Vol. 57, 2018 (update: 2018.05.24; 06.14) Direct Growth Measurements of Two Deep-sea Scalpellid Barnacles, Scalpellum stearnsii and Graviscalpellum pedunculatumYoichi Yusa1,*, Natsumi Yasuda1, Tomoko Yamamoto2, Hiromi Kayama Watanabe3, Takuo Higashiji4, Atsushi Kaneko4, Kazuki Nishida5, and Jens T. Høeg6 doi:10.6620/ZS.2018.57-29
1Nara
Women’s University, Kitauoya-nishi, Nara 630-8506, Japan (Received 5 March 2018; Accepted 4 May 2018;
Communicated by Benny K.K. Chan) Yoichi
Yusa, Natsumi Yasuda, Tomoko Yamamoto, Hiromi Kayama Watanabe, Takuo
Higashiji, Atsushi Kaneko, Kazuki Nishida, and Jens T. Høeg (2018) Little
is known about the growth rates of invertebrates living in ordinary
deep-sea habitats such as continental slopes. Thus, the growth rates of
two species of the deep-sea scalpellid barnacles, Scalpellum stearnsii and Graviscalpellum pedunculatum, were
studied in two aquaria (at Nara and Okinawa Churaumi, Japan). In
addition, growth of an S. stearnsii
individual after 1 year of deployment was measured in the field.
Overall, adult individuals of both species showed slow growths over 8
months (at Nara) and 2 years (at Okinawa) of rearing (e.g., at Nara: 2.0 ± 3.6 μm d-1
for S. stearnsii and 5.9 ±
2.7 μm d-1 for G.
pedunculatum; mean ± SD). In contrast, growth rates of juvenile S. stearnsii at Nara were greater
(15 ± 7.7 μm d-1). The in situ growth rate of the adult S. stearnsii (3.4 μm d-1)
was greater than the average, but within the range of the rates of
similar-sized individuals recorded in aquaria. Compared with other
pedunculate barnacles, both species show small growth rates typical for
deep-sea animals. Key words: Cirripedia, Field measurement,
Growth rate, Pedunculata, Rearing. *Correspondence: E-mail: yusa@cc.nara-wu.ac.jp |