Watching Our Water Ways

It’s the water, or maybe it’s just the nasty stuff that’s in the water.

A new series of studies by federal researchers is delving into the question of which pollutants in urban streams are killing coho salmon.

David Baldwin of Northwest Fisheries Science Center mixes a chemical soup of pollutants found in urban stormwater. Coho salmon will be kept in the brown bath for 24 hours to measure the effects.
Photo by Tiffany Royal, Northwest Indian Fisheries Commission

As I describe in a story in today’s Kitsap Sun, the new studies involve coho returning to the Suquamish Tribe’s Grovers Creek Hatchery in North Kitsap.

Of course, pollutants in streams are just one factor affecting salmon in the Puget Sound region, where development continues to alter streamflows and reduce vegetation, despite efforts to protect and restore habitat. But pollution may play a role that has gone largely unnoticed in some streams.

The new studies continue an investigation that began more than a decade ago with the involvement of numerous agencies. By now, most of us have heard about the effects of copper on salmon, but the latest round of studies will look at the collection of pollutants found in stormwater to see how they work together. It may be possible to pinpoint the chemical concentrations that result in critical physiological changes in salmon.

The latest work involves a team led by David Baldwin of NOAA Fisheries and Steve Damm of the U.S. Fish and Wildlife Service. The Suquamish Tribe is providing the fish, along with facilities and support.

For information on the ongoing effort to understand how toxic chemicals affect salmon, review these pages on the website of the Northwest Fisheries Science Center:

Acute die-offs of adult coho salmon 
returning to spawn in restored urban streams

The impacts of dissolved copper on olfactory 
function in juvenile coho salmon

Mechanosensory impacts of non-point source pollutants in fish

Cardiovascular defects in fish embryos exposed 
to polycyclic aromatic hydrocarbons

A page called “Coho Pre-spawn Mortality in Urban Streams” presents a series of videos that show the advance of an apparent neurological disease that first causes disorientation in coho salmon and then death. The video is taken in Seattle’s Longfellow Creek, an urban stream.

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Barnacles and other organisms that attach themselves to ships’ hulls are the focus of an enormous amount of attention, as experts try to find nontoxic methods of keeping hulls clean.

Historically, bottom paints have included compounds that deter organisms with their toxic effects. To be successful, such antifouling paints must slough off at a sufficient rate. That places these toxic compounds into the water, where they can build up in enclosed bays.

When and where such compounds actually reach toxic levels in the environment is a complex problem, involving the toxicity of the compound, the amount that gets released within an enclosed inlet and the level of mixing that occurs in the waters.

Puget Sound Naval Shipyard in Bremerton is struggling with the issue of copper, a primary component in antifouling paints now that tributyltin has been banned. TBT builds up in marine life and is quite toxic to clams and oysters.

The Navy recently reached an agreement with the Department of Ecology to reduce the amount of copper in its stormwater discharges. Most of the copper comes from releases during sandblasting and painting activities. The Navy has tightened up its processes. (See Kitsap Sun, May 29.)

The Navy is considering treating such stormwater before release, and negotiations are under way for a new federal discharge permit. I’ll be writing more about this issue in the coming weeks.

Behind the scenes, the Navy is spending an enormous amount of money to develop new materials and processes to prevent growth on the hulls of ships. The reasons are obvious. Fouling of ships hulls can reduce vessel speed by up to 10 percent, requiring a 40 percent increase in fuel consumption to counter the extra drag. That’s amounts to roughly $1 billion a year the Navy has to spend, according to the Navy’s own figures. (See story on the Web page of the Office of Naval Research.)

It’s hard to tell whether there are any absolute breakthroughs, but some interesting findings are coming out of studies into why barnacles attach to some marine animals, such as gray whales, but not to sharks. Anthony Brennan at the University of Florida is looking at the unique surface pattern found on sharkskin and trying to mimic that for a ship’s hull. The best explanation of the concept can be seen in a video produced by the Office of Naval Research (bottom of page).

That report also mentions work by Shaoyi Jiang at the University of Washington, who is working on anti-fouling coatings that incorporate mixed-charge compounds, which alternate between positive and negative charges and seem to keep organisms from binding.

For recreational boaters, the University of California Sea Grant Extension Program has been studying alternatives in San Diego Harbor and Newport Bay with the idea that the ideas could be applied elsewhere. One study looked at silicone- and epoxy-based coatings.

For more details, check out “Demonstrating a Solution to Copper Boat Bottom Paint Pollution!” (PDF 28 kb).

When you think about it, the need for a low-cost product that will keep hulls clean is obvious, but I’m frankly amazed at how many ideas are floating around, as can be demonstrated by plugging the words “antifouling” and “hull” into a search engine.

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