150 EEPORT OF COMMISSIONER OF FISH AND FISHERIES. 

 37. SALMO OQUASSA, Girard. 



BLUE-BACK LAKE-TROUT ; THE OQUASSA TROUT. 



Syn. — Salmo oquassa, Grd. Proc. Bost. Soc. Nat. Hist., vol. iv, p. 262. (Read 

 before the society October 20, 1852.) 



Sp. Ch. — [Condensed from Dr. Girard's description, and tlie examin- 

 ation of eight specimens.] Leugtli (of fnll grown adnlt ?) from 8 to 10 

 inches. Body snbfusiform, slender, graceful. Head proportionally 

 small, conical. Month smaller than in S. fontinaUs, from which it 

 also differs in the structnre of the opercular apparatus. Fins 

 placed in the same relative positions as the latter, but larger, excepting 

 the adipose, which is considerahl}^ smaller. Margin of the caudal some- 

 what forked and undulated. Scales much like those of the brook-trout, 

 but larger. Lateral line similar in both species. 



Colors. — A bluish tint extends all along the back from the head to 

 the tail, so that when seen from above the fish appears entirely blue. 

 Sides and abdomen silvery-white in the female, and of a deep reddish- 

 orange in the male, spotted in both sexes with the same hue as the 

 abdomen. Dorsal and caudal fins brownish-blue, bordered with pale- 

 orange in the male; the pectorals, ventrals, and anal of a fiery-orange, 

 blackish-blue at their bases, and margined with white. 



Hab. — Moosemeguntic Lake, Kenebago Eiver, Lake Oquassa, Maine. 



According to Dr. Gii'ard this is a lake species, of great delicacy and 

 beauty. It is found on Lake Moosemeguntic, making its appearance 

 fiom the depths about October 10, and, coming near the shore, ascends 

 the Kenebago Eiver in shoals. Half a mile from its mouth the Kene- 

 bago receives the outlet of Lake Oquassa. The trout there leaves the 

 Kenebago and enters Oquassa Lake, where its voyage comes to a close. 

 After the middle of Xovember it returns to Moosemeguntic, and is not 

 again seen till the following year. It is known to the residents of that 

 region as the blue-hacli. 



Dr. Girard adds the following remark: " The flesh of the fish is highly 

 flavored and more delicate than the brook-trouts in Europe and America. 

 It resembles that of S. uinblaj of the Swiss Lakes, both in the peculiarity 

 of its habits and its delicacy. Salmo umhla is a lake-trout, an inhabit- 

 ant of the deep, making its appearance near shores January and Febru- 

 ary to spawif, and never ascending the brooks or rivers, tributaries of 

 the lakes. 



Diagnosis. — From 8. gloveri, by lacking black spots ; by its smaller 

 scales. From S. fonthialis, or the common brook-trout, it can be distin- 

 guished by the uniform color of the back; its unsi)otted fins, (tail in- 

 cluded;) slightly larger scales; small, conical head; slender body; small 

 size of the light spots along the flanks, and by the colors, as given. 



