FISHERY BULLETIN: VOL. 80, NO. 2 



Table 1.— Age and sibling relationships for Ascelichthys rho- 

 dorus larvae used for descriptions. 



'1 = siblings, all one age. same source. 

 2=2 sibling groups, mixed age, different source. 



juveniles from both tanks were reared to matur- 

 ity at the Vancouver Public Aquarium. 



Taxonomic Specimens 



Measurements 



The following measurements were made on 64 

 unstained larvae of A. rhodorus (5.9-15.8 mm SL) 

 using an ocular micrometer in a stereomicro- 

 scope: 



Standard length (SL)— Snout tip to notochord tip 

 prior to development of caudal fin, then to 

 posterior margin of hypural bones. 



Head length (HL)— Snout tip to posterior mar- 

 gin of opercle. 



Snout to anus length— Distance along body mid- 

 line from snout tip to a vertical line through 

 center of anal opening. 



Body depth at pectoral— Vertical distance from 

 dorsal to ventral body margin at pectoral fin 

 base. 



Meristic Structures 



A total of 49 larvae was cleared and stained for 

 observation of various meristic structures and 

 sequence of bone ossification. The following size 

 ranges inadvertently were not preserved and are 

 not represented in our discussion: 9.5-10.0 mm 

 SL and 11.5-12.5 mm SL. Bone terminology fol- 

 lows Richardson and Washington (1980). 



Specimens were stained using alizarin red and 

 alcian blue (Dingerkus and Uhler 1977). Struc- 

 tures were considered ossified even if only 

 slightly stained with alizarin red. Counts on 

 stained larvae were made of dorsal fin spines and 

 rays, anal fin rays, left pectoral fin rays, caudal 



fin rays, branchiostegal rays, and abdominal and 

 caudal vertebrae (including the terminal ural 

 centrum). Counts of caudal fin rays in juvenile 

 and adult A. rhodorus were made from radio- 

 graphs of six specimens (46-101 mm SL) from 

 the collections in the College of Fisheries, Uni- 

 versity of Washington, Seattle. Twenty adult 

 specimens (57-99 mm SL) were also cleared and 

 stained for examination of the caudal fin. 



The problems and inconsistencies of head 

 spination terminology in cottid larvae have been 

 discussed by Richardson and Washington (1980). 

 We follow their terminology by using names pro- 

 posed for Sebastes spp. (Richardson and Laroche 

 1979). Head spines for A. rhodorus larvae were 

 examined on cleared and stained specimens in 

 order to determine the origin of the spines. 



Illustrations of larvae were made with the aid 

 of a camera lucida. 



IDENTIFICATION OF 

 ASCELICHTHYS RHODORUS 



The eggs of A. rhodorus range from 1.7 to 2.0 

 mm in diameter. Larvae hatch at approximately 

 6.0 mm SL and the yolk is absorbed by 6.5 mm 

 SL. Notochord flexion begins between approxi- 

 mately 8.8 and 9.0 mm SL and is usually com- 

 plete by 11.0 mm SL. Transforming larvae 

 (about 12.0-13.0 mm SL) were distinguished by a 

 combination of characters including changes in 

 pigmentation and ossification of fin rays. Our 

 largest specimens (15.0-18.0 mm SL) were newly 

 settled and exhibited increased juvenile pigmen- 

 tation. 



The work of Richardson (1981) attempts to 

 organize the cottid genera from the northeast 

 Pacific that have been divided into phenetic 

 groupings based on larval characters. In the 

 northeast Pacific, larvae of 25 of 40 genera are 

 described and most of the genera can be placed in 

 6 groups. Several genera are ungrouped (e.g., 

 Enophrys, Gymnocanthus, and Myoxocepha- 

 lus). 



The present study indicates that Ascelichthys 

 is most similar to the genera of Richardson's 

 Group 2 (Paricelinus, Triglops, Icelus, Chitono- 

 tus, and Icelinus) which all possess the following 

 characters: 1) moderately slender body form; 2) 

 pointed snout; and 3) four prominent preopercu- 

 lar spines. Most members of this group also have 

 postanal ventral midline melanophores some- 

 times extending along the caudal fin base. 

 Although Richardson considers Group 2 coher- 



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