RICHARDSON and LAROCHE. DEVELOPMENT AND OCCURRENCE i iF ROCKFISHES 



flexion, larvae. Developmental series could not be 

 carried back to newly extruded larvae in the 

 plankton samples with certainty. Pigmentation is 

 the primary character used to distinguish small 

 larvae prior to development of fin rays and head 

 spines. Pigment patterns of newborn larvae are 

 often similar among a number of species and these 

 patterns may change considerably by the time the 

 yolk is absorbed (Westrheim 1975: Moser et al. 

 1977). Preextrusion and newborn larvae have 

 been described for 29 of the 36 species o{ Sebastes 

 off Oregon, but larvae reared to yolk absorption 

 have only been described for 15 (Table 1). The 

 number of species which have patterns similar to 

 those that have been described is unknown. Rear- 

 ing larvae of the remaining species to yolk absoi-p- 

 tion will be necessary to provide an adequate 

 foundation for identification of small larvae in 

 plankton samples. We had no opportunity to rear 

 larvae from known parents. 



Meristics" 



Counts were made on unstained material as not 

 enough specimens were available to make com- 

 plete stained series for developmental ossification 

 studies. [One to several pelagic juveniles of S. 

 crameri , S. pinniger, and S. helvomaculatus were 

 stained with alizarin red S (Taylor 1967) for 

 examination of general bone structure, spination, 

 and secondary caudal rays.] Fin spines and rays 

 were only counted when they appeared to be fully 

 formed structures under magnification, which 

 may approximate initial ossification. Bases of fin 

 rays, visible prior to actual ray formation, were 

 not counted. In Sebastes , the 13th dorsal spine and 

 the 3d ana! spine form first as soft rays which then 

 transform to spines beginning at the basal portion 

 and continuing distally. These were considered to 

 be "prespines" until spine formation was com- 

 plete. 



Counts were made of dorsal fin spines and rays, 

 anal fin spines and rays, pectoral fin rays, pelvic 

 fin rays, principal caudal fin rays, gill rakers on 

 the upper and lower limb of the first gill arch, 

 lateral line pores, and diagonal scale rows below 

 the lateral line. In some cases Inda ink was applied 

 to the right side of a fish to increase visibility of the 

 latter two features. 



^The term "meristic" is used here to refer to all countable 

 characters. 



Morphometries 



Measurements of various body parts of selected 

 specimens were made to the nearest 10th or 100th 

 of a millimeter using an ocular micrometer in a 

 stereomicroscope as follows: 



Standard length (SL) = snout tip to notochord 

 tip preceding development of caudal fin, then to 

 posterior margin of hypural plate. 



Snout to anus length = distance along body mid- 

 line from snout tip to vertical through posterior 

 margin of hindgut at anus. 



Head length (HL) = snout tip to cleithrum until 

 no longer visible, then to posteriormost margin of 

 opercle (SL of 30.3 mm on S. crameri, 16.8 mm on 

 S. pinniger, 41.6 mm on S. helvomaculatus). 



Snout length = snout tip to anterior margin of 

 orbit of left eye. 



Upper jaw length = snout tip to posterior mar- 

 gin of maxillary. 



Eye diameter = greatest diameter of left orbit. 



Interorbital distance = distance between dorsal 

 margins of orbits. 



Body depth at pectoral fin base = vertical dis- 

 tance from dorsal to ventral body margin at base of 

 pectoral fin. 



Body depth at anus = vertical distance from 

 dorsal to ventral body margin immediately poste- 

 rior to anus. 



Pectoral fin length = distance from base to tip of 

 longest ray. 



Pectoral fin base depth = width of base of pec- 

 toral fin. 



Pelvic spine length = distance from base to tip of 

 pelvic spine. 



Pelvic fin length = distance from base to tip of 

 longest ray. 



Snout to origin of pelvic fin = distance along 

 body midlme to vertical through insertion of pel- 

 vic fin. 



Parietal spine length = distance along posterior 

 margin of parietal spine from insertion to tip. 



Nuchal spine length = distance along posterior 

 margin of nuchal spine from insertion to tip. 



Preopercular spine length (third spine, posteri- 

 or series) = distance from tip to basal insertion if 

 visible, or to a line connecting the points of deepest 

 indentation between preopercular spines 2 and 3 

 and spines 3 and 4 (posterior series). 



Length of angle gill raker = distance from tip 

 of gill raker to point of articulation with gill 

 arch. 



