera- 

 ture contours for 1968 and 1969 (figs. 9, 10, 11, 

 and 12) showed that the surface isohaline dis- 

 tribution resembled that of surface isotherms 

 during both years. The areas of strong surface 

 salinity gradients were located further northwest 

 in 1969 than in 1968. The average surface 

 salinity in 1968 (31.5Voo-33%o) was approxi- 

 mately 0.5°/oo-l°/oo lower than the 1969 average. 



Salinity gradients of the surface layer in 1969 

 (figs. 54, 55 and 56) were stronger and tended 

 to be more horizontal than those in 1968 (figs. 

 21, 22, and 23). 



River runoff for the major New England rivers 

 in 1968-1969 appeared to have a more conclusive 

 effect than did precipitation on surface salinity. 

 Table 3 summarizes the runoff for the Pemig- 

 wasset River extracted from "Water Resources 

 Data-Surface Water Records" (1967, 1968, and 

 1969). The flow for the Pemigw^asset River is 

 considered to be typical of the major New Eng- 

 land rivers (Chase, 1972). These data show 

 that the monthly flows for the major rivers dur- 

 ing the period of September- December 1967 were 

 from two to five times as great as the runoff ob- 

 served for the same four month period in 1968. 

 It has been estimated that it takes approximately 

 3 to 4 months for flow conditions observed up- 

 stream on major New England rivers to be re- 

 flected in offshore salinity conditions (Bigelow, 

 1927; Ketchum and Keen. 1955). Thus, the 

 lower salinity conditions observed in the surface 

 layer of the Gulf of Maine in January 1968 were 



at least partially influenced by the high river 

 runoff of the preceding few months. 



Wind conditions observed for the periods of 

 December 1967 through February 1968 and 

 December 1968 througli February 1969 for se- 

 lected coastal, inland, and offshore stations of 

 the Gulf of Maine region were also studied. In- 

 land and coastal observation station data showed 

 that the predominant direction of wind set for 

 both years was from the northeast with an aver- 

 age speed of 4 to 6 knots. Wind observations re- 

 corded at Coast Guard offshore light stations and 

 light vessels showed that the resultant average 

 wind set was from the northwest witli average 

 speeds of 6 knots for the 1968 season and 9 to 10 

 knots for 1969. 



Undoubtedly, weather coiiditions immediately 

 preceding and during the cruise periods did 

 affect the surface salinity conditions in the Gulf 

 of Maine in both years. 



Intermediate and Bottom Waters 



Comparison of salinity vertical profiles for the 

 midwater layer inside Georges Bank for both 

 years revealed similar salinity values and dis- 

 tribution of salinity gradients (figs. 21-23 and 

 54-56). The salinity gradients showed a weak 

 to moderate vertical distribution throughout the 

 region, with values ranging from 32.8°/„o at 100 

 meters to 34.3°/oo at 150 meters. Bottom waters 

 within the Gulf of JIaine Basin were well mixed 

 and had a salinity approximately 0.5°/oo higher 

 than that of the midwater layer directly above. 



Transition Zone 



Salinitj' gradients of transition zone waters 

 approximated those of temperature for both 

 1968 and 1969. Again, a narrow band of strong 

 horizontal gradients was observed for both years. 

 For example, in 1968 between stations 3 and 4 

 of section 1 (fig. 21), there was a change of 

 >2°/oo within a distance of 15 nautical miles. 



6 



