Turkish Journal of Fisheries and Aquatic Sciences
2019, Vol 19, Num, 6 (Pages: 529-539)
Empirical Predictions of the Trophic Consequences of NonNative Freshwater Fishes: A Synthesis of Approaches and Invasion Impacts
John Robert Britton 1
1 Bournemouth University, Department of Life and Environmental Sciences, Faculty of Science and Technology, BH12 5BB, United Kingdom
DOI :
10.4194/1303-2712-v19_6_09
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Predicting the ecological impacts of invasive fishes is crucial for understanding their
risks in the environment. Experimental approaches that provide empirical data on
invasion impacts provide both theoretical insights and data of high management
utility for prioritising high-risk invaders. Here, a synthesis of some experimental
approaches that predict invasion impacts of non-native fish is presented, where the
focus is on impacts relating to the trophic impacts of the invader on either native
trophically analogous fishes or prey populations. Experiments in tank aquaria are
advantageous in providing homogenous and controlled conditions that also enable
high replication. Competition-based studies can determine invasion impacts via
exposure of fish to fixed food rations, although these experiments tend to produce
results in intensely competitive conditions that might not occur in the wild.
Comparative functional response experiments in tank aquaria have been successfully
applied to determining the relative impacts of invaders compared with native species
on prey populations, and have revealed high resource efficiency in globally invasive
piscivorous fishes. Experiments completed in mesocosms and small ponds have the
advantage of providing replicated systems in semi-natural conditions. They have
been successful in revealing that rather than competing with native fishes, many
invasive fishes show strong patterns of trophic niche partitioning. These patterns are
also evident in these fishes when in natural invaded communities. Thus, whilst it is
often suggested invasion impacts from non-native fishes result from inter-specific
competition, evidence for this from experimental and field-based predictions is
equivocal.
Keywords :
Impact assessment, Stable isotope analysis, Non-native species, Competition