MOVEMENTS OF MENHADEN. 571 



peratures, as indicated by monthly averages, fall below 51 F., and that their departure in the 

 autumn is closely connected with the fall of the thermometer to 51 F. and below. In 1877 a cold 

 summer seemed to threaten the success of the Maine Menhaden fisheries. In September and 

 October, however, the temperatures were higher than in the corresponding mouths of the previous 

 year, and the scarcity of the early part of the season was amply amended for. , 



The season of 1878 in Maine was fairly successful, the three summer months being warmer 

 than in 1877, but cooler than in 187G. The absence of the Menhaden schools north of Cape Cod 

 in 1879 is also easily explained by the study of temperatures of the water of the Gulf of Maine, as 

 indicated by the observations made in Portland Harbor. The averages for the three summer 

 months are as follows, the numerator of the fraction being the average surface temperature, the 

 denominator that of the bottom : 1870, 62o.5-57.9 ; 1877, 58.5-56.7 ; 1878, Gl.5-58.l ; 1879, 

 5(J0.1-54.6. 



The average for the three summer mouths of 1879 is less than that of June, 187G. 



This may perhaps be explained by a study of ocean temperatures. In August, 1878, there 

 was a very rapid fall in the temperature of the surface in the Gulf of Maine, so that the average 

 temperature of that month was less than that of July, instead of being higher, as is usual. This 

 may have had the effect of driving the fish into the warmer water of the bays and estuaries. The 

 monthly averages for 1876, 1877, 1878, and 1879 are as follows: 



1876 June, 56Q.9-540; July, 660.7-590.4; August, 63o.9-6(R4. 

 1877 June, 54o.9-53.3; July, 58.l-56o.3; August, 62.4-60o.6. 

 1878 June, 56o.8-55.2; July, 66Q.9-590.3; August, 6(P.7-59o.9. 

 1879 June, 520.9-510.7 ; July, 55O.9-54O.1; August, 59.6-58o. 



The arrival of the Menhaden is announced by their appearance at the top of the water. They 

 swim in immense schools, their heads close to the surface, packed side by side, and often tier 

 above tier, almost as closely as sardines in a box. A gentle ripple indicates their position, and 

 this may be seen at a distance of nearly a mile by the lookout at the masthead of a fishing vessel, 

 and is of great assistance to the seiners in setting their nets. At the slightest alarm the school 

 .sinks toward the bottom, often escaping its pursuers. Sailing over a body of Menhaden swimming 

 at a short distance below the surface, one may see their glittering backs beneath, and the boat 

 seems to be gliding over a floor inlaid with blocks of silver. At night they are phosphorescent. 

 Their motions seem capricious and without a definite purpose; at times they swim around and 

 around in circles; at other times they sink and rise. While they remain thus at the surface, after 

 the appearance of a vanguard they rapidly increase in abundance until the sea appears to be alive 

 with them. They delight to play iu inlets and bays, such as the Chesapeake. Peconic, and Narra- 

 gansett Bays, and the narrow fiords of Maine. They seem particularly fond of shallow waters 

 protected from the wind, in which, if not molested, they will remain throughout the season, 

 drifting in and out with the. tide. Brackish water attracts them, and they abound at the mouth 

 of streams, especially on the Southern coast. They ascend the Saint John's River more than 

 thirty miles; the Saint Mary's, the Neuse, the York, the Rappahannock, the, Potomac nearly to 

 'Washington, and the Pawtnxent to Marl borough. They come in with or before the Shad, and are 

 very troublesome to the fishermen by clogging their nets. I am not aware that this dilliculty 

 occurs in Northern rivers, though they are found in the summer in the Iludsou and its tributaries, 

 tho ITousatonic, Mystic, Thames, and Providence L'ivers, in the creeks of Cape Cod, and at the 

 mouth of the Merrimack. A curious instance ol'capriciousness in the movements occurred on the 

 coast of Maine, where much alarm was felt, because their habits were thought to have been 



