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Piling on Puget Sound (Part 1): Cumulative impacts and how they’re hurting natural resources and Treaty Rights

Oct 12th, 2011 • Category: NWIFC Blog, Perspectives

The cumulative effects of shoreline modifications – such as bulkheads, mooring buoys, boat ramps and docks – are among the most significant contributors to the loss and decline of salmon and their habitat in western Washington. They also threaten – and in some cases prevent – the ability of tribes to exercise their treaty-reserved fish and shellfish harvest rights.

The shores of Puget Sound bristle with docks, bulkheads and other structures. While individual shoreline projects may have minimal effects on local ecosystems, their sheer number results in cumulative effects that are causing severe damage to salmon and salmon habitat in the nearshore environment.

Each of these docks, bulkheads and other shoreline changes shown here were permitted individually, while their cumulative effects are largely ignored:


View Larger Map

Here it is, by the numbers:

  • Every year more than one mile of Puget Sound shoreline is lost to armoring.
  • Today almost 1000 miles of the Puget Sound basin is lined with bulkheads, docks and other structures.
  • On the western shoreline of the Hood Canal alone, more than 80 percent of the shoreline is -modified

Nearshore habitat provides a critical nursery for juvenile salmon as they prepare to make their seaward migration, and also serves as migration corridors for returning adult salmon. One of the many ways that bulkheads and other shoreline modifications greatly affect the marine environment is by disconnecting land and marine ecosystems. This disconnection prevents important terrestrial inputs such as logs and bugs from entering the water, which ultimately alters the food chain and eliminates important habitat. Another impact from shoreline modification is that it affects currents, which change where and how much sand is deposited. This in turn harms habitat of forage fish and invertebrates that are an important source of food for young and returning adult salmon.

A striking example of the problem can be found off the mouth of the Nisqually River. The Nisqually is one of the few watersheds in Puget Sound where significant habitat gains have been made in recent years. More than 85 percent of lower river estuary habitat has been reclaimed through cooperative federal, tribal, and state work to remove dikes; nearly 75 percent of mainstem river habitat is in permanent stewardship through a land trust.

Yet despite the massive effort and cost of the cooperative effort, research shows that young ESA-listed salmon and steelhead from the Nisqually River are dying before they can reach Tacoma, just 30 miles away. A major contributor is believed to be a lack of good nearshore habitat caused by ongoing shoreline development practices.

Other shoreline changes, such as the placement of mooring buoys can contribute to pollution in Puget Sound because they are magnets for recreational boaters. It’s not uncommon during boating season to see 50-75 boats tied to the scores of mooring buoys in 100-acre Mystery Bay on Marrowstone Island. Some boats are moored in the bay year round.

The resulting pollution from human waste and other contaminants has led to closures of nearby shellfish beds, denying tribes the exercise of their treaty-reserved shellfish harvest rights. Mooring buoys can also lead to damage of eelgrass beds that are an important part of the marine ecosystem.

In other areas, such as along Hood Canal, mooring buoys have been anchored in longstanding tribal fishing locations, preventing tribal fishermen from setting their nets and denying their treaty right to harvest salmon.

It’s possible that in many parts of Puget Sound we’ve passed a point of no return in terms of these cumulative impacts.

Information and Education Manager, NWIFC
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