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PostPosted: Wed Jul 19, 2017 11:27 am    Post subject: Eels, Eelgrass&The Bay Scallop Fisheries 1880 -2000 #61- Reply with quote

IMEP #61-B Habitat Information for Fishers and Fishery
Area Managers
Understanding Science Through History
(IMEP History Newsletters can be found indexed by date – Title on the BlueCrab.info™ website: Fishing, Eeling and Oystering thread)
The Sound School ISSP – Capstone Series
Do Climate Factors Lead to Habitat Failures?

Vibrio Bacterial Series in Eelgrass/Sapropel
- A Multidiscipline Approach – for Several Capstone Questions

Timothy C. Visel, Coordinator
The Sound School Regional Vocational Aquaculture Center
60 South Water Street
New Haven, CT 06519
Revised for Capstone/SAE Proposals, April 14, 2017
ASTE Standards Aquaculture #6 Natural Resources #6, #7, #9
This is a two part report readers should review IMEP #61- A posted on March 28, 2017

(This report reflects the viewpoint of Tim Visel. On February 16, 2016 and on February 8, 2017 I asked our EPA habitat committee of the Long Island Sound Study to identify Sapropel as a distinct habitat type. No consensus has been reached as to the existence of Sapropel. This is not the viewpoint of the EPA Long Island Sound Study.)

* A Note from Tim Visel

As the climate changed in early 1920s New England small boat fishers were ready. After some brutal winters in 1921-1922 the Great Heat was over. Rhode Island shellfish managers had dropped the Bay Scallop report section from 1910 which now saw its once nonexistent crop soar to over 300,000 bushels for the 1923 harvest (Rhode Island Annual Report of the Commission of Shellfisheries for the year November 30, 1923 – print date 1924). And the harvest was still coming in as the reporting year ended in January. The Bay scallops were heavy over the oyster beds (an alkaline habitat type) and one company reported harvesting 400 bushels of bay scallops each day, pushing the season crop to February to as high as a half million bushels. This was a surprise to Rhode Island’s shellfish commissioners, making note of the crop “in spite of the fact that the winter of 1922 - 1923 was one of the most severe that we have had in a number of years.” The habitat conditions were changing and as storm intensity increased, Sapropel now disappeared. The clearing of built-up organic deposits from 1880 to 1920 took time, but by 1938 eelgrass disease had uncovered vast deposits of soft Sapropel and what the cold 1920s winters started, the Great New England Hurricane of 1938 finished. The intensity of the storm cleared out coves and bays and re-cultivated sandy soils. The first change was most likely soft shell clams. They set again in huge numbers into soils now free of organic acids.
These sandy areas now held winter flounder as the 1940s ended. Soft shell clams thrived in the absence of eelgrass, bay scallops driven inshore by a series of stronger nor’easters increased and by 1944 hard clams started to increase as well. Locally called round clams in central Connecticut, the 1938 had destroyed many inshore beds but recultivated the deep water beds and in those in shore areas that once held oysters. Bay bottoms became firm and “clean,” John Farrington, on Cape Cod had knowledge of this habitat reversal and clearly describes this habitat change in an article in 1983 (see appendix) and during many meetings of the Bourne/Sandwich Shellfisheries Association I attended on Cape Cod in the early 1980s while working for the Cape Cod Cooperative Extension Service at the time. The resurgence of eelgrass was not the return of an old friend but an old foe, one that changed the bottom attracted waterfowl and seemed to hasten the spread of the green crab. I had heard this before from members of the Madison Shellfish Committee in the early 1970s that the return of the green crab was devastating to the soft shell clam that both the resurgence of eelgrass and green crab happened around the same time the early 1950s. Later in the middle 1980s, serving on the Madison Shellfish Committee (CT) as I found in the old files a 1953 letter from Victor Loosanoff to Madison mentioning both the increase of the green crab and predation upon soft shell clams, steamers.

That letter is found in the Appendix and connects a growing green crab population in the early 1950s. In the early 1980s, John Hammond made the direct eelgrass green crab habitat connection, they needed each other as eelgrass, is now being recognized as important (crab species) habitat. It was the shellfishers on the Cape whose families also fished that told of the eelgrass expansion between 1880-1920 a generation ago, not only slowing currents and the suffocation of sets (shellfish mostly hard clam) but into the 1960s a growing green crab population and waterfowl than fed upon the eelgrass itself defecating in these same areas that conained shellfish. In no uncertain words eelgrass was a foe, an enemy that after a key struggle had “won” against these shellfishers.

Sherril Smith, a Division of Massachusetts Extension agent then was experimenting with hydraulic shellfish harvesting (from a skiff) and I accompanied him during a few tests on Pleasant Bay, Chatham/Orleans, Massachusetts in the early 1980s. On several tests we hit eelgrass and dead quahog clams below it.

The return of eelgrass on Cape Cod had taken its toll on small boat fishers, in fact, not a good habitat sign, but indications of a system wide habitat reversal which meant less product and less income for them. Under eelgrass meadows and in areas of slow current Sapropel (Black Mayonnaise) now formed finishing off what little shellfish was left.

When I started working with the Bourne-Sandwich Shellfish Association in 1981 the association had already conducted two soft shell clam tests and one public hydraulic harvest jet clamming demonstration on December 30, 1979. They were very careful to avoid eelgrass areas as these contained then only dead clams. In many areas dying eelgrass exposed Sapropel and under them held dead soft shell clam of all ages. When Sapropel was disturbed the smell of sulfides was very strong and far beyond the shellfish equipment capacity to reverse habitat conditions. The 1982 tests were discouraging to some association members since the 1979 – Sapropel had covered large sections of Buttermilk Bay killing the sets of 1980 and 1981. From a 1981 paper – Hydraulic Harvesting of Soft Shell Clams – a report of the first six months, March 20, 1981 Barlow et al The Bourne – Sandwich Shellfish Association Inc 14 pages discovered the rise of dead bottoms (my comments are in brackets T. Visel) pg 9.

“These areas contained a great many empty shells and high incidence of dead or dying clams (thought to be high temperature sulfide toxicity T. Visel) when the manifold {A low pressure 1961 design MacPhail hydraulic rake T. Visel} was rolled across the bottom gases formed from the decaying matter (organic sulfur reducing bacteria T. Visel} were observed bubbling to the surface {suspected to be hydrogen sulfide gas as comments to me included – sulfide match stick smells were common T. Visel} the substrate was devoid of the usual animal life, such as sea worms and the winkles {similar areas were observed during a similar test with the Waterford – East Lyme Shellfish Commission in Niantic Bay 1983 Tim Visel}. We have also encountered certain spots where this dying process is complete, {suspected of Sapropel formation frequently termed Black Mayonnaise T. Visel} and only the many clam shells remain beneath the substrate” {This was usually soft bottoms adjacent to eelgrass that was in the process of fungal/decay T. Visel) Marine soil cultivation and sulfide/pH study of marine soil studies have yet to be fully understood. What the shellfishermen association study had found in 1981 that as the spoil pH drops – fatal to clam sets eelgrass could still survive – longer (see a more recent study NSF Grant old Dominion University Eelgrass Win, Clams Lose in Ocean Acidification Study” 2013).

{The use of cultivation energy has created a question about spawner sanctuaries. In some locations in New England spawner sanctuaries have been designated for both clams and oysters – something the oyster industry did here in Connecticut a century ago. But soon after these areas were “put aside” their soils changed as recorded by the Connecticut Oyster industry and Canadian researchers in the 1960s – found without energy (cultivation) they (habitat types) “failed” faster. Clam and oyster sanctuaries may well provide increased spawning potential but they need to be cleaned, recultivated and reshelled to remain viable by energy every few years. Organic matter build up transitions these marine soils and some of the best evidence of habitat succession in sanctuaries called reserves comes from Canada and the Ellerslie Reserve Benthic Studies Faunal Survey of Ellerslie Reserve in 1962 (Fisheries Research Board of Canada Annual Report 1965). Here researchers detailed the successional characteristics of an oyster bed to a soft mud community that now held low biomass and sets of shellfish that can only withstand higher sulfides such as Macoma batthica (they grow in acid soils with “chalky” shells – T. Visel) (B-9). Here is some of the most detailed information that the environment in the Ellerslie Reserve was transitioning to fauna associated with mud while cores of the bottom shown that the area was at one time a “true oyster bed.”} But the impacts of stagnant sulfide soils was easy to see on the eelgrass.
The eelgrass was covered in black spots and broke easily shells of soft shell clams below it were thin and crumbled when handled. (T. Visel, 1982 observations). Its role in trapping organics in a suffocating mat, when I worked with shellfishers on the Cape eelgrass had climate cycles and few shellfish friends.

I respond to all emails at tim.visel@new-haven.k12.ct

Eelgrass coverage increases after energy – and decreases from a lack of energy – temperature largely controls successional time, the numbers of years for a complete cycle. As eelgrass builds it favors the sets of crab megalops – in southern areas the blue crab and further north the green crab. It is suspected that both North Sea – Thames River eelgrass arrived at the same time as the invasive green crab Carcinus, maenas as the green crab in colder climates grows quite large and is an edible crab in Europe. In the cold and stormy 1950s and 1960s green crabs quickly spread north to the Canadian Maritimes. Researchers have now linked green crab and eelgrass habitats as cyclic in the North Sea. Recent interest in the green crab has caused investigations in the marketing and sale of the green crab as food. It is an interest to those who shed blue crabs to our south that Venice Italy has green crab shedding operations since the 1600’s. Soft shell green crabs (see The Search for Megalops Report #3 Northeast crabbing resources thread June 1, 2016 The Blue Crab Forum™) ready to shed are called “moleche” and shed green crabs called “Muta” and bring as much as $50/pound.

Bay scallops also respond to temperature and energy cycles – much faster at times while others seem to slowly fade away. When climate and energy levels do not favor New England bay scallops they “retreat” into the last colder and energy areas – the deeper waters off the mouths of bays and coves. Over time it is the small boat fishers who experience these cycles and the “data” from them in their catches. Eelgrass shares a similar habitat profile – cold clear waters over cultivated marine soils (low in sulfides) are some of the best soils for eelgrass. Both species also depend upon suitable habitats in long cycles in the North Sea/German Bight regions.
The colder 1950s and early 1960s prepared shallow marine soils in New England for the first growths of eelgrass, small isolated patches of the “clean and green” eelgrass. Bay scallops fed heavily upon nitrate sustained algae as the 1960s had Long Island Sound support dense blooms of chlorella. High amounts of nitrate came from organic matter and the oxygen reducing bacteria setting up the nitrite-nitrate-nitrogen pathway from it. Bay scallops could in fact set upon clean sand and pebbles including clean eelgrass, but as a substitute spat collector not the primary setting algal species. That feature belongs to the coralline red algal species that secrete a gray paste that resembles a grey peanut butter sticky deposit that contains thousands of pieces of shells called Maerl.

I have seen a maerl like deposit a few times – it is distinctive – sticky grey paste and sometimes called “money dung” in the otter trawl fishery. If anything it resembles a thick grey paint poured into crushed bivalve shell. It is plastic and like a clay. One sample caught in a trawl net in Block Island Sound had thousands of bits of shell and coral in it. This is the alkaline deposit mapped overseas termed live Maerl beds that are so important to scallop sets. It is a cool or cold water species as this species does not do well in high and high organic loading as these deposits have a low pH as a byproduct of sulfate reducing bacteria (SRB) and contain the ability to form organic acids including sulfuric acid. Shellfish veligers on acidic bottoms perish in a few seconds. (See IMEP #47 Climate Induced Acidification of Marine Soils, February 6, 2015 The Blue Crab Forum™ Fishing, eeling, oystering thread), Coralline algae likes alkaline bottoms and if torn is now subject to the bleeding grass syndrome, scallops that prefer these bottoms can now perhaps sense them after storms, they follow the chemical scent. In the historical literature you see heavy inshore sets following storms, these spawning and setting compounds with live Maerl may provide important answers to these observations. (In Connecticut the bay scallop landings have surged after hurricanes.)

As the 1960s went into the 1970s or climate pattern “moderated” gone were the 48 hour gales of the middle 1960s when Long Island Sound would freeze up; ice slush walls then formed along Hammonasset Beach, sometimes several feel high, and numerous strong storms kept estuarine bottoms in motion. New cuts appeared in barrier spits and beaches sometimes themselves were washed away. The 1950s and 1960s were cold and contained energy levels not seen since the 1870s when subzero temperatures in the mid-1870s killed apple trees here in Connecticut by thousands. But this cold and energy had tremendous implications for marine coastal soils, washed by strong storms, cold sea water meant oxygen reducing bacteria could live in them and multiply. Those bacteria that turned ammonia into nitrite and nitrate could live and that nitrate fed high lipid calorie algal strains important to diet of the bay scallops. In the cold and oxygen sufficient shallow waters bay bottoms were often observed as clear, clean or hard. That would all change in the 1970s. By the time I accepted employment with the University Cape Cod Extension Service, (part of the University of Massachusetts Cooperative Extension System) I had already seen what a buildup of organic matter could do to oyster beds when it covered them. I watched it happen as high bacterial counts closed Tom’s Creek in 1972 Madison, Connecticut by 1978 leaves had turned black and covered the bottom. In time, the jelly like “Black Mayonnaise” substance killed oysters and when disturbed, gave off a match stick sulfur smell. The energy and temperature cycle had changed – it was now “quiet” and had few storms, summer heats extended into fall and spring warmth lengthened the growing season. Habitat conditions would now change as well.

The Habitat Services of Eelgrass

Eelgrass by its very organic matter holding ability (as with any common grass) accumulated organic matter in cold, the “clean and green” eelgrass but in high heat as lower oxygen levels now favored sulfur reducing bacteria and very different habitat conditions. Habitats now “reversed” in eelgrass peat as the sulfides increased, the bottom turned soupy and sulfuric acid formation weakened the plants roots which if it didn’t kill it outright, weakened it such that molds and fungus finished the job – eelgrass plants now just “wasted away” – leaving a deposit that in high heat supported “little life” or signified in shallow water the “dead bottoms” – that often emitted sulfur smells.

It is the shallow water fishers that observe this habitat change and in many parts of the United States and it carries the term “black mayonnaise.” In this “heat” the Sapropel could heat up further increasing the toxic impacts of sulfides now building in marine soils. Sapropel habitats became toxic sending sulfides into the water column. If dense enough would give rise to “black waters” often just before a fish kill.

As the heat continued in the 1970s sulfur reducing bacteria now largely displaced oxygen requiring bacteria using sulfate which is “non-limiting” in marine waters. As this organic eelgrass peat putrefied in heat, it then became a toxic habitat killing the eelgrass and any seafood, especially larval veliger forms as the heat could if long enough create black water (fish kills) deaths of the last century, massive harmful algal blooms could now occur that required ammonia, not nitrate; so it was natural as Sapropel became toxic to see declines in fish and shellfish, near them and in times leaving a blue-black jelly wax like deposit with few life forms. In the final stages of this habitat cycle eelgrass was brown, black and covered with bacterial films or fungus – known as the “brown and furry eelgrass,” it signaled massive habitat change from a natural cycle. The eelgrass services of warm (water) now hot in areas of good tidal exchange holds crab megalops and is an important nursery habitat for the blue crab (and other crab species). The warm habitat benefits are closely linked to oxygen in times of excess heat and nutrients (mostly organic matter) the high heat habitat collapse as the sulfur cycle strengthens. This occurs as the “blue crab jubilees” in the historical fisheries literature. If oxygen drops low enough Sapropel kills seagrasses as well.

While the clean and green eelgrass of cold water did hold many organisms, fish, crabs, bay scallops and shellfish along the edges. In time as eelgrass meadows grew thick, it suffocated shellfish by the millions but it was great food for the ducks, especially Brant. As eelgrass moved into these estuaries after the cold and stormy 1870s, so did species that depended upon it, especially Brant which was a popular duck hunting species. The thick eelgrass meadows of the 1890s were great for Brant but it turned thousands of acres of bay bottoms into Sapropel by sealing its root tissue in organic gelatin from oxygen in a long successional pattern that is 50 years or more long. When eelgrass died-off in the 1930s, hundreds of thousands of Brant also starved to death. It is not surprising, therefore, that nearly all of the first studies about eelgrass importance and habitat services were from the prospectives of Fish and Wildlife Service waterfowl researchers such as Clarence Cottam who wrote and reported about eelgrass populations in the 1940s and 1950s. At the end of a 50 year period, longer winters now allowed sulfuric acids to form – oxygen requiring bacteria was displacing those that needed low oxygen. A bacterial “battle” now raged in eelgrass peat and acid sulfate soils now made root tissue die from sulfuric acids in the colder oxygen water, and in time, this weakens the plant.

As storm energy increased and temperatures continued to fall, (the 1922 to 1926 winters were particularly severe) soil conditions now turned against eelgrass, sulfuric acids formed in the Sapropel below its root/peat. When this occurs in a salt marsh in high heat the bacterial decay may cause sections of salt marsh to even sink – subside, but eelgrass peat dies off. As storms increased they now washed away any remaining eelgrass root tissue uncovering Sapropel deposits, especially after the 1938 Hurricane. As the climate feature NAO turned negative, coastal soils now became unstable, washing and rinsing these soils of sulfuric acid and made these marine soils suitable for eelgrass again, but the increase of energy made it impossible for eelgrass to immediately reestablish the thick and often devastating growths of the 1900s. However, this habitat succession pattern takes time. In numerous shellfish reports and bulletins including records of the oyster industry, mention overtime the destructive habitat successional attributes of eelgrass are frequent.

Grasses form monocultures and have successional habitat services in cold and heat that are quite different, the impacts of habitat succession would be witnessed by those fishers who fish the shallows, especially fin and shell fishers. They were the first ones who noticed that eelgrass would “move in” and “take over the bottom,” great for the Canada geese but a very different habitat observation for New England bay and cove fishers, they would come in time to despise eelgrass; this is a section of an article titled “Present Eelgrass Condition and Problems on the Atlantic Coast of North America,” by Clarence Cottam, C.E. Addy, (both of the US Fish & Wildlife Service) Transactions of the North American Wildlife Conference, Volume 12, 1947 which mentions previous cycles or what Mr. Hammond on Cape Cod in the early 1980s explained “a habitat reversal” and on Page 393 found this section which mentions a cycle/pattern.

“There have been other periods of eelgrass decline Cottam 1936- 1935 and as pointed out by Stevens 1936-1939, those periods have followed solar cycles rather closely, whatever the agent agents responsible for the decline, the fact that the plant disappeared abruptly and is returning slowly in about the same proportion throughout most of its range, points to a force of “hemispheric scope.” Whether it has been of direct or indirect influence; perhaps a study of the changes in ocean currents, temperature, salinity and similar conditions during the joint 30 years might shed some light on the problem.”

We know this force of hemispheric scope as persistent or semi-prominent low pressure systems such as the North Atlantic Oscillation or the “NAO”. But it was not “30 year study time,” but one that is between 50 and 60 years- the change from a negative NAO to one of largely a positive NAO. And later in the same period the energy impacts of “new sand” in a storm layer mentioned to me so many times while working on Cape Cod and especially in accounts of habitat reversals. John C. Hammond of Chatham describing new cuts in the Monomoy barrier beach system for example, which would provide new shellfishing income to fishermen there. (See IMEP #12 Blue Crab Forum™, Fishing, Eeling and Oystering thread, February 28, 2014. Brief Habitat Histories for the Niantic River, and Clinton Harbor). Every time a new cut appeared in Monomoy system, storm waves would deposit “new sand,” and in this new sand shellfish sets were the most intense. (John Hammond personal communications T. Visel 1981-83). Another example illustrates the impact of rinsing and cultivation of marine soils is from dredging. To complete the Cape Cod Canal, a dike was built with some pumped up from the bottom of Buzzards Bay in 1936, the pumping action (dredging) had no doubt removed fines, rinsed soil of sulfuric acids sulfides and reduced organic matter content, perfect for eelgrass to move in and now stabilize this energized/cultivated marine soil, and that is exactly what occurred. “The soil” or new sand was again suitable and cultivated – free of Sapropel (black mayonnaise) a product of energy pathway which could be natural, or in this case a manmade dredging activity. Understanding the biochemical reactions in the soil below the surface provides information on the health of eelgrass plants that grow in it. That is how marine soils benefit from energy (cultivation and rinses soil pore waters of toxic sulfides) which also occurs during dredging.

On Pg. 394, Cottam comments about excellent eelgrass in “new sand” after dredging:

“This dike was built with sand pumped from the bottom of Buzzards Bay; work on this dike was beginning June 1936 and finished February 1937. The dike thus consists of “new sand” that is sand which hasn’t’ been in the shallow water for many years, probably in historic times. Yet on both the north and south sides of this dike, are healthy stands of eelgrass, standing which are among the best when I saw during the entire summer.” (Stevens 1946)

And further, “It appears that fairly quiet water and freedom from deep mud and silt are major factors in the re-establishing of eelgrass.”
In other words, it is the soil condition that results in the differences of the habitat coverage of eelgrass and in time with habitat succession energy which occurs from the warm to cold or cold to warm periods, Mr. Hammond as part of his climate/shellfish study of Monomoy (Chatham) kept a journal of the number of storms and even what quadrant the wind vector which could change soil conditions and resultant clam sets. (The difference in wind direction according to fetch could cultivate different sides of bays and coves and also change movement of larval forms). These soil conditions were in fact also mentioned by Cottam:

“In areas where that is not eelgrass, the bottom is covered with a rather deep layer of silt, and fine mud, quite in contrast to the condition for example, on Hog Island Dike (mentioned above) where there is abundant “clean sand”.

The clean sand could occur by dredging energy or natural storm energy as long as the soil was cultivated, free of organic acids eelgrass could in time recover them. Clean and free of organic acids eelgrass could cover them much quicker and areas of bivalve shell hash, broken bits of soft and hard shell clamshells, a natural acid buffer material (lime for example in terrestrial soils) (coral down south) these soils eelgrass much preferred. The deep layers of mud and silt were terms used to describe the “dead muds.” Muds that seemed to support little or no life, now suspected of being Sapropel deposits. Many times in the historical literature these areas were noted as “dead bottoms” areas that contained little life – often called dead zones today. Although the destructive storms often brought hardship to those on the coast they moved Sapropel out and increased suitable habitats for all marine life, fish, shellfish and in time vegetation.

Sapropel as a District Type

Many environmental agencies and conservation groups have not adopted the term Sapropel from the Greek words sapros and pelos therefore its definition of putrification of organic matter in the absence of oxygen. This is thought to be in response to decades of public policy position papers about the negative aspects of coastal dredging. Instead nearly all estuarine papers continue to use the term “sediment” a geologic term used to describe the impacts of rain, ice and wind on the erosion of minerals into coastal margins. To describe organic deposits (mostly leaves and dead grass in northern waters) some 30 different terms have been identified leading to confusion and misidentification. Sapropel describes the role of sulfate reducing bacteria (SRB) in low or no elemental oxygen, they as a part of their reduction process utilize sulfate as an oxygen source the sulfur cycle and produce sulfides, sulfuric acid, complex heavy metals (even mercury compounds) and cause the release of aluminum. The ability of SRB to complex heavy metals is so intense that in Europe Sapropel is used as an environmental hazard clean up media for heavy metal (spills) contamination.
In Europe, it is a valuable soil nourishment product, and uses include restoration of metal salts to soils leached of essential plant growth metals by acid rain, a carbon source, a bio-organic fertilizer, and is an international plant growth product. Historically Sapropel and humis were extensively harvested for hay fields and salt marshes in New England as “mussel mud” or “marine mud” in or near oyster beds. It was such a valuable soil nourishment product in the Canadian Maritimes it was (dredging rights) subject to public bid (see Drawing Lines In The Ice: Regulating Mussel Mud Digging in the Southern Gulf of St. Laurence by Josh MacFadyn). The harvest of the marine Sapropel included the use of oyster and lobster shell to correct acid pH of sulfuric acids.
The commercial sale of Sapropel fertilizers to the middle east for specialized greenhouses has recently grown quickly to provide valuable soil conditioners and increase crop production over 25 percent (Food and Agriculture Organization of the United Nations Application of Organic Fertilizers Based on Sapropel and Peat In Countries Of Middle East (2014). Sapropel fertilizers once harvested in CT from coastal rivers were tested by the Connecticut Agriculture Experiment Station (New Haven, CT) beginning in 1879 (see IMEP Habitat Newsletter “Connecticut Rivers Lead Sapropel Production 1850-1885 on the Blue Crab Forum™ Fishing Eeling and Oystering thread, Posted, September 29, 2014) and continued to about 1931 when the commercial (chemical) fertilizer market displaced organics.
The EPA studied SRB for clean up of acidic mine waste water in the early 1970s (EPA 670 12 – 73 – 080 Sept 1973 Removal of Heavy Metals From Mine Drainage By Precipitation, but suddenly abandoned this SRB effort).
Sapropel is often characterized by the type of bacteria in layers of reduction, the top layer with oxygen reducing bacteria – termed humus or humic layer – the second layer sealed from oxygen or in oxygen limited waters (hypoxia) the sapric layer – here are the sulfate reducing bacteria and Vibrio bacteria, and finally the formic layer – here is the domain of the primitive bacteria that need no oxygen source compounds at all, the Methanogens. In some cold texts it is referred to the Methangenic layer.

In cold oxygen rich conditions the oxygen requiring bacteria turn ammonia compounds into nitrate – an important nutrient for shellfish algae we know these bacterial processes as the Nitrosomonas and Nitrobacter bacterial groups. These bacteria are generally nontoxic and form the foundation of the aquaculture and aquaria closed system filters. This layer can become acid if not enough oxygen is present immediately below a thin oxygen layer. In heat or when eelgrass roots trap leaves and leaf parrafins (wax) they can in time seal organic deposits below from oxygen – it now becomes sapric subject to sulfate reduction from the desulfvibrio series the byproduct of which is found in the historical fisheries literature as the late August “rotten egg smells” from marshes creeks and salt ponds – when sulfide smells are evident it is already deadly to fish and larval forms which are acutely sensitive to sulfides.

Dead bottoms or bottoms that smelled of sulfur were often termed “dead waters” or “black waters” in the historical fisheries literature. (Black Bay, Dead River, Blackwater River, etc)

It is interesting to note in the discussion session after the presentation of this paper by Cottam and Addy (1947) some interest in habitat succession of eelgrass was mentioned. Mr. Bruce S. Wright (New Brunswick, Canada) commented “What is the reaction of the fisherman on the coast to the appearance of eelgrass. I know in the Maritimes, they deliberately dig it out when it comes back; they don’t want it back” Dr. Cottam explains that the eelgrass has come back at times so thick it hinders navigation, “It is either feast or famine, when you have too much of the stuff, it is too hard to get through. When there isn’t any, the fish or organisms that go with it suffer.”

That is a great explanation of habitat succession, a natural cycle for eelgrass that is dependent upon energy and temperature – not us. It is also why the Fish and Wildlife Service researchers were involved not as an aspect of fish and shellfish but as a cause of waterfowl Brant starving in shallow waters. What was not reported by USFWL researchers in the 1940s was the often devastating habitats impacts of the first eelgrass plants to shellfish. In other ways the appearance of eelgrass soon signaled another shellfish habitat challenge – the soon arrival or presence of waterfowl feeding upon it. This was quickly apparent in shellfish surveys of Centerville River and Lewis Bay (1982) on Cape Cod here large groups of geese ripped and stomped eelgrass roots – dislodging plants which soon accumulated in large wracks on shorelines. Newspaper articles on Cape Cod then at the time blamed “jet clamming” for the eel plant loss but clammers avoided these areas (they would quickly block intake pipes pumps would lose suction – it was up to 30 minutes to clear pipes and reprime the pump each time a great loss of tidal productive shellfish time) for they held far fewer clams. Although geese directly did not consume small seed scallops and quahog seed (about the size of a nickel) black ducks did and between the root pulling and washing of the bottom with feet from geese and the predation of black ducks (Mergansers were observed eating small winter flounder) the bottoms in the fall were turned up masses of brown eelgrass roots, but this process was out of sight of the general public and the jet clammers much more visible “took the blame.” Although the damage were observed by shellfishers and some case natural resource officers from Falmouth (shellfish wardens) the bottom was ripped up and peat with masses of eelgrass roots exposed in these depressions, waterfowl was rarely associated with loss of eelgrass, even though they eat its roots?

On Cape Cod shellfishermen were still mentioning other negative impacts of duck and geese from fecal build ups upon shellfish bottoms. Some areas in shallow waters subject to waterfowl defecation had fouled the bottom – similar to impacts in the fisheries literature about the Eastern New York (Long Island) duck farms. Other comments including swans consuming large quantities of winter flounder and even seed bay scallops. Later concerns on Cape Cod involved the impact on bacteria counts from fecal waste (waterfowl) in shallow waters (1980s). In some Cape Cod shellfishing areas you could see the fecal material on the bottom in the Centerville River – Barnstable MA (shellfish survey T. Visel). The shellfishers felt that this waterfowl manure delivered on top of the eelgrass plants and fertilized them.

In a conversation with John Hammond he said that similar damage was done 1900s but at that time open “winters” (little or no ice on salt ponds) duck hunting with guides had become a rewarding economic activity – residents and visiting duck hunters would shoot them. A Forest Field and Stream Article April 7, 1881 pg 186 mentions “Brant feeding in Chatham in the channel area between Monomoy channel near Nauset” (volume 16) and mentions duck hunting in the “shore community of Chatham” (Similar references exist in the lower Connecticut River as “duck boats” low profile sculled row boats took hunters out in the river to shoot ducks became a guide/boat business for off season shad fishers.) The relatively mild winters were good for duck hunters but signaled a changing habitat profile as decades of heat/few storms changed the habitat profile in shallow waters. Eelgrass soon covered the bottom killing any benthic shellfish species below it.
That is why shellfishers so despised it on the Cape in the 1980s; they had watched eelgrass come in and take over acres and acres of Quahog bottom and then followed by feeding waterfowl destroying seed clams. Within two decades of this paper Cottam 1947, The Fisheries Research Board of Canada (Manuscript Report Series No. 905, titled: Experiments in the Chemical Control of Eelgrass Zostera marina 1967) would organize an entire resource team to investigate if eelgrass could be controlled or possibly eradicated and its transition of oyster beds to eelgrass peat halted. They could not and largely failed to stop eelgrass turning oyster beds to eelgrass peat and abandoned experiments to control eelgrass by 1972. Massachusetts abandoned similar eelgrass control programs in 1972 and Connecticut in 1976. What had often occurred that control measures actually thatched the roots (John Hammond personal communication T. Visel 1982-83) and made conditions for eelgrass to grow – improve with drag chains, and cutters. Chemical control according to Mr. Hammond occurred in Pleasant Bay as a test to see if anything could stop eelgrass. Those chemical efforts were abandoned as well. (See Quahoggers make final stand against eelgrass IMEP #30 post on the Blue Crab Forum™ fishing, eeling, oystering thread October 9, 2014).

The amount of healthy grass monocultures could be determined by the type of bacteria in the soil below them high heat allowed sulfides to build while colder temps with energy would prepare these soils once again similar if not exactly, the same habitat cycle as forest soil succession after a forest fire. It is the type of bacteria in marine soils that is largely governed by temperature and the amount of organic matter in the soil itself.

Except in the marine shallows, temperature shifts and energy levels take much longer, from a high habitat coverage of the 1850s, to low coverage in the 1870s, to incredible coverage in the 1890s to increased coverage in the 1930s to low coverage in the 1940s, to increased coverage in the middle 1970s to die-offs again in the 1990s. Within 150 years eelgrass has reversed three complete times largely in response to climate pattern temperature and energy shifts, the NAO (Northeast Atlantic Oscillation) from positive to negative phases. It also coincided with a decline of oyster, striped bass and blue crab fisheries, as these warm water fisheries collapsed as years of cold and energy built a multi-tropic collapse, after Sapropel was washed from coves, a new “clean” cultivated sand has sparse organic matter, but in a few years, organic matter builds (one of the first organisms to re-establish themselves are clams—in heat, the soft shell clams in cold the quahog). The 1940s and 1950s were known for tremendous sets of the quahog Mercenaria mercenaria (see Rhode Island catch records during this period). Cottam 1935 makes mention of the soil – (1935, The Present Situation Regarding Eelgrass by Clarence Cottam). “It (eelgrass) seems to do best in fairly firm rich soil (rich is an agricultural term reserved for organic humus) in water from two to five feet deep, but the vigor of the plant is reduced if the soil is too soft (thought to be sulfide toxic in heat) too hard or too sandy.”

Note “new sand” is mentioned in the historical literature many times around breaks or breaches in barrier inlets. The energy from storms would wash in “new sand” and sets of clam species would increase. This also occurred following dredging projects that pumped sand and redistributed them often found tremendous clam sets after these cultivated soils stabilized. The improvement of clam setting potential was demonstrated by the use of “Yarmouth wands” or jet clamming in some of the Dennis salt ponds allowed gasoline powered pumps to produce a stream of concentrated sea water (a jet) that when utilized in a subtidal harvest – duplicated the soil cultivation impacts of storm – resulting in very heavy sets of soft shell clams in the jetted areas. The growth of clams in this cultivated soil which contained the pieces of previous shellfish generations (termed shell halsh) was tremendous a legal size clam in only two years. Areas that were not jetted held large adults, heavy predation by sand worms and a lack of seed clams. Al Keller demonstration on Cape Cod 1982) see also Bourne/Sandwich Shellfishermens Association Demonstration of Jet Clamming. Paul Galtsoff the American Oyster 1964 and Dr. David Belding (Massachusetts Shellfish Studies) mention “new sand” or washed soil – this is an except from page 42 of this 1930 report about the soft shell clam on the Blue Crab Forum™ fishing eeling and oystering – also IMEP #1 Soft Shell Clams in Connecticut – A New Opportunity? Feb 7, 2014 posted on the Blue Crab Forum™ fishing, eeling and oystering thread. Historic impacts to fisheries IMEP #11 posted February 28, 2014 on the blue crab forum™ (fishing, eeling and oystering thread) Describes dredge material on page 398 as a manmade habitat reversal, and then a species change.
Fishers and fishery managers in the 1960s did recognize the problems of pH and would resort to the direct application of agricultural lime with mixed results (hard to spread, did not last long). The best recorded results have been the thin application of oyster and clam shell to “sweeten” marine soils. The oyster shell would help buffer acidic soils and add structures of the ripple effect mentioned above. One of the best examples of soils rinsed of acid and mixed with oyster shell resulting in a good set of Quahogs is found in Paul Galtsoff’s 1964 bulletin The American Oyster (US Fish & Wildlife Service). On page 398 a man made “habitat reversal” created by dredging near the Buzzards Bay entrance to the Cape Cod Canal Massachusetts is recorded.” Between 1935 to 1938 here an oyster bed was buried by 8 to 12 inches of dredged material that settled on the oyster grounds. Three to four years later the area was repopulated by quahogs and continues to remain highly productive, although the species composition has been completely changed.” It can be assumed that Dr. Galtsoff’s term “highly productive” signifies active digging or dredging for hard clams – mixing in old oyster shells into these soils – extending the habitat successional clock for Quahogs for decades. Oyster growers always reported finding Quahogs under thin oyster shell layers. Rhode Island Bullrakers also noticed areas of heavy sets and faster growth “sharps” were on bay bottoms that contained shell fragments. Sometimes in abandoned oyster culture areas.
Out of all the hundreds of eelgrass papers in the present or recent literature only a few have mentioned soil and pH conditions or the cycles of energy and temperature as directly influencing eelgrass habitat quality or density. Despite our immense knowledge of agriculture or soils, or even the concept of grasses (monocultures) as a successional plant apparently did not influence many eelgrass reports as to its formation of peat, or the bacterial reduction below its roots, or the presence of Sapropel itself. (Several New England states have yet to accept that Sapropel itself exists as a habitat type – T. Visel).

This causes serious questions about the objectivity of eelgrass reports as to the promotion of public policy rather than a full public explanation regarding all the environmental conditions that illustrate rise and fall of eelgrass populations (my view T. Visel).

It is still too early for fully access the scope of the research/science bias regarding the “eelgrass problem” but a continued omission of Sapropel/peat formation, the role of sulfur reducing bacteria of sulfide toxicity or the condition for sulfide and sulfuric acid conditions, and at times aluminum discharges from eelgrass peat begs the question, why? The bias in conservation/preservation points of view may take decades to fully describe and has set back marine soil science and habitat services research decades (my view). One positive side is that more citizen/resource organizations have begun to recognize Sapropel (black mayonnaise as a concern by themselves.

Serious research questions remain about eelgrass habitat services, chief of which almost none of the basic agricultural information about soils and bacterial reduction of humus (compost) are not mentioned in eelgrass research although it is a “flowering” plant, has a defined root system and provides many if not all of the soil binding attributes of terrestrial grass? The concept of soil pH pore space, circulation, and oxygen renewal and soil circulation of oxygen requiring bacteria is rarely mentioned. The aspect that eelgrass can suffer natural “extinction events” as related to habitat succession that for most purposes the habitat reversal mechanism of forest fires is our hurricane equivalent is absent from many eelgrass reports. It is natural for monocultures to succumb to catastrophic habitat failures and then have gradual restoration as a response to climate patterns. This is why so many under go devastating western forest fires 1880-1920 caused restoration researchers to focus upon forest soil recovery and the need to rebuild bacteria in burned soils so that grasses could grow and halt soil erosion from exposed forest soils.

Although many eelgrass papers point to nutrient enrichment or nitrogen contamination for the decline of eelgrass and policies of non-disturbance these beliefs are subject to a review, when eelgrass made its recovery in the 1950s and 1960s, nutrient levels did not reflect abatement programs, rather the impact of an immense natural habitat successional event, colder temperatures and more energy had prepared coastal marine soils for another period of habitat coverage expansion in the 1950s and 1960s. As eelgrass died off in the 1920s and 1930s, it was often reported to die off first in the very shallow waters. These waters subject to the greatest organic matter inputs (oak leaves are especially damaging because the leaf contains a high amount of wax); these would fail first for eelgrass because they had less energy and the warmest of waters. This is the black spot eelgrass that was also brown and furry eelgrass observed during these warm cycles. As the NAO climate pattern extended in the 1980s, these eelgrass meadows died off first while deeper more energy prevalent areas of the mouth of bays and coves eelgrass “hung on” the longest. A sudden storm or cooler temperatures can reactivate long dormant marine soils again preparing them for eelgrass expansion by cultivating them. At times even the smallest cultivation that disturbs the sulfide layer get more oxygen into these soils and extend eelgrass soil “health.” The geochemical aspect of eelgrass in marine soils can benefit in fact from energy – contrary too many of the anti-disturbance policies that do not include the correct chemistry foundation. That is why the largest eelgrass habitat coverage expansions occur after a cold and storm filled period and reflects a cycle. Thousands of acres of marine soils were prepared for eelgrass growths. Cycles of high temperatures and low soil energy help eelgrass habitats fail faster. That is why shellfishers have mentioned that it is beneficial to “work the bottom;” it is.

It will be difficult for some groups to realize (when the chemistry of marine soils is more fully explained to the public) that some energy (frequently termed bottom disturbance) is actually beneficial to eelgrass monocultures. Eelgrass like terrestrial grasses builds up over time thick root tissue – a peat that can seal surface plants from a compacted thatch below. As more fines are trapped by surface eelgrass plants, it seals and fills soil pores below reducing the ability of marine soils to allow water circulation and oxygen exchange in areas of the root tissue. Any energy (disturbance) that disturbs the bacterial mucus or allows alkaline sea water into soil pores releasing sulfides helps eelgrass to live. It is the progression from cultivated to compacted acidic soil that determines the length of eelgrass cycles. The belief about bottom disturbance is not supported by soil science chemistry nor the impact of energy that may cut or thin eelgrass meadows. In the lawn care industry cutting the grass once – does not save the grass in fact the grass habitats succeed to under story plants from lack of energy (cutting) eventually to forest much faster without the cutting (energy). In the case of terrestrial soils they become compacted, and the weight of water compacts marine soils as well – Athletic fields have special drainage systems to keep soils well aerated to keep grass cover (vegetation) healthy. But in time these terrestrial grass monocultures can “fail” lack of soil circulation (aeration) can lead to fungal and mold disease and root rot/failure. The same is true for eelgrass and waterfowl thatch it as good as any terrestrial commercial lawn care aerators that punch and remove soil plugs to open up root tissue build up below. This energy improves the health of the grass and extends the monoculture by reducing terrestrial soil compaction. Marine soils also become compacted soil pores filled and need oxygen to prevent the toxic sulfur cycle. Mother nature provides its own “core punch aerators” in the way of storms - violent and destructive in our view but critical to the cycles of marine habitat succession.

Dr. David Belding a famous shellfish biologist in Massachusetts (his important shellfish works recently reprinted by the Cape Cod Cooperative Extension Service – my previous employer in the early 1980s, see appendix) mentions this soil compaction in his work titled The Soft-shell Clam Industry of Massachusetts, November, 1930. “Clams are usually absent from soils containing an abundance of organic material. Organic acids corrode their shells, and interfere with the shell- forming function of the mantle. Such a soil indicates a lack of water circulation within the soil itself, as indicated by the foul odor of the lower layers, the presence of hydrogen sulfide, decaying matter, dead eelgrass, shells and worms. If such a soil could be opened up by deep plowing, or resurfaced with fresh soil to a sufficient depth, it would probably favor the growth of clams.”

Eelgrass is in fact an amazing marine plant, it behaves much like terrestrial grasses, it is farage for waterfowl and helps crab Megalops settle and survive. However in heat (climate cycles) it turns against many of the species it once helped – it helps return the dreaded sulfur cycle deadly to life that needs oxygen – like us.

Any eelgrass habitat services study should include the biochemistry of peat in low oxygen conditions, observed by Waksman (1945).

Where do I look for information?

This study involves many scientific areas for Capstone projects – SAE credits

- Some reference materials are attached – however some basic areas to review can be obtained from T. Visel in the Aquaculture Office.

Coastal Erosion Processes – habitat sucession
The formation of Peat – sulfide toxicity
Fisheries/Habitat Information – historic fish catches
Fish/shellfish Diseases including human pathogens – marine pathology
Core studies – Coastal Geology – Rhode Island reports of cores in salt marshes for example
Sulfate Acid Soils – and Sulfuric Acid
NOAA Climate Prediction Center The NAO – North Atlantic Oscillation Climate Patterns
The Sulfur Vibrio Bacteria Series – and Desulfovibrio Bacteria
Corraline Red Algal – larval chemical fractions (live Maerl) to bay scallop habitats
The diseases of Sapropel – Red Tide and Other Hab Cysts – Vibrio series
The Biology of the Bay Scallop


Peat – “A layer of partially decomposed plant materials that accumulate on the land surface in environments of high acidity and little available oxygen, such as marshes and bogs.” Long Island Sound – An Atlas of Natural Resources
Connecticut, Department of Environmental Protection,
November 1977

The Scallop Fishery, by Ernest Ingersoll, US Fish Commission, Section V, Vol. 2, 1887, History and Methods of the Fisheries: “The scallopers will tell you everywhere that the more they raked the more abundant they become. I have heard this from many dredgers myself, and the reports of others contain the same assertions. Rakings, they say scatter the young, and keeps them from crowding as they in short, it lets them grow.” Pg. 570. [But by the 1880s, bay scallops were already in decline with the warmer temperatures. In the colder 1870s, Greenwich, Connecticut was a center for the bay scallop industry – T. Visel].

“At Greenwich, Connecticut, I was told that where 10 or 15 years ago [1870s, T. Visel] one could fill a dredge in a few rods, (rod 16.5 feet, T. Visel) and a boat would take 50 to 100 bushels a day, now only about 10 bushels a day was the average catch.” Pg. 571. (US Fish Commission 1887 – reference bay scalloping in Greenwich 1870s).

Tidal Marshes of Connecticut and Rhode Island, David E. Hill and Arthur E. Sherin, The Connecticut Experiment Station, 1970, New Haven, CT. Pg. 10.

“As marshes are drained or samples dried, oxygen permeated the sediment and sulfide is converted chemically to sulfate. Some sulfate combines with hydrogen and produces sulfuric acid and low pH.
The dramatic increase in acidity after draining and drying is caused by oxidation of sulfur or process called sulfur acidity. (Fleming and Alexander, 1961). Here, anaerobic sulfur reducing bacteria extract sulfate from sea water, use it and then concentrate it in the sediments. Thus the sulfate of sea water is transformed biologically and chemically to black, hydrous iron sulfide and hydrogen sulfide gas (Gallagher, 1933). The blackish subsurface sediments and rotten egg odor of the marsh is well known.”

Page 1. Salt Marsh Peat Hill and Sherrin 1970
“Essentially, there are four types of tidal marshes in Connecticut and Rhode island. Three of these types are along the coast and are segregated by total depth of the marsh peat and tidal sediments 6 deep shallow and very shallow.”

The Scallop Estuary – Nelson Marshall 1994

“It is well known that very young scallops need a surface such as the blades of eelgrass to attach to when they first settle out of the water column. It is not as widely appreciated that they can settle on a variety of alternatives about as well. We found them attaching to the filamentous red algae, Agardhiella, that grew in abundance where the eelgrass had disappeared” Pg. 42, The Scallop Estuary, Nelson Marshal 1994.

The Biology of Polluted Waters – Hynes 1971
Pg. 158.

“The results [of excess organics – T. Visel] was first codified by Kolkwitz and Marssen 1903-1907) who developed their well – known Saprobien system for the assessment of organic pollution – Polysaprobic the zone of gross pollution with organic matter of high molecule wet (oak leaves T. Visel) very little or no deprived oxygen and the formatting of sulfides”.

Pg. 95 Desulphovibrio Formation Bacteria (Vibrio) Hynes 1971

“All organic effluent therefore ultimately became inoculated with suitable bacteria- The range of types of bacteria involved is very great and many of them specialists. We have already seen that nitrification is carried out by certain genera (species, T.Visel). These areas also several species who inhabit totally deoxygenated water or the anaerobic layer of the mud in places where the overlying water contains some oxygen compounds (Hawkes 1957). Others reduce sulfates to sulfides under anaerobic conditions, thus releasing the obnoxious smell of hydrogen sulfide and black mud and sand where this gas combines with iron to produce black ferrous sulfide. These bacteria include the small coma – shaped Desulphovibrio desulphuricans (Postgate, 1954). HBN Hynes, The Biology of Polluted Waters (1971).

Pg 6, February 10, 1983

TOO MUCH EELGRASS? “Working Bay Bottoms”

I was pleased to read Mr. Nawoichik’s letter in the February 3rd edition of the Village Advertiser commenting on Mr. Dow’s January 20th article about shellfishing. One thing was mentioned in both the articles regarding how beneficial eelgrass is in our bays. I wonder how many studies have been done on eelgrass, codium and other grasses when they become over abundant.

In the Hyannis bays, the over abundance is more than obvious by the huge windrows piled high on the beaches, the nuisance caused by blocked marsh ditches as well as the considerable expense to the town to remove it each year.
If great amounts of eelgrass are the criteria for good crops of shellfish, then certainly this area should produce extremely well each year. Just the opposite is the case and it appears that other towns up Cape from Barnstable are experiencing the same effects. In some of the bays, the eel grass and codium are slime and silt covered, greatly reducing the flow of nutrients to the shellfish. This silt laden mess is certainly not preferred as a setting place for shellfish as they leave the veliger stage. When the roots finally get so thick that they crowd one another out, the losers decay; and with no oxygen in the soil create gases that shellfish cannot live in.

I have glassed the bays on the south side of the Barnstable for a third of a century and when I started, there was very little eelgrass, no codium, and small amounts of floating grasses. We had a good crop of scallops each year, were allowed a bushel of oysters per week on our family permit as well as a peck of clams and quahogs. As the grasses closed in, silting became much more noticeable. The oysters had no place to set except on the stones, shells or grass at the shore’s edge and this area is periodically blasted by severe winter weather and most oysters are frozen and lost. Finding very few areas to set, scallops have greatly diminished in numbers and are found in small places where the bay floor is grass free. I would assume that the grasses will again get blight as they did in the nineties and twenties and a more balanced shellfish situation will return.

During the late 1920’s and all through the 30’s, there were unbelievable amounts of shellfish and finfish in our bays. This was a period of practically non-existent eel grass. I realized that weather conditions during that period were the reasons for such unusual shell fishing because the predators were greatly reduced but also the bay floors were clean, creating a fine environment for shellfish and finfish to live on and in.
It is time to talk facts about our bays, their potentials and the wise use of them. There can be a very good shellfish resource there and with cooperation from the shellfishermen, users of the waterway, and the shore owners, this could be accomplished. The shellfishermen, by continually working the bay bottoms, prepare the soil for future crops by realizing predators’ eggs and destroying predators living there. With some help from Mother Nature in the eventual reduction of grasses and some work by the shellfish department when the time presents itself, all could enjoy much better fishing.

John B. Farrington
50 Fire Station Road, Osterville.

February 5, 1953
Mr. Gordon L. King, Chairman
Shell-Fish Committee
Town Clerk’s Office
Madison, Connecticut

Dear Sir:
This is to acknowledge receipt of your letter of February 4 requesting information on the culture of long and round clams and also inquiring about the reasons for the disappearance of clams from our waters.

We still do not know the primary cause of the mortality of clams occurring several years ago. However, we think that, to some degree, it was due to a parasite but largely to a great preponderance of clam enemies of which green crabs and horse-shoe crabs are probably the most important. These two species of crabs, as well as related forms, have increased in number quite substantially during the past eight years. This increase was characterized by relatively high winter temperatures. We think there is a correlation between the temperature of the water and the number of crabs.

Frankly, we know very little about the culture of clams, with the exception that they have to be rigidly protected against predators. However, we have done some work in respect to their artificial propagation and may soon offer some practical suggestions for raising clams artificially. I am enclosing reprints of two of our articles on this phase of our work, which may be of interest to you.
Sincerely yours,

V. L. Loosanoff
VLL:R Laboratory Director
(Duplicated by Susan Weber for Sound School, March 2017)


Michael Ludwig
Environmental Assessment Division
National Marine Fisheries Service
National Oceanic and Atmospheric Administration
U.S. Department of Commerce
Milford, Connecticut 06460

Data were obtained regarding the biological and physical impacts associated with using explosives as a herbicide for eelgrass (Zostera marina). Removal of the rooted marine vegetation from an area approximately 122 meter wide and 550 meters long within Niantic Estuary at Waterford, Connecticut has been proposed in an attempt to improve water quality and containment of egg and larval stages of the Bay Scallop (Argopectens irradians). Creation of a channel through dense stands of eelgrass should reestablish a persistent tidal eddy in the inner estuary which would improve dissolved oxygen levels and allow more complete habitation of the embayment. Relying on a physical model and in situa-generated information from both the private and public sectors it has been concluded that such an attempt, with proper constraints should be allowed.

Marshall’s 1960 discussion of this situation describes the scallops as setting on red algae in the absence of eelgrass within the estuary. Apparently the algae served as a suitable substitute for the destroyed eelgrass. As eelgrass reestablished itself along the coastline it also re-vegetated the estuary and had, by the early 1960s, extensively reduced the tidally-generated gyre’s persistence and mixing capabilities. During this same period bay scallop production suffered a serious decline. Compounding the reduction in numbers of juveniles the area experienced a series of concurrently occurring harsh winters which had caused the almost complete exclusion of bay scallops from the area.

The Works of David L. Belding M. D. Biologist
Early 20th Century Shellfish Research in Massachusetts
Quahaug and Oyster Fisheries The Scallop Fishery
The Soft Shell Clam Fishery
Re-published by Cape Cod Cooperative Extension
with the permission and cooperation of the Massachusetts
Division of Marine Fisheries 2004

Cape Cod Cooperative Extension is proud to present this re-published collection of reports on the shellfisheries of Massachusetts written by Dr. David L. Belding

“..the Legislatures of 1905 to 1910 directed the Commissioners on Fisheries and Game to conduct a series of investigations and demonstrations to determine methods of developing the shellfisheries.”

This publication, The Works of David L. Belding, MD contains three of the volumes of research completed by the Commonwealth’s Shellfish Biologist in the early 20th century. His work took place over many years, and was updated and re-printed on several occasions. To this day, Dr. Belding’s studies of shellfish have proven to be quite accurate, through, and remain a remarkable and classic pieces of research.

Cape Cod Cooperative Extension is proud to provide the shellfish community and all that love the history of Cape Cod and Massachusetts with this 2004 edition of Belding’s work.

Bill Burt, Marine Resources Specialist
Cape Cod Cooperative Extension, an agency of Barnstable County

Re-published by Cape Cod Cooperative Extension
with the permission and cooperation of the Massachusetts Division of Marine Fisheries
Copies available from the Cape Cod Extension Service


I take great pleasure in knowing that the public will once again be able to read the research work conducted by Dr. David L. Belding on the shellfisheries of Massachusetts during the first part of the 20th century.

In the preparation of this 2004 edition, the Division of Marine Fisheries (DMF) and Cape Cod Cooperative Extension agreed on an effort to present the material, as far as possible, in the original format of the last published editions of the works printed in 1930.

Dr. David Belding, a medical doctor, was also a fine biologist. He was assigned by what was then called the Massachusetts Commissioners of Fisheries and Game to conduct studies into the shellfisheries of the Commonwealth. These studies began in 1905 and continued through 1910, and during most of those years Belding had but a single assistant. Despite this fact, his work regarding the biology of shellfish remains extraordinary in terms of its accuracy, particularly when you consider the time period when this work was done, and the type of equipment and technology he had available for his research. When one reads this volume, keep in mind the amount of time it must have taken to travel from one location to another, as many of the rural roads at that time were just sand paths. The amount of work, attention to both the experiments and detail makes this a premier piec
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