Sponges face growing threats from trawling and proposed seafloor mining
Scientists at the National Oceanic and Atmospheric Administration have identified nine previously unknown deep-sea sponge species in the Gulf of Alaska and Aleutian Islands, the agency announced on Thursday. The discovery raises the total number of known sponge species in Alaska to 232.
The specimens were collected during NOAA Fisheries’ annual bottom-trawl surveys, which monitor groundfish and shellfish stocks. Researchers analyzed samples collected as far back as 2012, describing the new species in two recent scientific papers.
Sponges are among Earth’s earliest multicellular animals, dating back more than 600 million years, and act as what researchers describe as living water pumps. They filter seawater and help create habitats on the seafloor despite lacking a brain or complex organs.
“Sponges are ecologically important,” said Sean Rooney, a NOAA fisheries biologist and co-author of the studies at the agency’s Alaska Fisheries Science Center. “They aren’t plants, but like trees in a forest, they provide complex structure along the seafloor that creates habitat and refuge for commercially important fish and crabs.”
“Each time we find a new species, it opens up new doors,” Rooney said. “Deep water is hard to access, especially rocky places we can’t reach with bottom-trawl surveys. There are now more than 232 identified species of sponges in Alaska, and probably hundreds more that we don’t know about yet. The future in this field is exciting.”
Unlike most marine animals, which can be identified by visible traits such as fins and body shapes, sponges can be much harder to distinguish. Scientists often rely on their microscopic skeletons and genetic material to identify them.
“DNA barcodes provide a quick genetic reference,” said Meredith Everett, a biologist at NOAA’s Northwest Fisheries Science Center. “Sponge DNA can be tricky because they filter-feed, and within their tissues we may find foreign DNA and biochemicals that inhibit testing. But despite the challenges, we successfully developed several new barcodes for Alaskan species.”
NOAA considers dense sponge communities essential fish habitat because they provide shelter that supports fish survival, growth, and population recovery. Some sponge species produce chemicals to defend themselves against predators and competing organisms, and compounds derived from them have shown promise for potential use in cancer treatments.
Yet the habitats those sponges anchor are under growing pressure. The Trump administration has proposed expanding deep-sea mining in Alaska for critical minerals such as nickel and copper — used in military and technological applications — and the region is also subject to ongoing bottom trawling. Environmental groups have opposed both activities, warning they could damage fragile seafloor ecosystems as the climate crisis intensifies.
“Alaska’s sponge gardens do so much for a healthy ocean, including providing shelter and serving as vitally important nurseries for all kinds of fish and crabs,” said Cooper Freeman, Alaska director of the Center for Biological Diversity. “Bottom trawl fishing is so damaging and unsustainable because it indiscriminately destroys the habitats that support future generations.”
“Adding seafloor mining to the picture adds insult to injury, scraping up and devastating life on the bottom of the ocean,” Freeman said. “Instead of stewarding Alaska’s precious sponge gardens so they can support Alaskan coastal communities and wildlife, the Trump administration is pushing extractive marine activities on these irreplaceable seascapes for nothing but short-term profit.”
The administration’s deep-sea mining plans extend beyond Alaska. Federal proposals also call for exploring mining across millions of hectares of fragile Pacific ecosystems, including areas around the Northern Mariana Islands and Guam — a plan that has drawn backlash from the U.S. territories.