Researchers fromSimonFraserUniversitylooked at the effectiveness of ancient shellfish gardens created onQuadraIslandinBritish Columbia.  In these gardens, first nations’ peoples cleared rocks and small boulders down to the low ends of beaches to construct a sill.  These cleared areas filled in with smaller sized sediment particles and created areas of higher quality clam habitat. The sill wall also acted to deter some predators and was thought to increase larval retention.  When coupled with the first nations’ husbandry practices of removing predators to increase survival and removing competitors to increase growth they achieved clam aquaculture in a form that is not much different from what is practiced today.

 Another interesting presentation was of a study using acoustic multibeam ecosounder data, seafloor video, and sediment samples to identify and sample subtidal habitat in the San Juan Channel of the Pacific sand lance.  The sand lance is known to utilize near shore sandy substrates for burrowing emerging in daylight hours to forage in open water.  Sandy upper intertidal beaches are used by adults for spawning and egg deposition.  With this work, the natural history of the Pacific sand lance in its subtidal habitat has been greatly expanded.  A predictive model that uses seafloor characteristics of sediment wave fields was developed to locate potential subtidal sand lance habitats.  Densities of sand lance captured in this study were much higher than what has been reported intertidally, averaging 84 fish/m² rather than only 5 fish/m².  What I found the most intriguing was the collection of a single sand lance egg found in one of 59 samples.  This could indicate a low density late season subtidal spawning area that could be considered a “critical” habitat or just be an anomaly.

 Overall the conference presented a wide variety of interesting topics and studies about theSalishSea, its inhabitants, and how they interact with each other.  The Salish Sea Ecosystem Conference was an excellent opportunity to hear from and collaborate with researchers, policy makers, and natural resource managers.

Excess nitrogen in the marine environment fuels algae growth.  When the algae dies and is decomposed by microbial action, CO2 is produced–the more algae, the more CO2.  This CO2 from microbial respiration has the same effect as atmospheric CO2–it lowers pH.  Thus CO2 in marine waters has two sources–the atmosphere and microbial respiration.   And, as anthropogenic sources of nutrients increase algae growth, acidification and all its damaging consequences are accelerating.

What is most alarming is that the combination of the two sources of CO2  (atmosphere and respiration) seems to have more than an additive effect–there is some sort of synergy that lowers pH beyond what would be expected from the sum of the predictions for each of the two sources when modeled alone.  In the context of the relatively limited water circulation found in the Salish Sea and especially in South Sound where nutrients tend to linger for long periods of time, this emerging science increases the urgency to control or treat all sources of excess nutrients to help compensate for the effects of climate change.

Anderson Good Choice to lead WDFW

The treaty tribes of western Washington look forward to continuing to work with Phil Anderson as director of the Washington Department of Fish and Wildlife (WDFW).

Anderson was named the department’s permanent director Saturday by the nine-member commission….(read more at NWIFC website).

http://www.king5.com/localnews/environment/stories/NW_082609ENB_divers-freshwater-mussels-JM.11bc2a6de.html?rss

Tribal biologists are numbering clams with tiny numbered red tags and by simply writing on them.  Clam growth is typically measured by randomly surveying clams on a beach, but that technique isn’t very exact.

You can also hear about the project here.

The surveys will occur on privately owned tidelands within the bay. This area had previously been closed to commercial shellfish harvest due to water quality problems, but has recently been upgraded to approved status.

Approximately sixty parcels have been identified as possible clam beaches and will be surveyed by the Natural Resources Shellfish department this summer. The goal of the department is to maintain treaty harvest rights in this area and provide harvest opportunities for Squaxin Island tribal members.

Outside of Shelton Harbor, the dioxin is distributed uniformly with an average concentration of 35 parts per trillion (ppt or pg/g). “At first glance, the distribution pattern suggests the dioxin may be a historical legacy,” said John Konovsky, the tribe’s environmental program manager.

Oakland Bay is a very productive shellfish growing area. Studies elsewhere suggest there is very little connection between dioxin concentrations found in sediment and contamination in shellfish:

• In a 2008 Ecology report on neighboring Budd Inlet, sediment samples weretested for dioxin and concentrations ranged from 3 to 60 ppt. Concentrations in littleneck/manila clam samples averaged 0.5 ppt.
• In Similk, Fidalgo and Padilla Bays, a 2006 study by the Swinomish Tribe identified a range of concentrations of organic compounds including dioxin in sediment, but levels in shellfish from those same sites were more uniform and much lower. The report also suggested that health risks from sediment exposure – such as digging for clams – are even lower than eating shellfish.
• A 2007 Humboldt Bay study concluded that dioxin concentrations in shellfish tissue were independent of dioxin levels in sediment. All the tissue directly tested and most reported in the worldwide literature was below concentrations considered to be a risk to human health. Without continual industrial output, dioxin levels in sediment and shellfish decline over time.

“It’s not surprising that shellfish accumulate very little dioxin and are safe to eat,” said Konovsky. “This is because dioxin builds up in fatty tissue and shellfish have a very low fat content.”

Scientists from the state Department of Health also believe that dioxin in the sediment of Oakland Bay does not pose a public health concern for shellfish consumers. When discovered in sediments elsewhere around Puget Sound, dioxin in shellfish has never been found at levels of public health concern.

“Oakland Bay has always been a favorite spot for tribal members to dig clams,” said Andy Whitener, natural resources director for the tribe. “The tribe is committed to working with state and federal governments to do whatever is necessary to clean up the bay. We want to absolutely guarantee the health of our tribal members and the entire community.”

(END)

For more information, contact: Andy Whitener, natural resources director, (360) 432-3800. Jeff Dickison, assistant natural resources director, (360) 432-3815. John Konovsky, environmental program manager, (360) 432-3804.

Reports Cited

Science Applications International Corporation. 2008. Sediment Characterization Study, Budd Inlet, Olympia, WA: Final Data Report. Department of Ecology, Olympia.

Swinomish Tribe. 2006. Bioaccumulative Toxics in Subsistence-Harvested Shellfish—contamination results and risk assessment. La Conner, WA.

Pacific Shellfish Institute. 2007. Status Report and Synopsis of Organic Pollutants in Relation to Shellfish Safety in the Mad River Slough and Humboldt Bay, California. Humboldt Bay Harbor, Recreation and Conservation District, Eureka.

Photo 1. Geoduck Show Plot

Photo 2. Individual Geoduck "shows" marked with white stakes.

Photo 3. Eric Sparkman Marking Individual Geoduck Shows.