TITLE:
Starvation of the Respiratory Metabolism and Locomotion of Aurelia aurita s.l. Ephyrae
AUTHORS:
Zhilu Fu, Shin-Ichi Uye
KEYWORDS:
Aurelia aurita, Ephyrae, Starvation, Respiration, Pulsation
JOURNAL NAME:
Open Journal of Marine Science,
Vol.11 No.1,
November
30,
2020
ABSTRACT: Blooms of the scyphozoan jellyfish Aurelia aurita are greatly regulated by the survival rate of planktonic ephyrae. The
ecophysiology of ephyrae is poorly studied compared with polyps and medusae. As
extremely strong starvation resistance and recovery capability of A. aurita ephyrae may due to its low metabolic rate as well as starvation may reduce the
swimming ability of ephyrae which may lead to the higher predation loss, the
effects of temperature and starvation on their respiration and pulsation rates
were examined. In this study, ephyrae under different starvation conditions
were measured by a fluorescence-based DO meter after 72 h incubation. And the
pulsation rates were measured at every 10-d interval in 1-liter plastic bottle
by a hand-held counter. The results showed that the mean respiration rates of
newly released ephyrae were 0.24, 0.24 and 0.19 μl O2 ephyra-1 d-1 at 15°C, 12°C and 9°C, respectively, and the rates tended to
decrease with increasing starvation duration. Carbon weight-specific
respiration rates did not change significantly with starvation duration. The
dry weight-specific respiration rates of newly released A. aurita ephyrae (i.e., 11.7-14.6 μl O2 mg DW-1 d-1) were nearly one
order of magnitude lower than the rates for planktonic larvae of other taxa
(e.g., molluscs, crustaceans and fish). The maximum pulsation rate taken by A.
aurita ephyrae was 49.2 beats min-1, which represents the
maximum swimming velocity to be 8.87 cm·min-1. The pulsation rates
were not affected by temperature over the range between 9°C and 15°C. However,
they were influenced by starvation duration. Starvation-derived decrease in
pulsation together with associated body shrinkage may lead to lower encounter
rate of prey and lower escaping ability from predators, which may lead to
higher predation loss in the field.