Multi-year observations on the gametogenic ecology of the Antarctic seastar <Emphasis Type="Italic">Odontaster validus</Emphasis> |
| |
Authors: | Laura J Grange Paul A Tyler Lloyd S Peck |
| |
Institution: | (1) School of Ocean and Earth Science, University of Southampton, NOC, Southampton, SO14 3ZH, UK;(2) British Antarctic Survey, High Cross, Madingley Road, Cambridge, CB3 0ET, UK |
| |
Abstract: | This study reports the first multi-year observations on the reproductive patterns for an Antarctic predator/scavenger, Odontaster validus (Koehler 1912). Seastars were collected monthly from a shallow site (15–20 m depth) near the British Antarctic Survey (BAS) Rothera Research
Station (Adelaide Island, 67°34′S 68°08′W) from July 1997 to January 2001. Reproductive condition, oocyte size frequencies
and spermatogenesis were examined in at least ten seastars each month using histological and image analysis techniques. Gonad
indices (GI) and pyloric caeca indices (PI) were also examined in the same samples. Female and male GIs varied seasonally,
in parallel with a reduction in the proportion of large oocytes and mature sperm in the gonad in August to mid-October following
winter spawning. Despite there being remarkable consistency in the timing of spawning from year to year, differences in the
reproductive condition of individuals were apparent. Patterns in the digestive tissues also varied with season, peaking in
December and reaching a minimum in February in two of the three study years. This weaker annual pattern may partly reflect
the varied diet of this predator/scavenger species, which is not directly dependant on the timing and magnitude of the annual
phytoplankton bloom. Pooled oocyte size distributions and residual analysis suggested that oogenesis progressed over 18–24 months,
with the largest of the two size classes (maximum diameter = 183 μm) being spawned annually. This pattern of oocyte growth
and spawning was previously reported in the early 1960s for an O. validus population from McMurdo Sound, which lies south of Rothera by 10° latitude. The extremely catholic diet of this predator/scavenger
suggests the reproductive patterns of the seastar will be less susceptible to changes in food supply compared to polar suspension
feeders or deposit feeders.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|