FISHES OF THE GULF OF MAINE 505 



north of Cape Cod as well. Welsh also concluded from measurements gathered 

 from various sources that they are 5 to 7^ inches at 2 years of age, 7^ to 9J^ 

 inches at 3 years, and 9H to 10 inches long when 4 years old. Probably they mature 

 sexually at 3 years, for most of the spawners are upwards of 8 inches long. 



Breeding habits. — The winter flounder is a winter and early spring breeder, 

 spawning from January to May, inclusive, in New England. South of Cape Cod 

 and in the Massachusetts Bay region the season is at its height during February 

 and March, 79 but is somewhat later along the coast of Maine, for spawning com- 

 mences about March 1 near Boothbay and continues there imtil about May 10 or 

 15 with the chief production of eggs usually taking place from March 20 to April 20, 

 according to information supplied by Capt. E. E. Hahn, superintendent of the 

 Boothbay hatchery. This local difference in the spawning season is probably due 

 to differences in the temperature of the water, and after the severe winter of 1922- 

 23, when an imusual amount of ice formed and consequently when the vernal warm- 

 ing of the coastwise waters was slower than usual, Captain Hahn writes that "the 

 fish were 10 to 15 days later in spawning than in any previous year, the first eggs 

 being taken on March 24." 



Spawning takes place on sandy bottoms in 1 to 3 fathoms of water and through- 

 out the range of the fish including the Bay of Fundy, where Huntsman found its 

 larvre common near the mouths of estuaries. On the average individual females 

 produce about 500,000 eggs annually, and nearly 1,500,000 have been taken from a 

 large one of 3% pounds weight. Spawning is at its height while the water is at its 

 coldest for the year, this being about 32° to 35° in the Woods Hole region, about 32° 

 to 37° at Gloucester, and 31° to 35° near Boothbay according to precise locality and 

 depth. The major production of eggs takes place before the water has warmed 

 above 38° with 40° as perhaps the maximum for any extensive spawning. Cor- 

 responding to the estuarine or at least the inshore location of the spawning grounds 

 the salinity is likewise low, and "the winter flounder is even known to spawn in 

 brackish water. For instance breeding has been observed near Woods Hole in 

 water as little saline as 11.43 per mille, and the maxim urn salinity in which winter 

 flounder eggs are produced in the Gulf of Maine probably is not higher than 32.3 

 per mille. Winter flounders in the Woods Hole tanks (probably in nature too) 

 spawn at night. 80 



This species is peculiar among our local flatfish (or those whose breeding habits 

 are known) in the fact that its eggs are not buoyant but sink to the bottom, where 

 they stick together in clusters, usually so closely massed that the individual eggs 

 are forced into irregular outlines. They are 0.74 to 0.85 mm. in diameter. Newly 

 shed eggs have no oil globule but some, if not all, develop one as incubation pro- 

 ceeds. 31 Incubation occupies 15 to 18 days at a temperature of 37° to 38°, which 

 is about what they encounter in nature. The young larvae, which are 3 to 3.5 mm. 

 long at hatching, are marked by a broad vertical band of pigment cells dividing 

 the post anal part of the body into two parts, a very characteristic feature, and the 



■> This species is artificially propagated in large numbers at Woods Hole, Gloucester, and Boothbay hatcheries with an out- 

 put of 1,603,080,000 fry in 1920. 



» Breder (Copeia, Jan. 25, 1922, No. 102, p. 3) describes the act of spawning. 



8 > Breder. Bulletin, 0. S. Bureau of Fisheries, Vol. XXXVIII, 1921-22 (1923), Fig. 274g. 



