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Auke Bay Laboratory (ABL)  (cont.)

Habitat Program

Hydrocarbons and Fisheries Habitat in Berners Bay, Alaska: Long-term Monitoring Associated With the Kensington Gold Mine

Several projects associated with development of the Kensington Gold Mine have been proposed for the Berners Bay area 65 km north of Juneau Alaska (Fig. 4 below). Construction of two ferry terminals and other related infrastructure may affect as many as 80 hectares (ha) within the Berners Bay watershed. Potential sources of hydrocarbons to the bay include fuel spills, chronic pollution from vessels, and parking lot runoff near the terminal facilities. ABL researchers have documented damage to pink salmon and Pacific herring (Clupea pallasii) embryos by concentrations of polynuclear aromatic hydrocarbons (PAHs) as low as 1 ppb. Both species, as well as eulachon (Thaleichthys pacificus) and capelin (Mallotus villosus), spawn in intertidal areas of the bay. In 2004, AFSC scientists initiated baseline studies in Berners Bay to document hydrocarbon concentrations and fish use of important habitats (e.g., eelgrass and understory kelp) before mine development.

Figure 4, see caption

Figure 4.  Location of polyethylene membrane devices (PEMDs) that sampled hydrocarbons in seawater and air, integrated over two 30-day deployment periods in 2004.  Also shown are beach seine sites in eelgrass and kelp communities, and proposed ferry terminals and routes associated with the development of the Kensington Gold Mine in Berners Bay, Alaska.

Hydrocarbons were measured using passive samplers developed at ABL called polyethylene membrane devices (PEMDs). Samplers were deployed at seven sites in Berners Bay and at two sites in Bridget Cove, a nearby control site. These devices provide a sample of bioavailable PAHs in seawater and air integrated over 30 days. Conventional seawater, sediment, and mussel tissue (Mytilus trossulus) hydrocarbon samples were also taken at four of the PEMD sites to compare to state water quality standards for Alaska. Most hydrocarbon concentrations were at or below minimum instrument detection levels in PEMDs, seawater, sediment, and mussel tissue, indicating near pristine conditions in Berners Bay. Total PAH concentrations in all matrices were below levels considered baseline for Prince William Sound, Alaska: 10 to 100 ng/L for water, 100 ng/g dry wt for sediment, and 90 ng/g dry wt for mussel tissue. The PAH patterns observed in the PEMDs with the highest concentrations are consistent with patterns for diesel fuel, and the higher concentrations coincided with increased commercial fishing in the area.

Eelgrass beds were mapped and the linear extent of understory kelp beds were determined in Berners Bay and Bridget Cove with GPS (global positioning system) technology. Both vegetation communities are limited to relatively narrow bands during the summer by glacial turbidity that reduces light attenuation. Eelgrass beds consisted of Zostera marina with some ephemeral algae, Ulva, and Prophyra in the more sandy areas. Area of eelgrass mapped ranged from small patches to large beds; the bed in Bridget Cove is the largest (5.76 ha) measured to date in the Juneau area. Kelp beds were dominated by Laminaria and Alaria spp.

Fish were sampled in eelgrass and kelp with a 37-m long beach seine. Six hauls were done in Berners Bay and six hauls in Bridget Cove. Twelve seine hauls yielded 9,653 fish comprising 24 species; 18 species were in eelgrass and 16 species were in kelp. Chum salmon (O. keta) fry were the most abundant species, comprising 87% of the total catch. Other federally or state-managed species that were captured included coho salmon, pink salmon, crescent gunnel (Pholis laeta), rock sole (Lepidopsetta bilineata), snake prickleback (Lumpenus sagitta), great sculpin (Myoxocephalus polyacanthocephalus), walleye pollock (Theragra chalcogramma), Pacific cod (Gadus macrocephalus), capelin, and Pacific herring. Total catch per seine haul, species richness, and species diversity were similar to those parameters observed at other sites in northern inside waters of southeastern Alaska. Most captured fish were juveniles, indicating the importance of nearshore habitats as nursery or rearing areas.

After another year of baseline sampling in 2005, frequency of monitoring will be determined by the rate of development and length of operation of the mine. We anticipate a project duration of 15 to 20 years. Information from this project will help resource managers track changes in hydrocarbons, fish use, and habitat quality in Berners Bay before, during, and after closure of the mine.

By Pat Harris


Southeast Alaska Regional Science Fair

ABL scientists played an integral role in the 2005 Southeast Alaska Regional Science Fair. The fair, held on 5 March in Juneau, is for high school students in Southeast Alaska. The fair is affiliated with Intel’s International Science and Engineering Fair, which is the world’s largest science fair and has more than $3 million in awards in scholarships. Scientists from ABL mentored many of the 112 projects entered in this year’s fair, and 4 of the ABL-mentored projects advanced to the final round of judging.

One of the ABL-mentored projects, "Evaluating Changes in PAHs in Gastineau Channel" by students Brenna Heintz and Clay Wertheimer and mentored by ABL fisheries scientist Bonita Nelson, was among the four projects selected to advance to the international science fair in Phoenix in May 2005. Bonita Nelson, Ron Heintz, and Lawrence Schaufler of ABL were on the judging and organizing committee for the Alaska Science Fair. The ABL also provided several judges to the fair, including Molly Sturdevant, Bonita Nelson, Mark Carls, Dean Courtney, Pat Harris, John Thedinga, and Alex Wertheimer, (who also mentored projects), and Mitch Lorenz, Angela Middleton, Phil Rigby, Cara Rodgveller, JJ Vollenweider, and Neal Muirhead. Other project mentors from ABL included Lisa Eisner, Sharon Hawkins, Jon Heifetz, Tom Rutecki, and Bruce Wing.

By Bonita Nelson

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