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By Phil Colarusso
As summer slowly approaches, the boating season begins. Boat owners spend countless hours and lots of money readying their vessel for the season. They generally spend very little time thinking about the mooring which holds their boat in place all season. They generally spend even less time, if any at all, thinking about the environmental impact their mooring may be causing.
In New England, moorings tend to be a simple block and chain design. A heavy granite block is placed on the seafloor with a metal chain running from the block to a surface buoy, which the vessels ties up to. The size of the block varies with the size of the boat it is supposed to hold. Bigger boats equal bigger blocks. The size and length of the chain also varies, depending on the size of the vessel, the range of the tide and potential exposure to storms. In general, many boaters live by the adage of more chain is better. This often results in long stretches of metal chain sitting on the seafloor. Changes in wind direction and tides cause the chain to be dragged across the bottom. This dragging has a scouring effect on the seafloor often resulting in the loss of seagrass or macroalgae and the resuspension of bottom sediments back into the water column. The resuspension of sediment results in the water appearing cloudy and reduced light penetration, causing further problems for light dependent plants. This becomes especially problematic in crowded mooring fields where tens or hundreds of boats may all be contributing in a small way to a larger problem.
Fortunately, there now exist multiple mooring designs, generally referred to as conservation moorings that will eliminate or reduce many of these impacts. Helical or screw anchors are twisted into the bottom to eliminate the large granite blocks. Chains are replaced with either retractable elastic band systems or have internal floats placed on them to prevent them from contacting the bottom. The price of the conservation moorings vary based on the design and the size of the boat, but generally are in the range of $1500 to $3000. Boaters, who may be willing to spend just a small portion of their boating season budget on their mooring, can make a large difference in the health of our coastal waters.
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About the author: Phil Colarusso is a marine biologist in the Coastal and Ocean Protection Section of EPA New England, and is an avid diver. He’s living the dream in Wenham with wife JoAnn, two kids, dog and white picket fence.