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January 13, 2012 | 11:46 AM | By

Washington state invokes Clean Water Act for ocean acidification

willapalens / flickr

Oysters - particularly babies - are exquisitely sensitive to ocean acidification.

In the fall of 2010, the EPA issued a memo stating for the record that the Clean Water Act covers ocean acidification, as well as more traditional types of pollution. While widely hailed as an historic call to action, the memo was full of qualifiers and caveats. First and foremost, few states would be expected to have the data necessary to request an “impaired” listing. Perhaps more daunting, such a listing would trigger legal requirements for corrective action – essentially an impossible standard to meet since nothing a state could do on its own would even touch the global phenomenon of ocean acidification.

So was this just political grandstanding destined to go nowhere? Maybe not.

In their latest report to EPA, the state of Washington has listed Puget Sound as “waters of concern” based on the impact of ocean acidification on the local shellfish industry. That’s a strategy that takes advantage of a work-around explicitly mentioned in the memo – demonstrating biological or ecological impacts attributable to ocean acidification, rather than documenting the subtle and slow-moving chemical phenomenon itself. It will be interesting to see whether other states follow suit; it could prove more difficult in areas with less pristine waters facing multiple impacts.

But back to the listing, itself. As explained in a press release from the Center for Biological Diversity, it’s kind of a half-way move:

In its new assessment, Washington again declined to identify coastal waters as “impaired” by acidification — a classification that would have required steps to curb carbon pollution causing acidification. Instead, only Puget Sound was put on the “waters of concern” list, a less urgent category.

This listing may not match the urgency that shellfish growers in the area feel, but it does at least give the problem some official standing.

FILED UNDER: Ocean Change, EPA, ocean acidification, oysters
February 9, 2011 | 3:54 PM | By

Most oyster reefs gone, but don’t panic

Thanks to NPR’s April Fulton for pointing me in the direction of a great oyster blog – In a Half Shell. In her most recent post, Half Shell blogger Julie Qiu says that the global decline of natural oyster reefs is a sobering ecological fact, but not reason for oyster lovers to panic. Here’s why (spoiler: aquaculture):

1. The majority of oysters that we eat today do not come from wild oyster reefs.

flickr/swamibu

Rest assured that the next time you sit down for a dozen oysters on the half shell, you are probably not destroying the last remaining native oyster beds. According to Monterey Bay Seafood Watch, ”Farmed oysters account for 95 percent of the world’s total oyster consumption. Most oyster farming operations are very well managed and produce a sustainable product.” Today’s most sophisticated aquaculture methods do minimal damage to the environment.

2. Restoring the oyster reefs will be vital to our environment, but aquaculture is key to supplying to the world’s long-term oyster demand.

The oyster is an important keystone species, which means that despite their small size, they have the potential to greatly impact the environment that they live in. As the study points out under the Oyster reefs and ecosystem services section, “Native oyster reefs provide many ecosystem services including water filtration, food and habitat for many animals (e.g., fish, crabs, birds), shoreline stabilization and coastal defense.” Research has also shown that “lost habitat caused by declines in oyster reefs is also linked to broader drops in coastal biodiversity, which has both intrinsic and economic value.” So saving them is a no brainer, but not exactly for the reasons that many blogs advertise.

We cannot expect wild oyster reefs to sustain the world’s insatiable appetite for them. While there are still many fisheries in operation on the East and Gulf coasts, the ultimate goal is to evolve towards aquaculture. When you think about all the other foods that you eat–fruits, vegetables, meat, even fish–almost everything is farmed and oysters are no different. By farming oysters, we reduce the stress on wild oyster populations. Keep in mind that a farmed oyster does not taste any different than a wild oyster–the biggest difference is that their quality of life has been significantly improved; thanks to the TLC they get from farmers! On the other hand, saving oyster reefs could very well improve the bounty of other seafood that we enjoy. So helping restore oyster reefs and promoting oyster aquaculture is a two-prong solution to ensuring future generations of happy raw bar patrons.

3. The optimal path towards conservation and restoration is a gradual one: we need to take care not to disrupt economic stability.

Given the overwhelming benefits of oyster reef protection and aquaculture, you might ask, “why don’t we just do away with wild oyster harvesting entirely and rely on purely oyster farming?” Like most issues involving the environment, it is a fine balance between maintaining economic stability today and investing towards the future. Tommy Leggett of the Chesapeake Bay Foundation estimates that there are roughly 400 Virginia and Maryland watermen who make part of their living off of the Bay’s wild shellfish. The oyster industry in the Gulf, the largest and healthiest reef in the US (despite the oil spill), still also depends mostly on wild harvest. Aggressive restrictions or banning it all together will cost thousands of jobs and sabotage the economic foundation that communities need in order to support conservation initiatives.

Efforts are being made to gradually move the industry away from wild harvests and towards aquaculture. … I think that the oyster industry will undergo a big evolution in the next couple of decades: legacy methods of harvest will become limited to tourist demonstrations and aquaculture will become the next big investment opportunity. Hopefully conservation and restoration will go hand in hand with commercial development.

Elsewhere on the blog, she journals her experiences tasting oysters from around North American. Here’s what she had to say about Massachusetts oysters:

Continue reading →

FILED UNDER: Human Impacts, Ocean Change, oysters
February 7, 2011 | 12:39 PM | By

Maine oysters: susceptible to climate change

Catherine Schmitt of Maine Sea Grant says that, unlike most of the world’s oysters, Maine’s oysters didn’t fall prey to overfishing and disease:

This is not the history of Maine oysters, which once thrived in the upper reaches of estuaries where water was warmer and less salty than the open ocean, but was deep enough to prevent freezing in winter. Despite harvesting by the native Wabanaki people (as evidenced by the large shell mounds along the Damariscotta River), the disappearance of Maine oysters is believed to be the result of climate-driven changes in hydrology along the coastline since the last Ice Age …

As the glaciers retreated, sea level rose, expanding the area of warm, brackish (salty, but not as salty as the ocean) waters. Schmitt says that initially Maine’s oysters thrived.

But sea level continued to rise, bringing with it predatory snails known as oyster drills and other marine animals which, in addition to fluctuating climate in the Gulf of Maine, caused the oyster population to crash. While a few oysters likely survived in small creeks along the coast, there weren’t enough to sustain the natives who had moved on to other sources of food. Later, European settlers lined the shores of the Damariscotta with brick yards and sawmills and cleared the land of trees. Clay silt, sawdust, and soil washed into the river, making the Damariscotta inhospitable to any oyster that attempted to return.

flickr/Lincoln Smith

But Schmitt says the story has a happy ending. Scientists and fishermen have been able to restore the native Maine oyster and build a $3 million oyster farming industry.

Of course, the tale also raises a question: what is the fate of Maine oysters in an era of renewed and rapid warming?

FILED UNDER: Human Impacts, Ocean Change, oysters
February 7, 2011 | 12:21 PM | By

Oysters: get’em while you can

Zachary Feldman/eater.com

The Oyster Doomsday Map highlights thirty five great spots to eat oysters.

In response to the news that 85% of oyster reefs have disappeared, Eater’s Zachary Feldman has created an Oyster Doomsday Map of thirty five great places to eat oysters while you still can. Union Oyster and Neptune in Boston both make the cut. But despite the resurgence of aquaculture to replenish the Wellfleet oysters that were so desired they were fished to near extinction a century ago, there’s not a single mention of Cape Cod. So, Cape Codders, you tell me (and Zachary Feldman): what’s the best place on Cape Cod to eat oysters?

FILED UNDER: Human Impacts, Ocean Change, oysters
February 4, 2011 | 3:06 PM | By

Not-so-new report on global decline of oysters

Source: BioScience 61: 107–116 / www.biosciencemag.org

A global survey of the condition of oyster reefs graded areas by comparing current and historical abundances: less than 50% lost (good), 50% to 89% lost (fair), 90% to 99% lost (poor), more than 99% lost (functionally extinct).

There’s a lot of ink being dedicated to a new study on the sad state of oyster reefs around the globe. Discover News’ overview of the study begins with this summation:

  • Oysters are disappearing fast and 85 percent of their reefs have been lost due to disease and over-harvesting.
  • The decline in oyster population often begins when trawling or dredging destroys the structure of parts of the reef.
  • When non-native species are introduced, they often bring with them diseases that further kill off the native oysters.

When I first saw the story, it seemed awfully familiar. So I dug around a bit and quickly found this press release put out by The Nature Conservancy in May, 2009:

Today, The Nature Conservancy released the first-ever comprehensive global report on the state of shellfish at the International Marine Conservation Congress in Washington, DC.  The report, which finds that 85 percent of oyster reefs have been lost worldwide, concludes that oyster reefs are the most severely impacted marine habitat on the planet.

The new study appears to be a peer-reviewed publication of the same work detailed in the 2009 report – same map (above) and listing of “144 bays in 40 ecoregions”, same authors (with one addition), same website for the 2009 report and supplemental information for the new paper … you get the idea. So it’s not exactly breaking news.

Reef restoration: How it works

Going through the peer review process does give the data some additional cred, though. And it’s an important – if sobering – finding. Oyster reefs are coast-saving structures and incredible, natural water filtration systems, as well as a source of good eats.

Both reports end on a hopeful note, providing recommendations for improving the global condition of oysters that can be summed up in three words – preserve, restore, manage. We’ve got a bit of the latter two getting started here in Wellfleet Harbor, where wild oysters were fished almost to extinction a century ago. Check it out.

FILED UNDER: Ocean Change, oysters
December 21, 2010 | 1:55 PM | By

How bad will it get for oysters?

Aragonite is the form of calcium carbonate that animals like corals and oysters use to build their skeletons/shells. As carbon dioxide absorbed from the atmosphere increases the acidity of the ocean, the ocean’s capacity for carrying aragonite – aragonite saturation – decreases, making it more difficult for aragonite-dependent animals to grow and survive. If aragonite saturation drops below 100%, aragonite structures (that’s coral skeletons and oyster shells) would dissolve. These new maps from the European Environment Agency – based on figures from a 2007 report by the Intergovernmental Panel on Climate Change – bring the usually invisible problem of ocean acidification into plain view.

Copyright: European Environment Agency

FILED UNDER: Ocean Change, ocean acidification, oysters
December 6, 2010 | 11:27 AM | By

Nitrogen (and pharmaceuticals?) on the half-shell

flickr/coollibrarian

There’s more than one way to skin a cat, or protect Cape Cod’s coastal waters from septic system pollution. Local environmental reporter Elise Hugus says growing shellfish presents an economically-beneficial way to meet state-mandated nitrogen limits (so-called Total Maximum Daily Loads) without the “lengthy, costly, and energy-intensive installation of a sewer system.”

A 2006 study of aquaculture in Waquoit Bay by WHOI’s Marine Policy Center found that 500 oysters and quahogs removed 0.1 kilograms of nitrogen per liter from the water, and an additional 0.1 kg from the sediment underneath the growing tray per year. … If grown on an exponential scale, aquaculture could potentially meet [Total Maximum Daily Load]  targets, especially if the inlets to some coastal ponds are also widened.

In a spreadsheet analysis of four coastal ponds in Falmouth facing Vineyard Sound, Mr. Zweig recommends setting aside 8-9% of Bournes Pond, Great Pond, and Green Pond for aquaculture, and about 22% of the heavily polluted Little Pond, in order to meet the state-mandated [Total Maximum Daily Loads].

But Hugus admits the aquaculture option isn’t perfect:

One additional issue that aquaculture does not address is the need for a wastewater solution that removes not only nitrogen, but a range of “contaminants of concern” from products consumed and eliminated by humans, now concentrated in your drinking water.

Even if shellfish were capable of filtering and sequestering aspirin, Viagra, and shampoo chemical residues from the water, would that solve the problem? (And would you want to eat them?) Or does it just point to a larger question: why are we contaminating fresh drinking water with our waste?

In my humble opinion, we need a variety of options to deal with our wastewater worries. If it is not conceivable to place aquaculture operations in coastal ponds on the scale necessary to remove the entire nitrogen load, it would be wise to eliminate the main cause of the contamination: septic tanks.

FILED UNDER: oysters, wastewater