Description and Identification of Larval and Juvenile Stenodus leucichthys nelma (Güldenstadt) from Central Alaska

Newly hatched larvae of Stenodus leucichthys nelma ranged from 11.0-11.3 mm total length (TL). By 14 mm TL, pelvic buds developed, and seven to nine caudal-fin rays were visible. By 23 mm TL, the caudal fin had the full complement of 19 principal rays. Fin ray differentiation in the dorsal and anal fins was complete by 32 mm TL. The preanal finfold was retained in specimens at least as large as 60 mm TL. Transition to the juvenile period (loss of all finfold and acquisition of adult counts of fin rays in all fins) occurred by 70 mm TL. Stenodus leucichthys nelma larvae and juveniles can usually be differentiated from Coregonus nasus, C. clupeaformis, C. autumnalis, C. sardinella, and Prosopium cylindraceum by pigmentation patterns, the number of myomeres and anal-fin rays, mouth position and form, and snout-to-vent length.