Thursday, September 18, 2014

2014 Connecticut Blue Crab Special Report #8

From Tim Visel:
The Search for Megalops – Special Report #8 – September 4, 2014

Questions About Sapropel – Potential Impacts to Blue Crab Habitats

The Sound School Regional Vocational Aquaculture Center
A Capstone Project ISSP For Sulfur Reducing Bacteria
Blue Crab Research in Long Island Sound 2014
Tim Visel

I appreciated the responses about leaves filling in shallow estuarine habitats; the past two years I have mentioned those areas which smell bad and have streaming bubbles (Megalops #1, April 1, 2013 and #7, August 16, 2013) as not very productive for blue crabs.  Shallow areas may have become acidic and deadly to Blue Crab Megalops.

For those blue crabbers interested in shallow blue crab habitats a paper about Sapropel bottoms might be of interest.  (IMEP Newsletter #23 The Cycle of Sapropel and Estuarine Habitats). It is found under the Fishing, Eeling and Oystering Thread in the Blue Crab Forum.™ 

Questions about Sapropel –

Composting marine habitats has not been reported much in the recent scientific literature so many fishers have not really heard the term Sapropel, but it describes a sub tidal breakdown process of organic matter similar to that in backyard compost with oxygen.  That is why so many European organic growers now use it. (It is marketed as a natural soil enrichment). Terrestrial growers have long recommended that recycled organic matter (compost) often “be turned” to introduce oxygen for those terrestrial bacterial composers that consume it.  Marine compost contains most of the same soil enriching qualities (once rinsed of salt) and for centuries used for agricultural purposes even here in Connecticut.  Marine composts (humic) in oxygen limited conditions however, have sulfur reducing bacteria and that is the largest difference between terrestrial and marine composts, the type of bacteria within them.  A slippery or greasy feel to Sapropel described by agricultural researchers for over a century, is the remnants of leaf waxes, the relatively long chain hydrocarbon molecules that plants produce to protect the leaf – the “shine” on oak leafs for example that also protects trees in times of excessive drought.  Sulfur reducing bacteria leave the waxes behind (longer chain carbon molecules) and they give Sapropel the blue/black shine or glimmer in sunlight. 

Sapropel as Fertilizer

As early as the 1860s, descriptions of marine mud or mussel mud often contained the phrases of adhesive or sticky (Agriculture of Maine Forty-Fifth Annual Report of the Secretary of Agriculture, 1864). “When first taken out musle (mussel) mud is adhesive and somewhat like blue-clay and must be frozen before it can be spread on land.”  Some farmers reported very good results other mixed but many noticed its sticky consistency waiting for it to freeze.  Once frozen it lost its waxey adhesive features and could be spread on farm fields.

It is that same wax that plagues western farmers today in drip irrigation field out West when Sapropel from reservoirs is introduced into water distribution systems.  It is that wax that “clogs” drip irrigation systems in slow moving lines.  It’s also this waxy characteristic to have such estuarine bottoms noted as “sticky mud.”  Other than leaving waxes sulfur reducing bacteria produce sulfur compounds including acids and some highly toxic sulfide compounds to marine organisms.  Early agricultural use often noted its sulfur content.

Sapropel formation is aided by high heat and lower oxygen conditions driving out oxygen dependent bacteria in favor of sulfur reducing ones. It seems ironic that higher temperatures that favor blue crab reproduction at the same time favors sulfur reducing bacterial reduction. Not that much is known about recent Sapropel as most estuarine studies concentrate on unnatural coastal processes and frequently overlooks the natural impacts that fishers often observe themselves. (Winter flounder fishers were correct about Sapropel habitat change in the late 1970s and 1980s).

The use of marine mud or mussel (muscle) mud as fertilizers appears in New England coastal states experiment station reports for about half a century. The Connecticut Experiment Station appears to be the leader in recommendations. In a July 1917 bulletin (#94) titled “Manure From the Sea” (Jenkins and Street), the Connecticut Experiment Station (New Haven, Connecticut) recommends “1,000 to 2,000 bushels per acre has given excellent results “ (pg.11, Marine Mud section).  It was not only Connecticut following its use by shore farms as a soil amendment and at times a fertilizer. But the dangers of marine mud (Sapropel) were also noted a century ago although farmers did not know why. In an 1885 Maine experiment station report it issues a caution on page 35 in a section titled, “Harbor Mud” and relates the concern of oxygen absent reduction over a century ago.

“This station (Maine Experiment Station) was sent a sample by Fred Atwood of Winterport (Maine) the barrel of mud was received several weeks before being sampled and when it was opened it emitted a strong odor of ammonia.”

In 1903 a Dr. Knoblauch of Cologne, Germany patented an improved process of extracting ammonia from marine mud sediment by simply heating it (The American Fertilizer Magazine, January 1903, Vol. XVIII, pg. 14).  Coastal farmers were often perplexed. Some fields grew tremendous crops of hay while others languished in “mud dust” for years after treatments. A key to the sulfur/ammonia problem was known by just descriptions of odor –a link to age and heat but not well understood by the agricultural community. Today we know that as acidic sulfate soils. Mr. J.I. Stevens of Essex, Connecticut writing to the New Haven Connecticut Experiment Station in 1879 stated “Its effect as a top dressing for lawns and also on mowing land [hay fields] has proved greater for good than anything I have ever seen”. Pg 49, 1879. The same report also includes a caution “The only drawback to the use of the marine mud lies in the considerable proportion of salts, mostly common. Salt, which it contains, being nearly one percent, if thrown out in heaps and exposed to this rain, this salt will be mostly removed.”  The Connecticut (New Haven) Experiment Station also reported that “marine mud” contained high amounts of sulfuric acid “Unlike stable manure and ordinary composts, the mud (marine) contains considerable amount of sulfuric acid” (pg 49, 1879).

In one of the first agriculture references to Sapropel benefiting coastal farmers was from an 1854, September 14th address before the Rhode Island Horticultural Society Industrial Exhibition in Providence by Rev. William Clift of Stonington, Connecticut. In the speech he urges coastal farmers to look into local fertilizers,

 “The marine deposits in the bottoms of your bays, creeks and rivers are made up very largely of these decayed weeds; and could not fail to prove a valuable fertilizer” – and further – “Dead forests of gigantic dimensions lie entombed in them (Marine Humic). In these places the vegetable wealth of centuries is accumulated” and finally, “Let human skill breathe upon these reeking sepulchers of dead plants and they shall wake again to life, beauty and fruitfulness.”

It is the reference to “reeking” a historical reference to strong stench in this case was most likely toxic sulfur compounds. But the source of Reverend Clifton’s marine mud was the Mystic River (Connecticut) and in the 1860s Professor Johnson of Yale’s Department of Analytical and Agricultural Chemistry had it tested (Peat and Its Uses As Fertilizer and Fuel, Samuel W. Johnson, Yale College, 1866) and it revealed “high levels of sulfate of iron in considerable quantity” – and reviewed detrimental ingredients appears to be “sulfate of protoxide of iron” (p.56). Some farmers allowed it to overwinter and freeze, noticing that the presence of mussel or oyster shells seemed to bring it to fruition much quicker. Professor Johnson (1866) in a bulletin about the use of peat reported it to be mixed with lime and wood ash and to yield the best results,” adding many writers here asserted a hurtful “acidity” which must be converted before “they can be usefully employed.”

One of the reasons why Sapropel is not mentioned today is that the scientific community has had difficulty classifying it – as soil studies reflect mineralization processes and Sapropel is the product of living sulfur reducing bacteria. Estuarine studies refer to it as “sediment” while land application terms include acid sulfate material. This situation has been mentioned in several studies including a paper titled, (Subaqueous Soils: A  Pedologic Approach to the Study of Shallow-Water Habitats, Carl Demas et al, Estuaries Vol. 19 #2A, p. 229-237, June 1996). This quote from the paper’s abstract highlights this problem: “Present classification systems are inadequate because existing paradigm does not actually consider them as soils but merely as sediments” (from abstract). To add to the confusion Sapropel is often referred to as many as twelve different terms including marl, guttja, peat, green vitriol, mussel mud, marine snow, black mayonnaise, ooze, vegetable mold, benthic flux and coquina.

Exposure of Sapropel to oxygen causes the production of sulfuric acid and extremely low pH; sometimes approaching a pH of 2, toxic nearly to all plants (perhaps the only plant that can live in this soil is Phragmites). That is the reason for toxicity to plant life; it burns the root tissue, not unlike its destruction of eelgrass meadows reported in Megalops Newsletter #3, August 20th, 2014.  Is Sapropel responsible for the decline in blue crabs this year?  No, I don’t’ think so, but it may be a part of a long term climate pattern that degrades its habitats for many species of “value” including blue crabs for years. A retired oyster grower on Cape Cod, John Hammond once remarked to me “This stuff is bad for fish and shellfish,” and I agreed.

The Cycle of Sapropel

For blue crabs, a sandy, bivalve bottom and patches of eelgrass has shown to be key to post Megalops survival. The clean and green eelgrass is beneficial to blue crabs and green crabs as well.  Both eelgrass and shellfish also have habitat cycles that depend upon marine soil pH – acidic bottoms therefore, may have a long term negative impact.

The cycle of Sapropel is now thought to be connected to the natural cycle of eelgrass bottom habitats. Sulfur compounds have now been shown to be deadly to eelgrass as well as to clams and fish.  Blue crabs are very susceptible to sulfide bottoms for many years the scientific community has searched for “indicator” organisms that link pollution to habitat quality but one of the first such quality habitat indicators is perhaps Sapropel.  Most fishers have seen it, a soft blue black jelly like material and those that dig deeply into it, find that it emits strong sulfur smells. For decades estuarine studies have focused on the absence of oxygen (we need it also so a bias of “value” exists) and not the presence of sulfur.

It is now suspected that the increase in forest coverage, a warming climate (post 1972) and storm water movement of leaves has assisted the formation of Sapropel. Because this organic input is natural it is often excluded from nitrogen input studies.  A century ago Robert Lauterborn was the German biologist who brought the study of organic wastes (rotting sludge) without oxygen as the studies of “Saprobial life” to main street “science”.  Pollution of the Rhine River in 1900s led to studies of indexing habitat zones to the types of fish they could support.  In this regard it was mentioned that he relied on the experiences of inland fishermen and water authorities to characterize such habitats.  (Melkenion et al Robert Lauterborn 1864-1952 and his Paulinella chromatophara Protist, Vol. 156, August 2005).

For Connecticut it has been the river habitats that have supported the most consistent overwintering of blue crabs.  Tropical rains that started with the tropical storm Lee, then followed by Irene and Sandy may have moved huge quantities of leaves downstream covering former hibernation habitats both smothering crabs and providing organic matter for Sapropel reduction processes.  We may now have Sapropel accumulations and such deposits have been associated with fish kills, providing harmful algal blooms (HABs) with ammonia and sulfide smells. The presence of oxygen may produce very low pH “acid or sour bottoms.”  Sapropel may act as a huge nitrogen sink (storage) that now supplies far more damaging ammonia/nitrogen compounds for algal blooms.

Coastal Connecticut farms long ago used Sapropel as a fertilizer and noticed its high sulfur contents in deep aging deposits.  Deep organic deposits behind dams however were avoided for toxic sulfur conditions.  (CT Board of Agriculture, 1879).  As Sapropel ages it becomes more deadly.  Floods and heavy rains can dig into it and dislodge the toxic sulfides that may have accumulated for decades, rainfall moving toxic compounds downstream.  This event is usually short in duration but at the time very deadly, so without sufficient oxygen causes this deadly sulfide “wash” to flow downstream.  In time, oxygen changes the sulfides into acids. This sulfide release was often caused by ice in winter as tides found these tidal restrictions and speeded up and re suspended Sapropel deposits and the sulfides contained in them.  Warnings about this winter sulfide die offs still appear for Massachusetts coastal salt ponds.

One of the best descriptions of Sapropel harvesting was the digging of “mussel mud” by Canadian farmers to our north. The Canadian Oyster, page 103 printed in 1913 by Jos. Stafford, the Maritime Company, Ottawa) contains a section about its fertilizer use.  It was not a practice supported by oyster growers for many of the reasons listed above and in the process removed many oysters on shells growing over the “mussel mud.” [Several reports mentioned the presence of estuary shell (mussel, oyster clam) as a benefit to the use of this soil amendment.]

“A mud-digger consists of a framework suspending a huge dipper-like scoop with a bale and a long beam for a handle.  The sloop is lowered through a hole dug out in the ice and controlled by men at the end of the beam.  The power is applied through a chain that passes from the bale over a pulley and is wound around a vertical windlass turned by a horse.  The framework may be slid along to fresh places as the old ones become exhausted; the so called “mussel mud” is comprised largely of decaying oyster shells with some mussel clam quahog or other shells mixed with mud, and is used as a fertilizer for the land.”

But Connecticut River area farmers likely harvested it with the same methods and an Old Saybrook farm sold it by the cartload (full carloads delivered, $.25) but they stayed away from the deep accumulations behind mill dams.  A sample of black mud containing some seaweed from saltwater at Saybrook, was sent to the Connecticut Experiment Station by Geo. M. Denison, Esq., (1879) who states that it is exposed at low tide, and can be got upon the land for about 25 cents per load. I guess trial and error came into the process and a description of Sapropel made in 1879 is very similar to today.

Mr. Stevens of Essex also remarks: “Our mill ponds a few miles back from the river, contain a rich, black mud, quite deep and with a very strong smell.  It has been tried on various crops but kills everything. After being hauled and dried it turns from black to white, and puckers the mouth like alum.” (1879) I would match that 100 year plus description against any one made today for Sapropel.

Essex, Connecticut had a small parcel (Sunset Pond) dredged three years ago.  It had become a popular place for summer pond boat races and winter skating; leaves from the surrounds – trees are on the east and west edges were filling the pond and submerged aquatic vegetation (lily pads) growth made these activities difficult and at times impossible. The pond was dredged and a blue black mud (Sapropel) was spread on a grassy hill covering the existing soil.  For the first year, grass growth was a bit reduced as it took some time for the compost to become a part of the top soil, but today three years out, the grass is lush and thick – no doubt benefiting from this soil additive. 
Increases in “leaves” can occur downstream after heavy rains and often appear as a slurry of organic chaf (Cape Cod fishers called this material “oatmeal”).  I have noticed that some recent deposits contain mostly leaf stems; a few kayakers have noticed this soft bottom material in the Essex area primarily in North Cove.  This Sapropel appears to come and go over the past century and comments appear in historical literature that mentions the buildup of this organic material.  This is a reference to North Cove Essex, the site of “marine mud” production in the 1880s.

“In a recent note Mr. Stevens states that the mud sent by him was from a cove or pocket from the Connecticut River; the sediment is brought down in the spring freshets by the Connecticut, the cove connected with the river by a narrow channel. There is no current in it and suspended matters are deposited at such a rate as to have reduced the depth of the water three feet since the remembrance of elderly people”.

North Cove has in the past few seasons supported large populations of blue crabs, especially near recent dredging projects.  It is the deep and old Sapropel deposits in the coastal zone that is a problem; a thin layer seems to improve blue crab habitats, and it like all composts nourishes eelgrass plants but deeper layers kills most benthic organisms including clams, a major part of small blue crab diets.  As deeper layers become separated or “sealed” from oxygen in the water, they contain more sulfur reduction.  What was once good for eelgrass now turns against it.  Prolonged sulfur reduction finds that biological diversity drops and only a few species of primitive worms can survive in it.  As it “ages” toxic sulfide levels increases and the danger of sulfide washes downstream when disturbed.  In other words, in times of low oxygen (heat) it becomes deadly.  One of the coves reported to have the deepest Sapropel deposits at the turn of the century was Hamburg Cove in Lyme, Connecticut. Many boaters have reported deep deposits south of the Hamburg Cove entrance channel recently. Observations of Sapropel deposits would be appreciated especially if a thick blanket of leaves has appeared over once firm and shelly bottoms that had contained blue crabs.

All blue crab habitat observations are important.

Email your blue crab reports to:  All blue crab observations are valuable as we learn more about our blue crab population. Questions? Send me an email.

The Search for Megalops is part of a Project Shellfish/Finfish Student/Citizen Monitoring Effort Supported by a 2005 grant to The Sound School from the National Fish and Wildlife Foundation grant #2005-0191-001.

Program reports are available upon request.
For more information about New Haven Environmental Monitoring Initiative or for reports please contact Susan Weber, Sound School Adult Education and Outreach Program Coordinator at

The Sound School is a Regional High School Agriculture Science and Technology Center enrolling students from 23 participating Connecticut communities.

Friday, August 22, 2014

2014 Connecticut blue crab report #3

From Tim Visel at The Search for Megalops:

ISSP and Capstone Project
The Sound School Regional Vocational Aquaculture Center
The Search for Megalops – Program Report #3
August 15, 2014
You Do Not Need to Be a Scientist to Report

·        Crabbing in Saline Areas Improves
·        A Long Term View about Fishery Management
·        Blue Crabs, Sapropel and Habitat Capacity
·        Attention Connecticut Crabbers – Megalops Survey Postponed
Crabbing in Saline Areas Improves

Since the last report crabbing in deep saline holes has improved. The areas are best described as deep bends or rivers that act as linear salt ponds. Catches from these areas improved a bit while upper reaches have generally been slower.  Crabs seemed to expand into these areas slightly the first two weeks of August; however cooler temperatures and rains pushed back the crabs to these deeper more salty pockets.  Some areas that were productive previous years are now filled with leaves.  If these areas are leaf filled and periodically produce bubbles chances are it is now a sulfur reducing area (Megalops, Report # 2, August 4, 2014 ) try areas closer to the Sound.

This summer crabbers that had small boats and have been able to fish these areas and have consistently reported the best catches. We’ve had a relatively dry period and crabs moved into shallow areas, but after rainfalls seemed to push crabs back.  Blue crabs have appeared at the Essex Town Dock twice only to move after heavy rains. The upper Connecticut River crabbers continue to report slower catch rates, sometime is as few as one crab per hour.  This is of course, a marked difference from the past three years at Essex (see following section).

The cool summer temperatures have caused a second delay in looking for any Megalops sets.  A June/July spawn should be observable in September. 

Thank you again for all habitat and catch observations this summer

A Long Term View about Fishery Management
I have had dozens of dockside conversations with blue crabbers this summer. For those who started crabbing a few years back, the question is often brief, “what happened?” I have had many crabbers contacting me about the decline of blue crabs here and it’s far too soon to make predictions. That is something we like to do and avoids the phrase, “I’m not certain” or “I don’t know.” But that is just it, I don’t know.  That is why the fisheries history aspect I feel is important, especially with current climate change public awareness. Is our climate changing? Most certainly it is. Are we in new climate change habitats? No we are not. From the historical records it is reasonable to determine that warm and cold periods have happened here before, in fact many times. From current research into habitat trends, it has been three very cold winters in quick succession historically that resulted in the lowest blue crab catch outcomes (Although I am a member of the EPA-DEEP Long Island Sound Study Partnership, this discussion in no way represents the Long Island Sound Study, the Citizens’ Advisory or Habitat Working Group Committees).

The rise of blue crabs during increasing heat and followed directly after a die-off of lobsters as they did here a century ago. Many will look to human causes of these declines and events and that also appears as well in the historical fishery literature. As Rhode Island reports at the turn of the last century mentioned factory wastes as a cause of the lobster die-off in 1898, but remained quiet regarding the “oyster explosion” in the Upper Narragansett Bay or soft shell clams often within the same areas during the same year at the same time. (Rhode Island Report of Inland Fisheries, 1906, Section VI, page 14

As Rhode Island bay scallop production dropped by huge amounts believing that in 1898 bay scallops were perhaps extinct, striped bass then grew to enormous sizes. The 1901 Narragansett Bay soft shell clam set was so thick – over 7,000 clams to the shovel  as was described in the State of Rhode Island shellfish reports. Clams pushed each other out of the soil and the soft shell clam sets after 1898 were immense.  And in 1902, Newport, Rhode Island started listing crabs as an export item while swordfish catches started in 1896 and grew steadily as lobster catches continued to plummet.[1] (Annual Report of the Commissioners of Inland Fisheries, January Session, 1906, State of Rhode Island , Providence Plantations .) The best black sea bass year in decades that was also 1898, the year of the Narragansett Bay die-off. They arrived on May 10th and heavy catches began on May 12th, 1898.[2]  (Tracy -1909- Fishes Known to Inhabit the Waters of Rhode Island – Page 123)  In 1898 there were no regulations in Rhode Island for blue crabs and historically regulations follow a decline from high population levels. Lobsters, for example, were once used to be used for fertilizer or as “pig fodder,” but after declines in the 1890s management regulations were enacted. Although much can be learned from catch statistics when fisheries drop (and especially for those that drop quickly) the increase in regulatory authority and catch restrictions often follows a “fishery failure”. This appears often in the shellfish historical records for seasons, size and catch (creel) limits as well.  A fishery failure usually follows a habitat failure within two life spans, and for blue crabs with such a short life span these changes can be represented and large fluctuations in the history fishery landings in just a few years.  We may be seeing that now.

Some of the frustration experienced by blue crabbers this year as to what happened can be perhaps answered in the next few paragraphs. Habitat reversals tend to be quicker on land – the law of habitat succession but in the marine environment it takes decades. By the time habitats have reversed previous catch levels are forgotten. The recent “run-up” in blue crabs was set back in 1972 – successional habitat transition until 1998 reaching perhaps the highest habitat capacity in 2010 – nearly 3 decades later.

The following section describes the Narragansett Bay experience at the turn of the century. The Narragansett Bay (Rhode Island) records are more accessible currently than Connecticut fishery records. By 1895, Rhode Island fishery managers were aware that something was wrong with increasing heat huge species transitions were underway – New England was in a period of intense warming, very different from the 1870s of brutal cold.  The year 1898 was a tough one for Narragansett Bay (the fish die-off of 1898 was still talked about a decade later) and led to “investigations” almost as though something criminal had occurred. Fishery managers and officials were frustrated with changing climate conditions and one of the first questions asked in 1899 was what species were in fact native to Rhode Island waters? The first report developed by Dr. Bumpus (1900) was changed in 1901 and changed again with records on “rare species recently caught.”  The list was changed again in 1901 twice and also again in 1905 and 1906 and revised again in 1909. Some of the frustrations of fishery managers are evident as they tried to get a grip on rapidly changing observations. We often call that the “new normal” the problem is of course the new normal may not be that “new” after all. (Megalops Special Report #2, February 2014 )

This final 1910 Rhode Island report makes mention of “fishes which are particularly rare or whose distribution is of particular interest. The occurrence of such species in the waters in Massachusetts, southern New England and Long Island, is of special interest in the study of the fauna of Rhode Island” (page 37, Fisheries Known to Inhabit the Waters of Rhode Island, Henry Tracy, Biological Assistant, Wickford Station, 1910). In other words, what Rhode Island officials were experiencing also was regional in nature – What is going on in our neighboring states? The questions are very similar today and what Rhode Island officials found frustrating was they were experiencing the sharpest habitat reversal in perhaps three centuries back to the 1620s, the Mini Ice Age. It was hot and warm temperatures fish were now being seen in Rhode Island waters. One of the questions was should Tarpon be included in the list of Rhode Island fishes? Every time it seems the list was formalized, new species suddenly appeared. It was like trying to grab an eel with soapy hands just as researchers thought they had the list complete, changes needed to be made.

In 1895, two tarpon were caught in a fish trap in Coddington Cove, Newport, Rhode Island,  between 1895 and by 1906 fifteen more tarpon were caught; 9 alone in 1906. It was finally included in page 72 as “rare.” Then came a surprising haul of Mullet 500 barrels (1,200 bushels) in October, 1904 off Newport and a specimen of this catch was sent to the National Museum (which we now call the Smithsonian) for identification (1910, Tracy Report, page 97). This apparently was the “tipping point” and caused more studies of “the Bay.” Tarpon and mullet in Rhode Island waters, a die-off of lobsters and disappearance of bay scallops that is what was spurring public policy discussions (and studies) which was the sharpest habitat reversal in centuries. The Narragansett Bay “trusted” species of value were now gone – soft shells, oysters and later blue crabs surged instead in Rhode Island’s now warmer waters. Eelgrass meadows now covered previous bay scallop habitats. It just wasn’t Rhode Island, but the entire southern New England region. The Great Heat was happening and with it different habitat quality and new species not abundant here before for quite some time. In simple terms, “It got hot.”

Although tarpon was included in the species list finally in 1910, it would be another decade before it would turn colder. Land areas heat up faster than water in New England, but water (bodies) retains heat longer. That occurred in the New England Ice Panic of 1899-1900 when large bodies of water did not freeze, creating a shortage of ice and spurring the development of “commercial ice machines.”

The climate pattern changed in 1922; it started to get colder and the bitter winters of the middle 1920s surprised Rhode Island fishery managers who now witnessed the return of bay scallops. They were surprised to report that despite the bitter winters, bay scallops productivity had actually surged. They just could not understand it at the time. Bay scallops habitats had benefited from the cold. Their habitat quality has enhanced by storms and cold and improved habitat quality soon favored bay scallop abundance and then, of course, catches.

If it turns colder (still too early to tell), blue crabs will decline and lobsters over time will increase. That has happened here before. That is what makes the megalops set so important. It is thought that later megalops sets don’t survive here; year’s later blue crab catches quickly drop because of its short life span and limited “fringe” habitat capacity in northern waters.

The reproductivity of the blue crab could be an important indicator species for climate patterns and the “test” perhaps of such patterns is the strength, timing and duration of Megalops sets.

Blue Crabs, Sapropel and Habitat Capacity

One of the areas of recent study is the concept of bottom aquatic habitat stability. This a feature of often intense clam sets following severe storms, the wave and storm tides that act to cultivate sub-tidal marine soils freeing them of organic acids, opening pore space and reducing acidic conditions if this sounds like shoveling or cultivating garden soils, it is only on a much larger and natural scale. Some of the best soft shell clam (warm periods) and hard shell clam (cold periods) sets have come following hurricanes when habitats then stabilized.

For a warm water set the New England 1901-1903 sets of soft shells and the 1940-1945 cold water sets of quahogs are classic natural cultivation events. Marine soils that sit eventually become too acidic from organic matter, similar to terrestrial soils. The hurricanes of the 1950s and early 1960s are suspected of even helping offshore heavy sets of surf clams off the coast of New Jersey. But what if the soil is constantly cultivated? The habitat upon which clams set then becomes “unstable” and if constant any new sets are soon destroyed by the next storm. No master gardener would rototill a back yard garden, plant it and then rototill it again the next day, but nature can do that and a series of coastal storms can create long or short periods of habitat instability. That is aside from temperature, another huge factor in species abundance is energy.  Energy can be from wind or moving flowing water; one of the ways energy is applied to estuarine habitats is from rainfall.

Reports from Connecticut crabbers and some blue crabbers in southern areas report the upper reaches of rivers contain very few crabs, yet at the same time report changes in the bottom conditions (much mud, leaf material silt and other organic debris). Comments like grassed over, thick soupy bottoms soft muck or foul bottoms (odor) all signify a declining habitat quality. In some areas I suspect re-suspension of sulfur rich Sapropel under ice and movement of organic debris by heavy rains. This movement of long decaying organic material can release toxic hydrogen sulfide compounds; the same toxic material that has long plagued fish aquarists. It’s also very similar to organic material that collects above dams (Megalops Program Report #2, August 4, 2014).

New England blue crab habitats have recently had both, bottom instability (Irene, Sandy and Nemo) and currently much cooler temperatures. A third habitat issue has now come into view, precipitation. Over the last century Connecticut has “greened” once large areas of cleared agricultural fields have succeeded to forest cover and with the trees, come the leaves and leaves move with heavy rains. George McNeil, who once grew oysters in the lower Hammonasset River in  Clinton, Connecticut, used to wait with anxious anticipation, both ice and rain, seemed to assist leaf deposition in estuaries. Rains by active water flows (storm waters) would gather leaves and pieces them and brings them to the Hammonasset River as the current slowed leaf material would fall out covering his lower river oyster beds. Intense cold also would create scour water flowing under the ice created Venturi like “mud storms” that would under the right conditions move tons of leaves. It was according to Mr. McNeil as someone dumped 3 feet of leaves on your front lawn in just a few weeks.. He would rake off the leaves from the oysters using open frames in early spring before they suffocated. But what if he didn’t? The leaves would rot; suffocating bottom habitats (and oysters) and releasing in high heat high amounts of ammonia and concentrating sulfur compounds, many of which are highly toxic to marine life. And leaves, especially oak leaves already are highly acidic would compost over acidic marine soils.

The impacts of organic “debris” was well known by shellfish researchers in the 1890s.  Dr. G.W. Field of the Rhode Island Agricultural Experiment Station was asked to investigate the decline of the oyster fisheries in Point Judith’s Pond in 1896.  The final report in 1900 has this section in the Rhode Island Annual Report of the Commissioners of Shellfisheries to the General Assembly May session 1900,  “In brief, the cause of the decline was found to be the deposition of sediment upon the oyster beds; a condition brought about by the repeated closure of the breach, thus making the pond a settling basin for the silt brought down by the Saugatucket river. The silt and detritus, settling upon the oyster beds, kill the oysters by smothering.”

It is just not in Northern waters that organic matter impacted sub tidal habitats a century ago, but Southern areas as well.  E P Churchill of the Department of Commerce Bureau of Fisheries writing in 1919 (The Oyster and Oyster Industry of the Atlantic and Gulf Coasts)  details places in the Chesapeake Bay and bays on the New Jersey coast where rapid deposits of “vegetable matter” can cover oyster beds, on page 16 states: “During warm weather this organic deposit is likely to undergo rapid decomposition, the toxic products of which sicken and kill the oysters.”

Most references to decaying organic matter as a negative habitat type mention summer heat and the possible low oxygen formation of Sapropel.  Sapropel concerns continue today even in the fresh water habitats, especially canals and reservoirs out west.  A July 2012 Central Arizona Project (CAP) mentions the formation of Sapropel from bacterial reduction of organic matter in water with oxygen deficits (Pg 22 contains this quote):  “this reduction may lead to Sapropel formation a compound that is high in hydrogen sulfide and methane, and has a shiny, black color due to the presence of ferrous sulfide.  This compound is responsible for the occasional “rotten-egg” odor (of water).”

Something similar may be happening now to blue crab habitats, clam shell habitats and eelgrass. Eelgrass is the habitat to watch for crabs and like oyster beds, eelgrass cannot take vast quantities of decaying organic matter. Eelgrass as other organisms also appears to have a “habitat clock” and is killed by excess organic matter.  Two Danish biologists last year investigated the appearance of huge rings in dense eelgrass meadows in the Baltic Ocean.  The explanation was that eelgrass plants trap the mud and they also in the process trap poisonous sulfides.  “The high concentration of sulfides that is trapped, in the midst of the older eelgrass that is less capable of withstanding the effects of the poison gets killed off, leaving only eelgrass (younger plants) that encircles the deposits of sulfide-rich mud” thus a ring.  (University of Copenhagen – Jens Borum, “Coves of South in Denmark”, Mariane Holmer February 2, 2014.   Organic matter in high heat has the ability to transition habitat types in relatively short periods of time.

The past few years I now suspect that several western Connecticut coves and bays have obtained deep storm driven deposits of leaf matter. Storm water carries a brown, oatmeal chaf of ground up stems, blades and other terrestrial vegetation into water bodies. In the presence of oxygen, this appears as a brown chocolate layer, but below in the absence of oxygen, it turns black. Heavy rains can carry this organic matter and the event that makes me suspicious are the July-August 2011 reports from western Connecticut crabbers degraded blue crab habitats (Megalops Report #12 August 2 2011).                            

Some crabbers have noted this material as well, even from last year. In cold water this organic matter is broken down by grazers that consume it; some clammers that use a plunger for soft shell clams, for example, may recall immediately following seeing sand shrimp come in close to feed. In warm water over time with less oxygen this material becomes Sapropelic, reduced by a host of primitive bacterial strains from the time when sulfur ruled the earth and not oxygen. The availability of oxygen in today’s atmosphere has pushed the sulfur cycle from the habitat agenda, but it is still here, mostly hidden from view. Not too much is written about Sapropel because it is usually associated with the older sulfur cycle and is, for the most part, a natural process. But every sub-tidal habitat is subject to it now when oxygen is in short supply; sulfur reducing bacteria lie in wait ready to again consume organic matter (leaves) as they have done for millions of years. It is this process that creates very deadly sulfides and ammonia, nutrient that supports harmful algal blooms (HABs). It is this material that when disturbed by crabbers gives off the smell of sulfur.  When sulfur is noticeable to our senses, 100 parts per billion it is at a level that is toxic to crab Megalops. (Reefkeeping Magazine – hydrogen sulfide and the reef aquarium).  A byproduct of the sulfur bacteria is sulfuric acid and this lowers the pH level of marine soils making clam sets almost impossible; it kills clam larvae on contact. Sandy, bivalve shelly bottoms also hold small blue crabs providing cover and feeding opportunities. Thick soupy rotting organic matter rich in sulfides is not a preferred habitat for blue crabs.

Attention Connecticut Crabbers

NAO – A Cool Summer The Megalops Survey Postponed Now Until September

For those crabbers who follow the NAO climate pattern, it has deepened now to a negative 1, but zonal flows have flattened out across the United States the horseshoe bulge and moved the storm track to the east. It now resembles a winter Northeaster storm track in which coastal lows approach Cape Cod before veering off to the northeast. This has kept Long Island Sound waters cooler. Although summer temperatures also remain cool, the polar air has moderated but has kept us cooler than average. One of the questions asked recently regarded a prediction for the 2015 blue crab season and one parameter is the timing of the Megalops set, which because of the cooler temperatures, the Megalops survey has been postponed again until September. I want to thank those crabbers who offered to contribute to the survey, but now it looks like September 10th to the 15th will be the best time. If the blue crab larval stage Zoeae survives, it should appear around mid-September.

The spring Megalops set (carry over from last fall) was most likely victim to cooler temperatures, habitat instability ice and freshwater runoff from the spring melt. Several reports have indicated that the upper tidal reaches of large tidal rivers (including the Hudson River in New York) have obtained tremendous amounts of organic debris from heavy rains associated with tropical storm Lee and Hurricanes Irene and Sandy. Most of this leaf debris appears to be oak species, a leaf material with a pH of 4.5 to 4.76, and in the absence oxygen contributes to the bacterial decay (reduction) in the sulfur cycle. The residual compost is often Sapropel which can emit toxic hydrogen sulfide and suffocate crabs in hibernation. When leaf material is too deep it rots in heat releasing hydrogen sulfide which is toxic to fish, crabs and even shellfish. This is not the preferred habitat type for blue crab Megalops, in fact blue crab Megalops are killed by it.

It is thought that some of the previous productive up river blue crab areas now have inches to several feet of dead leaves over them. Many crabbers have posted on regional websites that the lower more saline portion of rivers are more productive. This habitat feature may be a part of this observation. Hydrogen sulfide toxicity may have a part in this habitat transition and why the upper reaches report a very low blue crab presence. One Connecticut River that appears to have obtained tremendous quantities of leaves and now possibly a reduced acidic bottom is the upper sections of the Saugatuck River in Westport.

A notice will be sent out with the September Megalops survey date.

Thanks again for your interest and support.

Tim Visel

[1] Annual Report of the Commissioners of Inland Fisheries, January Session, 1906, State of Rhode Island , Providence Plantations
[2] Tracy -1909- Fishes Known to Inhabit the Waters of Rhode Island – Page 123

Thursday, August 7, 2014

2014 Connectict Blue Crab Report #2

From Tim Visel at The Search for Megalops:

ISSP and Capstone Project

The Sound School Regional Vocational Aquaculture Center

The Search for Megalops – Program Report #2

August 4, 2014

“You Do Not Need to Be a Scientist to Report”


  • Small crabs increase in central Connecticut
  • What About Our Megalops?
  • Habitat Changes – Long Term Bottom Conditions Are Key Indicators

Reports continue to come in detailing larger numbers of small crabs in central Connecticut—1 to 2 inch size higher in the marshes and 3 to 4 inch towards higher salinities.  Adult crabbing did pick up a bit, then slowed and suspect the first round of shedding is now occurring—look for soft shells and paper shells to increase.  The amount of small crabs for some reports mention 5 to 1- some as high as 10 to 1 which are good signs that crabbing will improve in some areas.

High tides are the best and deep holes that held adults over the winter can be the best place to start and some really hard shells (their shells are often muddy – yellow or moss covered but they are packed) are being caught in these areas.

Crabs have shown in Essex, but freshwater flows make catches difficult- hook ups occur but let go when they sense the surface waters?  Catches remain slow – the Baldwin Bridge is only at 3 to 4 crabs per hour.

The summer continues to be cool, with colder air pushing for south, only two 90° days so far according to my records and the NAO projections continue to be negative.  A negative NAO opens the door so to speak to allow cooler air to sink south into the central US.  The storm track also shifts- a negative rating a more coastal track; a positive, a more offshore track.  Some of the worst hurricane seasons are associated with the occurrence of negative NAO patterns.

With the temperatures so cool, I doubt if habitat compression will start this summer, there should be enough oxygen in the Sound for most organisms.

I appreciate all the reports,



Small Crabs Increase in Central Connecticut

 Around the middle of July came the first reports of small crabs but usually around vegetation or shelly, sandy shores. Some crabbers have reported soft muds over firm bottoms and the winter ice maybe changed the habitat type which small blue crabs prefer. Areas with bivalve shell and patches of eelgrass appear to be the best post Megalops stage areas for blue crabs. However, the reports of mud smelling crabs and crabs covered in mud do lend some questions of Sapropel deposits (see last section) during the winter.

Sandy, shelly areas have the best small crab reports also tidal rivers known to contain natural oyster reefs (beds). It is these areas that small blue crabs can find food and cover from predators. Featureless soft bottoms provide little cover and lower feeding opportunities. Soft mud bottoms usually suffocate shellfish populations and may explain (partially) why some areas that used to contain large populations of small blue crabs last year do not this year. The other explanation is that the winter temperatures killed many blue crabs and mud suffocation maybe one of the possible ways that this occurs. Retired oyster growers would tell me that thick river ice would accelerate outgoing tides under the ice and move huge underwater “mud” deposits from upstream, downstream covering lower river oyster beds, suffocating them. Over the winter sometimes three or four feet of leaves were moved this way.

After severe winters, oysters were “winter killed” and paired “matched” shells of dead oysters were then called “stools.” Areas with soft bottoms that when disturbed emit sulfur “match stick” smells are now suspected as being extremely toxic to young blue crabs (Sapropel toxicity). Look for areas of bivalve shell to contain the most sublegal blue crabs and channel edges or transition areas from deep river bends to hold the most adults.


What About Our Megalops?

After two weeks of no reports regarding small crabs, the first reports mid-July came in from the lower Hammonassett River. Some sightings were also reported in the RT 146 Guilford area, the Branford River and East Rivers. All reports mention an increase of small 1 to 2 inch crabs, although reports of 1 to 2 inch crabs have been also mentioned in the Lower Connecticut River and North Cove, Old Saybrook. Reports of increasing numbers of small crabs are a very good sign. Crabbing generally has been very slow and it seems that in previous great blue years, the numbers of 1 to 2 inch crabs that overwintered along our shore (IMEP #22) and observed in early spring did not occur. A look at the 2011 and 2012 blue crab years show a distinct change and completely agree with Masspi and his report for Massachusetts (July 3, 2014) the same can be said for Connecticut as well.

Our winter last year represented a negative or neutral NAO pattern allowing massive bulges in cold air sinking south while pushing sub-tropical moisture north along our coast- more snow. Since 2008 the NAO has been more and more in the news (especially after NOAA rocked the fishing community linking NAO patterns to the abundance of the American eel in 2008) with its polar vortex, (Megalops Report #1, January 2014) (Megalops Report #2, February 2014) Anyone following the last two winters would agree the numbers of inches of snow and “ice on” days have increased. We might see increasing offshore ocean temperatures pause after these past two winters, but that data has not been available much before May 19 (NOAA Newsroom –SS14.04). The May 19th, 2014 report mentions a shift in average temperature of one month (seasonal) from November 20th to December 20th. If cooler waters prevail we may see a shift back. Many crabbers have commented that the season is “later than usual” and they are absolutely correct.

Shorter lived / high reproductive capacity organisms have long served as the “watchmen of climate change” and one of those (I feel) is the blue crab. It is more difficult to follow changes of long lived species like the Quahog clam (which live to be 80) than short lived species like the blue crab. In our area, the blue crab might not only be an indicator for climate change but important climate patterns (NAO) as well.

It is very responsive to habitat and natural conditions including predator / prey, reproductive capacity, habitat quality and climate temperature / energy factors. This makes short term predicative models for the blue crab almost impossible requiring long term observations (my opinion.). Many biologist and naturalists decades ago urged caution in very short term observations to make long term population estimates or habitat values (Roberts, 1985, Pauly 1995). A few years ago an article titled, “The Blue Crab Conundrum” (Chesapeake Quarterly, Vol. 11, #2, July 2012) authored by Michael W Fincham examined all factors associated with rapid changes in blue crab abundance. It was a good article looking at all the factors and recognized that any one of them could make the difference. One of the indicators is the timing and strength of our Connecticut Megalops set. The set was very “late” last year, so I feel this year perhaps as well. The capacity of blue crab Megalops to survive cold winter is now being researched in other New England states.

There is a growing interest in long term resource surveys when compared to climate, but there is the problem short lived species often provide the poorest short term models. That in part led to my original research question the rise of blue crabs from 1998 to 2008 was steady until the NAO changed. Some great blue crab years and then none was the first blue crab report of fisher observation trends (2010).  I follow historical fishing trends and one species that has been an indicator of cold has been the halibut (see Megalops #4, April 25,2014) and latest reports from Maine Working Waterfront News (August 2014) report that halibut are slowly increasing. These colder temperatures might be helping them and lobsters here also.

When I started the newsletter, I did not feel that blue crabs could complete the reproductive cycle here. I feel differently today. The 2008, 2010 blue crab seasons changed my view entirely. However, patterns do emerge; something that has not been discussed enough (my view); it gets colder than warmer and habitats reverse with storms and species abundance directly follows.

Many fishers (including this one) have noticed a dramatic increase in the reproductive capacity of Black Sea Bass (a tasty fish of reefs, rocks and shoals) these past two decades. Its scientific name is Centropristis Striata – it is a type of grouper (serronidare) and can grow up to a 9 pounds / 19 inch fish. They are strong and have sharp gill and dorsal fins and frequent lobster trap visitor when I lobstered with my brother, Raymond off the coast of Madison.

When we first started lobstering in the late 1960s, Tautog (Blackfish) was more numerous and often entered lobster traps to eat our lobsters. By the mid-1980s, Black Sea Bass increased and now has become very prevalent. But this is not always the case.

In the May 30 1884 volume from the United States Commission of Fish and Fisheries, David S. Jordan talks about several dramatic changes in “sea bass” populations (the name has had several changes the past two centuries)

136, The Sea Bass – Serranus atrarius

“Previous to 1878, there were no records, only four instances its occurrence east of Monomoy (Cape Cod) but in summer of 1878, several were taken in (the) Milk Island weir, off Gloucester.  There is no reason to believe that fifty years ago (1834) Sea Bass was much less abundant in southern New England than it is now.

In Linsley’s catalog of The Fishes of Connecticut, published in 1842, the species is described as a great novelty.  It is curious however, that some time between 1830 and 1840 there were according to Storer, fifty or sixty vessels fishing for sea bass in Vineyard Sound.  In 1787, if Schoepf is to be believed, they were rarely seen in the New York market.”

But in 1915, they were in the New York City markets listed as “sea bass.” In 1884, the average size of Sea Bass was one and a half pounds, but later as the warmth increased, Black Sea bass (and also Striped Bass) grew larger.  In the 1870s an eight pound Stripped Bass was newspaper article material, one would hardly consider that the same way today.

The reproductive capacity of Black Sea Bass has increased with our most recent warm period 1972 to 2008 – most indices mention the rise, it also occurred during a dramatic downturn in Tautog, also a favorite reef fish. And recall it was black sea bass that was consuming large quantities of blue crabs last fall (Megalops #6, October 24, 2013) as reef dwelling and deep water the Megalops set had occurred in deep bottom waters and fell victim to such “top end” predators – and not the preferred habitat for blue crab Megalops. Most fishers in southern New England I feel will agree that Black Sea Bass has become at times more abundant that Tautog – they have reversed in abundance since the 1950s.

Habitat Changes Long Term Bottom Conditions Are Keys Indicators

Several crabbers have commented upon the impacts of tropical storms and hurricanes recently on blue crab habitats and looking into the historical references, two basic conditions occur. I agree that both “energy” and temperature can and do have substantial habitat impacts.

  1. The Deposition of organic matter from watersheds (leaves) may have delivered a huge amount of leaf rot into the lower western Connecticut Rivers. The Saugatuck River especially appears to have been most impacted. Leaves decay in high heat reducing to toxic sulfur compounds toxic to most marine life. See footnote #1.
  2. The high heat in 2011 and 2012 while not having a direct impact upon adults - they were able to get into more oxygen sufficient areas as reported by several 2011 observations. Post Megalops stages may have been killed by this high heat and sulfur reduction process. This could explain the inshore waves of crabs migrating east in 2011 perhaps toward cooler eastern waters.
  3. Tropical storm energy (and tides) has a tendency to sweep Megalops from estuarine areas out to sea. This is frequently mentioned in the Chesapeake Bay historical literature.
  4. Tropical storms’ rainfalls can cause salinity “shock” mortality – sudden changes in salinity are often deadly, especially in warm water (Megalops report #12 August 2, 2011).
    The pattern here has abruptly shifted from very hot (which may have been too hot for Megalops) to cool which may have delayed the set so late in the fall that they didn’t have a chance to survive the brutal winter – winter kill is also a term often found in historical literature.
  5. Tropical storms, even Nor’easters, can remove eelgrass meadows, a key habitat type for the Megalops and star crab sizes. The amount of submerged aquatic vegetation (SAV) can lead to a “habitat bottleneck” and an increase of predation – no cover. A key measure is bottom oxygen levels – extended periods of high heat can be as dangerous as extended periods of very cold. In high heat eelgrass “wastes away” from disease. In cold, strong storms rip it up. What appear to be the best habitat conditions are cold to warm (transition) with little in the way of strong storms.
    Footnote #1
    “This putrefied organic matter is a Sapropel and as these organic deposits “age” they become more toxic to marine life.
    It is organic Sapropel that is linked to the high heat black water fish kills of the last century. Organic matter when trapped in sluggish coves or blocked by manmade dams collects in high heat. This Sapropel then releases hydrogen sulfide into the water with its toxic impacts. Bacterial breakdown of this bottom organic matter converts to a slower sulfur cycle of bacteria that live in the absence of oxygen. Although marine compost (mostly leaves and dead shore grasses) has been used as a fertilizer for centuries (mussel mud), Connecticut farmers discovered the dangers of using old Sapropel that underwent sulfur reduction behind dams. It is in this area that toxic Sapropel formed with its characteristic pungent sulfur smell. This is an excerpt from the Connecticut Board of Agriculture 1879-80 that provides the account of Mr. J. I. Stevens of Essex, CT on page 49 of the 2nd report of the Connecticut Agriculture Experiment Station, 1879 which perfectly describes Sapropel toxicity. The river mentioned in the report is the Falls River which runs from Ivoryton to Centerville sections of Essex today.
    Mr. Stevens then as most commercial fertilizer producers were “invited” to provide samples to the experimental station for analysis contained sulfuric acid and notes in a letter the sample should have been from the middle of the cove (North Cove Essex – not the upper section). One source although had already been found to be toxic the organic debris trapped behind mill ponds (Falls River)
    “Our mill ponds a few miles back from the river contain a rich, black mud, quite deep and with a very strong smell. It has been tried on various craps but kills everything – after being hauled and dried it turns from black to white, and puckers the mouth like alum.” The experiment station then adds “the astringency here referred to Mr. Steven’s letter is due to soluble salts of iron or alumina. Composting with a small proportion of slacked lime will decompose these salts and render the black mud a safe and serviceable application.” The description by the Experiment Station in 1880 fits the one provided Dr. Donald Rhoads of Yale in 1985.”
    In one of the first comprehensive Long Island Sound Environmental workshops – sponsored by the NOAA Estuarine Programs Office and US Environmental Protection Agency EPA (US Dept of Commerce 14th and Constitution Avenue May 10, 1985 – Battelle Contract E68-03-3319 and was published 1//15/1986.  The subject of bottom sediments and oxygen depletion were discussed, one presenter Dr. Donald Rhoads of the Dept of Geology and Geophysics of Yale University reviews this topic on pages 47 to 57. Dr. Rhoads mentions the need to study the role of sediments in low oxygen conditions and Long Island Sounds organic matter loadings.  In his summary on page 56 Dr Rhodes asks what the distribution of Sapropels is.  What are the distributions of the biological storage system low sulfide and purging systems high sulfide?  The write up at the end of the report includes a question and answer session in which Sapropels are highlighted many times and included as a critical study area.
    “Underlying the dysaerobic and anaerobic water one typically finds organic rich black (i.e. sulfidic) muds that are termed Sapropels.  These are rich in iron monsulfides; the physical properties of these muds are distinctive and the best description that I have heard of them is that they are like a “black mayonnaise.”  Dr. Donald Rhoads workshop participant, May 10, 1985.
    Sapropel toxicity is a huge area of marine habitat change and the negative impact of sulfur rich sapropel is just now being reviewed. Dredging and composting Sapropel deposits is the only long term solution. Some dams in Connecticut have tens of feet of decaying leaves behind them – and in high heat Sapropel forms which is deadly to most marine life. In times of heavy rains or floods, huge quantities of Sapropel are washed downstream. This is what I believe happened in some areas of western Connecticut in 2011. “
    The first direct use of Sapropel used as a fertilizer I observed was on Cape Cod. It was mixed with old oyster shell and used to nourish a tomato patch owned by John Hammond. It was Mr. Hammond who called it nature’s “first fertilizer,” but because of its acid / sulfur makeup, excellent for tomatoes.”
    I am going back to my former fisheries teacher at the University of Rhode Island, Bernard Skud, and a statement made in class over three decades ago “it’s not the ducks but the duck habitat that determines populations.” Bernard Skud was a former U.S. Fish and Wildlife Service regional director and very familiar with the “duck stamp” -a partnership to conserve the habitat important to migrating duck populations and hunters. These habitat discussions always left an interest and a question about sub-tidal habitats and the long term impacts of habitat reversal mentioned so many times in the fisheries historical literature. For blue crabs, eelgrass habitats seem to be critical second only to estuarine shell. Post Megalops stages during times of constant storms and habitat instability are periods that show the lowest catch landings.
    New England it seems has had four such recent habitat reversals; about one complete reversal about every century. I look at catches of fish for links to habitat conditions. For example, in 1842 the capture of a Black Sea Bass was considered a unique and rare catch, or in terms of language at the time “on oddity.” That would hardly fit today’s Black Sea Bass population – the reproductive capacity of the Black Sea Bass in this latest period of heat has soared here – no one would consider catching Black Sea Bass today as “odd,” but at one time people here did an excerpt from the U.S. Fish Commission 1884 details these changes, but were not climate questions but one’s related to catches.
    The cold reversals are roughly detailed as 1650 (early settlers picked a very cold time for our shores) 1770, 1850-1880. The negative NAO cold period of 1950 to 1972 is not included in many historical records because it is still “young” as compared to the others. Warm periods follow the cold and last about 4-5 decades. For Long Island Sound have good information for the cold 1850-1880 period “Devil’s Belt” and the 1880-1920 period of great heat that followed. Some reversals have transitions – great cold and heat as weather patterns conflict as a type of battle to what will eventually win out. It is now suspected that scores of estuarine coves and bays over recent geological time will produce increases in oysters following each warm period; blue crabs and soft shell clams also in heat. In periods of cold, bay scallops, lobsters and the hard shell clam (Quahog) will do better.
    This appears consistent with fish landing records over the past 150 years. The problem is of course that these trends are longer than our life spans, giving the family fishing journals of the last century the advantage of defining cycles. The oral history of fishing cycles is one that can be found in most fishing communities and helps explain the firm belief in them that fish populations appear to come and go in long patterns and when you examine climate records, fish landing records and habitat descriptions you see this pattern also; they do reverse.
    *see The Embryology of the Sea Bass (Serranus Atrarius) by Henry Wilson, Assistant - U.S. Fish Commission (1884), pg. 209. Local names include “Blackfish – Blackwill, Black Harry and Hannahills.”
    For blue crabbers wishing to read more about the eelgrass/ Sapropel habitat see IMEP habitat newsletter #13, March 2014 “Did Eelgrass Help the Rise of Blue Crabs 1998-2012” on the Blue Crab Forum™ ‘s  fishing, eeling, oystering thread.
    Every observation is valuable as we learn more about our blue crab population.
    The Search for Megalops is part of a Project Shellfish/Finfish Student/Citizen Monitoring Effort Supported by a 2005 grant to The Sound School from the National Fish and Wildlife Foundation grant #2005-0191-001.
    Program reports are available upon request.
    For more information about New Haven Environmental Monitoring Initiative or for reports please contact Susan Weber, Sound School Adult Education and Outreach Program Coordinator at
    The Sound School is a Regional High School Agriculture Science and Technology Center enrolling students from 23 participating Connecticut communities.
    The latest Search for Megalops (BlueChip) newsletters can be found on The International Blue Crab Blog Spot™, The Blue Crab Info forum™ (Northeast Crab Resources) and Connecticut Fish Talk™ Salt Water Reports.
    Email your blue crab reports to:
    If interested in helping with the Blue Crab Census, please email me at and register as a volunteer.
    Tim Visel
    The Sound School