FISHERY BULLETIN: VOL. 78, NO. 4 



Table l. — Summary of adult meristic counts for MicrogaduK proximua, Thcragra chal- 

 cogramma, and Gadus macrocephalus. Data for T. chalcogramma is after Wilimovsky et 

 al. (1967)' except where noted. 



'From Wilimovsky, N. J.. A. Peden, and L. Peppar. 1967. 

 Pacific Ocean. Fish. Res. Board Can.. Tech. Rep. 34, 95 p. 

 ^From this study. 



Systematics of six demersal fishes of the North 



Table 2. — Distribution of caudal rays on the superior hypural 

 element in Microgadus proximus, Theragra chalcogramma. 

 andGadus macrocephalus (Walters' and this study). 



'G. E. Walters, College of Fisheries, University of Washington, Seattle, WA 

 981 15, pers. commun. January 1979. 



development, and by 16.0 mm SL it becomes more 

 concentrated on the jaws, jaw angle, snout, be- 

 tween the eyes, and over the head extending to the 

 nape (Figure 2A). Several melanophores appear 

 ventrally along the median cartilage between the 

 dentaries and urohyal. With transformation 

 (completion of fin development) at 22.0-28.0 mm 

 SL, small and densely concentrated melanophores 

 are added to the jaws and dorsal head (Figure 2B). 

 The opercular area is unpigmented. 



Gut Region 



Melanophores line the dorsal surface of the gut 

 cavity in the smallest larva (2.7 mm SL), and 

 several spots are on the ventral abdominal surface 

 anteriorly. The isthmus is pigmented by 4.0 mm 

 SL. Melanophores increase in number on the dor- 

 sal and ventral gut surface with development. 

 Melanophores are added laterally, occurring first 

 anteriorly near the base of the pectoral fin at 5.0 

 mm SL (Figure IB). The melanophores on the ven- 

 tral surface of the gut extend more posteriorly, 

 forming a rough line nearly to the anus by 8.0 mm 

 SL (Figure IC, D). Gut pigmentation changes 



little through transformation, except for ad- 

 ditional melanophores on the lateral surface (Fig- 

 ure 2A). In early juveniles, the lateral pigment is 

 more internal than external and the overlying 

 skin is unpigmented (Figure 2B). Along the ven- 

 tral surface of the gut is a single row of small 

 melanophores. The base of the pectoral fin is pig- 

 mented. 



Postanal Region 



Pigment in the postanal region is an important 

 diagnostic character for M. proximus larvae. The 

 smallest larvae (2.7-3.6 mm SL) have two pigment 

 bars, anterior and posterior. The stripes within the 

 pigment bars are double rows of melanophores 

 with pigment on both sides of the body along the 

 dorsal and ventral midline. At first, the dorsal 

 stripes consist of only 1 or 2 melanophores on each 

 side, but increase to 2 or 3 anteriorly and 6-8 

 posteriorly by 3.6 mm SL (Figure 1 A). The ventral 

 stripes on each side have 4 or 5 spots anteriorly 

 and 7 or 8 spots posteriorly by 3.6 mm SL (Figure 

 lA). At 3.6 mm SL the anterior bar is located at 

 42-50% SL (myomeres 16-22) and the posterior bar 

 is at 59-72% SL (myomeres 29-37). With develop- 

 ment, melanophores are added along the ventral 

 stripes between the bars, becoming continuous 

 with them by 5.7 mm SL (Figure IB). The two 

 dorsal stripes remain separate until 15.0 mm SL, 

 although occasionally a few melanophores may be 

 seen between them. Pigment is added along the 

 body midline, externally at 7.5 mm SL and in- 

 ternally at 9.5 mm SL (Figure IC, E). Postanal 

 pigmentation changes are minimal for larvae be- 

 tween 10.0 and 14.0 mm SL, except for the addi- 



928 



