{
  "id": 14045256,
  "title": "Chinook salmon return to historical habitat following removal of four US dams",
  "url": "https://urgent.news/2026/10/12/chinook-salmon-return-to-historical-habitat-following-removal-of-four",
  "topic": "science",
  "section": "Science",
  "published": "2026-10-12T21:11:47.000Z",
  "source": {
    "name": "Mongabay",
    "slug": "mongabay",
    "url": "https://news.mongabay.com/short-article/2026/10/chinook-salmon-return-to-historical-habitat-following-removal-of-four-us-dams/"
  },
  "original_language": "en",
  "account": "The Klamath River, located in the United States, faced significant obstruction in the 20th century due to the construction of numerous dams, which impeded the natural spawning grounds of Chinook salmon. Consequently, the population of these fish that once spawned in the river, traversing through Southern Oregon and Northern California, experienced a staggering 90% decline. However, a recent study has revealed that the removal of these dams has led to a rapid resurgence of the fish in the river.\n\nIn 2024, four dams were taken down from the Klamath, thereby permitting the Chinook salmon (Oncorhynchus tshawytscha) to reclaim the habitat that had been inaccessible to them for nearly a century. Shortly after the dams' removal, around 7,742 Chinook salmon embarked on their journey upstream along the Klamath River, bypassing the former dam sites. This number surged to over 13,000 in 2025. The study discovered that the fish had expanded into 345 kilometers (214 miles) of waterways that were previously blocked, recolonizing approximately 88% of their known historical spawning grounds.\n\nThe study's lead author, Damon Goodman, expressed in an email to Mongabay that while they anticipated the Chinook's return to the river, they were taken aback by the speed and magnitude of the fish's response. Goodman noted, \"These fish navigated challenging rapids, engineered fishways, and a large lake to reach habitats that had been inaccessible for more than a century.\" To observe the fish's movement, Goodman and his team utilized a specialized underwater sonar camera that employs sound waves rather than light to generate moving images of fish swimming through the river. This innovative technique allowed them to track the fish's progress and observe their ability to navigate through the various obstacles.",
  "summary": "The Klamath River in the U.S. was heavily dammed over the 20th century, blocking spawning Chinook salmon. As a result, the population of salmon that spawned in the river, which runs through Southern Oregon and Northern California, declined by roughly 90%. However, a recent study found that removing the dams resulted in a quick return […]",
  "key_points": [],
  "editors_take": null,
  "illustration": null,
  "coverage": {
    "outlets": 1,
    "also_reported_by": []
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}