Loss of riparian vegetation alters the ecosystem role of a freshwater crayfish (Cherax destructor) in an Australian intermittent lowland stream

2009 ◽  
Vol 28 (3) ◽  
pp. 626-637 ◽  
Author(s):  
Darren Giling ◽  
Paul Reich ◽  
Ross M. Thompson
Keyword(s):  
Riparian Vegetation ◽  
Freshwater Crayfish ◽  
Lowland Stream ◽  
Cherax Destructor

Riparian vegetation removal alters consumer - resource stoichiometry in an Australian lowland stream

2012 ◽  
Vol 63 (1) ◽  
pp. 1 ◽  
Author(s):  
Darren P. Giling ◽  
Paul Reich ◽  
Ross M. Thompson
Keyword(s):  
Riparian Vegetation ◽  
Anthropogenic Impacts ◽  
Negative Relationship ◽  
Canopy Cover ◽  
Ecological Impacts ◽  
Molar Ratio ◽  
Freshwater Crayfish ◽  
Resource Quality ◽  
Lowland Stream ◽  
Eastern Australia

Anthropogenic impacts on stream ecosystems generate changes in nutrient and carbon availability which act as stoichiometric challenges to consumers. We tested the hypothesis that removal of Eucalyptus riparian vegetation alters in-stream resource stoichiometry with flow-on effects for a benthic consumer (the freshwater crayfish, Cherax destructor). Sites with high and low riparian canopy cover were selected on a lowland stream in south-eastern Australia. A reduction in riparian vegetation canopy cover was associated with decreased terrestrial detritus (low nutritional quality; high carbon to nitrogen (C : N) ratio) and increased cover of macrophytes and filamentous algae (high quality; low C : N ratio). This resource-quality shift was associated with a small but significant decrease in C. destructor C : N ratio (molar ratio of muscle tissue). This suggests that the animals are deviating from homeostasis and may be in better condition in the stream pools dominated by in-stream productivity. A significant negative relationship between C. destructor length and C : N ratio was observed, suggesting that resource-quality impacts may differ with age. The present study has shown that riparian loss alters stoichiometric interactions in stream benthic ecosystems, with potential consequences for stream processes such as nutrient cycling. Ecological stoichiometric theory should therefore be further utilised to make predictions of ecological impacts in freshwater systems.

Phylogeny of the Australian freshwater crayfish Cherax destructor-complex (Decapoda : Parastacidae) inferred from four mitochondrial gene regions

2005 ◽  
Vol 19 (3) ◽  
pp. 209 ◽  
Author(s):  
Thuy T. T. Nguyen ◽  
Christopher M. Austin
Keyword(s):  
16S Rrna ◽  
Cytochrome Oxidase ◽  
Mitochondrial Gene ◽  
Large Subunit ◽  
Strong Support ◽  
Interspecific Variation ◽  
Rrna Gene ◽  
Freshwater Crayfish ◽  
Cherax Destructor ◽  
Australian Freshwater

The phylogenetic relationships among 32 individuals of Australian freshwater crayfish belonging to the Cherax destructor-complex were investigated using a dataset comprising sequences from four mitochondrial gene regions: the large subunit rRNA (16S rRNA), cytochrome oxidase I (COI), adenosine triphosphatase 6 (ATPase 6), and cytochrome oxidase III (COIII). A total of 1602 bp was obtained, and a combined analysis of the data produced a tree with strong support (bootstrap values 94–100%) for three divergent lineages, verifying the phylogenetic hypotheses of relationships within the C. destructor species-complex suggested in previous studies. Overall, sequences from the 16S rRNA gene showed the least variation compared to those generated from protein coding genes, which presented considerably greater levels of divergence. The level of divergence within C. destructor was found to be greater than that observed in other species of freshwater crayfish, but interspecific variation among species examined in the present study was similar to that reported previously.

Effects of gear type, entrance size and soak time on trap efficiency for freshwater crayfish Cherax destructor and C. albidus

2015 ◽  
Vol 66 (11) ◽  
pp. 989
Author(s):  
Paul Brown ◽  
Taylor L. Hunt ◽  
Khageswor Giri
Keyword(s):  
Field Experiments ◽  
Freshwater Crayfish ◽  
Recreational Fisheries ◽  
Air Breathing ◽  
Fixed Ring ◽  
Cherax Destructor ◽  
Fishing Gears ◽  
Opera House ◽  
By Catch ◽  
Aquatic Mammals

Freshwater crayfish support significant commercial and recreational fisheries worldwide. The genus Cherax is fished in Australia with a variety of fishing gears, yet little is known of the relative efficiency of the different fishing gears and methods. Additionally, freshwater-crayfish traps can pose a risk to air breathing by-catch such as aquatic mammals, reptiles and birds, so by-catch mitigation is important. We sought to understand whether freshwater-crayfish fishing can be undertaken efficiently, using passive traps and nets, without undue risk to air-breathing by-catch species. In field-experiments, we compared the efficiency of six gear types and tested the effect of five exclusion rings on catch performance over three soak times. The efficiency of gear types varied significantly by soak times. In productive locations, catch can be maximised by repeatedly deploying open-topped gear for short soak times. Opera-house traps fitted with fixed entrance rings (45–85-mm diameter) were not size-selective for yabbies. Encouragingly, open-topped gear and opera-house traps fitted with fixed ring entrances much smaller than many commercially available (45-mm diameter) still fish effectively for yabbies. We believe that smaller fixed ring-entrance size is likely to be correlated with a reduced risk of by-catch for air-breathing fauna.

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