Bristol Bay Salmon Ecosystems

Science to guide conservation

Our easy-to-use interactive map equips people who are reviewing the mine plan with relevant data about the risk of the proposed Pebble mine in Alaska’s Bristol Bay. 

Everything runs on wild salmon in Alaska’s Bristol Bay. Nature runs on salmon. Communities. Business and industry. Salmon is the basis of millennia-old Indigenous tradition. The lands and waters of Bristol Bay produce more wild salmon than anywhere else on Earth and that fuels a sustainable commercial salmon fishery valued at $1 billion annually. 

Bristol Bay is home for half of the Earth’s wild sockeye salmon. Why? It’s the wealth of healthy streams and rivers, wetlands and lakes. This mix of pristine habitat creates a diverse genetic portfolio of several hundred discrete sockeye salmon populations – and this diversity is key to productivity and long-term sustainability. 

Bristol Bay’s portfolio of genetic diversity – much like a diverse investment portfolio – contributes to a more resilient ecosystem and bolsters local fishery-dependent economies. Wiping out or harming any of these discrete salmon populations puts the productivity of the larger Bristol Bay salmon system at risk over time.

To protect this globally significant diversity of wild salmon populations and the people who depend on them, The Nature Conservancy has invested in a science-led process to assess the risk of developing the proposed Pebble mine in the headwaters of two major salmon rivers. 

current status

The Pebble mine was first proposed more than a decade ago for the headwaters of the Nushagak and Kvichak rivers in Bristol Bay in southwest Alaska. In late 2017, the Pebble Limited Partnership submitted a mine plan in its permit application to the U.S. Army Corps of Engineers. That documentation described plans to fill thousands of acres of wetlands – initiating a formal review process as established by the National Environmental Policy Act, or NEPA.  

The Pebble copper and gold mine proposal calls for an unprecedented level of development for western Alaska, including a 188-mile gas pipeline, a 65-mile road, port infrastructure to support an ore-hauling barge on Lake Iliamna, and a tidewater port site at Amekdedori Creek on the western shore of Cook Inlet located 95 miles southwest of Homer.

The U.S. Army Corps of Engineers is now accepting comments during the scoping period as it prepares to develop an environmental impact statement for the proposed Pebble project. Until June 29, comments can be submitted at the U.S. Army Corps of Engineers Pebble Project EIS website

NEW! INTERACTIVE MAP

Our Bristol Bay Interactive Map sheds light on an interconnected and complicated landscape and pulls together data from across the region so that scientists, decision-makers and concerned citizens can see in one place everything from the footprint of the proposed Pebble mine to at-risk salmon streams.

Since the Pebble mine was proposed for the headwaters of the Nushagak and Kvichak rivers in the early 2000s, The Nature Conservancy, tribal environment programs, and other research organizations have compiled thorough inventories of the region’s salmon streams, hydrology, traditional use areas, water quality and more.   

Baseline Studies

Fish Surveys in Headwater Streams of the Nushagak and Kvichak River Drainages, Bristol Bay, Alaska, 2008-2010
Source: The Nature Conservancy

Maps: Bristol Bay Salmon Inventories: 2008-2010
Source: The Nature Conservancy

Investigations of Surface Water Quality in the Nushagak, Kvichak and Chulitna, Southwest Alaska, 2009-2010
Source: The Nature Conservancy

Baseline Macroinvertebrate and Diatom Surveys in Wadeable Streams of the Kvichak and Nushagak Watersheds, Bristol Bay, Alaska 
Source: The Nature Conservancy

Accounting for the Influence of Large Glacially Carved Lakes on Upstream Fish Assemblages
Source: The Nature Conservancy

Ecological Risk Assessment - Literature Review

A Literature Review of Effects of Cadmium on Fish
Source: The Nature Conservancy

A Literature Review of Effects of Ammonia on Fish
Source: The Nature Conservancy

Annotated Bibliography: Effects of Cadmium on Fish
Source: The Nature Conservancy

Annotated Bibliography: Effects of Copper on Fish
Source: The Nature Conservancy

Annotated Bibliography: Effects of Zinc on Fish
Source: The Nature Conservancy

Ecological Risk Assessment - Synthesis

A Preliminary Framework for Assessment of Ecological Risk to Wild Salmon from Large-scale Mining in Bristol Bay, Alaska
Source: The Nature Conservancy

Acid Mine Drainage

Acid Mine Drainage and Effects on Fish Health and Ecology: A Review
Source: U.S. Fish and Wildlife Service

Acute Toxicity of an Acid Mine Drainage Mixing Zone to Juvenile Bluegill and Largemouth Bass
Source: Transactions of the American Fisheries Society

Acid Mine Drainage Prediction
Source: U.S. Environmental Protection Agency

Effects of Metals on Fish

An Overview of Sensory Effects on Juvenile Salmonids Exposed to Dissolved Copper: Applying a Benchmark Concentration Approach to Evaluate Sublethal Neurobehavioral Toxicity
Source: National Oceanic and Atmospheric Administration 

Water Reservations

Instream Flow and Lake Level (Reservation of Water) Protection Report
Source: The Nature Conservancy

Fact Sheet: Kaskanak Creek

Fact Sheet: Lower Talarik Creek

Fact Sheet: Mulchatna River

Fact Sheet: Stuyahok River   

 

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