[BlueChip]

Crabbing Increases Reported in Eastern and Central CT
The Search for Megalops
The Sound School Regional Vocational Aquaculture Center
Blue Crab Research in Long Island Sound 2016
“You Do Not Need to Be a Scientist to Report”
July 26, 2016
Tim Visel
View Megalops Reports on Blue Crab Info™ 2011 to the present Northeast Crabbing Resources Thread
Report #5 2016

• Important Notice to Crabbers
• Small Jelly Fish with Potential Toxic Sting
• Crabbing Increases in Eastern and Central CT, “rusty crabs”
• Large Crabs Moved up Rivers
• Western CT Crabbing is Slow
• Oxygen Saturation Falls in Western CT


Important notice to Crabbers

Since the Megalops report issued last February 9th 2016 Vibrio bacteria has been in the recent news media – any cut or wound that does heal properly should checked out. Blue crabbers that fish in very warm waters and those containing Sapropel deposits should be very careful. For Connecticut crabbers The Blue Crab Forum™ has some threads that mention crabbers experience with Vibrio bacterial infections from more southern waters. It appears that very warm waters are associated with this bacterial species – Florida has recently issued additional cautions. For those who have missed the earlier report it was Megalops #1 issued on February 9, 2016, it is on The Blue Crab Forum™ Northeast crabbing – NE crabbing resources thread.

And now something that could impact Connecticut crabbers this season. This information notice was sent to Connecticut Shellfish Commissions on July 19th regarding an invasive jelly fish that has a powerful sting from Connecticut Sea Grant. The warning and contact information is repeated below, Small Jelly Fish With Potentially Toxic Sting – Groton, CT – Connecticut Sea Grant July 18th Gonionemus vertens (notice).

Small Jellyfish With Potential Toxic Sting

Annette Govindarajan, a biologist with the Woods Hole Oceanographic Institution, would like your help in tracking a small jellyfish, Gonionemus vertens, in Long Island Sound. These jellies are about the size of a dime to a quarter, and are transparent with brown or orange details. While these jellies have been in the Sound for about a 100 years in a non-toxic form, a highly toxic variant from the Western Pacific Ocean has apparently reached our shores and has been reported in Mumford Cove (a cove in Groton, CT – T. Visel). Dr. Govindarajan is studying the DNA of these jellies and would appreciate learning about any sightings. The jellies are usually found in quiet, sheltered areas in the back of bays, especially in areas with eelgrass habitat and occasionally around floating docks. They are not known from exposed sandy beaches. On a practical level, people should avoid contact with the jellies either by swimming or wading, or allowing their hipboots to be flooded with water with jellyfish. Do not touch the jellies. If you are stung, seek medical attention if necessary. Symptoms may include severe pain, respiratory distress, and possibly paralysis, and may last 3-5 days. Sightings should be reported to Annette by email (afrese@whoi.edu).

One of the more interesting aspects this season is that crabbers at Westbrook and in the CT River have been snagging bunker for crab bait (most still used chicken) while crabbing. I timed a school of small Menhaden passing by the Baldwin Bridge Boat Ramp Pier (DEEP has done a great job with public fishing piers in our state – visiting both sides on Saturday – July 9th CT River, I watched dozens of crabbers having a great time. These fishing piers have provided hundreds of thousands of enjoyment with adult and very young crabbers!) taking over 20 minutes! The schools of bunkers in the CT River this year have been just enormous. It is not uncommon to see menhaden mixed in with the blue crabs this year in pails.

See you at the docks Blue Chip.

Crabbing Increases in Eastern and Central CT

The mid July reports continue to mention large numbers of 3 to 4 inch crabs at the mouth of rivers in central and eastern CT. Up river and at high tides catches of much larger “rusty crabs” those brown and very hard shells have increased and continue to provide great catches. Several questions have come in recently about “rusty” “yellow face” and white belly crabs if they shed and why the colorations and how old they are? To be honest I don’t know the age – I believe “rusty” 4 to 5 years, yellow face 3 to 4 and white bellies - which often have new shells much younger. As for the color some veteran crabbers told me that “rusty crab” are those crabs that winter upriver in brackish waters – yellow face crabs dug into mud (perhaps Sapropel) and might have sulfide yellow stains and those crabs who dig into sand, shell or eelgrass meadows tend to have little staining. From my lobstering days this makes sense, I recall that hard shell lobsters were darker, had growths, scales and even barnacles on a rock hard shell. The yellow face and rusty crabs did move east in 2011 and smaller movements in 2012, and perhaps those comments about ocean crabs waves Truit 1939 and Jeffries 1966 mention a similar event (Megalops Report #1 August 2012). These crabs mixed in and became very noticeable in 2011-2012.

One thing that I have also noticed is that rusty and yellow face crabs are packed with meat, have very hard shells from examination these crabs have not shed for some time – perhaps years? For some reason these crabs have stopped shedding but are now the larger crabs. In some observed catches they appear to be half perhaps more of the catch? The white belly crabs have clean shells and at times appear to have different shapes. This was reported in as special report in August 23, 2012 “Waves of Crabs Detected Perhaps Moving East” (Connecticut Blue Crab Special report #1 August 2012 Northeast Crabbing Resources The Blue Crab Forum) with a large number of yellow face/rusty crabs having a second growth claw and a brown growth. “They are what has been described as “rock hard shells.” All the years crabbing in Tom’s Creek Madison CT I did not catch these crabs but were all white shells clean and little staining – it could be the result of where these crabs hibernate during the winter but not certain. We may get some answers to these questions from soil scientists shortly.

The color of the blue crabs might be from the type of bottom they chose to over winter in crab shells contain three basic components about half calcium carbonate and the remainder split between proteins and chitin – a polymer of sugar compounds. Chitin contains chitosan a very valuable compound used in a variety of substances that include food products.

It is Chitosan - Carotenoids that gives salmon its pink or red color from crayfish ingested in fresh water streams when they return to spawn. It is also what gives crabs that red coloration when cooked.

The shells of crabs could react to bottom chemicals over the winter. Upriver locations have high tannins – it is the “oak leaf tea” described in many IMEP/or Nitrogen/Bacteria papers (IMEP habitat papers are found in the fishing eeling oystering thread while bacteria/nitrogen papers on the Environmental/Conservation threads of the Blue Crab Forum™).

Tannin is a natural substance found in leaves especially oak leaves (and the root of the word Tannenbaum – oak tree). It has a brown color and can stain surfaces brown. Crabs leaving in such areas may pick a the brown tannin stain (tannins is what stains teacups, etc.). (See IMEP #27 Blue Crab Forum™).

The yellow coloration of those distinctive crabs that moved east in 2011 and 2012 or “yellow face crabs” may have two possible reactions, proteins in acidic conditions reacts with aluminum to produce a yellow color. When Sapropel is oxidized in the winter (acid sulfide soils) pyrite iron forms a sulfuric acid which then reacts in aluminum and causes a yellow stain or it is not a stain but a chemical reaction with calcium and iron sulfate forming copiapite a calcium iron sulfate with a distinctive yellow color. I tend towards this reaction as water movement would give this reaction more time to happen – the mouth area is where the most water movement occurs thus the yellow coloration would be highlighted here which is how this yellow (which at times can be a brilliant yellow) presents.

Most books on the biology of blue crabs highlight a 50 to 60 day molting process. So this coloration would not be transferred to the “new shell” but here the life span of blue crabs in our area may not be at all accurate. These rusty and yellow face have stopped shedding and when cooked do not present a new shell in the process of formation? I think these are the remains of the 2010, and 2011 years and have ceased to shed for at least two possibly three years explaining perhaps why these older crabs now make up such a large proportion of the catch and “packed with meat.”

I stopped by the Oyster River in Old Saybrook recently as crabbers there returned legal “white belly” crabs but retained the much larger rusty crabs believing that they contained twice possibly three times the meat in them (I would tend to agree – my own experience confirms this).

But soil scientists studying submerged estuarine soils might be able to answer some of these color questions shortly.

Very little has been published recently about the biochemical reactions in Sapropel (Acid Sulfate Submerged Soils) although the chemistry has been studied for about a century on land – referred to as “muck soils.” This is what fishers have termed Black Mayonnaise. Toxic substances from organic matter reduction including toxic aluminum and sulfur compounds have also been known – but because of the term “sediment” is most nearly inclusive of all substances – from powered rock to leaves it is very hard to find specific articles about it (I agree its not very “media appealing” but important none the less). Although previous researchers have urged a narrowing of terms even Sapropel this material is still often called sediment. When Sapropel (Acid Sulfate Soil) is trapped in bed rock we do hear about sulfide biochemistry its ability to attract and react with water to produce sulfuric acids – in concrete and the yellow stains on porcelain. In fact, the concrete issue is happening in Connecticut – foundations that had rock with trapped Sapropel itself (termed Pyrehotite) have had problems and roads out west built with Copiapite have buckled when exposed to air and water. Both list the ability of these iron (sulfur) compounds to react with (air) oxygen to produce sulfuric acids.

Farmers in CT learned the hard way about old “blue – black mud Sapropel” and its ability to produce sulfuric acid a century ago. Once analyzed by the CT Agriculture Experiment Station who then urged farmers to cut in oyster shell, (The Marine Experiment Station urged lobster shells) to neutralize this acid. After that happened farmers boasted about improved productivity from “mussel mud” dug from coastal rivers and its use resulting in increased crop yields. In Europe “Sapropel” (they call it “Sapropel”) is a valuable soil conditioner and a source of metals to those soils leached by acidic rains. (The marine and brackish water compost has a interesting history in the Northern Maritimes Josh MacFadyen has detailed the production and reuse of mussel mud detailing the existence of hundreds of “Mussel Mud” machines that harvested Sapropel for agriculture use in the Gulf of St. Lawrence). Interest in mussel mud peat/lobster shell compost has been growing (natural fertilizers) and tomatoes seem to be the most suitable plant to grow in Sapropel once rinsed of salt and acidic conditions offset by calcium/shell. Because sulfate reducing bacteria naturally complex metals overseas it is used to both remove (bio extract) heavy metals while replenishing those same metals to soils leached by acid rain (in Europe).

A group in Prinee Edward Island has successfully rebuilt a mussel mud machine as an historical exhibit to show how this rich marine compost was used on hay fields. John Hammond the retired oyster grow I met while working on Cape Cod had tomatoes growing Sapropel mixed with of course oyster shell – the tomatoes were huge. (See IMEP report #26 CT Rivers lead Sapropel Production 1850-1885 The Blue Crab Forum fishing eeling and oystering thread Sept 29, 2014).

Sapropel when stabilized by a vegetation cover becomes peat while retaining many of the biochemical aspects termed acid sulfate soils – acidic, high in sulfur and able to hold large amounts of water. The culture of rice and sugar cane in a way are dependent upon these wet acid sulfate soils – and have a sulfur tolerance as does salt hay and eelgrass along our coast.

More recent studies of Subaqueous Soils and giving them a classification of soils itself is given to Dr. George P. Demas the concept of submerged soils is attributed to his review of the presence eelgrass and widgeongrass in Maryland – the heart of the United States Blue Crab Fishery and he published a paper titled “Submerged Soils – A New Frontier In Soil Survey” in Soil survey Horizons 1993 (Stolt and Rabenhorst 2010). Dr. Demas passed away n 1999 but his work is now carried on by soil scientists across the globe. In fact scientists met last week (again in Maryland) in an eighth international conference for “Acid Sulfate Soils” and I look forward to reviewing the conference proceedings if and when they should become available. However important studies are already underway here in Connecticut. A Connecticut study conducted by NCRS (Natural Resources Conservation Service) presented at a University of Connecticut Sea Grant meeting of CT shellfish Commissions here at The Sound School last winter by Debbie Surabian State Soil Scientist for CT and RI. An excellent powerpoint titled “Coastal Zone Soil Survey, April 2016” is on the internet.

We may soon learn about the soils in which blue crab hibernate and habitat impacts upon them in severe coid and in intense heat. The soil chemistry in time may answer crabbers questions about “yellow face” and “rusty” crabs and the impacts of energy (storms) and temperature (climate change) the critical role of sulfur cycle to fish and shellfish species that both live in or near these marine soils.

Large Crabs Moved up River

In late June crabs left the deeper holes and headed up river. The low rainfall has allowed the salt wedge to move up the Connecticut River and reports of crabs now reaching Chester.

By early July some great blue crab catches were reported in central CT in the very furthest up reaches of rivers – large jimmies in two feet of water or less. As the water warmed large adults moved from the shallows and the highest moving tides were better – boats are now doing better than shore/bank areas (except at high tide). Look for crabs to be in deeper water as seawater temperatures continues to rise.

Western CT Crabbing Is Slow

A small movement of 3 to 4 -1 inch crabs was detected moving east from the mouth of the Housatonic River at the end of June (nothing like the waves of crabs following tropical storm Lee, 2011 (IMEP #27) posted September 30, 2014. The Blue Crab Forum™ Fishing and Oystering thread.

These crabs would reach legal size this fall but low or lower oxygen conditions could be driving them from these western CT shallows now, these waters typically warm first and therefore are also the first at times to report fish kills in the shallows. In fact, last Friday, July 22, 2016, an article in the Stamford Advocate seemed to point in that direction: a fish kill has already occurred there. “Marine Experts Anticipate Late Summer Fish Die Off” Stamford Advocate July 22nd 2016. If water saturation (oxygen) is low I suspect sulfate digestion has replaced oxygen digestion of organic matter (and perhaps an increase in ammonia) reducing oxygen levels even more. Although human pollution is often looked at for the cause of these fish kills, they are natural in very warm shallow waters and those subjected to tremendous amounts of storm driven organic matter. After our hurricanes in 2011 and 2012 wind driven shredded leaves, stems and bark coated cars in an organic paste – I can only imagine how much organic matter ended up in the estuaries. In 2011, I obtained several reports that once very productive blue crabs locations in Western CT were ruined by these storms – large rainfall events as crabbers sent in reports that crabbing locations were now smelly and filled with brown leaves the beginning marine composting in high heat, Sapropel.

In fact some blue crabbers in Chesapeake Bay continue to mention that some areas that held good blue crab habitats there have yet to recover from Agnes in 1972 (Agnes is associated with a huge decline in soft shells clam production also in Chesapeake Bay).

Large amounts of organic matter does find the warm water sulfate reduction stripping whatever oxygen is available in warm water (and nitrogen compounds that contains in oxygen as well) as bacteria struggles to breakdown theses oxygen compost – sulfate reduction areas. We are experiencing a drought so saline waters have reached for up into the rivers and I suspect sulfate reduction is driving oxygen levels lower, a bad sign for crabs and fish as well, blue crabbers might want to look at – this seawater quality comparison for explanations for poor crabbing such in shallow waters. This is a look at three stations in Long Island Sound July 26 under three parts per liter oxygen is considered borderline anoxic oxygen saturation and harmful to sea life.

My Sound University of Connecticut – Eastern Long Island Sound
Water Temp 68° (f) Salinity 29 ppt oxygen 7 mpl 02 Saturation 97%

USGS Site Essex Island CT River (Middle of State) United States Geological Survey
Water Temp 82° (f) Salinity 3 to 4 psu (tides) Oxygen 5 to 7 mpl 02 Saturation 94%

My Sound University of Connecticut – Norwalk Harbor – Western CT
Water Temp 78° (f) Salinity 13.1 pss oxygen level 1.1 mpl 02 Saturation 14%

You can quickly see the very low oxygen level in Norwalk Harbor only 1.1 mpl oxygen and long enough that can kill fish and shellfish if this condition persists for days at a times. This is some of the habitat conditions that Blue Crabs now face in shallow areas.

Unfortunately it may take years for this organic matter to be broken down. I did hear this happened on Cape Cod, a coastal pond had its inlet close up, warming and lack of flushing it smelled of sulfur; it was reopened and shellfishers noticed that built up Sapropel (Black Mayonnaise) deposits melted away – what most likely happened is that cooler water had more oxygen for bacterial decomposers who now could consume it (imagine if someone dumped 5 feet of compost on a lawn, etc).

Even if blue crabs are abundant, they will not seek out Sapropel with sulfate reduction – sulfides and the smell of hydrogen sulfide, is the cause of a “blue crab jubilee”. Once sulfate reduction increases ammonia from these deposits can shed sulfide waters into surface waters starting a fish kill. In addition the organic bacterial breakdown releases ammonia a plant nutrient for macroalgae especially sea lettuce Ulva lactuca. In the historical fisheries literature oyster farmers mentioned thick growths of “sea cabbage” following hot spells that killed oysters by the thousands. (See appendix).

This is an account of organic matter putrefying in high heat in upper Narragansett Bay from (Nixon 1989) Following heavy rains (most likely flooding) heavy amounts of sewage manure and organic matter was swept down the Providence River into upper Narragansett Bay followed by a heat wave and then next was a classic, Jubilee as crabs (even shrimp) tried to crawl out of the water from Nixon - the account of then Professor A. D. Mead of Brown University – 1898 Rhode Island.

Heavy rains on July 13, 1898 into the Providence River Watershed occurred before an intensive heat wave August 18 to September 5th 1898. A record rainfall contributed to a tremendous watershed removal of tannin – the final breakdown of wood tissues and in our area mostly leaves. Tannins (three major types) are brown and give wood its typical brown hues. The New England region recorded intense heat waves in much warmer than average summers between 1895 and 1901.

Professor A. D. Mead of Brown University wrote up the 1898 event in an article titled “An Investigation of the Plaque which destroyed multitudes of fish and crustacean during the fall of 1898” and later submitted his article for Science Magazine (S. Nixon Coastal and Estuarine Studies – Novel Phytoplankton Blooms Vol. 35, pg 430 1992). The description of Professor Mead (1898) details the appearance of chocolate waters which signifies Tannin in huge amounts, followed by harmful algal blooms (HABS) and then sulfide induced toxicity from low oxygen conditions. Sulfide toxicity is often rapid and prevents the “flee factor” of declining oxygen levels – fish can move if the transition is slow but if quick fish and blue crabs often perish. One indication of sulfide events (other than the stench of sulfur) is the “Jubilee factor” blue crabs climbing out of the water which according to Professor Dr. Meads’s account did occur. Dr. Nixon repeated Dr. Mead’s account and his description which is still very valid today following a second very warm period in New England 1974-2004 is included below. A century later it is still valid and is repeated here.

After heavy July 1898 rains – Dr. Mead Reports the following:

“During the last two months the inhabitants of Rhode Island witnessed the following remarkable phenomenon. The water of a considerable portion of the Bay became thick and red, omitting an odor almost intolerable to those living near by. The situation became alarming when, on the 9th and 10th of September {1898}, thousands of dead fish, crabs and shrimps were found strewn along the shores or even piled up in windrows.

During the last of August, throughout September and a part of October streaks of red or ‘chocolate’ water were observed from near Quonset Point and Prudence Island, north to Providence, and, on the flood tide, up to Seekonk River, nearly to Pawtucket, a range of about fifteen miles. In other parts of the Bay, as far as could be learned, the phenomenon had not been observed.

On the 8th and 9th of September the water became extremely red and thick in various localities from East Greenwich to Providence, and the peculiar behavior of the marine animals attracted much attention. Myriads of shrimps and blue crabs, and vast numbers of eels, menhaden, tautog and flatfish came up to the surface and to the edge of the shore as though struggling to get out of the noxious water. Indeed, the shrimp and crabs were observed actually to climb out of the water upon stakes and buoys and even upon the iron cylinders which support one of the bridges and which must have been very hot in the bright sun.” This is the “heat” blue crab jubilee of southern waters that occur here in hot weather.

We may have a blue crab habitat history on Long Island, New York that may help answer some of these composting crab habitats in cold - Mecox Bay – Here for hundreds years the bay has been reopened after closure and reportedly has had blue crabs populations. Its also a shallow bay and could provide what happens in very shallow areas in cold. It is in the shallows that cold and heat habitat changes are most noticeable and where blue crabs live.

Thank you for your reports as we learn more about Blue Crabs in New England.

All blue crab catches, habitat observations and conditions are important.

Email questions or habitat observation to Tim Visel at tim.visel@nhboe.net. I respond to all emails



Appendix I

New London, The Day, November 11, 1889
Quiambaug Oysters
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Fresh Water and a Hybrid Plant Has Destroyed Many Bivalves

Mystic Bridge, Nov. 11 – “The oyster crop in Quiambaug cove this year is nearly a total failure. Of some 4000 to 5000 bushel of seed oysters planted last spring a good part are dead and the rest are very poor and watery, with the exception of a few that have been taken up and transplanted near the shore and which are in fair condition. The main trouble, as far as can be learned, is caused by a cabbage like plant* {suspected to be sea lettuce- Ulva lactuca} - (as the growers term it), which grows over and entirely, covers the beds. It is also said the trouble is in part caused by the unusual amount of fresh water that has flowed into the cove the past spring and summer. A well-known Norwich oyster grower by the name of Church put in some 1200 to 1500 bushels of seed last spring. Despairing of their even fattening he came down about a week ago, dug up the whole lot and sorted them over. About half of them were dead. Church carried the remainder to Norwich and transplanted them, with the hope of their fattening up in time for market.

The first oysters ever grown in the cove were put in by one Horton 10 years ago. Not long after, he transferred his bed to Elias Davis, who in turn transferred it to one Price who increased the bed and sold the oysters around the country. Their general excellence soon gained for them a widespread reputation, causing other beds to be taken year by year until at the present time nearly all of the available space is occupied. The beds for the most part are owned by residents thereabouts but several large beds are owned by well-known oystermen. The oysters have thrived wonderfully and increased year by year up to the present time.”

Sea lettuce is suspected of producing a natural biocide in low oxygen conditions that is toxic to blue crab larvae (Journal of Experimental Maine Biology and Ecology 1985- Donna A. Johnson and Barbara C. Welsh. University of Connecticut)

[PECo]

Asianfisher (aka Billy) and I caught about five dozen keepers in West Haven, last night. We saw many mating crabs (i.e., larger males atop smaller females). Many of the crabs had brittle shells, although only two had soft shells.
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