The sockeye salmon that come from the Koktuli River aren’t like most other fish in Alaska\u2019s Bristol Bay, where a thriving fishery provides nearly half of the world\u2019s wild sockeye. These salmon represent a rare class of sockeye with unique genes and a singular life strategy that sets them apart from the millions of fish that spawn in the rivers and streams that feed into Bristol Bay. Now, Koktuli River sockeye are in the spotlight because the Pebble Mine, a copper and gold mine proposed for southwest Alaska, is slated for the water in which they live.<\/p>\n
On Monday, August 24, the latest development arrived in the long and controversial story of the Pebble Mine<\/a>. The US Army Corps of Engineers (USACE), the agency in charge of permitting the mine, posted a letter<\/a> officially informing the project\u2019s developer, Pebble Limited Partnership (PLP), that the open-pit mine, as proposed, would \u201ccause unavoidable adverse impacts\u201d to the surrounding watershed, resulting in \u201csignificant degradation.\u201d<\/p>\n That determination would be a death knell for the project per the Clean Water Act\u2014unless the company takes appropriate steps to mitigate or offset the damage it will cause to more than 1,300 hectares of wetlands and nearly 300 kilometers of streams, most of which lie within the Koktuli River watershed. In recent weeks, prominent Republicans, including President Trump\u2019s oldest son, Donald Trump Jr., and Fox News commentator Tucker Carlson, have voiced opposition<\/a> to the mine, feeding speculation ahead of Monday\u2019s letter that the administration might block or delay the project.<\/p>\n Bristol Bay is one of the last places in the world that consistently produces huge numbers of wild sockeye, and the fishery that relies on them contributes US $1.5-billion a year<\/a> in economic activity. That consistency stems from the region\u2019s diversity: it is home to many different salmon populations and many different kinds of salmon habitat. Each year, the contributions of each to the total catch in the bay varies considerably. And the variation creates resilience\u2014a so-called portfolio effect\u2014that is key to this region\u2019s ongoing productivity<\/a>, according to Daniel Schindler, a University of Washington ecologist who has studied Bristol Bay salmon for decades. But even among this diversity, Koktuli River sockeye are particularly interesting.<\/p>\n After hatching, most Bristol Bay sockeye swim downstream and spend a year or two fattening up in the region\u2019s abundant lakes before continuing on to the Pacific Ocean. These are the plentiful “lake-type” sockeye. But the rarer \u201criver-type\u201d sockeye\u2014including those in the Koktuli River\u2014don\u2019t have the luxury of lakes to serve as a nursery. Instead, they head out to sea in their first year of life.<\/p>\n Lake- and river-type sockeye differ not only in their survival strategies but in their genes. Furthermore, a growing body<\/a> of genetic evidence<\/a> suggests that river-type sockeye are the ancestral form of the species that \u201cacts as a seed source\u201d for establishing new populations in new habitats, says Gordon Reeves, a retired US Forest Service fisheries ecologist. Geneticists believe these more versatile salmon were likely the first to colonize Bristol Bay after the last glaciers retreated, and have repeatedly evolved into the lake-type sockeye that now dominate the bay.<\/p>\n Analyses first published in 2012<\/a> by the Alaska Department of Fish and Game (ADFG) suggest that the Koktuli\u2019s river-type sockeye are a separate genetic population, though one that is closely related to three other river-type populations in the Nushagak River, which drains into Bristol Bay. That and subsequent research seems to have flown under the radars of USACE and the US Environmental Protection Agency (EPA) until recently, but it shows that, together, these four populations make up half of the river-type sockeye in the Bristol Bay watershed, says Tyler Dann, an ADFG fisheries geneticist who is also Saint Lawrence Island Yu\u2019pik and grew up in Alaska subsistence and commercial fishing.<\/p>\n Of the 98 populations the state has identified in its genetic analyses in Bristol Bay sockeye, only eight are river-type, he says. Dann adds that they represent an important and unique life strategy among sockeye and are \u201ccertainly part of the variability that helps maintain an overall stable and healthy commercial fishery and ecosystem.\u201d<\/p>\n In May, the EPA wrote a letter<\/a> to USACE calling attention to Dann\u2019s research and Koktuli River sockeye, writing that these river-type fish are \u201cevolutionarily important and distinctly unique within the Bristol Bay watershed and Alaska.\u201d<\/p>\n The distinctions of this rare class of sockeye make the ones in the Koktuli River a potential problem for the proposed Pebble Mine.<\/p>\n According to USACE spokesperson John Budnik, PLP\u2019s path to securing a federal permit for the mine lies in it producing a suitable compensatory mitigation plan. USACE says that for every hectare of wetland and kilometer of stream damaged, the company must make up the difference by restoring, mitigating, or preserving an equal amount elsewhere. But USACE\u2019s most recent stance is that these mitigation efforts<\/a> must now occur in the same watershed as the damage. And the mine is planned to be built squarely in the largely undisturbed, wetland-rich Koktuli River watershed.<\/p>\n Reeves says that though USACE\u2019s final environmental impact statement for the mine acknowledges the EPA\u2019s focus on the Koktuli salmon, the document goes on to dismiss how the project could undermine the portfolio effect that sustains the region\u2019s broader salmon population.<\/p>\n At the end of July, USACE suggested that the mine would not measurably hurt Bristol Bay\u2019s salmon, citing \u201cthe vast breadth and diversity of habitat (and salmon populations).\u201d But this view, says Schindler, is shortsighted.<\/p>\n \u201cIt is easy to assume that habitats, and their associated salmon populations, are interchangeable across any river basin,\u201d Schindler says. But that isn\u2019t the case. Lake-type sockeye are not adapted to thrive in the Koktuli River\u2014there is no lake\u2014meaning the Koktuli is an important habitat for these rare river-type fish.<\/p>\n