FISHES OF THE GULF OF MAINE 



281 



Figure 143. — Larva, 5 mm. 



Figure 141. — Egg. 



Figure 142. — Larva, 4.5 mm. Figure 144. — Larva, 8 mm. 



Winter flounder (Pseudopleuronectes americanus.) 



The youngest larval stages are made indentifi- 

 able as winter flounders by the pigment bar just 

 mentioned. After the fin rays appear their small 

 mouth separates them from any of the large- 

 mouthed flounders; their short, deep body, com- 

 bined with the small number of fin rays, separates 

 them from the witch; and the number of fin rays 

 marks them off from the yellow tail (p. 273). The 

 winter flounder also completes its metamorphosis 

 at a smaller size than either of these other small- 

 mouthed flatfishes (pp. 287 and 273). 



The rate of development of the larvae is gov- 

 erned by temperature, occupying from about 2}i to 

 about 3% months, according to the data available, 

 and the larvae that are hatched later may catch 

 up with the earlier hatched ones before their meta- 

 morphosis takes place. Larvae in their later stages 

 have been taken in abundance in the tow nets at 

 Woods Hole. But their habits in aquaria suggest 

 that they are less at the mercy of the tide and 

 current than our other flatfishes are, for they have 

 been described as alternately swimming upward 

 and then sinking, to lie for a time on the bottom, 

 instead of remaining constantly adrift near the 

 surface, as the larvae of most of the flatfishes do 

 at a corresponding stage in their development. 

 At any rate, we have not taken any in our tow- 

 ings in the open Gulf 63 that were certainly iden- 

 tifiable as winter flounder. 



Judging from a large aeries from Casco Bay, 

 measured by Welsh, and from others seen by us 

 off near Boothbay Harbor and at Mount Desert, 

 the fry of the previous winter grow to an average 

 length of \% to 3% inches by August, with an 

 occasional specimen as long as 4 inches; they are 

 2 to 4 inches long by the end of September; and 

 4 to 6 inches long off southern New England in 

 January and February, when nearing 1 year old, 

 which probably applies north of Cape Cod as well. 

 They may grow somewhat faster in more southern 

 (warmer) waters, as in Chesapeake Bay, where fish 

 of the year are 4% to 7 inches long in January and 

 February. 6 * 



Welsh also concluded, from measurements 

 gathered from various sources, that the winter 

 flounders are 5 to 7K inches in length at 2 years of 

 age, iy% to 9% inches at 3 years, and 9% to 10 inches 

 long when 4 years old, which accords with 8 to 10 

 inches at 2 to 3 years in New York waters as 

 reported by Lobell 65 and by Perlmutter. 68 Prob- 

 ably they mature sexually at 3 years, for most of 

 the spawners are upwards of 8 inches long. Our 

 only information as to the rate of growth of older 

 fish is that one tagged near Block Island, 

 April 17, 1941, when it was 10% inches long, was 

 17 inches long when it was recaptured on Georges 

 Bank, 4 years and 4 months later. 



'i Three larvae taken in the Quit in July 1912, were provisionally identified 

 by Welsh as this species. 



210941—53 19 



« Hildebrand and Schroeder, Bull. U. S. Bur. Fish., vol. 43, Pt. 1, 1928, 

 p. 169. 

 « 28th Rept., New York Conserv. Dept. 1939, Sup., Pt. I, p. 86. 

 " Bull. Bingham Oceanogr. Coll., vol. 11, Art. 2, 1947, p. 17. 



