320 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



the first part of November the fish begins to withdraw from the deepest 

 water of the lake and may be taken at depths of CO to 80 fathoms. 

 The number of fish in water of that depth increases with the advance 

 of winter, and when fishing; is brought to a close by the formation of 

 ice the fish are at the height of their abundance. When the ice breaks 

 up between February and April the fish begin to move into deeper 

 water, and by May fishing is done in water 100 or 110 fathoms deep. 

 During the warmer mouths this is about the minimum depth at which 

 the blackfins are regularly found. 



A favorite resort for the blackfin is Mud Hole, a large depression in 

 the bottom of the lake, located about 20 miles east of Sheboygan ; it is 

 7 or 8 miles square and about 90 fathoms deep. Another ground that 

 is frequented by large bodies of blackfins is Grand Traverse Bay, on 

 the east side of Lake Michigan. 



17. Argyrosomus tullibee (Richardson). 

 Tullibee; Mongrel Whitefisii. 



Salmo (Coregonus) tullibee Richardson, Fauna Bor.-Auier., m, 201, 1836, Cumberland 

 House, Pine Island Lake. 



Description. — Head, 4 to 4£; depth, 3 to 3|; eye, 4 to 5; snout, about 5. 

 Dorsal fin with about 11 developed rays, the number varying from 10 

 to 12; anal, 11 or 12. Maxillary, 3£ in head; mandible, 2 to 2^; scales, 

 9-68 to 71-8; gillrakers, 10 to 18+30 to 34; 1-1£ in eye. 



Body short and deep, compressed, the dorsal and ventral outlines 

 similarly curved. Head small, conic and compressed; mouth large, 

 lower jaw projecting; middle of upper lip on a level with middle of 

 pupil, maxillary long, moderately broad, reaching anterior edge of pupil, 

 the width about one-third its length; supplemental maxillary bone well 

 developed, nearly half length of maxillary, its width 2f times in its 

 length ; mandible long, reaching posterior edge of pupil. Distance from 

 tip of snout to occiput half that from occiput to origin of dorsal fin, 

 which is midway between tip of snout and base of caudal fin. Caudal 

 peduncle short, compressed and deep, its least depth about 2^ in head. 

 Fins rather large; height of dorsal, li in head; base of fin, If in longest 

 ray; anal base very oblique, equal to length of longest ray, which is 

 about equal to base of dorsal fin; pectorals and ventrals long, almost 

 equal to height of dorsal. Scales firm, considerably enlarged anteri- 

 orly; free margin of scales less convex than in other species, often 

 emarginate, especially on anterior part of body; lateral line straight 

 and in a line with upper rim of orbit. Tongue with a patch of fine 

 teeth near the tip. Gillrakers numerous, long and slender, the number 

 varying from 47 to 52. Color iridescent bluish above, sides and under 

 parts silvery; older individuals darker above and with more golden 

 reflection on sides; fins all more or less evidently black-tipped; upper 

 edge of pectoral margined with black. 



