The refuse recovered from the bottom appears to be a combination of intentional littering by throwing items overboard, and items that have probably been dropped or blown overboard by accident. The lack of plastic items, including plastic bags, suggests the recovered refuse is the component which sinks more readily. Substantially more items may be ending up in the water than indicated by these clean-ups. This combination of intentional littering and lack of due care is polluting the Great Barrier Reef Marine Park at this location. One area of concern in a coral reef environment is that of submerged clothing or materials.
Clothing can wrap around the coral and smother it by cutting out light and water circulation.
The wrapped material also traps silt, further smothering the coral and eventually killing it. The amount of snagged fishing line cannot be used to determine actual fishing effort. However, it can provide a relative indication of effort, albeit a very rough indication. Continued fishing pressure may be indicated if fishing line accumulates at a similar rate from one year to the next. West Butterfly Bay is a Marine National Park 'B' zone where fishing is not permitted and, as such, there should be no fishing line in this bay.