Brief description
A comparison was made of sediments and associated macrobenthos at sites sampled within 42 fish farm leases distributed across Tasmania. Several key biotic and abiotic metrics recommended in previous studies for assessing environmental impacts of fish farm waste were investigated.Lineage
Maintenance and Update Frequency: notPlannedTriplicate macrofaunal samples were collected < 5 m apart at each site using a Van Veen grab (0.07 m2 surface area) or diver operated corer (150mm diameter) pushed into the sediment to a depth of 100mm. Samples were sieved in the field using a 1 mm mesh sieve, and retained material placed into vials and fixed with 5% buffered formalin. In the laboratory, the collected material was washed through a stacked series of sieves (1, 1.4, 2, 2.8 and 4 mm) using the methods described by Edgar (1990).
Material retained on each sieve was sorted, with animals separated into species groups and counted.
A Craib corer was used alongside the Van Veen grab at each site to collect triplicate sediment cores (43 mm in diameter) for analysis of sediment properties. Redox potential was measured in millivolts at the surface of the sediment and at 40 mm depth below the sediment surface.
After redox measurements were completed, two sub-samples were separated from each Craib core. The top 30 mm of sediment was collected in a vial for analysis of organic content, %C, %N, stable isotope ratios and particle size. The next 70 mm was used for particle size analysis only.
The two samples comprising the top 100 mm of each sediment core were combined for particle size analysis.
Notes
CreditAdam Davey, Aquenal Pty Ltd.
Colin Shepherd, Marine Farming Branch, Department of Primary Industries and Water
Aquenal Pty Ltd.
Tassal Operations Ltd.
Huon Aquaculture Company Pty Ltd.
AMD Pty Ltd.
Dom O.Brien
Aquatas Pty Ltd.
This study assessed the efficacy of a variety of physical and biological metrics in discriminating fish farm impacts at different distances from cages, with emphasis on the more distant effects.
Created: 09 11 2007
Data time period: 01 01 1997 to 31 12 2004
text: westlimit=144.5; southlimit=-44.00; eastlimit=148.5; northlimit=-39.00
text: uplimit=47; downlimit=7
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