Abstract
Caprellids are epifaunal crustaceans, widely distributed in marine environments. The life histories of many temperate caprellids have been described, but the growth pattern of a boreal species has not previously been observed. To fill this gap, a boreal species, Caprella acanthogaster, was reared at 5℃ under laboratory conditions and observed it from hatching to maturation and oviposition. Males were recognizable from instar IV and females from instar V. Female maturation was observed at instar VIII (115 days) and instar IX (126 days), whereas males did not mature morphologically in this study. The females matured at instar IX and oviposited subsequent to molting. These periods from hatching to maturation and oviposition are the longest known among previously reared female caprellids. Caprellids are known to mature rapidly in temperate regions. However, female C. acanthogaster required 4 months to mature at 5℃ while males need an even longer but unknown period. These observations at a low temperature fill a gap in the current information on caprellid life histories.
