[BlueChip]

Brown Waters, Menhaden Fish Kills and Blue Crabs
The Search for Megalops
“You do not need to be a Scientist to Report”
Megalops Special Report #2 September 15, 2016
A Capstone Project – Blue Crab Chemical Concerns
View all Megalops, Environment Conservation and Habitat History Posts on The Blue Crab Forum™
Tim Visel, The Sound School, New Haven, CT 06519

This is the Viewpoint of Tim Visel – October 4, 2016

- Important Addendum – October 31, 2016

The Search for Megalops Northeast Crabbing Resources thread, post the Blue Crab Special Notice #2 was finished on October 3rd and posted on October 6th. A few hours later I learned about the Domoic Acid shellfish closure in Maine that soon impacted Massachusetts and Rhode Island shellfisheries as well. The diatom Pseudo-nitzschia was responsible for these shellfish closures and the presence of toxins in the blooms it caused. More research (Davidson, et al 2014) is linking harmful algal blooms (HABs) to organic nutrients and ammonia generated by bacteria consuming organic matter. Additional research is underway looking at historical deposits of cysts/spores in deep organic matter layers. I frequently term this layer black mayonnaise (Sapropel). Ammonia –nitrate levels may in fact become one of the indicators of potential HABs occurrence “blooms” (warm water indicators).

Some blue crabbers may have read about a Domoic acid closure from new/media accounts delaying or cancelling the Dungeness crab season on the west coast last fall. National Public Radio (NPR) did a segment on November 17 2015 (Lauren Sommer) which was titled, “Why Is A Neurotoxin Is Closing Crab Season In California” and gives a very good explanation of the toxic impacts of this diatom.

To my knowledge, no information has been released about blue crabs here in the Northeast although one Massachusetts advisory suggested that the lobster tomalley be discarded in certain areas; blue crabbers should follow state issued seafood advisories until the Pseudo-nitzschia bloom subsides.

A Connecticut Sea Grant report funded by the EPA Long Island Sound Study, “Don’t Dump Your Bait” analyzed recreational fishing bait worm packing materials worm weed (Ascophyllum nodosum) as a potential vector of toxin producing micro algae.” Dr. Charles Yarish reports (University of Connecticut, Stamford) that worm weed carried two species of harmful micro algae (Alexandrium fundyense), and Pseudo-nitzchia multi series). Dr. Yarish concludes in a final report for the Long Island Sound Study – “In our 18 month study of four locations, we discovered the harmful nonnative microalgae Pseudo-nitzschia multi series in 58% of our samples.” For a complete review of this study interested blue crabbers should review a report titled, “Don’t Dump Bait: Marine Bait Worms as a Potential Vector of Non-Native Species.” (see links below)

Short fact sheet: http://web2.uconn.edu/seagrant/whatwedo/ais/btwrms.pdf

Full research report: http://digitalcommons.uconn.edu/ecostam_pubs/2/


The California, Department of Health now posts Domoic Acid concentrations in crab species and blue crabbers may access these reports, if you wish to learn more about these West coast monitoring programs.


Can I eat the blue crabs I catch?

This summer 2016 has been very dry and hot at times. The reduced rainfall has allowed blue crabs to go further up estuaries and very few strong rains to push them back. This has put blue crabbers into the shallow waters near the edge of saline waters that warm up and provide good algal growing conditions – warm close to land and ample nutrients yet stable low oxygen conditions. But these same shallow warm waters are subject to algal blooms and at times fish kills.

Earlier this summer I had several conversations with blue crabbers during periods of “brown waters” and menhaden fish kills - certainly less than appealing situations and understandable questions about the quality of blue crabs came up. Some crabbers asked if it was okay to eat crabs caught in such waters – the answer is yes. It is natural to have menhaden perish in warm shallow waters – especially if after a long hot spell or rainstorm. Low oxygen and salinity shock can kill blue crabs as well. If warm enough and in those areas of high ammonia, the blue-green algae may bloom; these can contain toxins (natural) as well when water temperatures get very warm become toxic to marine species and even us. The heat helps return the sulfur cycle, deadly to the seafood we harvest. These are great questions and ones that have a sulfur cycle connection but as yet, do not appear in many estuarine programs with water quality studies. Something perhaps to include in some future report cards.

See you at the docks!

Did Blue Crab waters fail?

Some estuary programs in New England have started issuing estuary score report cards that focus upon cold water indications or cold or cool weather species. These indicators often include bacteria, turbidity, eelgrass abundance bay scallop abundance, and dissolved oxygen. Nearly all of them measure nitrogen but even that contains a cold water bias, in colder water nitrate levels for bacterial digestion of organic matter (OM) increases and in warm water decreases. Much of that change depends upon bacterial strains consuming the organic matter. To accurately assess changing habitat quality warm water factors could include benthic bacteria monitoring, the ratio between nitrate/ammonia levels, for example, presence of blue green algal species and volatile sulfides heavy metals, and the mapping of Sapropel. Most of the effort is to assess the quality of the water not the condition or quality of the seafood in it. The relationship of low report card scores to seafood quality is frequently not that well explained and something to consider in the future – My view.

Blue Crabbers Ask Questions

Some habitat concerns, some chemical as well have been raised recently as to the condition of these waters, and whether such areas are safe to crab with nitrogen, cloudy waters and low oxygen “scores.” Some very productive blue crab areas have had menhaden kills and at times brown waters in hot weather. Some questions have come up about estuary score cards reports – issued by some New England estuary programs. While many water quality indicators measure oxygen, nitrogen, and bacteria – they contain a cold water bias, and few mention the sulfur cycle indicators, of sulfate to nitrate ratios, sulfides, aluminum or ammonia. In August all of these warm water indicators happen and can result in fish kills. These same areas can be productive for the blue crab. Brown waters however are frequent after heavy rains.

Blue crabs can carry at times Vibrio bacteria – the warm water sulfate reducing bacteria that can be at times pathogenic they also live in the shallows. (Thorough cooking kills these bacteria). These strains thrive in low oxygen environments and readers may be interested in a series on the Blue Crab Forum™ - Environment/Conservation thread that talks about Vibrio and Sapropel cautions for estuarine crabbers. Also the general caution about Vibrio bacteria was the topic of The Search for Megalops Special Report #1 posted on the Blue Crab Forum™ Northeast Crabbing Resources on February 15, 2016.

We may need to review the cold water quality indicators and revise them for warmer waters. These indicators should have a sulfur cycle connection – my view. The exception is those areas that have chemical closures from spills or discharges or contain heavy metals. States post these areas (like Perry Mill Pond River in Fairfield CT for lead) and issue seafood advisories as well – contamination events that are chronic or historical. These closures rarely cause fish kills especially for menhaden – which are usually oxygen saturation related. Within the last decade to communicate pollution concerns estuary score cards have been issued and the shallows usually score “low.” This has raised concern from inshore fisheries and at times Blue Crabbers. Can I eat the crabs coming from these waters?
Estuary Score Cards

The “scorecard” concept did originate in part from industrial pollution abatement efforts of the 1960s – the scores were in fact levels not to exceed – ranges or test results. The biodiversity (species) index of pollution frequently mentions “species” relationships ratios as scores, and the “report card” of course from education. Climate patterns can influence reports and scores for example Douglass Moss in his 1965 report about the Connecticut River fisheries was very pleased by increasing oxygen saturation levels and attributed that to decreasing pollution but in fact was just measuring colder water – oxygen saturation test results in 1914, 26% and in 1929, 43% and later 1953, 65% all showed oxygen saturation was increasing representing over time perhaps cooler water – not less pollution. (History was eventually to show this climate pattern). Even in the middle 1960s oxygen was looked at for water quality measures (Moss 1965 notes “percent saturation of dissolved oxygen is often employed as a criteria for indicating water purity.” A better indicator than oxygen might be necessary as warm water naturally contains less oxygen?

The water clarity and turbidity indicators for shallow poorly flushed areas close to land are also problematic as they can record rain induced tannin flocculation and bacterial mucilage (this is the material that clogs fiber filters). In shallow areas in which organic matter is present bacteria grow and consume it. As a result nitrate levels increase and support the marine food web plankton. These shallow warm areas sustain dense cultures of algae (like so many small farm ponds in summer). These areas are subject to heavy rains such as a thunderstorm when torrents of warm street water carries pollen and leaf fragments into streams that themselves frequently empty directly into small harbors. After such rain events came the brown or “chocolate waters” that feed bacterial and algal blooms which also shed fragments of cells for days or weeks. Anyone that has a pool with a back wash filter system understands the pollen and duff dried bits of organic leaf dust that can be blown into pools (algae also). Without a back wash feature those filters systems eventually clog and waters become cloudy. Sometimes a complete water exchange may become necessary or “flushing.”

Bacterial Films – Natures filter

The bacterial mucus in closed systems also presents a problem and menhaden in shallow areas shed proteins into the water with tannin from leaf fall (a brown pigment as well) clump this protein together on the bottom forming gelatinous coating that is easily resuspended. That is why some of the first closed fish systems needed a protein “skimmer” to remove these sticky proteins. Many people do not recognize nature’s protein removal as bubbles that can form from waves as sea foam which is typically brown from the tannin. I can recall some 1960s gales in Long Island Sound when the sea foam could reach several feet high along the beach, natures protein skimmer. (A sign of the fish culture system in need of flushing is the protein skimmer is creating huge amounts of foam). Some inner bays may have also a “tannin signature” in organic matter easily resuspended by waves or currents, the more tannin usually means greater turbidity, from organic flocculation sometimes referred to as unconsolidated flocculent material or “UFM.” It is the surface area of sand grains rocks or vegetation that contains bacterial algal films.
In the current science literature these films are called periphyton.

It is a bacterial algal film that grows an oyster shell that makes them (surfaces) “slimy” and prevents oyster spat attachment (set). It is also this bacterial coat on shell that makes them so valuable to closed filter systems for crabs and lobster (even some blue crab soft shell shedding systems) in the late 1970s and 1980s. (For a description of these early oyster shell pillow filters see Bacteria, Disease and Warm Water Concerns, posted July 23, 2015 Environment Conservation post # 6: Blue Crab Forum™. These shell surfaces provided ideal surfaces for bacteria to convert toxic ammonia to less toxic nitrate.

In Sapropel, bottoms (mucky) the acid conditions give rise to “black shells” acid has cleaned off the bacterial coat making these oyster shells again biologically clean and now has a chance to catch an oyster set as demonstrated to the Connecticut oyster industry by Clyde Mackenzie, Jr. in the late 1960s. A rainfall (acidic) cleans shells stored on docks (dock dried shell) for the same purpose. Shell fouling time is a warm water indicator. (A write-up of this process is on the Blue Crab Forum™ Fishing, Eeling and Oystering thread IMEP #32, October 23, 2014.) See Oyster Culture In Long Island Sound (1966 - 1960), 1970, C. Mackenzie, Commercial Fisheries Review pages 27-40.

Most of the foam in estuaries can come from natural substances proteins and fats in algae that decompose (breakdown) in a black jelly like marine compost humus/Sapropel. On days with little wind, a surface film will form a mucilaginous layer that with a small breeze forms small bubbles. A large wake can bring those sticky or greasy molecules to the surface and over time produce foams that can now reach several feet high. This is evident after dense algal blooms as when algae perish they contain fats and oil and mucilaginous bacteria can purge mucus into the water. I recall one Niantic Bay Connecticut experience in which the mucus formed a drool when picked up, the water actually had viscosity. Some algal strains (D. geminata) produce a “tough” mucus protein called “rock snot.” But all of this can be natural even red tide aerosols which in the 1970s Florida issued respiratory warnings as rough surf as winds suspended these toxins into the air. All of this can make a stagnant pool, pond or bay shoreline resident recoil, and seek a human event or action for an explanation. While we can certainly appreciate human impacts these bacterial and algal species have inhabitated the shallows for millions of years. The heat welcomes organisms that can tolerate sulfur – the cold welcomes those that prefer oxygen. Scorecards in the shallow areas contain a natural temperature bias – if it excludes dissolved oxygen as the chemical respiration of the bacterial reduction that often includes a sulfur cycle link. Warm shallow poorly flushed areas will naturally score “low.”

Bacteria in shallow waters influence nitrogen levels

It is the nitrogen scores that remain so problematic in shallow waters because they often do not include what is termed “benthic flux” a term associated with nitrogen bacterial pathways – the composting of organic matter in shallow waters. Although the term “flux” has been used in oceanography for decades its use in coastal studies contains a bias that is chemical, that is most indicators do not include organic matter (OM) because instruments only detect dissolved nitrogen molecules not nitrogen locked up in organic matter. That has caused some nitrogen models to undergo “recalibration” – to account for this nitrogen that enters shallow bay waters by way of bacterial action from land organics. The absence of this nitrogen source was questioned on Cape Cod about a decade ago (especially Sapropel formation) and one segment raises a very important point, (2008) about the Water Quality Modeling (Waste Water Management Validation and Design Committee 19 November 2008 pg 130. “Are these measurements that show the relative proportion of inorganic (chemical) and organic nitrogen (tissue)? Would it show the relationship between sources (1) people and (2) from natural decay from vegetation and marine life.”

These indicators often contain a temperature and biological bias as well, in cold water aerobic (oxygen requiring bacteria) reduce or fix nitrogen into a gas or nitrate a much less toxic nitrogen compound. Sulfur requiring anaerobic bacteria becomes a nitrogen source, they can produce ammonia – a very toxic nitrogen compound. While aerobic bacteria are very efficient at removing nitrogen from the water, in cold water they are very slow. At times these very cold waters become “nitrate limited” (as they did in Long Island Sound in the middle 1950s). Very warm waters hosting sulfate reducing bacteria now as part of their breathing sulfate which is non limiting in sea water produce tremendous amounts of ammonia – since this is soluble in water and therefore measurable by instrumentations this “flux” is attributed to (often) human source nitrogen when it is always not so (my view).

It is the ammonia that nourishes the harmful algal bloom or “HABs” the by product of bacteria glucose metabolism the breakdown of organic matter in water. It is here that sulfate reducing bacterial can cause low pH levels, the leaching of aluminum, complexing of heavy metals and purging of sulfides. The geology of many small bays exchange water slowly (or poorly flushed depending upon perspective) called residence time – the time it takes for a body of water to completely exchange itself. Such areas tend to have higher residence times so any nitrogen source from benthic organic matter tends to slosh back and forth increasing ambient measurements providing for the counting of the same nitrogen many times. As a rule hot organic filled section of estuaries will have higher ammonia levels than nitrate, in cold water they will reverse, as the bacterial natures filter themselves change, (see EC #8 posted on Blue Crab Forum™ on October 30, 2015) change the products from organic matter digestion or to use a terrestrial process “composting.” This compost is visible and measurable as many fishers and shoreline residents have termed it Black Mayonnaise (A Boston Globe article on November 26, 2011 has this quote). Bourne Massachusetts “When the tide rolls out, the beaches on the west coast of Cape Cod often turn a shade of lime green, with splotches of a slimy substance that locals say resembles black mayonnaise and smells like rotten eggs (hydrogen sulfide – T. Visel). In the warm months, a film of algae spreads through the harbor in Cataumet and the opaque waters turn a copper color, veiling the little life left on the seabed” Dave Abel – The Globe staff.

At times inshore waters can look and smell bad, they can bright green, brown purple and even red, but with climate and energy patterns – natural.

The score cards for shallow – poorly flushed areas also contains a natural energy bias – these areas by oceanographic currents or geology formation tend to naturally score “low” and why I continue to discourage such reports – because the inner poorly flushed areas contain this flushing bias – my view. It is a concern to blue crabbers who often fish these same areas, warm shallow and not subject to tremendous tides – poorly flushed. These areas are often “good” habitats for blue crabs but often poor for cool water indicators. The Weweantic River in Wareham Massachusetts has recently been questioned for its “low” score a “28” for the inner river. This score according to the Buzzards Bay Coalition website reflects some of those cooler water – indicators. We had a similar situation occur here in Long Island Sound where civic groups had worked hard for decades to reopen closed shellfish areas in Hempstead Harbor, New York and after years of efforts and hard work they did it, and that area is again producing certified shellfish but the inner Hempstead Harbor obtained a low score – D+ indicator. The Coalition To Save Hempstead Harbor has an excellent newsletter online Harbor News dated June 18, 2015 which explains this low score and the return of shellfishing.

The Natural Cycles of Eelgrass

It is the eelgrass indicator that is most in question, it is natural for eelgrass to move into clean cultivated marine soils after cold and storms. This is frequently mentioned in the marine biological technical bulletins produced by the State of Massachusetts in the 1960s and early 1970s. It is natural for eelgrass habitats to expand as they did following the cooler 1870s and 1950s. The cooler water and storms make marine soil conditions better for eelgrass. It is also natural to have eelgrass die offs in a period of few storms and prolonged heat – as marine soils become acidic and marine soils sulfide rich. In the end of eelgrass habitat succession the organic matter trapped between its blades – becomes deadly. In heat, this organic matter feeds sulfate reducing bacteria which cause pore sulfide levels to rise. In time this process damages eelgrass roots and weakens the plant as eelgrass meadows now “waste away” from habitat succession.

Warm waters will naturally contain less oxygen – Impacting many factors

Species often have a temperature affinity or bias as well eelgrass and bay scallops are species for example that do much better during cold and energy filled periods such as the 1950s and 1960s. Eelgrass moves into clean cold cultivated marine soils (after storms) and bay scallops prefer cool alkaline soils after periods of cold. These species appear to be influenced by the NAO negative phase climate pattern that is marked by more coastal storms and cooler temperatures. Both were more prevalent during the last negative NAO of the 1950s and 1960s. Bacteria also have a warm water bias as most do better in shallow warm water (bacteria spoilage in heat, etc) than cold. Much of the rise in bacteria counts can be attributed to warmer water and more shore life bird, animals (pets – yes) and our inputs as well (sewage). A January beach test was always lower than July in my area of Long Island Sound so you need to know if it is a warm weather testing program etc. (A much more significant indicator is a benthic Vibrio bacterium – a warm water species that lives on organic matter). One of the things that occurred here in New England is that as the cold water indicators declined (scores) blue crab habitat quality actually increased. The things that were listed as “bad” were for the most part indicators of climate conditions that preferred the blue crab habitat quality. The indicators that were often listed as “bad” were for the most part indications of climate conditions that preferred the blue crab reproductive capacity and the rise in blue crab populations after 1998 compared to lobster in our region. The 2006 to 2010 years were especially good for blue crabs in southern New England.

Climate Cycles Alters Habitat Capacity

Another aspect is that blue crabs live in microhabitats that many species cannot – the mostly shallow and volatile the one meter and less – a very much “shore fishery.” Even with its hard shell, and claws it is no match for the deep water saline predators such as tautog or black sea bass, so it lives in oxygen poor areas away from them, the shallows and poorly flushed areas close to shore. It is therefore they are vulnerable to shore events like a heavy rains or a sharp cold. It lives at the edge of its biological parameters because it needs to, and therefore can experience the die offs and set failures dependent upon wind and temperatures. It lives where crabbers can catch them, close to land in the shallows that warm up first and at times become hot – a much better warm water index measures would be ammonia, aluminum, and sulfides as these have a warm water bias – they are always higher in warm or hot water than cold (The Blue Crab Sulfide Jubilees). Readers might be interested in some of my posts on The Blue Crab Forum™. The Environment/Conservation posts often mention these bacterial/nitrogen shifts.

Many estuary programs have struggled with climate cycles – as the estuary program itself evolved during a period of cold water species retreat, but also a time of warm water species return. The positive NAO which was so damaging to bay scallops, eelgrass, lobster, winter flounder would see black sea bass, sea lettuce, oyster and blue crabs rise. Several blue crabbers have asked how could Long Island Sound be so bad when blue crabbing in 2006 to 2011 was so good? It’s a great question but one that is also found in our fisheries history. The Search for Megalops report #6 The Blue Crab Forum™ Northeast Crabbing resources looked at the reversal a century ago – The Lobster Problem/Blue Crab question.

Fish/Fisheries have Cycles

Any climate patterns – cooling or warming will impact the shallows first. It is just the capacity of water to absorb or release heat. These shallow habitats provide the first change to observe fisheries cycles, especially those with man made tidal restrictions.

As for the Weweantic River when I worked on the Cape it seemed much like the rivers in Connecticut, tidal, subject to transportation rail crossings – the Northeast Corridor had bisected many eastern CT salt ponds/rivers, relatively shallow that received organic inputs from land – organic matter such as grass, bark, leaves and twigs. After heavy rains waters might appear brown and in these now poorly flushed areas. Sapropel (Black Mayonnaise) may have accumulated on the bottom north of any tidal restriction. Just before a menhaden fish kill perhaps the smell of sulfides – the stick match sulfur smell in these restricted areas. (Railroads have also isolated coast residents from shore access and many crabbing locations as well).

Shore areas at times can be the subject of “ribbon water” a banding of wind driven pollen on surface waters. I recall being called by an east shore Niantic River (north of the RR causeway) resident to look at a mysterious yellow growth in the water, only to find a ribbon of surface pollen and dust. The Coalition To Save Hempstead Harbor has a great article about pollen slicks in their newsletter of June 18, 2015 Sludge or Pollen Slick? It is an excellent article.

This group among others worked very hard to open closed shellfish beds to certified shellfishing in Hempstead Harbor after 40 years in 2011 – an environmental success story that reflects the hard work of countless hours to minimize bacterial inputs but obtained some negative media reports when the inner harbor only go a “D+” on its report card. The media reports somewhat highlighted the negative inner, Harbor score – minimizing the success of clean up efforts a somewhat mixed message to the public and perhaps a concern to those blue crabbing? It did cause a conflict between some environmental groups.

The water quality connection to the news media report/scores such as the Weweantic River in Massachusetts or the Connecticut River in Essex as hundreds of dead menhaden came a shore is visual point in time. This is often a very visual “mixed message” great crabbing amidst a fish kill causes these questions to occur. The quick answer is that blue crabs can live in lower oxygen waters, they “rest” on the ebb and move on the flood. When oxygen levels drop on a hot day they “rest” and are not active and conserve their oxygen (makes them hard to catch at times also). Menhaden cannot do that, they need to swim to keep oxygen passing by gill membranes and are often chased into the shallows by predators – right into the same areas of blue crabbing and very low oxygen. Fish kills often result that is natural.

Because our Blue Crab habitats are so shallow they warm quickly and can become very hot, so important warm water indicators could be benthic Vibrio – the dangerous bacterial family that has impacted blue crabbers to our south, the increase of Sapropel/Sulfate reducing bacteria aluminum, surges in ammonia and the increase of soil sulfides are far more representative indicators of heat – warming than the cold.

At the Edge – What Can Water Quality Tell Us?

Perhaps the blue crab lives in the most vulnerable habitats that can be influenced by the land nature or “us”. Although most water quality parameters attempt to portray best or ideal conditions even that is often up to debate. What is “good” water for blue crabs may not be for other species and vice/versa. The word vulnerable is also the foundation of most water indicators and the vulnerability contains a proximity bias – the closer to land the more pronounced the bias. This bias is often reflected in parts per million or billion and used in most studies of contaminants for toxic concentrations. What might be toxic in a small body of water (or an aquarium for instance) may only represent a limitation or not even be detectable in a much larger body of water. Most estuarine organisms are capable of withstanding some toxic residues and have biological filters (organs) that act to remove them. In Blue Crabs it is the hepatopancreas or “mustard.” It is known that certain molecules can be concentrated in these organs in fact that is their function to do so. The term bio accumulation often refers to the ability of some species to concentrate or collect them overtime. Oysters for example for heavy metals (The Minimata Oyster example of methyl mercury was one of the first in the 1950s) and Quahog studies in the 1970s for PCB – New Bedford Harbor, Massachusetts. Sung Feng told me that his studies showed heavy metal concentrations in oysters were dropping (a) and that transplanted clams actually could lower PCB levels in clean sand (b).

A) Sung Feng, formerly with the Marine Sciences Department of the University of Connecticut at Avery Point – Heavy Metal Baseline Data (1976).
B) The State of Massachusetts has issue an advisory and designated fishery closures in New Bedford Harbor from PCB contamination. (Quahog Transplants conducted in the 1980s (M. Hickey personal communications) of Quahogs showed a lowering of PCB levels over time.

Most of the water quality indicators in shallow bays do not indicate blue crab “edible” habitat quality, in fact, some researchers have suggested they help it. Blue crabs like shallow warm waters in summer, but will retreat to deeper edges and channels in late summer. Some dredged channels to keep ports and harbors clear over winter blue crabs. Salt ponds and coves with reduced flushing (residence times) may act to keep megalops trapped in them, or keep serious salt water predators out. Blue crabs live in areas subject to low oxygen, close to land away from the larger respiratory requiring predators, and also our inputs chemicals as well. It is these same areas that contain water from chemical residues we make.

Finally, blue crabs live among Sapropel bottoms those that obtain tremendous quantities of organic matter leaves and organic residues from forests, grasses and agricultural fields – and of course us - sewage. While many coastal programs look at turbidity, chlorophyll, bacteria, nitrogen, and oxygen these are all natural substances/chemicals. I am far more concerned about the unnatural ones or bacterial strains that are not surveyed for example – the Vibrio series often found in the same areas in which crabbers catch blue crabs.

{Crabbers should review the Blue Crab Forum™ thread Environment and Conservation threads or the Science thread titled “Marine Bacteria.” Many concerns from blue crabbers themselves can be found here}.

Did the Water “Fail”

Some recent estuary programs have issued “score cards” which attempt to grade estuarine waters on a A-F academic scale. The problem is that some of the areas will naturally score low, from natural conditions. These areas close to land is where crabbers (especially hand liners fish) are subject to chemical run off or “legacy” industrial contamination. Some of the best historical blue crabbing habitats in Massachusetts for example have been closed to certain fish and shellfish from PCB contamination. (See Massachusetts Fish Consumption Advisory – Inside The Hurricane Barrier of New Bedford Harbor) (There is a harvest Ban for lobsters). The Inner Weweantic River received a score of 28 recently and is a popular blue crab spot.

One proposal that looked promising for the Weweantic River was a project to restore herring (alewife) carrying capacity. Here sulfides would present a “sulfide block,” behind dams but they return in spring when the water is naturally cooler and oxygen levels high. Restoring spawning access is a long term goal for the Weweantic River and other streams in which spawning access has been blocked. Restoring habitat access for alewife is an important program for New England estuaries.

In 2014 the Connecticut Dept of Environment and Energy issued an advisory for blue crabs in the Fairfield CT Mill River (No harvesting of blue crabs) from lead contamination. Following a program to remove lead contamination “DEEP will sample Blue Crabs to evaluate the possibility of removing the fish consumption advisory for Blue Crabs” (which is due to lead contamination (see DEEP Mill River clean up Fairfield, CT fact sheet August 2014 but as of September 2016 the harvesting ban on blue crabs remains in place.

The estuary score cards have typically not looked at seafood contamination – investigating the blue crab may be one of the ways we will learn more about the chemistry of these habitats and perhaps provide the foundation for “new” water/habitat quality indicators.

A High School in Tennessee developed a very basic test for AVS – Acid Volatile Sulfides

On indicator that directly relates to heavy metals in shallow waters is the presence of acid volatile sulfide (AVS) and mostly iron sulfide FES – which are black (also related to black water sulfide fish kills). These sulfides are volatile (chemically active) and complex heavy metals such as the “big four” lead, cadmium, copper and mercury. Sulfides tend to bind to these metals preventing them from entering the marine food webs – they make these metals unavailable but add to the background contamination levels. A high heavy metal count may mean that sulfides are mobilizing them in the soils themselves. A high sulfide level is toxic to fish (the Source of the Blue Crab Jubilees) but acts at the same time to make metals less toxic. The amount of acid volatile sulfide in the soils helps make metals less toxic but kills eelgrass. The iron form of sulfide in low or no oxygen anaerobic soils are therefore critical in assessing potential marine food contamination.

A rapid low cost field test for AVS was developed by the Martin Luther King Magnet High School in 2000. (Eric F. Anderson and David J. Wilson). It utilized a closed jar with a strip of paper moistened with lead nitrate (with a detection limit of about 1 milligram of sulfide) and diluted acid. A soil sample (up to 500 grams) is mixed with an acid to free hydrogen sulfide from metal sulfides. If acid volatile sulfides are present the paper will turn black.

It is the process of low to no oxygen – sulfate reducing bacteria that acts to release sulfides that bind to metals.

The presence of oxygen tends to release these metals and make them again available to move into the marine food web and contaminate it. EPA has investigated the use of sulfate reducing bacteria, for example, to clean up acid metal wastes from mining operations. In shallow waters higher oxygen, therefore, can naturally lead to greater contamination and why we need indicators for sulfate reducing bacteria in low to no oxygen conditions as well. Many of these sulfate reducing bacteria strains can be found in Sapropel and why measuring Sapropel thickness might be an important habitat quality indicator (low oxygen). Some of the first studies of Sapropel occurred in the 1970s (Cita et al Destructive Effects of Oxygen Starvation and Ash Falls on Benthic life – A pilot study Quarterly Research Vol 13 pages 230-241 1980) and contains this statement about Mediterranean Sea Sapropels.

“Sapropels are generally unburrowed, but some can be burrowed. They are devoid of benthic fossils, especially in the first case. Stagnation resulted in the annihilation of the benthic life in the deeper parts of the basins. Repopulation presumably originated from the shallower slopes which did not undergo an oxygen crisis.”

The presence of acid volatile sulfides is an indicator for Sapropel formation.

Blue crab populations will always be subjected to fresh water toxicity, turbidity and sulfide events the “Blue Crab Jubilees” that is why surveying blue crab populations may provide an important climate change indicator for these shallow yet critical warming habitats. Most of the fisheries research has been in regards to offshore habitats – the shallows, the habitats closest to land have been at times ignored or minimized. It is safe to eat blue crabs – yes except those areas that have obtained chemical contamination. Many states have issued reports about inshore waters that have no crabbing but the information is isolated and fragmented. For the most part very little has been produced regarding this important area for blue crabs (my view).

Can I eat the crabs I catch –

In a review of the literature much of the concern is about the Blue Crabs ability (also lobster) to concentrate contaminates in the hepatopancreas a specialized organ that acts like a liver – cleaning (filtering) chemicals. As such they can concentrate a variety of chemical substances. It is the Blue Crab “mustard” a yellow to green color substance that can have a strong/bitter taste. It is similar to the green lobster “tomalley” that many people consume directly or in a sauce. Is it the blue crab mustard in which many agencies use as an indicator of chemical presence and sampling occurs. Cooking will kill bacteria – but chemicals such as PCB or red tide toxins are very stable and boiling them does not render them harmless. Instead crabbers need to rely upon seafood advisories – issued for algal toxins or closures from contamination such as lead or PCB. (Some bacterial strains have been identified that “eat” PCB breaking down these toxic compounds). When you look at the literature there is not much about the blue crab – which was sort of surprise to me considering the amounts of crabbing and the fact the closeness to possible pollution sites – the shore.

The lack of information is a concern because not all blue crab habitats have the same chemical/contamination history.

It is best to look towards your state agency that regulates fishing for the most current information. Over the winter I will try to compile some Blue Crab tests or perhaps could be the topic of a Senior Capstone report about blue crab advisories.

All Blue Crab population and habitat observations are important. I respond to all emails at tim.visel@new-haven.k12.ct.us



Appendix I

Marine Fisheries of New York State, J. L. McHugh Abstract

Marine Sciences Research Center, State University of New York, Stony Brook, NY 11790; Manuscript original, 1972. FISHERY BULLETIN, VOL. 70, No. 1, 1972.

BLUE CRAB

In the waters of New York State, the blue crab, Callinectes sapidus, is near the northern limit of its range. It has never been a major species in the catch in this area. Because the blue crab is highly variable in abundance from natural causes even in the center of its range (McHugh, 1969a), it might be expected to be extremely variable in New York waters, and the history of the commercial fishery suggests that this has been true (Figure 6). Landings have declined steadily but irregularly, since the maximum recorded catch of about 1.6 million pounds (725 metric tons) in 1880. Catches rose briefly in the 1930s, in a recorded peak of more than half a million pounds (270) metric tons) in 1935, but after a minor upsurge in the early 1950s the fishery collapsed. No commercial catch has been recorded since 1961.

In Chesapeake Bay, with major fluctuations, the blue crab catch has been increasing for about 35 years. It has been suggested that the increased catch has been caused by increased abundance generated by nutrient enrichment in the estuaries (McHugh, 1969a). There is no direct evidence to support this hypothesis, but it is not untenable. Other than the decade of increased landings of blue crab which began about 1929 in New York, and a longer period of highly variable but substantially increased catches in the middle Atlantic region which ended in the late 1950s (McHugh, 1973), there has been no similar continuing upward trend in blue crab production north of Chesapeake Bay. It is interesting to speculate that the enrichment of coastal waters and estuaries in the middle Atlantic region of the United States from domestic and industrial wastes may have stimulated blue crab production for a while, then became a limiting factor as eutrophication proceeded too far.

Note – Tim Visel – National Weather Service Climate Prediction Center (NOAA) has posted standardized 3 month running means for the NAO Index. Beginning in 1954 the NAD Index turned negative allowing for cooler temperatures in New England. Oyster sets also declined during this same time period. In late 1971 the NAO started to show a more positive mean, warmer temperatures for New England and oyster sets started to increase.

The 1980s and 1990s showed some of the most positive NAO indices it is thought since the 1890s.



Appendix #2

Estuaries and Blue Crab Quality

Some of the concerns around the use of estuarine report cards are that they themselves grew to represent natural substances or conditions. The measures of bacteria, algal growths, oxygen saturation and water clarity all have at times a temperature bias, and each factor may or may not influence the other. If the water is cold for example that would restrict bacteria growth, and algal strains that need warm water. Nitrogen poor waters are remarkably clear (and also on average produce for less seafood), but they are also less turbid if far from land. Because of the fact that shallow waters are closer to the land they reflect in general natural land impacts, run off, leaves and water shed organic matter and warm storm water. These inputs at times are much larger than human impacts and should be indexed or scored differently - my view.

Even the scientific community has weighed in and the use of indicators and Ramaroy et al in Chiang Mai Journal found in 2013 that chlorophyll a did not adequately represent algal bio mass 2013. San Francisco Estuary Indicators Team researchers (2011) reported concerns that some factors may be counted incorrectly, some multiple times – a concern in water bodies described as “poorly flushed.”

Areas closer to land naturally have higher nitrogen levels because they are subject to natural organic matter deposition – trees at times overhang water bodies and they obtain leaves directly from them. In other areas spring melts and heavy rain run off wash high amounts of organic matter (leaves) into them. A 50 x 100 square foot residential lawn can produce 80 pounds of grass clippings every 10 days in warm weather. Some larger trees are “dirtier” than others (in this case a measure of shedding woody tissue) twigs, bark, seed pods, nut shells, blossoms, etc but combined can be over 5 lbs or organic material weekly plus the “fall” leaves.

It is the fall leaves that are so damaging. Here vast amounts of organic matter can overwhelm bacteria that feed on it. In summer such organic matter can be a source of pollution and the CT DEEP has recently commented on the collection of leaves – “they are collected in a way that does not discharge pollutants – (seeking to reduce or eliminate)” the deposition of leaves in streets and other paved surfaces where they become a significant source of nutrient and bacteria pollution in runoff.” DEEP (CT) Response to Comments MS4 proposed general permit for The Discharge of Storm Water 1/13/16.

So how large is the organic matter pollution – it is huge almost beyond calculation. In Connecticut’s “Dairy Days” much of Connecticut’s 2.8 million acres were cleared for pasture by the late 1880s only about 1 million acres of forest remained.

As Connecticut became more residential and agriculture diversified the trees are “back” about 65 percent of (almost 1.8 million acres CT Forest Resource Fact Sheet 2016) the state is now forest or woodlands. With the return of trees came the leaves and now instead of the bacterial process under the forest canopy these leaves end up on paved surfaces and then in the estuaries. The land oxygen bacterial reduction process has been in a way been redirected to the slower sulfate reducing bacteria process in estuaries. It is easier to focus on one individual acre of oak trees – to get a sense of this organic matter production on a larger scale.

• Pin oaks a shore tree an acre of 30-year-old pin oaks can produce 4,000 to 20,000 acorns per acre see NRCS Plant Fact Sheet.
• One acre of oak trees produce one ton of leaves per acre
For even a single tree -
• A mature oak tree can produce a quarter million of leaves each year.
• A large oak tree can produce about 100 pounds of acorns each year.

I am certain that this information is not a complete surprise to those who have red oaks as yard or shade trees. But combined the amount of organic matter from oak trees in CT is tremendous.

Watersheds at times can produce tens of thousands of tons of organic mater swept downstream and carried directly into shallow tidal waters. It would be “natural” therefore that such areas are turbid, cloudy contain particulate organic matter (POM) which is then subject to bacterial decomposition on the bottom. In warm water, ammonia is a by product, in cold water nitrate – from this bacterial process termed in many studies as “benthic flux.” Benthic flux is a term from the 1950s which attempted to describe nitrogen cycle bacterial interactions between seasons. If cool or cold bacterial strains that required oxygen would reduce particulate organic matter (POM) to nitrate – if warm or hot water warm water strains would produce ammonia. This measure, however, did not take into account wide swings in bacterial “filter” capacity – it fails to describe what happens to extreme conditions (climate) when waters become very hot or very cold for long periods of time.

In this case, benthic flux is no longer a flux but a flood of nitrogen compounds – as explains why ammonia surges in hot weather, and during the winter nitrate levels slowly rebuild. It is the relationship between nitrate and sulfate in cool water and the relationship between sulfate and ammonia in warm that indicates these changes. In warmer waters that naturally contain less oxygen – bacterial strains that cannot use sulfate as an oxygen source should go down (die off) while ammonia levels rise. In the winter as water becomes colder oxygen levels rise and nitrate levels increase. Very cold waters can slow the bacterial production of nitrate and several papers mentioned limiting nitrate for algal blooms in Long Island Sound the 1950s. In fact human source inputs of nitrate were looked upon as a “help” in this time for keeping nitrate levels higher. Even at times it was thought that higher nitrogen levels had helped inshore fish and shellfish –even blue crabs and 1970s reports contain a water temperature species bias. Marine Fisheries of New York State J.L. McHugh 1972 Black Sea Bass which declined in New York Waters post-1951 were then scarce 1972 and “do not show that this (Black Sea Bass) is a very important recreational resource in this area. J. L. McHugh bias of perspective is so noticeable it is included as an appendix 1. How would McHugh react some four decades later to see the surge in Black Sea Bass or Blue Crabs in New York Hudson River?

The term “benthic flux” has also been widely used but fails to adequately explain water quality factors in coastal waters and adds to the bias of such report cards the “battle” between bacterial strains and its impact upon water quality is included in a recent blue crab forum post dated Natural Bacteria Filter Systems on the Environment Conservation thread on The Blue Crab Forum™.

Some Concern about Score Cards

A concise description of the Environmental score process and a review of the water quality indicators was published two years ago by the House of Commons England Environmental Audit Committee (HC – 215 September 16, 2014) and a previous review “A Critique of EPA’s Index of Watershed indicators by M. T. Schultz (Journal of Environmental Management 2001 pages 429-442 contains this statement.

{Schultz raises many questions about the development and use of watershed indicators but perhaps the most significant is the use of individual indicators is when independence is not assured – that is the changes in one indicator may impact others}. Pg 438 contains this section.

“Independence is violated when a change in the value of one indicator produces a change in another indicator” and in assessing environmental stressors (which could be natural) and describing vulnerability that “such dependencies invalidate the index because some changes in watershed condition vulnerability may be double counted”

With some bodies of water changes in temperature (higher) can alter oxygen saturation, changing benthic bacterial reduction favoring sulfur/sulfate reduction, nitrate availability and shifts to ammonia production. Since ammonia favor brown algal species that are able to mobilize it and that can reach densities to color the water clarity often declines in late summer. Many small bay reports do not include “benthic flux” or Sapropel respiration – composting processes. It is this Sapropel high temperature composting that has raised so many questions about Vibrio infections (see Megalops Special Report #1 Feb 1, 2016, Blue Crab Forum Northeast Crabbing resources, Important Notice for Blue Crabbers.

Eelgrass another common watershed indicator actually describes environmental habitat succession and is also influenced by climate – temperature and energy patterns. Eelgrass prefers energized marine soils and cooler temperatures. As water warms the organic matter eelgrass traps between its roots and blades and soil pore sulfides rise. As this habitat succession proceeds, sulfate reducing bacteria in the soil produces deadly sulfides that weakens the plant (even more its roots) making it vulnerable to fungal attacks. It is natural that eelgrass habitats expand following coastal storms and cooler water temperatures and contracts (die off) following years of heat and in low energy marine soils. The appearance and disappearance of eelgrass is largely natural and climate driven. In this case the indicator measures habitat succession more than water quality – my view. It is natural to see the clean and green eelgrass increase after a period of energy or increased tidal exchange - flushing (dredging) and in periods of prolonged heat and few storms – eelgrass appears to be “brown and furry” with mucus producing bacteria and fungal infections in soils now with high sulfide levels.

Many estuaries score cards do not adequately represent nitrogen loads from “benthic flux” the changes in bacterial filter systems present on all bay bottoms. This is happening in the Indian River Lagoon in Florida - large amounts of bacterial ammonia are now indicated by large deposits of Sapropel commonly called “Black Mayonnaise” in many parts of the Indian River lagoon (personal communication August 1, 2015 John Trefry Florida Institute of Technology).

In a United States Geological Survey paper Scientific Investigators Report 2014-5033 titled Quantifying Benthic Nitrogen fluxes in Puget Sound Washington 2014).

The report mentions the need to include it (many estuary reports tend to minimize the ammonia generated from Sapropel deposits) but in shallow water it is an important consideration and this section is found on page 2.

“In Puget Sound, Washington, ignoring or under representing benthic flux as a source of (nitrogen) to marine waters can result in ineffective management actions and can lead to chronic water quality problems in sensitive areas. Shallow areas near the shores of Puget Sound are most likely to experience low levels of dissolved oxygen because of the combination of low relative circulation, warm summer water temperatures, and proximity to watershed nutrient contributions; sediment nitrogen fluxes may also dominate in these shallow areas.”

Total suspended solids often shown as TSS did not correlate with Chlorophyll a to algal bloomass (Rameshprabu et al 2013 Chiang Mai Journal Science 40 (4) pages S47-555) Chlorophyll a the catalyst for the photosynthesis process is abundant in algal but is also present in other plants even some bacteria. It because of the species that grow in cooler water utilizes nitrate (some of the more nutritious shellfish algal food need high concentrations of nitrate) so it would as a measure fluctuate both with temperature and nitrate availability.

So many score card indicators are temperature sensitive and therefore subject to climate patterns. That seemed to have occurred in Long Island Sound in the 1950s – cooler waters had nitrate requiring algal blooms collapse because they simply ran out of nitrate. This cycle is part of spring blooms of nitrate requiring algal but later the warm summer “browns” that thrive on ammonia bloom often the by product of bacterial reduction. That was some concern when the nitrogen TMDL was being established on Cape Cod.

Many states have now recognized the impacts of organic matter (suspended solids) upon estuarine habitat quality. The EPA has also stepped in with guidelines to control or minimize the impact of “storm water” rainfall on streets and paved surfaces termed the MS4 national permit Connecticut, in addition, has acknowledged that leaves can damage or alter environments.

Benthic flux and ammonia generation had increased with the paving of surfaces that used to recharge rain water to ground water. This run off is now able to increase its ability to carry organic matter from land into estuaries. Forest canopy has again increased in New England from pasture lands of the 1800’s. Therefore the last two centuries have had the impact of increased organic matter generation and the run off from paved surfaces to move it. In hot weather, this run off is now warm – which adds at times thermal stress to cold water species.

Soils and Composts –

On land composting is acknowledge as a source of bacterial food and nitrogen. We need to do the same in the marine environment and the formation of Sapropel or marine compost from land organics would be a great start.