166 BULLETIN OF THE BUHEAU OF FISHEKIES 



It is not likely that it ever spawns in the cool waters of the Gulf of Maine, 

 for we have never taken its fry in our tow nets, although they are among the~most 

 numerous of young fish in the open Atlantic between the latitudes of 11° or 12° 

 and 40°N. It certainly spawns in the open sea, probably at the surface. Although 

 its eggs have been described as covered with filaments like those of the silver gars, ^* 

 they are not adhesive like the latter, but pelagic. The most interesting phase in 

 the development of the skipper is that the jaws do not commence to elongate until 

 the fry have attained a length of about 40 mm., and that the lower outstrips the 

 upper at first, so that fry of 100 to 150 mm. look more like halfbeaks (Hemiramphus 

 stage) than like their own parents. 



Food. — European students tell us that the skipper feeds on the smaller pelagic 

 Crustacea and probably also on small fish, for it is sometimes caught on hook and 

 line. One examined by Doctor Linton at Woods Hole contained chiefly annelids, 

 fragments of fish and vegetable debris, a few copepods, and crustacean larvae. 



Commercial importance. — The needlefish is not of much commercial importance, 



being too sporadic in its appearances. However, when large catches are made on 



Cape Cod they find ready sale to the local Portuguese population. If too many are 



caught for the local trade to absorb, they are sent to Boston, where they are sold 



for bait. 



THE STICKLEBACKS. FAMILY GASTEROSTEID^ 



Sticklebacks are rather small fish, easily recognizable by the presence of three 

 or more stout free spines on the back in front of the dorsal fin — spines that they 

 can erect or depress at will — and by the fact that each ventral fin is represented 

 by an even larger spine with but one or two rudimentary rays. Bony plates may 

 or may not be developed in the scaleless skin. The GuK of Maine species may be 

 named by the following key: 



KEY TO GULF OF MAINE STICKLEBACKS 



1. Not more than five large dorsal spines 2 



Seven or more dorsal spines Nine-spined stickleback, p. 166 



2. No bony plates on the upper sides, but there is a bony ridge on either side of the 



abdomen Four-spined stickleback, p. 171 



The upper sides are armed with bony plates, and there is a plate in the midline of the 

 belly, but there are no ridges on the sides of the abdomen 3 



3. Many (28 or more) plates on each side Three-spined stickleback, p. 168 



Only 5 or 6 plates on a side Two-spined stickleback, p. 171 



63. Nine-spined stickleback (Pnngitius pungitius Linnseus) 



Jordan and Evermann, 1896-1900, p. 745. 



Description. — The nine-spined stickleback is a slender little fish 5 to 6 times as 

 long (not counting caudal rays) as deep with very slim caudal peduncle, the latter 

 usually with a well-developed keel on either side. Occasionally, however, this keel 

 is very low or wanting. There are no bony plates along the sides of the body, 



•* Skipper eggs were so described by Haeckel (Archiv fiir Anatomie, Physiologie, und Wissenschaftliche Medecin, herausgegeben 

 von Dr. Johannes Miiller, Jahrgang 1855, p. 23, Taf. V, fig. 15. Berlin) 75 years ago. They were not seen again unti] 1910, when 

 similar eggs, 2.2 mm. in diameter, covered with filaments, were towed in the Atlantic by the Michael Sars (Murray and Hjort. 

 The Depths of the Ocean, 1912). 



