{"id":606131,"date":"2026-04-14T11:23:24","date_gmt":"2026-04-14T11:23:24","guid":{"rendered":"https:\/\/www.newsbeep.com\/au\/606131\/"},"modified":"2026-04-14T11:23:24","modified_gmt":"2026-04-14T11:23:24","slug":"why-san-francisco-bay-has-suddenly-become-a-death-trap-for-gray-whales","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/au\/606131\/","title":{"rendered":"Why San Francisco Bay has suddenly become a death trap for gray whales"},"content":{"rendered":"

As the climate changes, many marine animals are on the move: shifting their usual locations as they try to find food or more suitable habitats. Sometimes, this puts them in harm\u2019s way as they travel into regions busy with human activity.\u00a0<\/p>\n

Now, scientists are sounding the alarm that\u00a0gray whales<\/a>\u00a0might be in trouble for this very reason.\u00a0<\/p>\n

According to a new study published in\u00a0Frontiers in Marine Science<\/a>, gray whales have started travelling into San Francisco Bay and 18 per cent of those that do end up dead \u2013 often killed after being hit by fast-moving boats.\u00a0<\/p>\n

The Eastern North Pacific population of gray whales make long migrations from the Arctic, where they feed, to the tropical lagoons of Baja Mexico to have their calves. They don\u2019t usually eat on the journey from one to the other. But this is changing.\u00a0<\/p>\n

As the Arctic warms, it\u2019s impacting the whales\u2019 prey and, in turn, the gray whales themselves.\u00a0<\/p>\n

\u201cSome individuals have adapted to forage in habitats south of the traditional Arctic feeding grounds,\u201d write the authors in the study.\u00a0<\/p>\n

These enormous animals didn\u2019t used to visit California\u2019s San Francisco Bay \u2013 not until 2018. Now they\u2019re being seen there, and scientists are worried. These waters are known for their intense boat traffic.\u00a0<\/p>\n

\u201cSan Francisco Bay is a highly trafficked waterway, and the Golden Gate Strait serves as a bottleneck through which all traffic and whales must enter and exit,\u201d says lead author\u00a0Josephine Slaathaug<\/a>\u00a0of Sonoma State University in a\u00a0statement<\/a>.<\/p>\n

When these\u00a0baleen whales<\/a>\u00a0come up to breathe, it\u2019s incredibly hard for boats to spot them \u2013 putting them at risk of getting hit by vessels. \u201cGray whales have a low profile to the water when they surface, and this makes them difficult to see in conditions like fog which are common to San Francisco Bay,\u201d she adds.\u00a0<\/p>\n

\"GrayA gray whale known as ‘Ladybug’ (or TMMC-1-91) swimming in central San Francisco Bay. This individual later died. Credit: Josephine Slaathaug\/The Marine Mammal Center. NOAA-NMFS Permit #26532<\/p>\n

The researchers created a catalogue of whales using photos by citizen scientists and opportunistic surveys from 2018 to 2023 along with systematic surveys from 2023 to 2025.<\/p>\n

According to their paper, at least 114 individuals have visited San Francisco Bay between 2018 and 2025. Only four of those were seen in the bay again.\u00a0<\/p>\n

They compared the individuals with necropsies (animal autopsies) of 70 gray whales that were found dead during the same time: 45 were identifiable and 21 of those could be matched to the researchers\u2019 catalogue.\u00a0<\/p>\n

\u201cAt least 18 percent of the individuals identified in San Francisco Bay later died in the area,\u201d says co-author\u00a0Bekah Lane<\/a> of the Center for Coastal Studies. \u201cOur broader analysis of local strandings both inside and outside San Francisco Bay found that over 40 per cent of these whales died of trauma from vessels.\u201d<\/p>\n

Malnutrition was identified as another cause of death.\u00a0<\/p>\n

\"SanGray whales enter San Francisco Bay via the Golden Gate straight. Credit: Frank Ramspott\/Getty Images<\/p>\n

The researchers want more studies to help them get to the bottom of what\u2019s going on. \u201cThese results are an important piece of the larger puzzle of what is going on in the overall population as they attempt to adapt to climate change in real time,\u201d says Slaathaug.<\/p>\n

If they can learn more about what\u2019s happening, it will help them find ways to protect gray whales. \u201cProtecting this population along its migratory corridor as it contends with a changing environment will be critical for the species\u2019 ability to rebound from its current decline,\u201d write the study authors.\u00a0<\/p>\n

\"Gray‘Ladybug’ (TMMC-1-91) seen in the foreground while a whale necropsy takes place on the shoreline of Angel Island State Park in San Francisco Bay. Credit: Josephine Slaathaug\/The Marine Mammal Center. NOAA-NMFS Permit #26532<\/p>\n

Top image: Satellite view of San Francisco Bay. Credit: Satellite Earth Art\/Getty Images<\/p>\n

More wildlife stories from around the world<\/p>\n","protected":false},"excerpt":{"rendered":"As the climate changes, many marine animals are on the move: shifting their usual locations as they try…\n","protected":false},"author":2,"featured_media":606132,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[26],"tags":[64,63,128,338],"class_list":{"0":"post-606131","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-wildlife","8":"tag-au","9":"tag-australia","10":"tag-science","11":"tag-wildlife"},"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/posts\/606131","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/comments?post=606131"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/posts\/606131\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/media\/606132"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/media?parent=606131"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/categories?post=606131"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/au\/wp-json\/wp\/v2\/tags?post=606131"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}