Delayed onset of adult antifreeze activity in juveniles of the Antarctic icefish <Emphasis Type="Italic">Chaenocephalus aceratus</Emphasis> |
| |
Authors: | Kevin T Bilyk Arthur L DeVries |
| |
Institution: | (1) Department of Animal Biology, University of Illinois at Urbana-Champaign, 515 Morrill Hall, 505 South Goodwin Ave., Urbana, IL 61801, USA |
| |
Abstract: | Many Antarctic notothenioid species endemic to the Seasonal Pack-ice Zone have converged on adult blood serum freezing points
that are several tenths of a degree above the freezing point of seawater. While these fishes share high adult serum freezing
points, the development of their freeze avoidance during ontogeny has not been studied. We investigated this in wild caught
juveniles of one such species, Chaenocephalus aceratus (family Channichthyidae), using blood serum antifreeze activity as a proxy for their freeze avoidance. Juvenile serum antifreeze
activity was significantly below that of adults through the oldest year 2+ specimens collected. This increased at an estimated
rate of 0.368 × 10−3 ± 0.405 × 10−4°C day−1 which, if sustained, would leave C. aceratus below their adult serum antifreeze activity levels of 0.57 ± 0.08°C until 4.2 years after hatching. Underlying the 2.7-fold
increase in their serum antifreeze activity from late year 0+ juveniles to adults was an even greater 10.4-fold increase in
the concentration of their serum antifreeze glycopeptides, which increased proportionally across all of their serum AFGP size
isoforms. With insufficient antifreeze activity to avoid freezing in the ice-laden surface waters, both adult and juvenile
C. aceratus are most likely restricted to the year round ice-free waters where a metastable supercooled state can be maintained. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|