Departmental Bulletin Paper トクビレ科ヤギウオPallasina barbata(Steindachner,1876)の繁殖生態と形態発育
Reproductive Ecology and Morphological Changes during the Early Life Stages of Pallasina barbata(Steindachner,1876)

百田, 和幸  ,  宗原, 弘幸

67 ( 1 )  , pp.7 - 12 , 2017-03-15 , 北海道大学大学院水産科学研究院
Aspects of the reproductive ecology and early life history of the tubenose poacher Pallasina barbata(Steindachner,1876) were clarified based on observations on the development of eggs without artificial insemination and on morphological changes of larvae and juveniles. The reproductive mode was identified as internal gametic association, which has been reported in several cottoids. The inferred spawning periods and hatching periods were May and March, respectively, suggesting the embryonic period lasted 10 months, which is near the longest known among the Agonids. The eggs were found in the sponge Mycale adhaerens. Newly-hatched larvae were in the flexion stage, and the notochord length(NL) was 7.3mm. In the flexion larvae stage, two white spots occurred in the dorsal finfold, which have not been reported in larvae of other Agonids. Extension of the snout and protrusion of the lower jaw barbel began from 11.7mm NL at post-flexion. At 20.2mm standard length(SL), the finfold had disappeared, and all the fin ray number attained the fixed number. The scale number of bony plates reached the same number as in the adult at 28.7mm SL.

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