INVESTIGATION OF OYSTER SPAWNING, ETC., MILFORD, CONN. 447 



from the south in 1925 was 5,448 miles greater than it was in 1926. The effect of 

 wind on air and water temperatures depends largely on the original source of the 

 winds, which, in the case of the south component winds, for this region is both 

 land and marine. The southwest winds come from the adjacent Atlantic Coast 

 States lying in that direction, while the south and southeast winds come from over 

 the Gulf Stream. 



The wind has great effect on water temperatures in this region because of the 

 exposure of extensive tidal flats, where rapid changes in temperature were found to 

 occur with strong north or south winds. A good example of the effect of a north 

 wind was found on August 8 and 9, 1926, when the temperature dropped from 25° C. 

 at low water at 6 p. m. to 13.5° C. at low water 12 hours later. During this time, the 

 most sudden drops in temperature occurred on the 9th from 4.30 a. m. to 5.15 a. m., 

 when the water cooled from 20° C. to 13.5° C, a decrease of 6.5° in 45 minutes. 

 Although the opposite effect is produced by the south wind, the increase in tempera- 

 ture is not as great because of a certain amount of cooling by evaporation. The 

 wind is an important factor in changing inshore water temperatures, especially in 

 regions where the tidal movement and area of flats is considerable, because the rate 

 of exchange of heat between the air and water depends largely on the area of the 

 surfaces that are brought into contact and the extent of circulation of each medium. 



INFLUENCE OF TIDE ON WATER TEMPERATURE 



The tide is an important hydrographic factor indirectly affecting the temperature 

 of inshore waters. As a result of the tide, the water undergoes considerable vertical 

 and horizontal movement, thereby coming into contact with the tidal flats, which 

 greatly increases the effect of climatological conditions on its temperature. 



In Milford Harbor the mean range of tide is 6.6 feet and the spring range 7.7 feet. 

 The water temperature showed marked variations according to the range and stage 

 of tide and the time of high water in relation to the time of day. Besides solar 

 radiation and air temperature, the magnitude of the hourly and daily variations in 

 temperature was found to depend also upon the range of tide. 



The principal purpose in studying the tides was to determine their influence on the 

 development of the maximum temperatures that affect many physiological activities 

 of marine organisms. In comparing 1925 and 1926 water temperatures, it has been 

 found that during the periods of full-moon spring tides there occurred a definite 

 upward trend in the daily mean water temperature. 



During the spring and early summer, the ocean water that is brought into Long 

 Island Sound with the tides has a low temperature, while that from the rivers and 

 shallow tidal flats is considerably warmer. In the fall conditions are reversed, the 

 ocean and Sound waters persisting as a warm influence, while those from the land 

 rapidly become colder. The quantity of ocean water coming into the Sound varies 

 from day to day in accordance with regular changes that occur in the range of tide. 

 With spring tides, when the range is greater than the average, we have the maximum 

 inflow of cool ocean water; and with neap tides, the minimum, as at this time the 

 range is less than the average. 



In comparing conditions that exist at different tides, we find that during the 

 period of the full-moon spring tides, in July and August, the hourly water-temperature 



