Spatiotemporal variation in the distribution of eel (Anguilla spp.) populations in three New Zealand lowland streams |
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| Authors: | G J Glova D J Jellyman M L Bonnett |
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| Institution: | National Institute of Water &Atmospheric Research Ltd, Christchurch, New Zealand |
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| Abstract: | Abstract – Populations of shortfinned eel ( Anguilla australis ) and longfinned eel ( A. dieffenbachii ) were sampled at randomly chosen sites along the length of three New Zealand streams during summer for three consecutive years to determine their variability in size distribution between streams, reaches (within streams) and years. The longfinned eel was numerically dominant in two of the streams, whereas the shortfinned eel was more abundant in the third stream. For comparisons, the data were stratified into 100-mm size classes for eels ≤600 mm long, whereas eels >600 mm were pooled into a single class. Log-linear analysis indicated that the size distribution of both species differed significantly between streams. Moreover, the size distribution of shortfinned, but not longfinned eels, differed significantly between reaches. Neither species showed significant change in size distribution between years. In contrast to the shortfinned eel, the density of longfinned eel ≤100 mm long was consistently low for all three years, which probably indicates poor recruitment. |
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| Keywords: | Anguilla spp size distribution variation lowland streams reaches years |
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