Subtle 'boom and bust' response of Macquaria ambigua to flooding in an Australian dryland river
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The ecology of dryland rivers is driven by their highly variable hydrology, particularly flooding regimes, whereby intermittent floods typically generate 'booms' of primary and secondary productivity, including massive fish production.We tested these concepts in the Moonie River, Australia, using the percichthyid, Macquaria ambigua, a dryland river species known to display pronounced 'boom and bust' abundance patterns in response to floodplain inundation followed by extended periods of low to no channel flow. We expected that body condition (as measured by whole body lipid content) and biomass of M. ambigua would be related to prey biomass, and that these factors would all 'spike' following widespread flooding. Instead we found more subtle responses. There were 'booms' in biomass of Macrobrachium and zooplankton, two important food items, whereas M. ambigua maintained relatively low but sustained lipid and biomass levels following flooding. It appears that instead of a 'boom' in fish biomass, abundant invertebrate food resources and sustained lipid levels contributed to high survivorship of this species during the 'bust' period over cool dry months.
Environmental Biology of Fishes
Copyright 2012 Springer Netherlands. This is the author-manuscript version of this paper. Reproduced in accordance with the copyright policy of the publisher. The original publication is available at www.springerlink.com