The above analysis of the sources of debris does not include the rope and the polypipe, because they were not counted as individual pieces. Figure 12 shows that the east and west coasts of the Harbour are the places where most of the rope was found, and a similar pattern was identified during the polypipe retrieval. As these sites are closest to the aquaculture leases it is a logical assumption that this is where a lot of the aquaculture-associated debris ends up. The other location with a large amount of commercial debris was the King River and its delta. Much of this debris appears to be historical, dating from either the period when aquaculture pens were built at Lowanna before being towed to the lease sites, or the period when the Queenstown municipal tip was located on the bank of the Queen River, which flows into the King. Anecdotally, it seems that poor management practices in the past at this tip site contributed to the huge amount of rubbish (of all sources) in the King River and embedded in its banks and delta. Poor management practices may also have resulted in further pollution and dumping in the river, if residents had the attitude that “it was polluted anyway�. More investigation is required.
Figure 17. Rafters picking up tyres from the King River (low water level). Notice the tyre stuck in the bank below the usual water level. (Photo: I. Flett).
As well as the King River area, the other two sites where large amounts of recreational and domestic rubbish were found were unsurprisingly, in the vicinity of the Strahan township and the campsites south-west of Strahan. There is clearly a problem with people littering, dumping rubbish and/or deciding not to take their rubbish with them after recreation activities, and it conforms with patterns of marine debris around Australia: rubbish is more highly concentrated around population centres.
Transport The Harbour has been well-studied due to mine tailings rehabilitation efforts in the late 1990's, and then more recently, aquaculture activities. The hydrodynamics of the system are complex, related to a relatively high freshwater inflow compared to tidal influence, the shape of the Harbour’s entrance and its large overall size. Near the entrance, there is a tidal influence, with strong currents sometimes generated through the narrow gap, while the
Macquarie Harbour Shoreline Clean-up | Outcomes and Discussion
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