Harbor seals are unfortunate and unwitting barometers for our polluted environment. An ecosystem poisoned by mankind with contaminants, sewage, trash and inorganic marine debris directly impacts their health and that of all living beings in and around the waters of Puget Sound, Elliott Bay and the Duwamish River. Harbor seals in particular are affected by pollution because they do not migrate, but instead, live year-round in our region. Their thick layers of blubber absorb and retain pollutants from our industrial waterways. In fact, a 2005 study showed the harbor seals of South Puget Sound were 7 times more contaminated than those living in Canada’s Georgia Strait. Biologists use tissue samples from both live and dead seals to monitor the health of the Sound, measuring levels of PCBs, increasing numbers of chemicals used in flame retardants known as PBDEs, pesticides and other highly toxic waste.
While a ban of PCBs has reduced those toxins in recent years, the number of chemicals used in flame retardants (including those known as PBDEs) have greatly increased. Studies show that PBDE concentrations have been doubling every 3.5 years and have even been detected in the high Arctic. Contaminants are stored in the blubber of marine mammals at the top of the food chain, such as dolphins, seals and orcas. The Southern Resident orcas are among the most contaminated marine mammals in the world. These toxins pass from generation to generation through the milk of mothers to their offspring. Humans, of course, are also at the top of the food chain - and those who consume fish from these toxic waters have high contaminant loads.
Harbor seal pups from our area, the Main Basin of Puget Sound, are more highly contaminated with PCBs and PBDEs than other areas of Puget Sound. Sadly, because seal pups are so contaminated, they are considered the ideal subject for these studies. Read the full study of contaminants in Puget Sound here. Exposure to flame retardants causes physical abnormalities (including that of the brain, impairing the development of motor activities and cognition), behavioral changes, impairs reproduction and causes immune disorders.
Recently biologists have discovered alink between contaminants and compromised immune systems of harbor seals. Weakened seals become vulnerable to parasitic infections, low body weight and numerous viruses, often leading to fatalities. Harbor seals and pups forage for food and haul out on the wooden piers and beaches in the highly industrial and contaminated Duwamish Waterway, a superfund project. A number of pups in this location were found by PAWS and WA Fish and Wildlife to have lungworm infestation, pneumonia and/or a fatal virus. Storm runoff adds (among other pollutants) human and animal waste, agricultural chemicals, highway oil and gasoline residue. Additionally, household chemicals and pharmaceuticals flushed down a drain end up in our waters --- and ultimately into our fish, seals and other marine mammals. Puget Sound now has areas where no marine life can subsist, known as "dead zones". View the recent Frontline PBS documentary "Poisoned Waters" which features our troubled Puget Sound here. Marine debris and trash is dangerous to seals, sea lions and other sea life. Plastic bags and balloons are often mistaken for food. If consumed by marine mammals, it can result in a slow and painful death. Plastic litter does not biodegrade; instead, it “photo-degrades” --- a process where sunlight breaks it down into minute pieces of plastic that enter the food chain. These plastic polymers are a magnet for pcbs and other toxic chemicals. Once ingested they create hormonal imbalances and affect reproductive abilities and brain activity in fish, invertebrates and marine mammals. Plastic litter from all over the earth ends up in the ocean, gets caught up in ocean currents and has created a giant swirling mass of 7 million tons of toxic debris twice the size of Texas --- dubbed the "Great Pacific Garbage Patch." The waters in this immense area contain 6 times more plastic than plankton, a primary food source for fish and marine mammals. The contaminant-laced plastic is found at all levels of the food chain in our oceans, ultimately affecting humans as well who consume seafood. To find out more about this environmental health disaster and to view a video, please click here and explore the links listed below.
HELP CLEAN UP PUGET SOUND WATERWAYS Duwamish River Cleanup Coalition. An alliance of community, environmental and small business groups whose mission is to clean up the Duwamish River. Puget Soundkeeper Alliance. A team of dedicated staff and volunteers whose mission is to stop pollution from entering Puget Sound.
People for Puget Sound. Established to protect and restore the health of Puget Sound land and waters through education and action.