The impacts of Sphaeroma quoianum to Styrofoam floating docks in Oregon Bays |
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The highly destructive burrowing by dense populations of Sphaeroma quoianum can damage Styrofoam-based floating docks. Impacts to Styrofoam-based floats have been recorded in Coos Bay (JT Carlton, per comm; Davidson 2008) and Yaquina Bay (Davidson and de Rivera, unpublished) and to docks in San Francisco Bay (Cohen and Carlton 1995). However, it is likely S. quoianum is impacting docks in many of the 15 invaded bays on the Pacific coast of North America. |
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Figure 1A-B. Extensive burrowing by populations of S. quoianum (top) virtually destroyed the Styrofoam billets (bottom) in the floating docks used by Oregon Oyster (Newport, OR). |
The impacts of S. quoianum to Styrofoam floating docks Shoreline surveys conducted in summer 2007 detected extensive populations of S. quoianum throughout Yaquina bay. Evidence of very large populations of S. quoianum were found within the Styrofoam floats of Oregon Oyster.
Oregon Oyster replaced their dock floats recently and nearly every one of the estimated (50-60) one-meter long Styrofoam billets were riddled with S. quoianum burrows (Figure 1A-B). Thus, S. quoianum may be impacting the local economy of Yaquina Bay and other infested bays on the Pacific coast of North America.
Future research will quantify and predict both the physical impacts and economic effects of isopod burrowing to Styrofoam docks and floating marine facilities. |
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Figure 2. A piece of extruded Styrofoam with encapsulation material (black plastic) torn away. This firmer form of Styrofoam may prevent isopod damage.
Figure 3. A heavily burrowed piece of expanded Styrofoam. |
Reducing the impacts of S. quoianum to Styrofoam floating docks During shoreline surveys conducted in previous work (Davidson 2008, unpublished), I found that isopod burrow densities were much lower in the extruded type of Styrofoam than in expanded Styrofoam (the commonly used type of Styrofoam). In future work, I will test the hypothesis that isopod burrowing is inhibited in extruded Styrofoam (Figure 2) compared to expanded Styrofoam (Figure 3). |
