FISHES OF THE GULF OF MAINE 



273 



habiting the deep water ... in summer, and 

 approaching the shores in winter." 24 as do various 

 other ground fishes that tend to avoid high 

 temperatures. 



If the yellowtails are as stationary as they seem 

 to be, they must be subject to considerable range 

 of temperature from season to season at different 

 depths, in one part of the Gulf or another, from a 

 maximum of about 52°-54° to a minimum of 

 about 33°-36°. And some of them are exposed 

 to still lower temperatures on the Grand Banks, 

 and in the Gulf of St. Lawrence. 



The eggs of the yellowtail, artificially fertilized 

 by Welsh in 1912, and hatched at the Gloucester 

 hatchery, were buoyant, without oil globule, 

 spherical, very transparent, and with a narrow 

 perivitelline space. One hundred eggs measured 

 by him ranged from 0.87 mm. to 0.94 in diameter, 

 averaging about 0.9 mm. The surface of the egg 

 is covered with very minute striations, and the 

 germinal disk is of a very pale buff color while 

 alive. The embryonic pigment gathers in three 

 groups shortly before hatching (which takes place 

 in 5 days at a temperature of 50° to 52°); one 

 group on the head, a second group in the region 

 of the vent, and a third group half way between 

 the vent and the tip of the tail. Unfortunately the 

 fish which Welsh hatched were destroyed accident- 

 ally, so we cannot describe the early larval stages. 

 Larvae of 11 mm. are still symmetrical. But 

 the left eye is already visible above the profile 

 of the head at 14 mm. (fig. 139, Grampus specimen), 

 all the fins are outlined, with their rays present 

 in the final number (76 dorsal and 59 anal in the 

 specimen illustrated). Thus, they show enough 

 of the distinctive characters of the adult for posi- 

 tive identification. 



The early larval stages of yellowtails and of 

 winter flounders resemble one another closely; in 

 fact, it is probable that some of the young flat- 

 fishes pictured by A. Agassiz 25 as winter flounders 

 were yellowtails in reality. But the number of 

 fin rays usually places the larvae in one species 

 or the other after these appear. And the yellow- 

 tail does not take to bottom until upward of 14 

 mm. long, whereas the winter flounder completes 

 its metamorphosis when it is only 8 to 9 mm. long. 



Figure 137.— Egg. 



Figure 138. — Larva, 10.3 mm. 



« Qoode and Bean, Bull. Essex Inst., vol. 11, 1879, p. 6. 



>< Agassiz, Proc. American Acad. Arts, Sci., N. Ser., vol. 6, 1879, pi. 4. 



Figure 139. — Larva, 14 mm. 

 Yellowtail (Limanda ferruginea) 



Captures of young fish 2 to 4 inches long in 

 February; 2% to 4% inches long in April; 2% to 5% 

 inches long in May; 3 to 5 inches long in June; 

 and 3 to 6% inches in July indicate that the yellow- 

 tail grows to an average length of about 5 inches 

 by the time it is one year old. Its subsequent 

 rate of growth has not been traced. 



General range. — North American continental 

 waters, from the north shore of the Gulf of St. 

 Lawrence, the Labrador side of the Strait of 

 Belle Isle, 26 northern Newfoundland (there are 

 specimens from St. Anthony's in the Museum of 

 Comparative Zoology), and the Newfoundland 

 Banks, southward to the lower part of Chesa- 

 peake Bay. 27 It is most plentiful on the western 



» Recent records from the Labrador side of the Strait are of one from Barge 

 Bay, July 29, 1910 (Jeflers, Contrib. Canad. Biol., N. Ser., vol. 7, No. 16, 

 1932, p. 210); and of another taken at Forteau Bay, June 29, 1949, by the Blue 

 Dolphin Expedition, reported to us by Richard H. Backus. 



>' We have records of one taken off Hog Island, Va., In lat. 37° 41' S. (Big- 

 elow and Schroeder, Bull. U. S. Bur. Fisheries, vol. 48, 1939, p. 340). And it 

 was reported from the southern part of Chesapeake Bay by Uhler and Lugger 

 (Rept. Comm. Fish., Maryland, 1876, p. 95; 2d Ed., 1876, p. 79.) 



