notes from underwater

Sustainability 2: Renewable Seed Source

2011-12-07T09:55:00.001-05:00

Sprinkling seed clams during fall plantout

In our shellfish aquaculture farm we restock our growing area each Spring with seed clams from a hatchery. As growers, we are concerned with producing a natural, wholesome food with a minimum impact on natural resources and the environment. To avoid impacting the salt marsh ecosystem where we grow our shellfish we harvest only the shellfish that we stock in our area. Since we replace the shellfish that we remove with a new crop each year we maintain a stable, healthy population of shellfish. Oyster seed are either hatchery reared or seed are collected in the wild. Using cement dipped cones or tiles growers can induce wild planktonic oyster larvae to settle and grow (spat collection). The tiny larvae attach themselves to these substrates and then grow into little oyster set or spat. In the absence of proper substrates, most of these planktonic larvae would perish. By providing artificial substrates, growers can increase oyster recruitment into the system. Many oyster restoration projects are currently underway that use these enhanced oyster recruitment techniques to reestablish healthy populations of wild oysters. Using hatchery seed and spat collection techniques in aquaculture means that a healthy sustainable population of shellfish can be cultivated without impacting the wild fishery. Furthermore, oyster spat collection by providing substrate which is otherwise limited enhances oyster recruitment.

Top ten benefits of sustainable shellfish farming

2011-07-08T16:22:00.000-04:00

#1: Farmed clams and oysters are native species grown in their natural habitat and have a critical role in tidal ecology.

The quahog or hard clam Mercenaria mercenaria and the eastern oyster, Crassostrea virginica are common native species on the tidal flats of Cape Cod. They are co-evolved with other local salt marsh organisms and we grow them at densities that are similar to those of historical populations of these species. The ability of healthy populations of clams and oysters to act as estuarine filters, taking in large volumes of water has a positive impact on the nitrogen budget of a tidal flat (Rice, 2001). Phytoplankton, which take up nitrogen from the water, are consumed by shellfish which incorporate the nitrogen into their body tissue in the form of protein. When the shellfish are harvested nitrogen is removed from the local system which helps maintain a healthy nitrogen balance in the bay (too much nitrogen in tidal waters leads to eutrophication and oxygen depletion). Furthermore bivalves deposit organic nitrogen in the sediments enhancing denitrification by sedimentary bacteria. Bivalves can also reduce turbidity by filtering phytoplankton from the water which increases light penetration to ecologically important sea grasses and micro algae on the bottom (Newell, 2004). In our growing area we are nurturing healthy bivalve populations that contribute to the overall well being of the tidal ecosystem.

Newell, R.I.E, 2004. Ecosystem influences of natural and cultivated populations of suspension-feeding bivalve mollusks: a review. J. Shellfish Research. Vol. 23, No. 1, 51-61.

Rice, M.A. 2001. Environmental impacts of shellfish aquaculture: filter feeding to control eutrophication. pp. 76-86 In: Marine Aquaculture and the Marine Environment. January 2001, Cape Cod Press, Falmouth, Massachusetts.

New Seed of the Year

2011-06-08T14:48:00.000-04:00

For the past two weeks we have been getting our new crop of clam seed from the hatchery and putting them out in nursery trays on our growing area. These babies will spend the summer growing in the trays protected from all the crabs, birds and fish that would gobble them up if left on the open flats. This bucket contains 100,000 little clams. Barb and Sara are putting a cup full, about 3,300 in each sand filled nursery tray. Eat plankton and grow young clam and one day you will be a littleneck!

Grow Up!

2010-11-08T18:50:00.000-05:00

Clams grow by depositing calcium carbonate on the margins of their shells. The shell material is produced and laid down by the soft tissue called the mantle which is in contact with the edge of the shell. The lines that you see on clams are growth rings that are analogous to the rings on tree trunks. Each winter the growth rate slows down as the water gets cold and the clam produces a pronounced dark ring. The clams at right are between three and four years old and you can see the darker annual rings.

Zen Bullraking

2010-10-24T14:38:00.000-04:00

Flat calm fall harvest morning

We harvest clams several hours around low tide in 2-3 feet of water. The bullrake is a long handled basket rake with about 20 teeth. Raking underwater helps the teeth liquefy the sand and push the clams into the basket. There is a rope attached to the base of the basket and clipped to a waist harness that we wear, so that we can pull on the rake with our body weight and our arms. Once you get the hang of it you can tell what your rake teeth are hitting - clams, rocks, shell, how numerous, how large and even sediment characteristics. Bullraking is a kind of zen activity which requires little time to learn but a lifetime to master, grasshopper.

Cleaning Rows

2010-10-09T16:30:00.000-04:00

Barb heads over to the fresh-water seep to wash off after cleaning rows.

We've been scratching the last few rows to prepare them for planting seed clams. Using hand rakes, we go through the 14' x 50'-100' rows to remove any clams left from previous crops and also pick up any shell and debris. We'll rake it one more time on the day we plant seed clams to remove any small crabs in the sediment, then we'll cover the row with netting.

Fall Foliage

2010-10-03T22:34:00.001-04:00

Ahhh, fall on Cape Cod. The scrub pines and oaks aren't much for fall color but the marsh grass, Spartina, turns a vivid rust color (what, you don't see it) which intensifies to a magnificent light tan as the grasses die back.

Stuck on you

2010-09-26T15:17:00.000-04:00

The closures we use on our clam nursery trays are peppered with oyster set. Oyster larvae settle in July and cement themselves to the closures just as they would to a rock or another oyster. A new study has described the chemical makeup of the amazing oyster glue. It is a combination of calcium carbonate (like oyster shells) and protein that has the ability to wet-set and create a very strong bond. A better understanding of the glue may help scientists develop techniques to enhance recruitment in dwindling oyster populations, develop adhesives for medicine or design green alternatives to boat anti-fouling paint. When we bring in our clam nursery trays we take the closures and twist them to pop off the oysters then put them in a mesh cage to grow.

Shake Shake Shake...

2010-09-22T13:56:00.001-04:00

Barb shakes a suitcase at sunup

Watched the sun come up this a.m., the first day of fall and shook out a bunch of clam nursery trays (aka suitcases). Cages are flipped and shaken to remove the sand and all that is left are the clam seed. Back at the shop we remove all the tiny crabs that have settled through the mesh of the suitcase and grown inside during the summer. Next we weigh and count the seed volumetrically so that we can plant at a constant density.

Spritzing Clams

2010-09-14T16:42:00.001-04:00

Sara shakes out the seed

Every chance we get we are transferring the clam seed from the nursery trays and dispersing them in rows covered with netting. The mesh is held down by lines and stakes and tucked into troughs around the edges to keep out predators like crabs, moon snails and gulls.

Net covered row

Monday Monday

2010-09-13T18:19:00.000-04:00

It was flat calm and crisp this morning - just right for a Monday morning harvest.

Jim, Nick and Barb wading out to bullrake

Great Blue

2010-09-12T12:37:00.001-04:00

This fella showed up in one of the beds we were preparing for clam seed. Blue crabs are at the northern most part of their range on Cape Cod and this far up the bay they are pretty rare. Last year when we were shaking out clam nursery trays in the shallows a HUGE blue reared up out of the water at us clapping its claws together threateningly- I'm saying it had an 18" claw-span. Now legend, (Jim wasn't there and makes doubting remarks about the behemoth) the Great Blue hasn't been seen since...until today when we ran into his baby brother...

Not wanting to anger the Blue Behemoth we set this little guy back down gently

Sowing the Seed

2010-09-12T12:14:00.002-04:00

Preparing the bed for the clam seed.

The clam seed have grown all summer in the nursery trays and it is time to move them out into the sand where they will burrow in and grow for the next two to three years until they are market sized. Preparing the beds and shifting the seed is an all hands on deck time of the growing season.

Seed clams from the nursery trays are readied for planting

Trying to beat the thunder to sow the seed and cover them with netting.

Busy in the Nursery

2010-06-14T16:59:00.003-04:00

We have been getting the nursery trays ready for the seed clams that we get from the hatchery. The tiny clams need protection from predators so we put them in fine mesh trays filled with sand. Each bucket pictured here contains many thousands of seed clams. When the tide is in the trays are submerged and the clams feed on phytoplankton and grow.

Sunday/Monday

2010-05-04T19:19:00.008-04:00

Sunday shucking and grinning at B and G Oysters

Monday digging and pulling on the beds

AM Harvest

2010-04-26T17:15:00.004-04:00

Harvesting this morning at 5:15. A loose flock of redwing blackbirds flew over chattering as we dug. The hard work was over before I was fully awake.

Death Button

2010-04-16T17:10:00.004-04:00

Here is something you didn’t know. When you are bullraking for clams in your chest waders, in about three feet of water, you can get an agonizing pain in your ankle. Why? The death button! The death button (d.b.) is the fold in your jeans where the cuff meets the inseam, creating a small button where the jean material is overlapped about six times. So what’s the problem?

Pressure at 1 meter beneath the surface of the water is 1.1 atmospheres or approximately 1.1x14.696 pound-force per square inch = 16.166 lbs/square inch. The d.b. is approximately 0.5”x0.5” or 0.25 of a square inch. The stiff rubber outer of the wader boot receives pressure from the surrounding water and presses on the d.b. effectively concentrating the pressure from a large area onto a small focused area. If we assume that the rubber is more or less rigid and we conservatively estimate that approximately 2 square inches of the boot transmits pressure to the d.b., than we can calculate the actual pressure in pounds per square inch applied to your ankle. Calculating: 16.166 lbs/sq. inch x 2 square inches = 32.332 lbs of pressure transmitted to the d.b. The actual pressure at the death button in lbs/sq. inch is four times this amount since the d.b. has an area of ¼ of an inch or a total of 129.328 lbs/sq inch!!! OUCH!!! The way we prevent this from happening is to fold our cuffs and tuck them into our socks, which effectively neutralizes the d.b. But if you forget… I think you can say that the quahog may be the deadliest catch, no?

Early Spring

2010-04-11T13:40:00.002-04:00

Yay for the early spring this year. The kick off to our harvest season has been without the bitter remnants of winter. The clams have begun to grow and are showing a white edge of new shell on their lips.

The State Shellfish

2009-11-17T15:53:00.006-05:00

Pictured at right are a gaggle of what ought to be designated the state shellfish of Massachusetts-the quahog. While we seem to have committed to a state muffin (the corn muffin) and state polka song Say hello to someone from Massachusetts, we've yet to choose a bivalve. Come on people! Used in a zillion local dishes like chowder, pasta with clam sauce, on the half shell, casino... and with a long history of use by native peoples and settlers alike, the quahog is a perfect candidate. What's more the quahog is grown here in Massachusetts through sustainable aquaculture. The kids from a Taunton Middle School have been doing their part in promoting our two shelled treasure lobbying the legislature. It's time that the quahog gets the kind of recognition that the beloved corn muffin enjoys.

2009-11-04T14:00:00.004-05:00

The beach roses are turning color but still no frost yet. Last night we were coming off the flats at sunset and the western sky was firey and the moon sat like a big orange ball on the eastern horizon.

Planting Seed Clams

2009-08-29T09:59:00.010-04:00

The nursery trays are popping with clam seed. The clams are large enough to be spread out in the sand in rows and covered with nets for the next several years until harvest. As the tide recedes we shake all the sand out of the nursery trays leaving just the clam seed. The trays are brought back to the shop where we can sieve the clams into large and small grades.

Barb and Sara are weighing clams to estimate numbers to control planting density. The following day clams are spread in the sand and covered with netting to protect them from predators. The clams will grow from the thumbnail sized seed to littleneck size over the next two years. The planting process will continue during the extreme tides through September and into October if necessary.

Wellfleet Oyster Tasting Notes- August

2009-08-01T13:23:00.014-04:00

Barb and I had Katie and Jim over for an oyster tasting to compare the three Wellfleet oyster varieties that we carry. We all eat lots of oysters, but I thought it might be a good idea to do it together more regularly, so we can try to get a handle on the seasonal and micro-terroir/'merroir' variations among Wellfleet oysters. Jim brought a bottle of Polish Zubrowka Bison Grass Vodka which we had shaken (not stirred) with ice- Good Start! It is very smooth and earthy flavored with a blend of the bison grass and potato and a nice accompaniment to oysters. We also sipped prosecco which is so crisp, light and refreshing that it is also a great compliment to oysters on the half shell in summer.

The shell characteristics, shape, color and of course taste of oysters grown in different areas within Wellfleet are remarkably different. Even oysters within a specific growing area vary in flavor with changes in season. Superimposed on these variations are genetic differences between seed that are started in a hatchery and seed collected from spawning in the wild. As a consequence, there is an overall flavor character for oysters from a particular growing bed but there are subtle variations with season and genetic variations.

Here are some general tasting notes.

Indian Neck- The Indian Neck oysters are rack cultivated from hatchery seed and exposed to currents from the open bay. They are very uniform, slightly oblong and deep cupped, relatively small and because they are so fast growing, quite thin shelled. As a consequence, they are a little harder to open but their flavor is superb. They were briny with a hint of sweet finish.

Lieutenant Island- These oysters are grown from naturally occurring seed in trays in an inlet near Lieutenant Island. They are heavy-shelled, oval to round, relatively large and have an excellent mild, creamy flavor with a salty liquor. The last time I had them, there was a very little hint of brine.

Old Wharf Point- Grown from natural seed, these oysters have irregular relatively heavy shells and a sweet, full flavor and a light briny finish.

There was some variation among individuals within growing areas due to spawning in the past month. Before the oysters have spawned they tend to be high in fat and very creamy flavored. As they spawn, some may have smaller meats, but are still very flavorful.

2009-07-24T11:02:00.005-04:00

We are starting to clear areas that we will use in the late Summer and Fall for planting our baby clams. These are older clam rows that have already been harvested, but still contain a few bushels of clams that we missed. We'll go through them with bullrakes and remove the clams and shell material. Each row is about 12 feet wide by 100 feet long and will be stocked with about 80,000 seed clams. Meanwhile, the seed are growing in their nursery trays, protected from crabs and birds, bathed by the tides, until we are ready to plant them out in the sand.

2009-06-24T13:37:00.004-04:00

After blowing a northeast gale for two days straight, it was calm with a misty drizzle, but still cool this AM. It has been a cold Spring with rain, rain, rain. At 8:30 the sun glowed through the mist and all of a sudden it felt hot and without a puff of wind, the no-see-'ems started up...SUMMER!

2009-06-11T17:46:00.008-04:00

Bucket-of-Clams

We have just gotten our seed clams from the hatchery. This bucket contains 200,000 babies. The seed will spend the summer in the nursery trays to protect them from predators like crabs, fish and birds. This is the first step in our process (see items 2 and 3 below in my post about shellfish farming and sustainability).

We stock them at a density of about 3000 animals/tray and by the fall they will be about thumbnail sized.

2009-06-11T11:32:00.006-04:00

Counting Clams

We're packing orders today and listening to Mike S.'s show on WOMR, it's a beat channeling of sixties B sides. Nick thought we should request In-A-Gadda-Da-Vida. Before we knew it, Jim got this CD from his truck (recorded from his original vinyl copy, of course). It's clam counting music to be sure.

2009-06-02T16:31:00.003-04:00

Shellfish and the impacts of global warming

Thirty percent of all carbon dioxide produced by burning fossil fuels is absorbed by the ocean. As a result, seawater becomes more acidic reducing the amount of carbonate, a component of the shells of oysters, clams and other shelled marine life. A recent study found that shell formation of larval oysters was significantly impacted when they were subjected to acid levels expected in seawater in the year 2100 when compared with those levels found in the oceans before the industrial revolution. Ultimately high concentrations of carbon dioxide in seawater could effect growth, distributioin and survival of larval oysters and other molluscs.

2009-05-27T10:55:00.002-04:00

In which we deploy nursery trays

The boys are back in town. They jumped right in and together with S. are helping gear up for the baby clams. We’re putting out our nursery trays. Before we can take this years’ crop of clam seed from the hatchery, we need to put our nursery trays out on the bed.

We string the mesh cages along a length of rope to hold them down, then fill them with native

sand. The trays protect the little seed, keeping the crabs and fish predators at bay (n.p.i.) while the seed are small.

Forty trays down, two hundred to go…

2009-05-24T14:32:00.001-04:00

Eastern Mud Snail Mosh Pit

The mud snails are running late this year or maybe there just aren’t as many. In the beginning of May,they come in droves to the sandy flats here on the Cape. Small pieces of shell or rock, the netting that we use to protect our clams and even little strands of algae are like islands for the breeding snails, since they need to lay their eggs on something solid. The snails mate then mosh by the thousands on the hard substrates, deposit their eggs and then disperse. Each case has about a hundred eggs, which develop into planktonic larvae called veligers in about a week. The tiny veligers bust out of the case and swim in the water for two weeks being washed to and fro by the tides. Then, they grow a shell, transform into little snails and sink to the bottom to take up their glamorous benthic, lifestyle as detritus-eaters. You will begin to see the little mud snails scavenging individually or in small groups during the end of May and June.

Scientific Name: Nassarius obsoletus

Classification: gastropod molluscs

Habitat and Range: Tidal flats from Nova Scotia to Georgia

2009-05-20T11:20:00.002-04:00

New Growth

The clean white ring of new growth on the edge of the clam shells is always a welcome site in spring. The clams feed and begin growing as the water warms and the food supply (microscopic phytoplankton) flourishes. The rings that you see on a mollusc shell are analogous to tree rings, except they radiate out from the hinge area in a geometric spiral. Calcium is slowly added to the lip of the shell as the animal grows. The growth rate decreases in late fall so the lines are bunched together forming a distinct annual growth ring.

2009-05-16T18:03:00.001-04:00

Delivering in Boston

An amazing lemon tart from the folks at Rialto-a meringuey top and a tart lemon filling on a shell- OMG!

Rt 3 S. heading for the Cape- I strayed....

2009-05-14T13:14:00.001-04:00

Bullraking at 7:30, I'm attached to the other end of the rope.

2009-05-13T13:29:00.000-04:00

Chip Chip

Ever since I became a loco-vore I only eat potato chips that are fresh, locally grown and sustainable PERIOD.

The Blue Revolution will be Televised

2009-05-12T13:49:00.003-04:00

I will be having an ongoing discussion of shellfish farming and sustainability. I hope to tackle issues like recycling, green packaging, minimizing waste and energy consumption and I will also explore the actual carbon impact of our kind of shellfish farming. In addition, I would like to discuss the environmental costs and benefits of cultivating naturally occuring species in coastal embayments. For now here are….

10 reasons why farming shellfish is a sustainable way to produce wholesome seafood

Sustainability has become a mantra for thoughtful consumers and food producers, but what does it mean in the context of shellfish farming? Sustainability is the capacity to maintain a certain process or state indefinitely. Of course, with the laws of thermodynamics and the tendency for systems to increase in disorder, ultimately, there are no truly sustainable processes. And while people are looking for absolutes or quick fixes, in the real world, it comes down to being practical. For producers, the goal should be to develop growing processes that can consistently generate a wholesome real food with a minimal impact on the environment and the most efficient use of resources.

We have been farming clams and oysters in Wellfleet and I believe that shellfish farming, as we practice it, is a sustainable and green (blue) form of food production. Since we started, we have been dealing with customers who value local, artisinally grown fresh clams.

What does sustainability mean to us? Here are the key components of our methods for shellfish production and distribution that are consistent with the overall objective of being sustainable.

We grow our shellfish in a healthy tidal sand flat that is the natural habitat for clams and oysters.
All the shellfish that we farm are spawned in a hatchery or in the case of some oyster seed induced to naturally settle on substrates provided.
Each year the beds are seeded with a new “crop” of shellfish.
Our shellfish feed on naturally occurring phytoplankton.
We do not give our shellfish any kinds of artificial feeds, fertilizers or drugs.
We only harvest what we have planted.
We hand-rake our shellfish instead of using mechanical dredges to minimize environmental disturbance and damage to the product.
We’re fresh and local, distributing the majority of our catch within 150 miles of where we produce them.
We are constantly thinking of ways to reduce waste, minimize energy consumption and recycle in our work.
Growing shellfish for local consumption reduces our dependence on imported seafood and over-utilized wild populations of fish.

For these reasons I believe that shellfish farming is a very efficient way of producing a natural whole food with a minimal impact on the environment. Farmed clams and oysters get a “best choice” designation by Seafood Watch from the Monterey Bay Aquarium and from the Shedd Aquarium because their cultivation has a minimal impact on the environment.

2009-05-07T11:18:00.001-04:00

Harvesting clams at 5:45, raining like the devil.

2009-05-05T16:04:00.000-04:00

Cold and rainy May.