132 



FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



Description. — The humpback is of the familiar 

 salmon outline while living in the sea, the body 

 being deeper than thick, with rounded belly. The 

 head is naked but the body is covered with scales 

 large enough to be seen easily. The dorsal fin 

 stands about midway of the body above the ven- 

 trals, and the flaplikc adipose fin is over the rear 

 end of the anal fin. It agrees so closely with the 

 Atlantic salmon in all this that the one might 

 easily be taken for the other, were it not that the 

 anal fin of the humpback invariably has 14 rays or 

 more, whereas that of the Atlantic sahnon has 

 only about 9 rays. Also, the humpback is a 

 stouter-bodied fish than the Atlantic salmon. 

 The male humpback (like all the Pacific salmons, 

 and the Atlantic salmon to a lesser degree) under- 

 goes a very noticeable change in form in the 

 spawning season, with the body deepening and 

 developing a prominent hump in front of the dor- 

 sal fin; the jaws elongating and becoming hooked 

 at the tip and the teeth increasing in size. 



Color. — The back and tail of the humpback are 

 bottle green with poorly defined black spots, while 

 it is in the sea. These spots are particularly con- 

 spicuous on the tail, where they are oval in outline 

 and as much as a thud of an inch in longest diam- 

 eter. These spots are one of the distinctive marks, 

 whereby the humpback can be distinguished from 

 all other salmons. The sides and belly are sil- 

 very, with a faint pinkish tinge. Young hump- 

 backs are unique among salmon in being of prac- 

 tically adult coloration without "parr" marks 

 (p. 122). 



Size. — The humpback is the smallest of the 

 Pacific salmons and much smaller than the Atlan- 

 tic salmon, adults averaging only about b){ 

 pounds in weight and 20 to 25 inches in length. 

 Males weigh to about 11 pounds and females to 

 about 7% pounds. 



General range. — Pacific coast of North America 

 and of northern Asia, from Oregon northward on 

 the American side. This is the most abundant 

 salmon in Alaska. It runs up fresh rivers to 

 spawn, which it does but once and then dies. 

 It has been introduced in the rivers of Maine. 



Occurrence in the Gulf of Maine. — The history 

 of the introduction of this west coast salmon to 

 New England waters is as follows: 



Humpback sahnon eggs seem first to have been 

 planted in Maine rivers in 1906. In the autumn 

 of 1913 a large consignment of humpback eggs 



was shipped to the Craig Brook and Green Lake 

 (Maine) hatcheries, and the approximately 7,000,- 

 000 fingerlings hatched therefrom were distributed 

 in the Penobscot, Androscoggin, Damariscotta, 

 Dennys, Pleasant, Union, Medomak, Georges, 

 and St. Croix Rivers. A year later some 5,000,000 

 young fish were liberated. A third plant was 

 made in 1915; a fourth of 6,235,808 fingerlings in 

 1916; and a fifth of about 1,000,000 in the Dennys 

 and Pembroke Rivers in 1917. 97 



The results of this attempt at acclimatization 

 were first seen in the summer and fall of 1915 

 when fishermen reported large numbers of mature 

 humpbacks along the Maine coast, and when 

 humpbacks ran in the Dennys River (where many 

 were caught) from August 15 until September 24, 

 some probably spawning there, for the bodies of 

 spent fish were seen drifting downstream. Hump- 

 backs again entered the Pembroke and Dennys 

 Rivers during August, September, and October of 

 1917 with a few reported from the Penobscot, St. 

 Georges, Medomak, and St. Croix, the result of 

 the plant of 1915. And at least 2,000 mature fish 

 were seen that summer in the Dennys alone, where 

 many were caught averaging about 5 pounds, and 

 one as heavy as 10 pounds 9 ounces. Definite in- 

 formation is lacking for 1918. But even larger 

 numbers entered the Dennys and Pembroke Rivers 

 in the autumn of 1919 than in 1917, with smaller 

 runs in the Penobscot, Machias, St. Croix, and 

 Medomak Rivers. Enough spawned that year in 

 the Dennys and Pembroke Rivers for the fish- 

 culturists of the Bureau of Fisheries to artificially 

 fertilize half a million eggs there. And hump- 

 backs were caught in the weirs in Passamoquoddy 

 and Cobscook Bays during that season. 



Adult fish were taken again in the weirs in 

 1920, 98 and one fish was caught in a weir as far 

 from its native river as Lanesville, Mass. (near 

 Cape Ann ) " at some time during the summer of 

 1921. 



Large numbers of eggs were collected again from 

 wild fish between 1922 and 1926, the resultant fry 

 being returned to the Dennys and other rivers 

 nearby. Artificial propagation was abandoned 

 then, for it seemed that the species was estab- 



w More detailed accounts of these and successive plantings will he found 

 in the annual reports of the U. S. Commissioner of Fisheries for the years 

 1914 to 19S8. 



" Reported catch, 'Washington County, Maine, 1920. 310 pounds. 



" It was forwarded to the Massachusetts Commissioners as reported by 

 C. K. Grant of Olouccster. 



