Direct Growth Measurements of Two Deep-sea Scalpellid BarnaclesScalpellum stearnsii and Graviscalpellumpedunculatum

摘要

Little isknown about the growth rates of invertebrates living in ordinary deep-sea habitats such ascontinental slopes. Thus, the growth rates of two species of the deep-sea scalpellidbarnacles, and , were studied in two aquaria (at Nara and Okinawa Churaumi,Japan). In addition, growth of an individual after 1 year ofdeployment was measured in the field. Overall, adult individuals of both species showedslow growths over 8 months (at Nara) and 2 years (at Okinawa) of rearing( , at Nara: 2.0 ± 3.6 μm d for and 5.9 ± 2.7 μm d for ; mean ± SD).In contrast, growth rates of juvenile at Nara were greater(15 ± 7.7 μm d ). The growth rate of the adult (3.4 μm d ) was greater than the average, butwithin the range of the rates of similar-sized individuals recorded in aquaria. Comparedwith other pedunculate barnacles, both species show small growth rates typical fordeep-sea animals.