FISHERY BULLETIN; VOL. 78, NO. 4 



proximately 220 m (Miller and Lea 1972). 

 Planktonic larvae of M. proximus were the 

 dominant gadid and fourth most abundant taxon 

 in a coastal assemblage offish larvae occurring off 

 Yaquina Bay, Oreg., in 1971-72 (Richardson and 

 Pearcy 1977). 



Information on the biology and taxonomy of M. 

 proximus is limited. Schultz and Welander (1935) 

 presented counts of meristic structures and mor- 

 phological measurements of M. proximus. 

 Svetovidov (1948), in his review of Gadiformes, 

 provided some meristic data and a brief os- 

 teological description of M. proximus based on two 

 skeletons. Brief notes on the biology of the species 

 are included in Clemens and Wilby (1961), Miller 

 and Lea (1972), and Hart (1973). It is not of com- 

 mercial importance in part because of its small 

 size (to 30 cm) but it is taken in recreational 

 catches (Beardsley and Bond 1970; Hart 1973). 



METHODS 



Specimens 



Several hundred larvae of the three species were 

 examined in the course of this study. Microgadus 

 proximus larvae and juveniles were obtained from 

 plankton and trawl samples collected off Oregon 

 in 1971-1973 and 1979, by the School of Oceanog- 

 raphy, Oregon State University (OSU), Corvallis, 

 and off Washington in 1972 by the Northwest and 

 Alaska Fisheries Center (NWAFC). Additional 

 specimens were obtained from plankton collected 

 in Puget Sound, Wash., in 1977-79 by the Fisheries 

 Research Institute (FRI), University of Washing- 

 ton, Seattle; and in 1978 by Ecology Consultants, 

 Inc., Fort Collins, Colo. Larvae were also collected 

 from near Kodiak Island, Alaska, in 1977-79 by 

 FRI. 



Theragra chalcogramma larvae were collected 

 in the eastern Bering Sea (1971, 1976-78) and off 

 Kodiak Island (1972, 1977-78) by NWAFC. Ad- 

 ditional specimens from Puget Sound, Wash., 

 ( 1977, 1978) were provided by FRI and by Ecology 

 Consultants, Inc., and from off Kodiak Island 

 (1978) by FRI. 



Gadus macrocephalus larvae were collected 

 near Kodiak Island in 1978 by NWAFC and FRI 

 and from Puget Sound, Wash., in 1977-79 by FRI. 



Radiographs were examined of juvenile and 

 adult M. proximus and G. macrocephalus speci- 

 mens in the collections in the Department of 

 Fisheries and Wildlife, OSU, and NWAFC, and of 



adult T. chalcogramma specimens at NWAFC and 

 from the Institute of Animal Resource Ecology, 

 University of British Columbia, Vancouver. 



Illustrations of larvae were made with the aid of 

 a camera lucida. All specimens had been preserved 

 in either 3-5% Formalin,*^ buffered with sodium 

 borate, or 95% ethanol. Illustrations of caudal fin 

 development were drawn from cleared and stained 

 specimens. 



Measurements 



The following measurements were made on 72 

 unstained larvae and juveniles (2.7-46.6 mm SL) 

 of M. proximus using an ocular micrometer in a 

 stereomicroscope: 



Standard length (SL) — Snout tip to notochord tip 

 prior to development of caudal fin, then to pos- 

 terior margin of hypural element. (All body 

 lengths in this study are standard lengths.) 



Head length (HL) — Snout tip to posterior edge of 

 opercle (to pectoral fin base in yolk sac and very 

 small larvae before opercular margin is visible). 



Snout length — Snout tip to anterior margin of 

 orbit of left eye. 



Upper jaw length — Snout tip to posterior margin 

 of maxillary. 



Eye diameter — Greatest diameter of left orbit. 



Body depth at pectoral — Vertical distance from 

 dorsal to ventral body margin at pectoral fin 

 base. 



Body depth at anus — Vertical distance from dor- 

 sal to ventral body surface at center of anal 

 opening. 



Snout to anus — Distance along body midline from 

 snout tip to vertical through center of anal open- 

 ing. 



Snout to first dorsal fin — Distance along the body 

 midline to vertical through origin of anterior- 

 most dorsal fin ray of first dorsal fin. 



Snout to second dorsal fin — Distance along body 

 midline to vertical through origin of anterior- 

 most fin ray of second dorsal fin. 



Snout to third dorsal fin — Distance along body 

 midline to vertical through origin of anterior- 

 most fin ray of third dorsal fin. 



Snout to first anal fin — Distance along body mid- 

 line to vertical through origin of anteriormost 

 fin ray of first anal fin. 



^References to trade names do not imply endorsement by the 

 National Marine Fisheries Service, NOAA. 



924 



