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Population dynamics of natural colonies of Aurelia sp. scyphistomae in Tasmania, Australia

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Wilcox, S and Moltschaniwskyj, NA and Crawford, CM (2008) Population dynamics of natural colonies of Aurelia sp. scyphistomae in Tasmania, Australia. Marine Biology: international journal on life in oceans and coastal waters, 154 (4). pp. 661-670. ISSN 0025-3162

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Abstract

Abstract The aim of this study was to identify potential
environmental controls of the asexual phases of reproduction
by measuring the rates of asexual reproduction (budding
and strobilation) and mortality in naturally occurring
populations of Aurelia sp. scyphistomae at diVerent spatial
and temporal scales. The percentage cover, density of colonies
of Aurelia sp. scyphistomae, and density of the population
of two naturally occurring colonies of Aurelia sp.
scyphistomae were examined over 2 years in southern Tasmania.
ArtiWcial substrates were also deployed to investigate
colony dynamics when density dependent eVects were
reduced. Clear spatial and temporal diVerences in the population
dynamics of the colonies were observed. Density
dependent eVects controlled budding and recruitment of
new scyphistomae to the substrate when populations were
dense and space limiting. In contrast, environmental controls
of budding and strobilation were more apparent in a
colony with signiWcantly greater area of bare substrate and
hence room for expansion. Water temperature and rainfall
(as a proxy for salinity) were linked to changes in population
size. Annual and seasonal diVerences in population
dynamics were not observed in a colony limited by space
but were apparent in a colony where space was not limited.
When space was removed as a limiting factor by deploying
artiWcial substrates, a seasonal environmental eVect on the
rate of growth of the colony was observed. These studies
suggest that the growth, survival and reproduction of the
sessile colonial phase of Aurelia sp. is regulated by a combination
of density dependent factors and environmental
conditions, which are consequently important to the formation
of jellyWsh blooms.

Item Type: Article
Journal or Publication Title: Marine Biology: international journal on life in oceans and coastal waters
Page Range: pp. 661-670
ISSN: 0025-3162
Identification Number - DOI: 10.1007/s00227-008-0959-2
Additional Information:

The original publication is available at www.springerlink.com

Date Deposited: 07 Aug 2008 05:01
Last Modified: 18 Nov 2014 03:48
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