FISHERY BULLETIN; VOL, 77. NO, 1 



rays and gill rakers. Spawning is known to occur 

 in the Northern Atlantic area. Eggs have been 

 taken from surface tows in Passamaquoddy Bay, 

 where spawning peaked at bottom temperatures 

 of 9° to 10°C (Battle 1930). In Long Island Sound 

 eggs were found to be most abundant in the upper 

 12 m (Williams 1968). In reviewing the natural 

 history of E. cirnbriuK in the Gulf of Maine, 

 Bigelow and Schroeder (1953) mentioned the pos- 

 sibility of planktonic existence as long as 3 mo. 

 Given such a time span, the complex hydrographic 

 regime of the area might occasionally distribute 

 early stages to the south inshore of the Gulf 

 Stream or even more rarely might transport them 

 via the Gulf Stream to the eastern Atlantic. 



Iceland rocklings are usually light colored, as 

 are fish from the Northern Atlantic and Europe 

 areas. For counts of dorsal and anal fin rays, and 

 vertebrae, Iceland fish have the highest means of 

 all (ignoring the two fish from Africa); perhaps 

 these characters are influenced by temperature, as 

 Iceland has the lowest temperatures of any of the 

 six areas. In numbers of pectoral rays, Iceland and 

 European fish are identical and in gill rakers 

 nearly so, and different from counts of North 

 American ones. Adults at least of the Iceland 

 population may be isolated as Kotthaus and Krefft 

 (1967) did not catch E. cinibritis along the 

 Iceland-Faroe ridge. Enchelyopus cinihrius 

 spawns at least around the southwest coast of Ice- 

 land (Einarsson and Williams 1968). 



The linear range of the fourbeard rocklingalong 

 the coasts of Europe is about as great as along the 

 coasts of North America. We have examined only a 

 small sample, from southern Scandinavia; hence, 

 it is possible that more variation exists than we 

 have recorded. However, we point out that in our 

 sample the color pattern resembles that of Iceland 

 and Northern Atlantic fish, that counts of anal and 

 dorsal fin rays and vertebrae are lower than those 

 in Iceland, and that in numbers of pectoral fin rays 

 and gill rakers Europe and Iceland fish are more 

 like each other than they are like North American 

 populations. Rocklings are known to spawn in 

 European waters [Svetovidov 1 1973) gives several 

 references]. Enchelyopus cimbrius could have 

 reached Europe from the west via the Gulf Stream 

 system; it seems unlikely that east to west disper- 

 sal is possible. 



We do not know whether the West Greenland 

 specimen of E. cimbrius represents a breeding 

 population or a stray. 



The two West African examples are so far re- 



98 



moved from their nearest known neighbors ( Bay of 

 Biscay ) that we forego conjecture as to their origin. 



THE GENERA OF ROCKLINGS 



The rocklings are classified in the subfamily 

 Lotinae of the family Gadidae (Svetovidov 1948) 

 and can be distinguished by the nature of the three 

 dorsal fins, which, although scarcely separated 

 from each other, bear quite different kinds of rays 

 (Figure .5). The first dorsal fin consists of a single, 

 unsegmented ray which is not bilaterally divided 

 (we have examined microscopic sections) and is 

 supported by a strong pterygiophore. The ray is 

 thicker than any others in the dorsal fin and in 

 many species is longer as well. In Enchelyopus 

 cimbrius it is soft, being ossified only proximally. 

 Sharply distinguished from the first and third dor- 

 sal fins is a row of small, unsegmented, bilaterally 

 divided filaments which appear fleshy, although 

 they stain with alizarin. These small rays origi- 

 nate on a compressed ridge that rises from a mid- 

 dorsal groove. Although Bogoljubsky (1908) fol- 

 lowed by Svetovidov ( 1948) did not consider these 

 filaments to be true fin rays they should be consi- 

 dered as such, as examination of an alizarin prep- 

 aration and of sections shows that a simple, os- 

 sified, rod-shaped skeletal support is present for 

 each. The third dorsal fin is composed of ordinary, 

 bilaterally divided, segmented rays, each with a 

 well-developed pterygiophore. 



A second characteristic of the rocklings is the 

 presence on the snout of prominent barbels ithe 

 closest approach to this character among other 

 gadids being a nasal cirrus in Lota ) in addition to 

 the barbel at the tip of the lower jaw. 



Thus, the rocklings are distinguished by two 

 specialized characters and can be considered as a 

 distinct tribe of Lotinae, the Gaidropsarini [clas- 

 sified as a distinct family by some, for example, de 

 Buen (1934)]. 



Although rocklings have been treated under as 

 many as 14 different generic names [see 

 Svetovidov (1973) for synonyms], many 

 ichthyologists (for example, Andriyashev 1954; 

 Norman 1966) follow Svetovidov (1948) in recog- 

 nizing three. More recently, however, five genera 

 have been recognized (Wheeler 1969). How many 

 genera should be recognized and why? 



In his 1948 treatment of the rocklings, 

 Svetovidov provided diagnoses for the three gen- 

 era that he recognized based on barbel number, 

 skull shape, vomerine tooth patch shape, and 



