The Pissing Off of Summer Lawns

Way to go Falmouth. The Cape Cod town that is home to the Woods Hole Oceanographic Institution, one-third of Cape’s estuaries, and the state’s Alternative Septic System Test Center  wants to restrict lawn fertilizer in an attempt to cut back on the amount of nitrogen flowing into its estuaries; those coastal ponds and embayments that tragically have a tradition of turning colors and killing fish.

Guess who doesn’t like the idea?

In this morning’s Cape Cod Times, Sean Teehan reports the town is working on a bylaw that:

“…would prohibit nitrogen-containing fertilizer applications between Oct. 16 and April 14 each year. It would ban applications during heavy rain or within 100 feet of water resources and bar applications to turf of more than one pound of nitrogen per 1,000 square feet each year.”

Yes, most  of the nitrogen polluting the harbors, bays, coves, coastal rivers and streams of Cape Cod comes from urine, aka wastewater. It also comes from dogs who take dumps during their beach walks, Canada Geese who deposit their green cigar turds, and, most maddeningly, those big ChemLawn trucks with their sloshing tanks that trundle down streets with names like Oceanview and Seaview and then spray their chemical contents all over the lawn of some CEO’s starter castle so it will look all lush and green like the back nine at Augusta when Courtney gets married to Alistair this summer.

Opposed to Falmouth’s bylaw are:

  • The Massachusetts Association of Lawn Care Professionals
  • The Retailers Association of Massachusetts
  • Scotts Miracle-Gro Co.
  • Assorted local landscapers

They are arguing to the Massachusetts Attorney General that Falmouth’s proposed bylaw conflicts with a pending regulation that would let the State Department of Agricultural Resources regulate the stuff. Seems logical to categorize lawn grass as agriculture. I  enjoy tucking into a nice bowl of mower clippings myself.

Unfortunately, it appears Falmouth is pushing for the fertilizer limits so it can discharge some of its effluent from its wastewater treatment plant, a request the state has said no to because the town is already exceeding its nitrogen limits:

“DEP officials granted a discharge permit for Falmouth’s wastewater treatment plant on the condition that the town eliminate other sources of nitrogen in the groundwater, Town Counsel Frank Duffy said. They ordered the town to look into controlling fertilizers.”

The Cape Cod Commission and every other town on the Cape needs to get a copy of Falmouth’s bylaw and enact it from the Sagamore Bridge to the Pilgrim Monument in P-town.  Cleaning up dying harbors and bays seems more important than lush lawns or a green golf courses overlooking floating mats of brown slime and algae.  Wastewater treatment solutions, sewers, composting toilets, and the like may take decades to happen, but banning or cutting back on fertilizer can happen now and make a bit of a dent as well as a strong statement that the Cape can be mended and not written off like Long Island or South Florida.

Last July Falmouth’s Little Pond suffered a fish kill when warm weather and eutrophication depleted the oxygen in the salt pond and left a lot of dead striped bass on its shores.  Another fish kill happened in North Falmouth the year before.

Lawn lovers of the Cape, think twice this spring before you load up the SUV with a couple bags of TurfBuilder and spread it over your grass. Embrace the Brown and let it die this summer. Save on your water bills, your back, and your future and just say no to the ChemLawn.

If you want to take care of your lawn, then do it organically. There’s a lot of free advice, I’d start with which has an interesting history of the lawn, and how in America, it is a relatively modern phenomenon with roots in Levittown on Long Island:

“In the middle of the 20th century, three overlapping developments helped promote the lawn across North America. The first was Levittown, one of the first cookie-cutter affordable-dwelling suburbs, built between 1948 and 1952 by Abraham Levitt and his sons William and Alfred on Long Island. This was the first American suburb to include lawns already in place when the first tenants took possession (see Levittown: Documents of an Ideal American Suburb).

“The Levitts, who also build subdivisions in New Jersey, Pennsylvania, Cape Cod [emphasis mine, ed] , and Puerto Rico (several of them also called Levittown), pioneered the established lawn, which residents were required to keep up but forbidden to fence in. The importance of a neat, weed-free, closely-shorn lawn was promoted intensely in the newsletters that went out to all homeowners in these subdivisions, along with lawn-care advice on how to reach this ideal.”


Some resources on the topic of limiting fertilizer runoff:

Town of Nantucket Regulations: these are proof local municipalities can take some steps to limit landscaping fertilizer impacts.

The Buzzards Bay Coalition has a ton of stuff on the topic: 

Dead Neck/Sampson’s Dredging Hearing Tonight

The Barnstable Conservation Commission will return to the application by Massachusetts Audubon and Three Bays Preservation to dredge 800 feet off of the west end of Sampson’s tonight at the hearing room at town hall beginning at 6:30 pm.

I’ve heard some interesting rumors about the project over the past few weeks, so tonight’s meeting is probably going to be as lively as the last one was in terms of participation by foes and proponents. I’m planning on attending and may speak my mind on the project. I’ll post any remarks if I make them.

To that end I’ve been asked to post the following statements from a proponent and opponent to the project:

In favor is Andrew “Oggie” Pesek,  an officer of Three Bays and director of the Wianno Yacht Club, who forwarded this letter asking the membership of the Wianno Yacht Club in Osterville  for their support for the project. (disclosure: my family were briefly members of the WYC in the 1970s): DNSI_WYC_Letter

Opposed is Brad Wheelwright, a Cotuit resident, member of the Cotuit Mosquito Yacht Club (more disclosure, I am a lifelong member of the CMYC and former president of its association), and ace Cotuit Skiff racer. Brad sent the following:

“I am writing to express my views on the proposed Sampson’s Island dredging project.

I am strongly opposed to the project, mainly because I’m convinced that it would constitute inappropriate use of public funds and resources. An undertaking of this magnitude and expense should be easily justified from every perspective, not widely controversial and based upon questionable assumptions, as this proposal is proving to be.

However, even if dislodging, moving, and placing 11 acres of land wasn’t going to cost a great deal of money and require great quantities of labor, fuel, and machinery, I would still be firmly opposed to this project. First of all, moving that much sediment will cause dirty, disrupted water conditions for quite some time, undoubtedly harming the ecosystem of Cotuit Bay and West Bay. Shellfishing is a longstanding source of recreation, subsistence, and commerce for the residents of the count and should not be compromised without clear justification.

Secondly, I do not think there is a valid boating safety concern, as some proponents have indicated. I use those waters frequently and there is plenty of room for safe navigation as the geography stands. I believe my point of view on this matter is supported by a lack of any alarming history of accidents at the site. In fact the only fatality (or injury, for that matter) that I know of occurred nearly thirty years ago, when the distance from Reilly’s Beach to Sampson’s Island was much greater.

In addition, careful study (conducted by those in the hire of the project’s proponents) has demonstrated that widening the entrance will not in any significant way increase the Bay system’s tidal flushing or lead to cleaner water in the more inland connected waterways. The root of that problem clearly lies with septic inputs and fertilizer pressure, and it is of some concern to me that members of the public seem not to know how thoroughly the coastal engineering studies prove that dredging will not begin to address the issue.
The part of Sampson’s Island that is proposed to be removed is a heavily used recreational resource. Crowding is already a problem, and the destruction of many hundreds of yards of beach will only compound it (and perhaps also lead to unanticipated and unwelcome water safety concerns).

While it has been pointed out that several vacation houses on Grand Island and the navigability of the Seapuit River are at risk without the addition of sediment at the eastern end of Dead Neck, I do not think this justifies the proposed dredging project. Neither protection for the private residences or the easy availability of a Seapuit channel are publicly necessary; private funding could and should secure the former, and there are two very reliable alternative water routes between West Bay and Cotuit Bay, one of which is entirely protected.

Finally, I would like to bring attention to the worst case scenario associated with such intensive dredging of a protective barrier island. Typically, the failure of a coastal engineering project is marked by a return to the status quo (witness the Rushy Marsh Pond debacle). However, the dynamics of a bay entrance are beyond complex, and I believe there is potential for catastrophe here that very few people have considered. It is possible that this project could lead to dramatic, unanticipated changes to the area. Bluff Point, without protection, could be destroyed. The Cotuit entrance channel could become too shallow for conventional navigation. The balance that has allowed for a viable Bay entrance could be upset beyond all hope of repair.

Why do I think this could happen? Strikingly, the sea level has risen approximately four inches in the last sixty years, and according to some science, may rise twelve inches or more in the next sixty. There is reason to think that coastal storms will become stronger and more frequent. In so many ways, our climate is not the climate of the mid 20th century.

Some proponents believe that because the dredging will return the outline of Sampson’s to a former state, it is inherently a good thing. First of all, with the sea level four inches higher, and a catastrophic worst-case scenario accordingly possible, there is absolutely no reason to think that such an outline is sustainable now. Furthermore, this argument represents a flawed method of consideration; the historical proportions of Cotuit Bay once included a shipping channel where Cupid’s Cove now exists. Should we engineer THIS alteration, simply because it once was? (It’s really no more outlandish than the present proposal, in terms of scope and the amount of sediment that would need to be moved.)

Finally, I would like to point out that Three Bays Preservation has continually implied that dredging projects in the system improve water quality significantly, something that is not backed up by any of the data. Just as one example, their website mentions improvement and prospects for improvement, but on the very same website one can find evidence that eel grass existed within the three bays in 1995 but not in 2002, a timeframe that spans their first two dredging projects. Furthermore, the anticipated improvement in water quality (as estimated by their own engineers) is minimal enough that it doesn’t even appear within proposal documents as part of the list of expected benefits.”

I am “cautiously” in favor of the project with some modifications. I’ll post my points for and against later.

Dead Neck/Sampsons Island dredging update

Wednesday night the Cotuit Santuit Civic Association met at the Cotuit Library to hear representatives from Three Bays and Mass Audubon describe their proposed dredging and bird habitat restoration application. Engineers were also in attendance to answer questions.

This was an informational session for the members of the Association. January 8 the application will be presented to Barnstable’s Conservation Commission for its review, part of a long permitting process that will require sign off from the town’s waterways and shellfish committees, the state, and eventually the Army Corps of Engineers.

The application is for a permit to dredge, in three winter phases, about 800 feet or 11 acres of sand off of the western spit of Sampsons and backfill it through pipes to the east end by the Wianno Cut, the man-made breach dug through the sand spit in the early 1900s. This would build up the sand-starved section behind the western jetty of the cut, prevent an over-wash and breach of Nantucket Sound through the island into the Seapuit River, and re-establish a gentle berm on a beach that is now a sheer wall of eroded scarp unsuitable for the nesting shorebirds that make the barrier island one of the most important shorebird breeding areas in Massachusetts.

Here’s a bullet list of random new things I learned. If you want to get smart about the project, go to the 3 Bays website and take a look at the application and engineering plans yourself.

Conclusions: I remain in favor, but the sad reality is this is a Sisyphean project that will need to be repeated over and over. The culprit in everybody’s mind is the “armoring” of the coast line by the wealthy waterfront owners in the late 19th and early 20th centuries with groins, bulkheads and jetties. If we were to seek an everlasting solution then the answer would be to remove the Osterville jetties, plug the Wianno Cut, and force the removal of all man made structures along the coast line that now impede the natural coastal drift of the sand.

And even then, if that impossible vision were achieved, we’d need to confront that fact that rampant coastal development has utterly trashed the interior estuaries and getting nitrogen levels down is the only way to get water quality back to pre 1970-Rape-Of-The-Cape levels.

So, dredge away and dredge some more, don’t bring your dog to the island, read up, and get involved.

Wild Oysters

A reader of Mark Kurlansky’s excellent history of the New York oyster fishery knows the hardshelled bivalve (Crassostrea virginica) was an important piece of  19th century cuisine and commerce during the earliest years of the nation’s history. Vast “reefs” blanketed the shores and bottoms of the bays and inlets from New Jersey through the southern New England coastline, offering a plentifully cheap protein source that was the mainstay of most American diets.

Those reefs were once so extensive and played such an important role in the health of the estuarine systems that one writer, Paul Greenberg bemoaned their absence in the New York Times as a contributing factor to the devastation wreaked by Superstorm Sandy. A frightening 85% of the world’s oyster reefs have vanished since the 1800s. Oysters’ role as a stabilizer influence, but most encouragingly as a very effective water filtration system, makes them not only a delicacy but a necessity in the rebuilding of a sick coastal embayment. Greenberg wrote:

“Just as corals protect tropical islands, these oyster beds created undulation and contour on the harbor bottom that broke up wave action before it could pound the shore with its full force. Beds closer to shore clarified the water through their assiduous filtration (a single oyster can filter as much as 50 gallons of water a day); this allowed marsh grasses to grow, which in turn held the shores together with their extensive root structure.”

Yesterday I took an old friend and his wife for a brief oystering expedition. The boat had been parked in the yard for last week’s three-day northeaster. I pulled out handfuls of maple leaves from the bilge. Returned the gas tanks, and launched her back into the bay on the morning tide.  Being sunny, a veritable Indian Summer day* with no wind, sparkling sunshine, and a light haze on the horizon covering the beaches of Popponesset and beyond, it was a good day to take a break from the raking and the housework and get on the water. My friend is working on a photojournalism project about oystering, and she has been filming the various sources for the clams: fish markets, the Cotuit Oyster Company, and the town of Barnstable’s annual oyster season where the Department of Natural Resources lays out its crop of cultivated oysters on the bottom around a couple local beaches and turns loose the wadered permit holders to perform what Cousin Peter and I deride as “shopping” and not “clamming.”

Peter and I discovered a clutch of wild oysters in a never-to-be-disclosed location about ten years ago, and have been careful not to over-harvest from there, making one or two visits during the fall and winter months to pick up a dozen or so for the table. Reluctantly I took my friend and wife out yesterday in the name of journalism, imploring them to maintain some secrecy as the oysters are very tenuous and scarce compared to the wild abundance of oysters around the flats of Wellfleet’s Lieutenant Island. Put another way, when I was a kid, and the harbor was healthy, we never collected oysters. Steamers and quahogs were it. Oysters were nowhere to be seen (or we weren’t looking in the right places) and could only be bought from Dick Nelson at the oyster company (always with a reminder not to do something stupid like cook with them, since Cotuit’s are to be savored raw, on the half-shell, with only a squeeze of lemon juice if you must.)

I took along the dog (see the canine below in the dinghy and the halloween costume) as she is manic about “go-ride-boat” and beach walks. I dug out and pinned my shellfish license to my Kettleer’s cap, pessimistically brought along my leaky waders, Ribb rake and wire basket, and met my friends at the town dock on the afternoon’s low tide. It was an extraordinarily low one that exposed an extra rung of slippery ladder, but we boarded safely and put-putted across the deserted harbor, all boats gine but a few doughty fishermen’s, the field of white and blue-striped mooring balls replaced with winter sticks, giving the place the appearance of a military cemetery in Normandy. The channel cans were gone, prudently pulled by the harbormaster in advance of Sandy and the northeaster, so I was navigating by the seat of my pants, assisted by the completely clear water that revealed some of the dead, dead bottom below us.

As we motored away from the dock we talked about the recent kerfuffle raised by some of the town’s shellfish activists who donate their time and backs to relaying bushels of quahogs from “dirty” areas high in the tidal rivers to cleaner spots lower in the bays where recreational clammers get can get their limit without fear or picking up some nasty sickness. A crew of local commercial clammers have been flouting the laws and exercising their native-American aboriginal riparian rights to shellfish on any day of the week in any water of their choosing without a license. They allegedly wiped out the volunteers’ efforts to manually repopulate one or two local clean beds. I’d seen the Indian clammers in question working off of Lowell’s Point during winter beach walks this past winter. Their pickup truck had bumper stickers pledging their allegiance to the Wampanoag Nation, but I thought little of it until a family member active in the Barnstable Association of Recreational Shellfishermen ranted about their depredations over dinner a few weeks back. Now a big sign forbidding commercial shellfishing adds to the over-signification of the Cotuit waterfront (another rant for another day) but I doubt it will do much to deter the Indian clammers.

I am of a mixed mind when it comes to aboriginal fishing rights as I am solidly pro-Wampanoag to the point that I am sort of pissed off by the whole “kettle and a hoe” thing that defines Cotuit’s local waterhole, baseball team, and an ugly sign across the street in the park (yet another rant for another day). The connection between Wampanoag culture and shellfish is organically intertwined, with ancient “middens” or shell piles still to be found along the pine bluffs and beaches of the Cape’s harbors. Wampum, the woven currency of the tribes, is made from the purple part of a quahog shell; and the tribes used to move their encampments between an inland winter camp up near Hamblin’s Pond (according to local historian Jim Gould) and summer coastal camps generally picked based on proximity to shellfish. It has been often said that the bravest man in the world was the first man to dare to eat an oyster, and doubtlessly that man was some long passed Wamp who watched a gull drop one from a great height onto a boulder to crack it open and then sagely wondered what morsel lay inside that could be eaten. Anyway, more on the Indian clamming issue later, I am not that ardent a shell-fisherman to contribute my time to the relays and in fact, will use this post to make a controversial contrarian statement in favor of encouraging the comeback of our wild stock as a harbinger of healthy waters, rather than promote more aquaculture and its veneer of health and well being.

Back to the hunt for the wild oyster. We anchored, we went to the beach where they have been found in the past, and lo and behold, despite my pre-expedition pessimism that we would be lucky to get one or two, we found an abundance tucked on the verge of the beach grass along the rockweed and the horse mussels, sticking up plain as day in their  glued embrace to the allegedly inedible mussels. Pictures were taken, video videoed, and within half an hour my friend had his fill, and we had ample opportunity to marvel as the health of the wild oysters.

Our theory is these are refugees from the Oyster Company’s owner Chris Gargiulo’s cages of cultivated oysters laid on the bottom of Cotuit Bay in the company’s grants , arguably the oldest brand name in American clams, a holdover from the days when the bilious gourmand Diamond Jim Brady would tuck into three dozen Cotuits at Rector’s in belle epoque Manhattan before settling in for a full meal. I still feel a pang of homesick pride whenever I meet a friend for a bite and a drink at Grand Central’s Oyster Bar and see Cotuits on the menu. The Oyster Company represents all that is good and all that is lost from Old Cotuit, and no one is more devoted to the bay than Chris.

And, I like to think thanks to his seeding efforts, some microscopic spat** have escapes from the cages on the floor of the harbor and make their way on the currents to the mussel beds, where they glue themselves on and flourish. Oysters are unique clams in that they can live exposed to the air and do not need to be submerged all the time. Tropical oysters festoon mangrove roots, wild Cotuit oysters like the very verge between grass and water — submerged half the time and exposed the rest.

The foodie fad that has gives us “locavores” would put a premium on these wild clams. The fact that Cotuit’s wild oysters are thriving — there must be ten times the abundance there was when Cousin Pete and I first discovered their existence — is good news of a sort in a time of very bad news over the bad quality of the coastal estuaries. I continue to maintain that change and action to restore the bays to their former perfection are doomed unless those who remember what we’ve lost are able to share that picture of what could be to the new wave of residents and washashores who look out at the pretty vistas and see nothing but twinkling waves and picturesque sailboats. These oysters are there, they are visible. They aren’t under a foot of sand, masked by algae blooms or turbid waters churned up by weekend propeller parades, they are right on the water’s edge, waiting to be picked up, volunteering their siphons and gills to filtering the mess we’ve managed to make over the last 50 years. And I have no idea what the place looked like before the Army trashed North Bay with Camp Candoit in World War II. I imagine the shoreline was a very very different place 100 years ago.

The clam activists are on the forefront of the outrage of what is now called our “beautiful dirty waters.” They were able to put in place a ban on private piers (with the extraordinary backing of Cotuit’s former town councilor Rick Barry). They wade the muddy waters, they tote the bushels and lobby for the equipment and budgets to keep the clams going strong. I propose they also push for wildness — and use the presence of healthy, wild shellfish as a sort of litmus test for their efforts. Want to “vista prune” your bluff so your starter castle can have a water view? Then you better be able to prove a healthy intertidal zone with oysters that test out pure and clean. Need to truck in a couple barges of boulders to build up a groin or some riprap to keep the next superstorm from eating away at your Chemlawn? How are those wild oysters doing? Need to drive some toxic “pressure-treated ” wood into the sand to form a tidy bulkhead? Not so fast.

I took water samples for the Three Bays Preservation Society during the summer months (I was Test Station #19), driving them to the County Lab in Barnstable Village. I do so happily, but something tells me that seeing an oyster peeking out of the mussels and rock weed at Ropes Beach would say more about the health of the harbor than a parts-per-million bacteria test.




*: “Indian Summer” is technically any day when the temperature reaches 70 degrees following the occurrence of a killing frost.

**: “Spat” is the oysterman’s term for oyster spawn. Oysters grow incredibly quickly and achieve maturity in one year.

Cape Cod Fish Kills: How Much Worse Is It Going to Get?

In the department of poo:

Depressing news out of Little Pond in Falmouth, one of the long salt ponds along the Falmouth shore from the Inner Harbor to Waquoit Bay: over the weekend a bunch of striped bass –some apparently up to 40 inches in length — were found dead on pond’s shores. The culprit? According to the press it’s septic tank pollution from the gazillion houses that surround the pond.

Looking at the density of the houses some lucky developer was able to cram into the area long ago, and add in the fact that each and every one of those houses flushes their toilets into big holes in the sandy ground, who can be surprised that a ton of effluent is leaching into the water? I’m amazed that a significant stack of bass were up inside of such a stagnant pool this time of year (perhaps they followed a school of baitfish in from the clean water of Vineyard Sound) and I can’t understand how anyone, particularly the people who live around there, can sit back and do nothing. The alarm is ringing and it doesn’t smell very nice.

This isn’t Falmouth’s first fishkill. Another one occurred a year ago, nearly to the day, in North Falmouth. Fish kills aren’t rare — so-called “oxygen events” occur regularly in ponds and backwaters with restricted water flow.

The density of development along the south shore of the Cape is astonishing and one has to wonder what the town officials thought they were doing when they zoned postage-stamp lots along the estuaries.  It’s obvious to me that something has to be done to get the shit out of the bays, and the shoreside ghettos of Falmouth seem as good a place to start as anywhere with small, local cluster treatment plants. A big pipe solution is not going to fix these neighborhoods anytime soon, and persuading, even mandating everyone starts pooping into composting toilets is laughable.

I’m starting to warm up to composting toilets (not a great choice of words). Last year Barnstable County had a program offering to install the things on a 20-year, zero interest loan in the homes of people with failed septic systems who were considering a Title 5 septic project. Two friends in Cotuit have installed the technology. One was put in at least a decade ago, the other is going in right now in a new construction project. I was given a tour of the installation and it was pretty amazing — it’s called a Phoenix –but had some limitations in a retro-fit scenario as the composing tanks need to be located generally directly below the toilet itself (which looks like any ordinary toilet). As I have a minimalist Cape Cod cellar (essentially a round, brick lined root cellar sort of thing) I’d have to jack the house up, excavate a new basement, and then, and only then could I consider a composting solution (I could consider a composting outhouse I suppose ….)

People will going to freak out at whatever solution is proposed because it will cost them a lot of money to get there.  When Barnstable hooked the Paine Creek neighborhood in Hyannis up to the municipal waste water treatment center there were pitchforks and torches at the town council meetings.

The estimate for a new Title 5 compliant septic tank is generally $20,000 — and those do nothing to get nitrogen out of the watershed.

The state has an online tool to search for your local beaches and the results of their water tests. Here in Cotuit, water is tested outside of the harbor at Loop and Oregon Beaches. I’ll be working later this week with the Three Bays Preservation organization to initiate private testing at Ropes Beach, where we had a town ordered closing in 2007. Here’s a link to the Barnstable County department of health’s site for beach testing. One beach in Barnstable failed this week – Lovell’s Pond in Cotuit.


Cape Cod Times story

Falmouth Enterprise story

State report on Little Bay nitrogen sources.

Natural Nitrogen Mitigation: “bionutrient extractors”

In evaluating the options available to remove nitrogen from the Cape’s estuaries, there are both mechanical and biological solutions to look at as well as “social” actions to reduce inflows. Mechanical solutions would involve sewers and a centralized sewage treatment plant or a complete rethinking of the state’s current state of the art in cesspool specifications, Title 5 systems, and replacement with a local, personalized nitrogen remediation system, composting toilets, and other emerging technologies. Social actions would cover actions such as the regulation of fertilizers.

Biological mitigation is interesting and has a nice “organic” ring to it. The science has been studied for years on the Cape at the Marine Biology Laboratories (MBL) in Woods Hole and at the Waquoit National Estuarine Research Reserve. This would encompass the use of shellfish to filter and process nitrogen and other pollutants, as well as the introduction of seaweed aquaculture. The Cape Cod Times of April 19 reports on the potential of an Asian species of seaweed — gracilaria — to capture nitrogen. Scientists at the MBL are studying the ability of gracilaria to process nitrogen in a study at Waquoit. [Link is to the Cape Cod Times which is pay-walled].

The town of Mashpee studied the ability of oysters to remove nitrogen in 2008. The shellfish constable reported on the effort which took place in the Mashpee River, once regarded as one of the finest sea-trout fisheries in the world and a fishing destination in the mid-19th century by the likes of Daniel Webster. The good news is that clams are good nitrogen-eaters. The bad news is they only make a dent in the problem:

“The 2008 harvest of 520,000 oysters removed about 260 kilograms of nitrogen from the estuary based on analysis of oysters sampled from the river (0.5 g N/oyster). This was about 4% of the 6563 kg of nitrogen reduction needed to meet the Total Maximum Daily Load (TMDL) for nitrogen in the river required by the Massachusetts Department of Environmental Protection (MA DEP 2006, Report #96-TMDL-4). New oyster seed is purchased every year with the goal of harvesting a million oysters a year removing 500 kg of nitrogen. This would be about 8% of the reduction needed to meet the TMDL for nitrogen.”

The Mashpee trial report is here.

(Side note — the Total Maximum Daily Load is the holy number at the center of the discussion. The Conservation Law Foundation sued the Environmental Protection Agency for not setting and enforcing the TMDL standards as set out by the Clean Water Act.)


The use of seaweed to mitigate nitrogen is a news to me.  My only reservation is the potential for an invasive species issue such as the one the Cape is suffering from codium, the thick, rubbery seaweed nick-named “deadman’s fingers” and “oyster thief.” That stuff invaded New England in the 1950s from Europe and is now regarded as a pestilence. According to the Cape Cod Times, gracilaria has proven itself in a trial on the Bronx River in New York State, “If the Waquoit plants do as well as their New York cousins, they’ll remove two to four times as much nitrogen from the water as do oysters, another highly touted bionutrient extractor, the fancy term for the process.”

And as an added benefit, the seaweed has commercial value and could become a cash crop.



Exit mobile version