{"id":36643,"date":"2026-09-12T09:39:00","date_gmt":"2026-09-12T13:39:00","guid":{"rendered":"https:\/\/www.ecoticias.com\/en\/?p=36643"},"modified":"2026-09-11T11:28:17","modified_gmt":"2026-09-11T15:28:17","slug":"sea-lions-learned-to-wait-below-bonneville-dam-and-the-fish-ladder-meant-to-help-salmon-became-a-dinner-bell","status":"publish","type":"post","link":"https:\/\/www.ecoticias.com\/en\/sea-lions-learned-to-wait-below-bonneville-dam-and-the-fish-ladder-meant-to-help-salmon-became-a-dinner-bell\/36643\/","title":{"rendered":"Sea lions learned to wait below Bonneville Dam, and the fish ladder meant to help salmon became a dinner bell"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\">At <a href=\"https:\/\/www.nwd.usace.army.mil\/fact-sheets\/article\/3485127\/bonneville-dam-and-lake-bonneville\/\" target=\"_blank\" rel=\"noopener\">Bonneville Dam<\/a> on the Oregon-Washington border, the sea lions from California learned that they can \u201cwait for dinner\u201d below the hydroelectric structure, since spring salmon go around that area searching for fish-ladder entrances.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The latest federal monitoring shows that this is not the best scenario. Between April 6 and May 17, 2025 it was estimated that sea lions ate around 2.943 spring Chinook salmon. The main story is not simply that the predators eat their prey, but that the <a href=\"https:\/\/www.ecoticias.com\/en\/beavers-kept-rebuilding-dams-in-oregons-aging-canal-turning-a-century-old-embankment-into-a-safety-hazard-engineers-finally-had-to-address\/35963\/\">human infrastructure<\/a> can teach intelligent animals where and whn vulnerable wildlife will be.<\/p>\n\n\n\n<figure class=\"wp-block-embed is-type-video is-provider-youtube wp-block-embed-youtube wp-embed-aspect-16-9 wp-has-aspect-ratio\"><div class=\"wp-block-embed__wrapper\">\n<iframe loading=\"lazy\" title=\"Leaders urge action to stop \u2018repeat offender\u2019 sea lions eating salmon at Bonneville Dam\" width=\"1200\" height=\"675\" src=\"https:\/\/www.youtube.com\/embed\/u7i0cEW90a8?feature=oembed\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share\" referrerpolicy=\"strict-origin-when-cross-origin\" allowfullscreen><\/iframe>\n<\/div><figcaption class=\"wp-element-caption\"><em>Youtube: @KGWNews8<\/em><\/figcaption><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\">A human-made bottleneck became a dinner bell<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">What is happening at Bonneville can be compared to traffic jams, but in this case underwater. Here the concentration turns an enormous river into a dining area for sea lions. Specifically, <a href=\"https:\/\/www.ecoticias.com\/en\/a-fish-elevator-on-a-maine-dam-could-reopen-600-miles-of-river-to-a-small-fish-and-the-whales-people-keep-mentioning-are-not-part-of-the-story-yet\/35703\/\">fish ladders<\/a> help the salmon pass the barrier, but they end up crowded together in the tailraces where the sea lions can hunt them with much less effort than in an open river.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">California sea lions learned the pattern<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Researchers discovered that the animals learned that in the exact same place at approximately the same time of the year, they would find a lot of prey. of the year. Social connections influenced which animals found Bonneville Dam and if they came back, while <a href=\"https:\/\/royalsocietypublishing.org\/rspb\/article\/283\/1844\/20162037\/78331\/Epidemiological-models-to-control-the-spread-of\" target=\"_blank\" rel=\"noopener\">earlier modeling<\/a> indicated that information about the feeding opportunity could spread through the population much like an infection.<\/p>\n\n\n\n<div class=\"gb-element-4619900d\">\n<div><div class=\"gb-looper-da7f5719\">\n<div class=\"gb-loop-item gb-loop-item-d1345eab post-36643 post type-post status-publish format-standard has-post-thumbnail hentry category-environment resize-featured-image\">\n<h4 class=\"gb-text gb-text-e76a3fbb\">Read More: <a href=\"https:\/\/www.ecoticias.com\/en\/sea-lions-learned-to-wait-below-bonneville-dam-and-the-fish-ladder-meant-to-help-salmon-became-a-dinner-bell\/36643\/\">Sea lions learned to wait below Bonneville Dam, and the fish ladder meant to help salmon became a dinner bell<\/a><\/h4>\n<\/div>\n<\/div><\/div>\n<\/div>\n\n\n\n<p class=\"wp-block-paragraph\"><a href=\"https:\/\/www.fisheries.noaa.gov\/feature-story\/early-action-key-reducing-sea-lion-impacts-salmon-new-study-finds\" target=\"_blank\" rel=\"noopener\">NOAA researcher Zachary Schakner<\/a> said that starting earlier makes it easier and more effective to stop the spread. And this shows how big the problem is. In the same line, as he says, changing a food habit is difficult after it is sustained for a long time.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"1800\" height=\"1013\" src=\"https:\/\/www.ecoticias.com\/en\/wp-content\/uploads\/2026\/09\/california-sea-lion-surfacing-oregon-water.jpg\" alt=\"A California sea lion surfacing in river water\" class=\"wp-image-36704\" srcset=\"https:\/\/www.ecoticias.com\/en\/wp-content\/uploads\/2026\/09\/california-sea-lion-surfacing-oregon-water.jpg 1800w, https:\/\/www.ecoticias.com\/en\/wp-content\/uploads\/2026\/09\/california-sea-lion-surfacing-oregon-water-300x169.jpg 300w, https:\/\/www.ecoticias.com\/en\/wp-content\/uploads\/2026\/09\/california-sea-lion-surfacing-oregon-water-768x432.jpg 768w, https:\/\/www.ecoticias.com\/en\/wp-content\/uploads\/2026\/09\/california-sea-lion-surfacing-oregon-water-1536x864.jpg 1536w, https:\/\/www.ecoticias.com\/en\/wp-content\/uploads\/2026\/09\/california-sea-lion-surfacing-oregon-water-150x84.jpg 150w\" sizes=\"auto, (max-width: 1800px) 100vw, 1800px\" \/><figcaption class=\"wp-element-caption\">A California sea lion surfaces in Oregon water, photographed by the Oregon Department of Fish and Wildlife, one of the agencies that counts the salmon taken below Bonneville Dam.<\/figcaption><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\">The 2025 figures show the pressure is still real<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">During the spring 2025 monitoring season, the U.S. Army Corps of Engineers documented minimum counts of sea lions and how many fish they ate. Their data showed that California sea lions ate a disproportionate number of salmon.<\/p>\n\n\n\n<div class=\"gb-element-9a1973c8\">\n<div><div class=\"gb-looper-23e2e879\">\n<div class=\"gb-loop-item gb-loop-item-1db81efe post-36330 post type-post status-publish format-standard has-post-thumbnail hentry category-environment resize-featured-image\">\n<h4 class=\"gb-text gb-text-ce2edaf7\">Read More: <a href=\"https:\/\/www.ecoticias.com\/en\/three-harbor-seals-followed-turbine-rows-in-the-north-sea-turning-offshore-wind-foundations-into-hunting-stops-scientists-did-not-expect\/36330\/\">Three harbor seals followed turbine rows in the North Sea, turning offshore wind foundations into hunting stops scientists did not expect<\/a><\/h4>\n<\/div>\n<\/div><\/div>\n<\/div>\n\n\n\n<p class=\"wp-block-paragraph\">Observers estimated that sea lions ate around 2.098 salmon chinook, 102 white sturgeon and 28 steelhead during those monitorations. Researchers said that although some of the numbers for other fish can be quite small, they can still carry a heavy ecological weight.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Scaring sea lions away has clear limits<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Wildlife managers have tried many ways to see if they can push them away from the dam. They tried things like disruptive noise or pyrotechnics, but the results were not what they expected. A specific study of<a href=\"https:\/\/www.frontiersin.org\/journals\/conservation-science\/articles\/10.3389\/fcosc.2021.760866\/full\" target=\"_blank\" rel=\"noopener\"> Steller sea lions<\/a> showed how after a repetitive exposition, they became less responsible and sensitive to them.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Two wildlife protections now collide at the dam<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">This is not a simple story about a \u201cbad\u201d predator. Actually, the California sea lions could appear with more strength after the <a href=\"https:\/\/www.fisheries.noaa.gov\/west-coast\/marine-mammal-protection\/marine-mammal-protection-act-section-120-pinniped-removal\" target=\"_blank\" rel=\"noopener\">Marine Mammal Protection Act<\/a>. At the same time, several Columbia Basin salmon and steelhead stocks are still being protected under the Endangered Species Act. And at Bonneville, both conservation laws meet in the exact same stretch of water.<\/p>\n\n\n\n<div class=\"gb-element-5262ed70\">\n<div><div class=\"gb-looper-10d70170\">\n<div class=\"gb-loop-item gb-loop-item-eb41017a post-36506 post type-post status-publish format-standard has-post-thumbnail hentry category-energy resize-featured-image\">\n<h4 class=\"gb-text gb-text-ec3ac1e2\">Read More: <a href=\"https:\/\/www.ecoticias.com\/en\/a-wyoming-mountain-could-become-a-972-megawatt-water-battery-but-the-project-may-disturb-the-trout-waters-below-seminoe-reservoir\/36506\/\">A Wyoming mountain could become a 972-megawatt water battery, but the project may disturb the trout waters below Seminoe Reservoir<\/a><\/h4>\n<\/div>\n<\/div><\/div>\n<\/div>\n\n\n\n<p class=\"wp-block-paragraph\">Things reached such a point that NOAA authorized local agencies to remove some sea lions. Some of them could even face lethal removal when no zoos or aquariums accept the animals. With these measures, officials confirm that recent removals appear to be reducing the number of repeat predators, but the ethical and <a href=\"https:\/\/www.ecoticias.com\/en\/la-rioja-and-the-drained-reservoir-protected-species-emerge-and-experts-are-worried-about-what-could-come-next\/32520\/\">ecological tradeoff<\/a> is still uncomfortable.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Bonneville offers a warning for other dammed rivers<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Projects like the one at Bonneville can actually improve access around a barrier, but in doing so, tight zones are created and that makes things predictable for the predators. That is why new projects need constant control that goes beyond the analysis if fish technically pass, and instead looks at how much time they wait, where they bunch up, and what learns to hunt them.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Bonneville Dam&#8217;s fish ladders turned into a predictable feeding spot, teaching sea lions when and where to hunt salmon.<\/p>\n","protected":false},"author":19,"featured_media":36744,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"class_list":["post-36643","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-environment","resize-featured-image"],"_links":{"self":[{"href":"https:\/\/www.ecoticias.com\/en\/wp-json\/wp\/v2\/posts\/36643","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.ecoticias.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.ecoticias.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.ecoticias.com\/en\/wp-json\/wp\/v2\/users\/19"}],"replies":[{"embeddable":true,"href":"https:\/\/www.ecoticias.com\/en\/wp-json\/wp\/v2\/comments?post=36643"}],"version-history":[{"count":4,"href":"https:\/\/www.ecoticias.com\/en\/wp-json\/wp\/v2\/posts\/36643\/revisions"}],"predecessor-version":[{"id":36746,"href":"https:\/\/www.ecoticias.com\/en\/wp-json\/wp\/v2\/posts\/36643\/revisions\/36746"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.ecoticias.com\/en\/wp-json\/wp\/v2\/media\/36744"}],"wp:attachment":[{"href":"https:\/\/www.ecoticias.com\/en\/wp-json\/wp\/v2\/media?parent=36643"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ecoticias.com\/en\/wp-json\/wp\/v2\/categories?post=36643"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ecoticias.com\/en\/wp-json\/wp\/v2\/tags?post=36643"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}