FISHES OF THE GULF OF MAINE 57 



1. 13 miles from Gloucester, 2,540 baited hooks. Total fish caught, 540; 

 skates, 65; dogfish, 321. 



2. 15 miles off Monhegan, June 24-25, 1913. Total fish caught, 5,463; skates, 

 170. 



3. 20 miles east of Cape Cod, November 11, 1913. Total fish caught, 6,532; 

 skates, 202. 



4. Jeffreys Ledge, December 11-12, 1913. Total fish caught, 3,996; skates, 62. 

 Now and then a long line comes in with a skate on almost every hook, but this 



is unusual. Fishermen report them as present on the inshore as well as the offshore 

 fishing grounds throughout the year. 



On our seaboard skates are salable only in special markets and are of so Uttle 

 commercial importance that in 1919, which may serve as a representative year, 

 the total amount brought into the several ports of Maine, New Hampshire, and 

 Massachusetts was only 102,739 pounds, valued at $550. From time to time a 

 few have been utilized as fertilizer. All others caught are thrown overboard. 



All our common Gulf of Maine skates are oviparous, laying large eggs with 

 blackish or sea-green leathery sheUs, roughly oblong in outline with a hollow tendril 

 at each corner by which they cling to seaweeds. The empty egg sheUs — "mer- 

 maids' purses" — are common on our beaches among the fiotsam along high-water 

 mark. 



While still in the egg the embryos develop temporary external gill filaments 

 from the walls of the giU clefts, but these disappear completely after hatching. 



Many years ago Wyman (1867) published some notes on the development of 

 one of our local skates (species not named) and figured the newly hatched young, 

 since which time no attention has been paid to the development or life history of 

 any of the species that occur in the Gulf of Maine. Probably, however, all spawn 

 over a considerable part of the year with an incubation period of from 4 to 8 

 months, as is true of most of the European skates."" The sting rays are viviparous, 

 but it is not likely that any of these strays from the south breed in the Gulf of 

 Maine. 



It is easy to tell a skate from a ray (at least among species with which we are 

 concerned) by the presence or absence of a dorsal spine on the tail, while its large 

 caudal fin places the torpedo at a glance, but identification of the several skates is 

 proverbially difficult. In the following key we have endeavored to facilitate it by 

 characters obvious in handhng them at sea or on the dock. 



KEY TO GULF OF MAINE SKATES AND RAYS 



1. No lopg dorsal spine on the tail . 2 



Tail with long dorsal spines (sting rays) 8 



2. Two small dorsal fins, but no distinct caudal on the tail (includes all our common skates) . 3 

 There is a large triangular caudal fin as well as the two dorsals on the tail.. Torpedo, p. 68 



3. The midline of the ba«k, immediately over the backbone behind the shoulders, does not 



bear a row of large thorns, though it may be flanked by such 4 



The midline of the back bears a row of large thorns on the rear part of the disk, on the 

 tail, or on both 5 



<• Clark (Journal of the Marine Biological Association of the United Kingdom, New Series, Vol. XII, No. 4, Oct., 1922, p. 629) 

 described the eggs and young fry of several British species. 



