268 BULLETIN OF THE BUREAU OP FISHERIES 



Breeding habits. — Along southern New England scup spawn from May to 

 August — chiefly in June. Probabty spawning both commences and continues later, 

 in the case of the few fish that manage to summer in Massachusetts Bay, and it 

 may be assumed that the fish spawn wherever they summer. 



The eggs are buoyant, transparent, spherical, rather small (about 0.9 mm. in 

 diameter), and with one oil globule. Incubation occupies only about 40 hours 

 a't 72° — probably two to three days in the June temperatures of Massachusetts 

 Bay — and judging from the season of spawning at Woods Hole, it is not likely that 

 development can proceed normally in water colder than about 50°. At hatching 

 the larvae are about 2 mm. long, the yolk is fully resorbed within three days when 

 the larva is about 2.8 mm. long, and there is then a characteristic row of black 

 pigment spots along the ventral margin of the trunk. Fry of about 10 mm. show 

 the dorsal and ventral fin rays. At 25 mm. the pectorals have assumed their 

 pointed outline and the caudal fin is slightly forked, but the ventrals are still so 

 small and the body so slender that the little fish hardly suggest their parentage 

 until somewhat larger. 28 



Rate of growth. — In southern New England fry of 2 to 3 inches, evidently 

 the product of that season's spawning, have been taken in abundance as early as 

 September. In October they are 2)4, to 334' inches long, and may be as long as 4 

 inches at Woods Hole in November. Apparently young scup grow very little 

 during the winter, for in spring the large mature fish are soon followed by small ones 

 of 4 to 6 inches, probably the crop of the preceding season. It has been generally 

 assumed, following Baird (1873, p. 228), that the large fish of 12 to 14 inches, 

 weighing from \y<i to 2y 2 pounds, are 3 to 5 years old, but no growth studies based 

 on the scales or other exact data have been attempted for this fish. 



102. Sheepshead (Archosargus probatocephalus Walbaum) 



Jordan and Evermann, 1896-1900, p. 1361. 



Description. — The sheepshead so closely resembles the scup in its general 

 organization that the family relations between the two are obvious. Like the scup 

 it is deep bodied and much compressed, with similar profile. There is one long 

 dorsal fin, scuplike in outline, of which the anterior two-thirds is spiny (12 spines) 

 and the posterior one-third is soft (10 to 12 rays). The anal fin (3 spines and 

 10 to 1 1 rays) is about as long as the soft portion of the dorsal, under which it stands, 

 and both dorsal and anal can be depressed in deep grooves. The pectorals are long 

 and pointed, the ventrals are situated slightly behind the latter, the scales are 

 large, and the eyes are located high on the sides of the head, in all of which the 

 sheepshead agrees with the scup. It is readily recognized, however, by the fact that 

 its caudal fin is not so deeply emarginate as that of the scup, and has rounded and 

 equal corners instead of pointed and unequal ones, while its dorsal spines are alter- 

 nately stout and slender, its second anal spine much stouter than that of the scup, the 

 dorsal profile of its head is steeper, its nose is blunter, and its teeth are much broader. 

 Furthermore, the body of the sheepshead is noticeably thicker and the back is 



" Kuntz and RadcliBe (1918, p. 106) describe the early development ol the scup. 



