It All Flows Downhill

Storm drain with notice “No Dumping, Drains to Ocean”

From the time we were little we have heard that water flows downhill……and indeed that’s true. Water and all the “stuff” that’s in it, including chemicals, hormones, bacteria and viruses, parasite eggs (to say nothing of the “stuff” the parasite eggs are in), particulates and plastics, cigarette butts, all kinds of things. Creeks flow into lakes, lakes into streams, streams and rivers into the ocean. Gravity just about guarantees anything and everything we discard eventually gets into the ocean, because it’s about as downhill as you can get. Sometimes we call this “land to sea transfer”

Here, around Monterey Bay, the storm sewers and lots of street drains go directly into the ocean. Since oil floats on water, the tons of oil that cars leak onto the streets, and the toxic chemicals and metals that it contains, go into the ocean. More oil reaches the oceans from street runoff every year by far than all oils spills in any year combined. Really nasty and concentrated bursts of chemicals result when people pour crankcase oil, paint or chemicals are into curbside gutters or street drains.

Most of the time, in most of the cities around Monterey Bay, commercial and home sewage goes to treatment plants. Secondary sewage treatment, the most common form, eliminates most of the solids and many, but certainly not all, bad bacteria. However, recent studies at sewage treatment plants around Monterey Bay show that, some very bad bacteria not only don’t always get removed by treatment, but under some conditions, more of some dangerous bacteria come out in effluent water than are found in the incoming sewage. The eggs of some protozoal parasites, notably Toxoplasma and Sarcocystis, that cause serious brain and systemic infections is sea otters and other marine animals, are not only not filtered out or killed, but studies show they may actually become more infectious as a result of oxygenation during sewage treatment. An article in the April 2012 issue of Journal of Wildlife Diseases is the latest word on this form of land to sea transfer or “pathogen pollution.”

Unfortunately some older cities around the bay, Pacific Grove being an example, have sewer pipes that are old, small diameter clay pipes put in when Pacific Grove was plotted out as sites for summer cabins and tent camps for church groups 80-100 years ago. Clay pipes leak, get old and crack, particularly as ground settles. They were never designed to handle the sewage of a densely populated town, certainly never designed to take lots of street runoff, and things like food and grease from restaurants, one of the worst things for clogging small diameter pipes. And when sewer pipes clog the sewage often overflows to storm drains and goes to the ocean. Pacific Grove has a history of many small and some larger sewage spills and beach closures.

But, here’s some news. About half the population around Monterey Bay, those in the unincorporated areas, which includes large portions of Santa Cruz and most of northern Monterey County, are not on sewage lines. They rely on septic tanks and leach fields. Guess what, even under the best of circumstances septic tanks are designed to distribute waste out onto the land, and they fill up, leak and everything they release FLOWS DOWNHILL.

Much of the very productive farmland around the bay has been in intense production for 100 years or more. During the 1940-60’s this meant heavy use of DDT and other pesticides. The levels of DDT and its active breakdown products DDD and DDE, organophosphates, as well as dozens many other pesticides, herbicides, and also PCB’s, industrial solvent and insulating oils, as well as plasticizers, are found at levels in California sea otters that are anywhere from 30 to 100 times the levels seen in sea otters in more pristine areas of Alaska.

North of Castroville, Tembledero and Morro Cojo sloughs, empty into the old Salinas River channel. These are two of the most pesticide impaired waterways in California. These pesticides cling to tiny organic matter particles and all end up in Moss Landing Harbor, Elkhorn Slough and then Monterey Bay. No wonder sea otter males sampled in Elkhorn Slough a few years ago had the highest levels of multiple contaminants ever seen.

The intense agriculture in our area requires intensive use of fertilizers. Nitrates contaminate water in various parts of our area making it unfit for human consumption. There is a growing body of evidence that urea, a popular fertilizer, but also the form of nitrogen waste excreted by mammals (most of which live on the land) causes or contributes to harmful algal blooms (HAB’s) that produce a toxin called domoic acid (DA). DA quickly accumulates in top feeding small fish like anchovies as well as more slowly in mussels and clams that are eaten by sea lions, dolphins, pelicans, cormorant, sea otters and people. Remember the epidemics of seizuring sea lions of few years ago ? DA destroys parts of the brain causing depression, muscle tremors and seizures and in people permanent loss of short term memory (amnesic shellfish poisoning).

Phosphates from fertilizers, soaps and other sources can also contribute to harmful algal blooms. Although it is illegal under State laws to allow anything to flow into creeks, streams or the ocean that is harmful to marine birds, mammals or the ecosystems on which they depend, very little has been done to monitor these chemicals that act as fertilizer for blooms of harmful diatoms, dinoflagellates and algae.

One of the scariest recent local findings is that a some of our local lakes that are high in phosphates can foster massive blooms of cyanobacteria, so called “blue green algae”. They produce microcyctin toxins that are 1000 times more potent than DA and can destroy the liver of a dog or a human being in a few days. After finding sea otters near the mouth of the Pajaro River in 2009 dead from liver failure due to microtoxins, known to come from cyanobacteria, CDFG scientists tracked it back upstream. Increasing levels or microtoxin were found upstream in the Pajaro and into Corralitos Creek, and the levels found in surface waters from Pinto Lake, that empties into the creek, were over a million times higher than the level allowed by EPA in drinking water.

Sea otters are a sentinel, one of the most sensitive and useful wildlife sentinels ever found, of toxins, bacteria, parasites and chemicals flowing from land to sea in the Monterey Bay area. The effects on sea otters and their populations are so severe that these various forms of pollution are one of the more important reasons our California sea otters are not recovering from their “threatened” state. And, it essentially all comes from land, that means it comes from us, all of us. But there are things we can do about it. Some are simple but others are complicated and require sampling, monitoring, policy and law enforcement…..

These are things like:

Enforcing total daily maximum loads (TMDL’s) under the Clean Water Act.

Enforcing CDFG code 5650 for all point source, or suspected point source, pollutants.

Improving State and Regional Water Board oversight.

Improved sewage infrastructure.

Conversion from septic to sewage.

Reducing overuse and runoff of fertilizers and developing better and mandatory (not voluntary) agriculture best management practices (BMP’s).

Mitigating some of the worst polluted areas, like Moro Cojo and Tembladero Sloughs, maybe by use of artificial marshes and water impoundments.

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Make a donation to the California Sea Otter Fund. California taxpayers can support sea otter research and conservation by making a contribution on their California income tax form 540. Simply look for line 410, labeled CA Sea Otter Fund, under contributions and fill out the amount you wish to donate.


Miller, M.A.,I.A. Gardner, D. Paradies, K. Worcester, D. Jessup, E. Dodd, M. Harris, J. Ames, A. Packham, P.A. Conrad 2002. Coastal freshwater runoff is a risk factor for Toxoplasma gondii  infection of southern sea otters (Enhydra lutris nereis).  International Jour. Parasit. 32:997-1006.

Kreuder, C., M. Miller, D. Jessup, L. Lowenstine M.D. Harris, J. Ames, T.E. Carpenter, P.A. Conrad, J.K. Mazet. 2003. Patterns of mortality in the southern sea otter (Enhydra  lutris) from 1998-2001. J Wildl. Dis. 39(3): 495-509.

Kannan, K., H. Nakata, N. Kajiwara, M. Watanabe, N.J. Thomas, D.A. Jessup and S. Tanabe. 2003. Profiles of polychlorinated biphenyl congeners, organochlorine pesticides and butyltins in southern sea otters and their prey: Implications for PCB metabolism. Environmental Toxicology and Chemistry. 23(1): 49-56.

Jessup, D.A., M. Miller, J. Ames, M. Harris, P. Conrad C. Kreuder and  J.A.K. Mazet.  2004. The southern sea otter (Enhydra lutris nereis) as a sentinel of marine ecosystem health. Ecohealth. 1(3):239-245

Conrad, P.A., M.A. Miller, C. Kreuder, E.R. James, J. Mazet, H. Dabritz, D.A. Jessup, F. Gulland, M.E. Grigg. 2006. Transmission of Toxoplasma: Clues from sea otters as sentinels of Toxoplasma gondii flow into the marine environment. Int. Jour. Parasitol. 35, 1155-1168.

Jessup, D.A., M. Miller, C. Kreuder-Johnson, P. Conrad, T. Tinker,J. Estes, J. Mazet.  2007.  Sea otters in a dirty ocean.  Jour. Am. Vet. Med. Assoc. 231:11, 1648-1652

Johnson C.K., M.T. Tinker, J.E. Estes, P.A. Conrad, M. Staedler, M.M. Miller, D.A. Jessup, J.A.K. Mazet. 2008. Prey choice and habitat use drive sea otter pathogen exposure in a resource-limited coastal system. PNAS: Biological Sciences-Ecology 106(7); 2242-2247.

Miller M.A., B.A. Byrne, S.S. Jang, E.M. Dodd, E. Dorfmeier, M.D. Harris, J. Ames, D. Paradies, K. Worcester, D.A. Jessup, W. A. Miller.  2009. Enteric bacterial pathogen detection in  southern sea otters (Enhydra lutris nereis) is associated with coastal urbanization and freshwater runoff. Veterinary Research. 41:01.  doi:10:105/vetres/2009049

Miller M. A., P.A. Conrad, M. Harris, B. Hatfield, G. Langlois, D.A. Jessup, S. Magaral, A.E. Packham, S. Toy-Choutka, A.E. Melli, M.A. Murray, F.M. Gulland, and M.E. Grigg. 2010. A protozoal-associated epizootic impacting marine wildlife: Mass-mortality of southern sea otters (Enhydra lutris nereis) due to Sarcocystis neurona infection. Vet Parasitol. 172(3-4): 183-94.

Jessup, D.A., C. Johnson, J. Estes, D. Carlson-Bremer, W.M. Jarman, E. Dodd, T. Tinker, M. Ziccardi. 2010.  Persistent organic pollutants in blood of free ranging sea otters (Enhydra lutris) in Alaska and California. J. Wildl. Dis. 46(4):1214-1233.

Miller M., R.M. Kudela, A. Mekebri, D. Crane, S.C. Oates, M.T. Tinker, M. Staedler, W.A. Miller, S. Toy-Choutka, C. Dominick, D. Hardin, G. Langlois, M. Murray, K. Ward., D. Jessup. 2010.  Evidence for a novel form of harmful algal bloom: Cyanotoxin transfer from land to sea otters. PLoS One 5(9): e12576. doi:10.1371/journal.pone.

Brownstein D., M.A. Miller, S. Oates, B. Byrne, S.Jang, M.J. Murray, D.A. Jessup. 2011. Antimicrobial susceptibility of bacterial isolates from southern sea otters (Enhydra lutris nereis). J. Wildl. Dis. 47(2):278-292.

Miller M.A., B.A. Byrne, S.S. Jang, E.M. Dodd, E. Dorfmeier, M.D. Harris, J. Ames, D. Paradies, K. Worcester, D.A. Jessup, W. A. Miller.  2009. Enteric bacterial pathogen detection in southern sea otters (Enhydra lutris nereis) is associated with coastal urbanization and freshwater runoff. Veterinary Research 41:01.  doi:10:105/vetres/2009049

Daniel Rejmanek D., Vanwormer E., Miller M.A., Mazet J.A.K., NichelasonA.E., MelliA.C., Packham A.E.,Grigg M.E., Jessup D.A., Conrad P.A. 2009. Prevalence and risk factors associated with Sarcocystis neurona infections in opossums (Didelphis virginiana) from central California. Veterinary Parasitology. 166(1-2): 8-1

Jessup, D.A, Miller, M.A. The Trickle-down effect: How cat pathogens harm sea otters. Spring 2011 Wildlife Professional In focus: The impacts of free-roaming cats 64-66.

Schriewer A, W.A. Miller, B.A. Byrne, M.A. Miller, P.A. Conrad, D. Hardin, Hsuan-Hui Yang, S.C. Oates, N. Chouicha, A. Melli, D. Jessup, S. Wuertz.  2010.  Comparison of Bacteroidales markers, fecal indicator bacteria, and pathogens in rivers, estuaries, and wastewater treatment plants in the Monterey Bay region of California. Applied and Environmental Microbiology. Appl. Environ. Microbiol. 76(17): 5802-5814

Jessup D.A. 2011. Southern Sea Otters: Stuck in Recovery. Outdoor California. January

Miller M, R. Kudela, D. Jessup. 2012. When marine ecosystems fall ill: Harmful algal blooms and marine biotoxins. Wildlife Professional. 6(1):44-48.

Jessup, D.A, Miller, M.A. 2012. Southern Sea Otters as Sentinels for Land-Sea Pollution. IN: Conservation Medicine: Applied Cases of Ecological Health. A. Aguirre, R. S. Ostfeld and P. Daszak, Eds. Oxford University Press, NY, 10016

Yang H.H., W.A. Miller, S.C. Oates, M.A. Miller, N. Chouicha, D. Jessup, D. Hardin, C. Dominik, M. Harris, B.A. Byrne. 2012. Pathogen detection and indicator bacteria for evaluating water quality and ecosystem health along the California coast. Microbial Ecology. (in prep).

Oates S.C., Miller M.A., Byrne B.A., Chouicha N., Hardin D., Jessup D.A, Dominik C., Roug, A., Schriewer A., Jang S.S., Miller W.A. 2012. Epidemiology and potential land-sea transfer of enteric bacterial pathogens from terrestrial to marine species in the Monterey Bay region of California. J. Wildl. Dis.  (In press)

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About is dedicated to raising awareness about California's threatened sea otters and the role research plays in the species recovery and conservation. It's a collaboration of the Monterey Bay Aquarium, U.C. Santa Cruz, U.C. Davis, U.S. Geological Survey, U.S. Fish & Wildlife Service, California Department of Fish and Wildlife, among others. is also home of the world's first HD live stream of southern sea otters in the wild.