\n<\/p>\n
When Alaska\u2019s wolves began eating sea otters, it looked like a story of adaptation. Then they started getting sick.<\/p>\n
In the summer of 2013, two Alexander Archipelago wolves (Canis lupus ligoni), a subspecies of gray wolf, swam across a narrow channel to reach Pleasant Island, Alaska, a 19-square-mile rock jutting out of the stormy Gulf of Alaska. Wolves hadn\u2019t previously lived on Pleasant Island, and they quickly ran roughshod over the island\u2019s deer population. Within a few years, the wolves blossomed to a family of 13, and the deer, in turn, were entirely wiped out.<\/p>\n
As the deer declined, Gretchen Roffler, a biologist with the Alaska Department of Fish and Game, wondered about the wolves\u2019 fate. Would they abandon the island and swim back to the mainland, some 2 miles away? Or would they stay and starve to death? As it turned out, they did neither. Instead, the wolves adapted to island life in an unexpected way: They started eating sea otters.<\/p>\n
\u2018\u2019They\u2019ve learned how to kill them,\u201d Roffler says. By collecting and analyzing samples of wolf fur and scat, Roffler and her colleagues showed that sea otters now constitute a very large part of their diet. \u201cFrom 60 to 70 percent,\u201d \u00a0she said. The remainder is made up of salmon and other fish, as well as birds, such as ducks and bald eagles. The occasional harbor seal and Steller sea lion also make the menu.\u00a0<\/p>\n
In a rapidly changing world, predators adapting to new kinds of prey is, in many ways, a sign of adaptability and resilience. But unfortunately for Pleasant Island\u2019s wolf population, something dangerous was lurking in their new otter-heavy diet.<\/p>\n
In 2020, one of Pleasant Island\u2019s wolves \u2014 the pack\u2019s reproductive female \u2014 suddenly stopped moving. Roffler and her colleagues headed out to investigate, tracking the signal from the wolf\u2019s GPS collar. They discovered the wolf\u2019s emaciated corpse lying beneath a tree. Keen to get to the bottom of her death, Roffler and her team analyzed the wolf\u2019s tissue. Their research revealed something unexpected: the highest level of the toxic heavy metal mercury ever recorded in a wolf.<\/p>\n
The discovery triggered a broader investigation; Roffler and her colleagues looked for traces of mercury in fur and scat samples they had collected between 2020 and 2023 both from wolves living on Pleasant Island and the Alaskan mainland. The recently published results show that Pleasant Island\u2019s wolves suffer mercury contamination at concentrations 278 times higher than wolves in Alaska\u2019s interior. The data clearly shows that as wolves increased their consumption of sea otters, the mercury levels in their bodies soared, reaching levels similar to those sometimes found in polar bears \u2014 animals with some of the highest concentrations of mercury.<\/p>\n
The study, says Roffler, is a \u201cred flag that shows that we should be investigating what the sources of mercury are in this particular system.\u201d While none of the wolves died specifically from mercury toxicity \u2014 not even the reproductive female \u2014 high mercury levels can cause a range of health effects, including damage to the liver and kidneys. \u201cIn general, exposure to methylated mercury has effects on reproduction, body condition, and behavior in terrestrial mammals,\u201d says Roffler.<\/p>\n
But where is all this mercury coming from? Roffler\u2019s not sure, but she suspects it has to do with the many melting glaciers ringing the Gulf of Alaska. As glaciers melt, Roffler says, mercury trapped in the ice or scoured from the bedrock gets flushed into the sea. The mercury moves up the food chain, becoming more and more concentrated before it reaches the sea otters, which accumulate it in their bodies over the course of their lives.<\/p>\n
The situation on Pleasant Island may be a sign of a broader problem unfolding along the coast. \u201cWe are just starting to measure the mercury at a broader scale,\u201d says Roffler. If Roffler\u2019s connection between melting glaciers, sea otters, and mercury contamination is correct, then wolves and other predators reliant on marine mammals around the state are also likely suffering from growing mercury contamination.<\/p>\n
\u201cYou always think, \u2018Oh, good, these animals are figuring out ways to adapt and survive under new conditions,\u2019\u201d says Julie Young, a wildlife scientist at Utah State University who wasn\u2019t involved in the research. \u201cAnd then it\u2019s like, \u2018Wait, wait, wait, hold on.\u2019\u201d<\/p>\n
\u201cThey had that original study that showed this prey-switching behavior, which was really interesting and unique on its own,\u201d Young adds. \u201cBut then to follow up and find out it\u2019s not all good news is kind of interesting and surprising.\u201d\u00a0<\/p>\n
The fate of Pleasant Island\u2019s wolves seems to indicate that other wolves and wildlife could be exposed to mercury through the same pathway, and Roffler\u2019s team is already hard at work looking for signs of this on Pleasant Island and in the surrounding region, including around Glacier Bay National Park and Preserve. \u201cWe\u2019re looking at how much mercury concentrates throughout the food web and [how much] then crosses the barrier from the ocean environment to the terrestrial environment,\u201d \u00a0she says.\u00a0<\/p>\n
Wild animals, says Tom Jameson, a conservation biologist at Forest Research in the U.K. who wasn\u2019t involved in the work, can be incredibly flexible. As the world changes, the biggest thing we can do to help ensure they can adapt is to \u201cjust make sure that there\u2019s enough nature to be resilient,\u201d says Jameson. \u201cSo that even if we do have these problems, like pollution, that might be really, really hard to control, we can at least have the confidence that those [wildlife] populations are resilient and adaptable enough because they\u2019re big and healthy.\u201d<\/p>\n
\u2014Gennaro Tomma, bioGraphic<\/p>\n
Rain Comes to the Arctic, With a Cascade of Troubling Changes<\/strong><\/p>\n","protected":false},"excerpt":{"rendered":" When Alaska\u2019s wolves began eating sea otters, it looked like a story of adaptation. Then they started getting sick. In the summer of 2013, two Alexander Archipelago wolves (Canis lupus ligoni), a subspecies of gray wolf, swam across a narrow channel to reach Pleasant Island, Alaska, a 19-square-mile rock jutting out of the stormy Gulf<\/p>\n","protected":false},"author":1,"featured_media":39994,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[50],"tags":[8447,10518,4972,2266,13893,1099,3145,12294],"class_list":{"0":"post-39993","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-environment","8":"tag-alaska","9":"tag-amount","10":"tag-contamination","11":"tag-growing","12":"tag-mercury","13":"tag-record","14":"tag-sign","15":"tag-wolf"},"_links":{"self":[{"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=\/wp\/v2\/posts\/39993","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=39993"}],"version-history":[{"count":0,"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=\/wp\/v2\/posts\/39993\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=\/wp\/v2\/media\/39994"}],"wp:attachment":[{"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=39993"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=39993"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=39993"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}