Salinity preference of the silvering Japanese eel Anguilla japonica: evidences from the pituitary prolactin mRNA levels and otolith strontium/calcium ratios
Resource
Marine Ecology Progress Series 259: 253–261
Journal
Marine Ecology
Pages
Progres-s
Date Issued
2003
Date
2003
Author(s)
Han YS
Yu JYL
Liao IC
Tzeng WN
Abstract
The salinity preference of Japanese eel Anguilla japonica during silvering was validated from the viewpoints of physiological ecology by examining the pituitary prolactin (PRL) mRNA expression and the otolith strontium (Sr) /calcium (Ca) ratios of the eels of different sexual maturity stages collected in an estuary of Taiwan. The PRL possessed a putative signal peptide of 24 amino acids and a mature peptide of 185 amino acids. Reverse transcription - polymerase chain reaction (RT-PCR) and real-time quantitative PCR analyses indicated that the transcript levels of PRL mRNA significantly decreased from yellow to silver stage. On the contrary, the Sr/Ca ratios at the otolith edge of silver eels, which recorded their latest experience of salinity history, significantly increased. The increase in otolith Sr/Ca ratios and the decrease in PRL mRNA expression are consistent with the timing of migration from freshwater to seawater during silvering of the eel.
Subjects
Japanese eel
Salinity preference
Otolith
Sr/Ca ratio
Prolactin
mRNA
Silvering