Wednesday, August 28, 2013

10,000 visits to Blue Crab Blog

The tracker ClustrMaps recorded its 10,000th visitor to Blue Crab Blog this week! Thanks for your continued interest in the Blog.
-Matt Ogburn

2013 Connecticut Blue Crab Report #8

From Tim Visel at The Search for Megalops:
The Sound School – the ISSP and Capstone Project Proposal
Building a Network of Citizen Monitors
The Search for Megalops
The Connecticut Blue Crab Population Habitat Study 2010-2015
You Do Not Need To Be A Scientist To Report! 

The Search for Megalops –Report #8 -2013 – Blue Crab Year
August 23, 2013

  • Watching for Megalops 
  • Connecticut River Crabbing 
  • Absence of Sponge Crabs Becoming a Concern
  • 1898 and 1998 Key Blue Crab Habitat Years Southern New England 
  • Western Crab Habitats – The Saprobien System  

Watching for Megalops

The first part of this reporting period had excellent catches especially now in eastern Connecticut. Some of the coves there were providing crabbers some excellent catches. The central Connecticut crabbing slowed in the last few days, and one Oyster River crabber said “It’s too hot,” and I agreed. The shore handliners in the Connecticut River were experiencing the same conditions. (See next section). Crabs have moved to deeper cooler waters; what was some good news is several very good reports from Milford, which had for the first time several days of good crabbing and a balanced year class mixture:  a good representation of 1 to 2 inch crabs, 3 to 4 inch and 4 inches and up.  Finally a glimmer of western CT good news including a report of two and three inch crabs in the Housatonic River, just observations. Just a few years ago, the Housatonic had thousands of 3 inch crabs moving east (June-July 2011) but now just the sight of a few crabs is noteworthy. Reports of a few crabs in the Norwalk River also were recorded; the Saugatuck River still remains quiet, no crabs as yet.

As it is now well into August, time is running out on a Megalops set, the post stage that first becomes visible in small minnow seines. It is these shallow hand drawn minnow seines that often pick up 30 day post Megalops about the size of a dime. This is the size that depending upon water temperature can reach 1 to 2 inches by late fall, and emerge next spring. The first two chances are gone, an over wintering stage (May), a drift in set from southern waters (July) and our “own” native (August) Megalops set, but even that seems now at risk. (See next section).  The next few weeks will tell and some shallow water creek surveys are planned this fall.  It could be just everything is a little late from a cool spring, but a good Megalops set now and then “star” crabs this fall means next year’s legal crabs are already here.

Watching for Megalops

Tim Visel

Connecticut River Crabbing

So many first year blue crabbers have emailed me about Connecticut River crabbing with questions about where to go – where are the big crabs and the like.  I just can’t say because crabbing is so variable, one day good, the next day very poor.  Add to the equation that crabs swim and move very well, and you can be chasing what was good yesterday but not today.  Some recent reports from Old Lyme has recently shown that change and it quickly changes!

Crabs have been abundant in Essex for about two weeks but as in previous years they have moved into deeper waters – away from most of the shore crabbers reach except at high tide.  Lower tides seem to be the least productive generally in hot weather as warm water holds less oxygen so they tend to slow down.  So some deeper dock observations are good – like the Baldwin Bridge DEEP fish Pier – Old Saybrook and the next tide cycle not so good.

My brief experience in southern waters was detailed a bit in 2012 August 30th Report #9, my attempts to run a trotline, something I watched many years ago.  I did speak to a crabber who had scouted the area in 2010 and found that Nott Island Bay in 10 feet of water had the best crab population then.  So in 2010 I went to hard bottom off Essex first to set the trotline and hit them immediately – what wasn’t discussed was “finding the crabs.”

In 2010 when I set the trotline with my friend Brian Sullivan we knew exactly where they were.  I didn’t have to spend time looking for them.  In my brief southern experience that was a completely different matter, the person who set these trotlines which as I recall was very long did take the time to find the crabs – first.  Remember it was a long time ago (before GPS) so I don’t know if they still do this down south but the fellow I went with made small test lines to see where the crabs were, and then tried them at different depths.  They were sections of line between two window weights (those old iron weights in older homes).  The line was three strand medium hard twist – opening up a section of rope and putting soaked salt brine skin strips (bull lips?) between them.  I also recall eels – salted the same way in chunks between the strands, no snood or connection between the lines 10 or so baits, 10 feet apart to test an area.  If one of these test lines came up with crabs a yellow plastic bottle went over with another window weight as a marker.  When two lines hit, the full trotline was set between the “two markers” as it was much effort to set in.  One of those trotlines with hundreds of bait pieces which was 2,000 feet in length, (it was told others were even longer) so before setting in it was worth the time to find them “the crabs.”  The salted bait strip was tough so it didn’t pull apart easily.  I did see a variant of this “test trotline” 2 years ago on a row boat off Nott Island, five baits on a line with a large lead sinker on each end – a small float marked the line, similar to hand lining only five baits at a time.  The person had two or three of these and rowed between them, checking them, current was slack, I don’t know how this would work in a strong current.

At this time of year it is the boat handliners and dippers who do the best.  The crabs move out to deeper waters, and two runs with the trotline in 2010 yielded over 80 crabs (report #9, August 30, 2012) off Nott Island then – a shallow set yielded only a few crabs.  A handliner in shallow water would have listed the area as “poor” that day while 200 feet off Nott Island the bottom was thick with crabs in 2010 – our fishing day was “great” and thus the difference in some recent Connecticut River reports.

Look for the largest concentrations of crabs in deeper waters with firm sandy bottoms.

Absence of Sponge Crabs Becoming a Concern 

One of the things I have noticed this summer is a decline of female “sponge” crabs – those with extruded orange to brown maturing egg mass.  From conversations and observations this summer female sponge crabs are largely absent, expect perhaps in the Old Lyme area earlier in the year.  Clinton Harbor last year was a significant producer of sponge crabs but noticeable absent this year.  In a few dock conversations crabbers also acknowledged this change.  

In the fall females tend to group at higher salinities in areas at the mouth of rivers or heads of bays (thought to help disperse larval hatches) areas that could be susceptible to storm damage and helps explain why in the 1960s and 1970s I did not see that many egg extruded sponge crabs in central Connecticut.  Another reason perhaps is that in the more saline areas offshore contain significant blue crab predators such as the starfish and conch.  In the 1960s and 1970s starfish were reported to be a significant predator of an overwintering blue crab populations between Kimberly reef and Faulkner’s Island (report #2, May 15, 2013).  The lower rivers often dredged may now have characteristics of a salt pond – lower salinities help keep these salt water predators out. 

These offshore crabs in the 1950s and 1960s had left the rivers most likely seeking shallow soft bottom eelgrass environments as in southern areas.  Instead many no doubt found a stormy firm bottom filled with hungry predators and absent offshore eelgrass meadows (except during periods of few storms and very warm water temperatures).  The key point may in fact is not having crabs leave the lower salinity areas at all and brings into view the value of dredged channels something that crabbers have mentioned to me before (2009) but I dismissed them then, but shouldn’t.  Dredged channels in lower reaches do have habitat value and in the case of blue crabs can help explain why they were able to survive last year’s winter storms.  Dredged channels may simply act as linear salt ponds – long and narrow but valuable none the least (Report #1, April 17, 2013) .  Connecticut lost many of its valuable salt ponds during the Great Heat 1880-1920 when summers here were brutally hot.  Malaria outbreaks then soon identified salt ponds (stagnant and often foul smelling) as mosquito breeding habitat and many were filled in, often under state and local health department orders.  (Climate Change and Public Opinion A Case History of Salt Marshes and Malaria Tim Visel, August 2008).   

Other eastern CT coves were bisected by railroad causeways (1890s) removing a large portion of tidal energy and in times of increased heat these environments became composting and then formed Sapropel.  Over time the loss of these salt ponds as blue crab habitat happened as they slowly filled in.  With decaying leaves on the rise with a restored forest canopy the importance of dredged channels increases especially for the females. 

The tendency for female crabs to “head out the sea” had been known for a half a century by the time the State of Massachusetts commissioned its excellent technical marine series, made available by the State of Massachusetts Office of Coastal Zone Management, Bruce Carlisle Director in the 1960s.  In a publication printed in 1969 as monograph series #9 (Division of Marine Fisheries – Dept of Natural Resources, Massachusetts title “A Study of the Marine Resources of the Waquoit Bay – Eel Pond Estuary this break out in female over wintering patterns was detailed on page 32. 

Blue Claw Crab Fishery (1968 Observation of Waquoit Bay) 

“A limited family fishery for the blue claw crab, Calinectes sapidus, occurs near the mouth of the Quashnet River in late summer and early fall.  Most of these crabs are taken by dipnet in shallow water.  A total of 150 blue claw crabs were observed near the mouth of the Quashnet River, near the mouth of Eel Pond, along the bay side of Washburn Island, and near the boat ramp at Edwards Boat Yard.  The blue claw crab is an estuarine species favoring mud bottoms with abundant vegetation.  Most of the bottom in the Waquoit Bay Eel Pond estuary provides ideal habitat.  

Larval blue claw crabs normally develop in high salinity water, 23 0/00/32 0/00 (Sandoz and Rongens, 1944).  Young crabs are more tolerant of the lower salinities of the upper estuary while adults remain in more saline water.  In summer crabs live in shallow water near shore, and move to deeper water in winter (Van Engel, 1958).  Adult crabs also exhibit partial sexual segregation.  In Chesapeake Bay, this separation is apparent in winter when males remain in brackish water in tributary streams and rivers, and females locate in the more saline water in deeper channels (Van Engel, op cit.).  

Until recently, many bays and estuaries, including Waquoit Bay, have supported a substantial family fishery for these delicious crabs.  Cause for the general decline of this species in Massachusetts is unknown.” 

Although the report writers mention the decline in blue crabs it is important to remember this was at the end of the cold and stormy period - known as the New England Oscillation.  It is during this period of colder temperatures and frequent storms habitat conditions reversed and marine soils became more alkaline especially after 1938.  As blue crab populations declined, the increased energy applied to marine soils rinsed them of Sapropel (acidic) compost and loosened soil compaction – aiding quahog sets along the entire Cape Cod South shore proceeding a surprising return in Bay Scallops as noted on page 28. 

Bay Scallops –

“In 1967 the bay scallop was the second most important shellfish crop harvested in Waquoit Bay.  Scallops were present on the east and west flats, along sections of the eastern shore of Washburn Island and in the Eel Pond-Childs River area (Fig. 7).  Although the location of concentrations of scallops is known to change, it is believed that historically the areas noted have been the most productive.” 

The productive bay scallop areas held out the longest on Cape Cod in the 1880s but they also failed as a result of extended hot temperatures at the turn of the century – the “return of bay scallops” followed the huge sets of qhahogs and a resurgence in winter flounder fisheries in the 1950s.  This was a surprise as scallop fisheries had greatly declined by the 1920s.

Although colder temperatures and increased storms would be good for bay scallops and quahogs – the catches of blue crabs and soft shell clams soon decreased on Cape Cod.  It is in these small coves and salt ponds we may be able to learn more about long term habitat changes (see next section).  And the areas that would be hit the hardest by storms would be the deeper higher saline areas – the areas closets to full salinity, the areas that would tend to hold more female “sponge” crabs. 

A loss of the female sponge crabs in one year would go perhaps largely unnoticed, if the jimmies and small crabs were higher up in the estuaries away from the more active high energy zones.  It could also explain why the salt pond blue crab fisheries on Cape Cod, far north of the southern crab regions continue to hold some blue crabs even in the colder and high energy times.  Just before Sandy last year crabbers reported in the Mystic River crabs were moving up river. 

Dredged channels may provide a key habitat refuge area for female crabs and why some of the first Old Lyme catches this spring were largely female.  It is now important to monitor the location and abundance of female sponge crabs and the areas in which they overwinter.     

Last year a significant female overwintering population was observed off the Coast Guard Station on the east side of New Haven Harbor, this spring no such population was observed. 

1898 and 1998 Key Blue Crabs Habitat Years for Southern New England

As we learn more about the resurgence of blue crabs in Southern New England, habitat quality and recruitment capacity (Megalops sets) remain two of the most important indicators. Recent information contained from the Massachusetts Division of Marine Fisheries (DMF), the State of Rhode Island’s Dept. Of Environmental Management (DEM) and Connecticut’s Marine Fisheries (DEEP) all indicate a dramatic increase in blue crab abundance after 1998, identifying perhaps a very significant regional habitat event. 

The Rhode Island Narragansett Bay Trawl Survey is perhaps one of the longest marine sampling programs in the country and ironically started a century ago, attributed to a high temperature low energy species reversal then in Narragansett Bay.  In a 1906 Lobster Aquaculture Hatchery report for Rhode Island is mentioned this concern as barracuda were now reported off Wickford Beach in 1905 in Dutch Harbor (pg 51, 1900) and tarpon were being caught.  Two years later (1908) Rhode Island issued another report, this one expanding the southern “range” of several fish species north into Rhode Island waters as they were starting to experience a habitat reversal of unprecedented scale.  To the fishery managers who recalled the 1870s, (see program report #2, May 30th, 2013) the change of species and relative abundance was the cause of great concern and a shock. Thirty years later at that time, Rhode Island was very serious about its “cold water fisheries” especially the lobster fishery.  But inland, fishery departments were also transplanting into Connecticut and other New England states more heat tolerant species of trout, rainbows and browns, complaining that native brook trout could not take the warmer weather.  They (inland fishers departments) were also seeing the same thermal water species change.

The Rhode Island Trawl Survey Report for 2012 (November) contains a graph (pg.2) which shows after 1998 blue crab prevalence as measured by sampling trawls between 1959 to 1998 and rose 450%.  The same basic trend is reported for the Buzzard Bay district, after 1998 blue crabs became more prevalent, and by 2002 and 2003, four years later, blue crabs were everywhere: Buzzards Bay, Narragansett Bay and into Long Island Sound. Southern New England was experiencing a dramatic rise of blue crabs following a lobster crash of 1998 just as it had a century before.

Several fisher reports include increased blue crab abundance in Connecticut post 1998, but that was at the same time lobster populations were crashing, also across the same basic region. Lobsters die offs received most of the media and regulatory attention at that time and the blue crab explosion went largely unnoticed for almost a decade.  We don’t really have good abundance inshore shallow water data on blue crabs in northern waters.  It was mostly a recreational fishery for almost a century.  Fishery management efforts have been directed mostly at high economic value species, and not the sporadic blue crab populations.  In 1984 the State Department of Environmental Protection issued a Marine Fisheries Management Plan. Blue crabs obtained one paragraph on page 151, but lobsters had a five page report.  All that was to change by 1998 and for ten years after the blue crab populations tended to do one thing, get bigger.  By 2007, blue crab populations were just too large to ignore, something was happening and the public began to ask questions and habitat quality was one of them.  What happened and do we know the factors involved in this dramatic decade long blue crab increase?

Other species were also changing, one of which was the oyster industry. In 1898, a century ago Southern New England had almost the same events, oyster sets increased as lobster populations collapsed.  1899 it seems brought a record Narragansett Bay oyster set and the 1900 Annual Report of the Rhode Island Commissions of Shellfisheries (May session 1900) contains this quote from page 3:

“In our last annual report, we had the pleasure of reporting great increase in the development of the oyster industry for the year 1898, since which time the development of this industry far surpassed our most sanguine expectations.” The 1899 oyster set was the set of the century in Connecticut not to be surpassed until the sets of 2004 and 2008.   As the New England oyster industry surged north into Maine, lobster fishers pulled up empty pots and recorded shorts perishing in shallow water.

One factor that seems to be unique is that following the Portland Gale  of 1898 (most likely classified a November hurricane within today’s criteria), the sets of soft shell clams and oysters now both increased, while quahogs and bay scallops are not even mentioned in the Rhode Island 1900 Shellfish Report.  Oyster habitats and soft shell clams are both closely associated with food for small blue crabs.  The soft shell clam sets in Massachusetts, Cape Cod, South of Boston, Buzzards Bay, were immense post 1899 and from very small production in the 1870s, Chatham Massachusetts would soon find itself the capital of a new exploding soft shell clam fishery.  For Cape Cod soft shells soon followed the set of 1900.  An immense habitat reversal and a new fishery was well underway by the time Dr. David Belding was concluding his famous soft shell clam research in the 1920s; for a discussion of the soft shell clam sets following The Portland Gale, see Long Island Sound Study Paper cited below.[1]

And the year that Rhode Island started to survey Narragansett Bay, that would also be 1898.  Henry Tracy of Brown University writes on page 38 (1906) in the key Rhode Island Study, was given the charge to investigate species changes. “In the year 1898, the Commission of Inland Fishery began “systematic examining the physical and biological conditions of Narragansett Bay.” The heat and few storms created vast changed habitat conditions.

A decade later, Henry Tracy would complete his 1909 Bulletin (printed in 1910 as the “Annotated List of Fisheries known to inhabit the Waters of Rhode Island, 176 pages.

In 1909 The Great Heat was beginning to moderate and although Tarpon was included as a species in Rhode Island waters the last large Tarpons were actually caught in 1906.

Dr. Tracy mentions the problem of expanding the range and listing of southern species into Rhode Island’s waters many times in his 1909 publication. On page 42, his includes this passage: “The Study of the Fauna of Block Island would be a subject of unique interest…fishermen say that frequently in these offshore waters, they take fish which are new to them and that they see even whole schools of unfamiliar species.”

And the coincidence that 1898 and 1998 would both come to mark years in which Southern New England lobster populations would start to die off? As far as I know, it’s just a coincidence, but efforts are now underway looking at 1998 for unique indicators for habitat succession similar to those recorded in 1898 and one of these is eelgrass and Sapropel habitats.

Long term surveys can pick up species abundance and changes in habitat quality. They can help us explain “surprising” increases in some species at the same time prevalent species declined.

Dr. Tracy at Brown University should be credited with the first efforts at conducting such a long term systemic accounting of the fisheries in Narragansett Bay; that study was picked up by another Brown University Professor Charles Fish who conducted his own fisheries research at Woods Hole.        

In the summer of 1922, Paul Galtsoff later reports that then instructor Charles J. Fish (embryologist at Brown University and Bureau of Fisheries biologist) conducted plankton studies that focused upon seasonal variations (page 73).[2]

It was Dr. Fish that instituted the Narragansett Bay species survey that continues today. Many feel it is the longest marine science survey effort in the United States and extremely important when it comes to measuring species shifts- especially for lobsters and blue crab in nursery areas; the areas that biologists have come to realize are so important to both these species.

Western Crab Habitats - The Saprobien System 

The Saprobien System (1909) offers an interesting look at long term habitat reversals. In the historical reports about early studies that lead up to the Saprobien System were the reports of fishers, fish wardens, and river keepers in Europe. They reported upon the impacts of high temperatures and organic matter loadings to river fisheries, and the association of temperature to them is now a century old.  Although here in Southern New England we had The Great Heat beginning in 1880, Europe and especially Great Britain had “The Great Stink” beginning in 1858. Here the Thames River with vast amounts of organic matter putrefied in high heat sending nauseating “bad airs” onto London Streets that were so intense, sheets soaked in vinegar were hung over Parliament windows in an attempt to quell the stench.  (Cairns and Pratt, A History of Biological Monitoring Using Benthic Macro Invertebrates, 1999).   

Although the Saprobien system would be modified many times, its first premise included time, as “self purification” of organic wastes, animal and human sewage, and in time slowing moving rivers could “recover” from organic pollution to pre event status.  Unfortunately in high heat, the fish (certain species) had long since “vanished” and one of its primary initial indicators was fish species “zones” and the ability to survive in stressful conditions.  The events that drive our habitat intervention unfortunately are historically most severe and public. Hugh Hammond Bennett, in his attempts to gather a national consensus here about soil loss and habitat conditions of the growing dust bowl in the 1930s was unsuccessful in Congress until a huge dust storm actually hit Washington, DC.  Alerted of its Capitol approach by colleagues in field stations, he timed a congressional debate hearing for 2 pm and arranged for drapes to be removed from the windows and tables pushed to them.  At 10 a.m. in the morning D.C. street lamps came on, residents were frightened by darkening of the sun, people swarmed hospitals with respiratory distress coughing and eyes watering from the dust as Congress started the debate over a national soil conservation program at 2 pm. Bennett is told to have addressed the group and said something to the effect, “Gentlemen, this is the situation that I have strived to communicate to you, as you can now see, it is here.”  Legislation for the Soil Conservation Service was approved shortly later. In the marine field we also react slowly to such large habitat changes.  After returning to the University of Connecticut in 1983, I had worked with Richard Loring of then Culture Clam in Barnstable, a hatchery producing hard clam seed on the Cape. 

Hard clam (Mercenaria mercenaria) inshore sets had largely failed on Cape Cod and the hatchery produced “seed clams” for a growing Quahog aquaculture industry.  Soon my work with area fishers I learned that widespread hard clam sets had mostly stopped on the Cape and the need of hatchery produced seed soon increased. My interest in the box culture of clams and the soil growth characteristics in them grew; when I returned to Connecticut many formerly productive inshore coves and bays for hard clams that had also become nonproductive. Upon the request of the Waterford –East Lyme Shellfish Commission, (Robert Porter, chairman), a similar culture experiment was conducted in Smith Cove, a westerly lobe of Niantic Bay.  Several thousand Mercenaria seed were purchased and planted in a wood rectangular box placed with j hook re-rod metal stakes, similar then to the Wellfleet method; we wanted to be able to then return to the same location to monitor growth. Several months later we returned to check on the growth of clams but instead found a black soupy leaf mixture that had covered the culture box. The characteristic sulfur smell soon became noticeable as we examined the clams, most had died, and the shells were soft and chalky. 

The blanket of oak leaves no doubt had suffocated the clams and now the acidic conditions from the oak leaves themselves had eroded shells. In many instances the clams had come smaller. It was disappointing for Mr. Porter to see this type of bottom, it certainly wasn’t like the one he had experienced growing up on Niantic Bay. Smith Cove had a sandy and shelly estuarine bottom then. It was now a soft organic filled mucky organic bottom, the habitat clock for that habitat succession period had long expired. He tried to save as many clams as he could but was interrupted by a neighbor dragging a tarp full of leaves to dump in the cove, and the discussion then became somewhat “heated.”   I left and later Bob told me that after the leaf burning ban, neighbors just started dumping leaves into the cove, believing the tides would take them out to sea. We had no idea at the time how leaves would impact the clams, but taking what I had learned on the Cape, we changed the soil for some gravel and bagged sand, and as John Hammond and George McNeil suggested, mixed in some crushed clam shell (obtained in buckets from Harborside Seafood in RI). It came as an aggregate (mostly driveway material) and we mixed that in to this “new bottom,” Clam growth of the remaining clams was nothing short of spectacular; I wrote this restoration project up in 2005 and presented it in 2006 at the International Conference for Shellfish restoration in Charlestown, South Carolina.[3]

Although the hard clams grew well in the culture box, when planted into the adjacent areas, they did not grow and eventually died off. Although Bob blamed the neighbors for the leaves, trees had grown up along the entire Niantic Bay and the marine soil itself had changed; it was acidic and under the remaining eelgrass patches we did find buried dead hard shell clams. The clock of habitat succession had simply run out for hard clams. In this section of Niantic Bay, the ice filled cooler and stormier 1960s had gone and with them hard clam habitats, but continued shellfish survey work showed Niantic Bay now had a huge set of sub tidal soft shell clams, (steamers) in areas of no leaves. Bob was surprised to see them, as when he was young, steamers (Mya) were rare and largely nonexistent in Niantic Bay, to him, it was perplexing to see a reversal of species and habitat types over several decades. In the marine environment our dust storms are our forest fires and hurricanes and the winter equivalent Nor’easters, our floods. 

And, it is not just one event usually, but habitat reversals sometimes take decades. One of the chief aspects of the Saprobien System is time for “self” purification for habitats to “restore” themselves to a certain expected level of habitat quality.  In marine studies this puts researchers at a great disadvantage; we need much longer periods of study (time) to review changes. In 1990, few saw the lobster die off of 1998 and a decade later, a surge of blue crabs. I didn’t either, but I would very much recall the habitat reversal pattern.  Just as Bob Porter returned to his hard clam grounds of the 1960s, that habitat had “succeeded” as new trees grew up and matured, although neighbors dumping leaves certainly had helped speed the succession process.   

The entire state of Connecticut was recovering its forest canopy, once largely cleared for agriculture; the stormy period of the cooler 1950s and 1960s was over. Leaves now collected over marine soils once cleared by waves and the areas that obtained the least energy. In 1935, agricultural fields occupied 67% of Connecticut’s land acreage; by 1985, only 13% (Lewis, 1980). Many rivers blocked by tidal restrictions (undersized culverts and poorly designed railroad crossings) or had long connections to the sea, slowly started to fill with organic matter, primarily leaves. This can also happen during long periods of heat, or when sand waves or sand bars can be driven into the mouths of rivers and coves creating a “sill” or bar partially blocking tidal exchange. Alewife Cove between Waterford and New London is an excellent example of sand bars restricting tidal exchange and buildup of black mayonnaise behind them.  The formation of a barrier sill reduces flushing so trapped nutrients and organic matter collects even faster, as organic matter builds that reduces hydraulic capacity less oxygen containing sea water is exchanged during tides and coves “fouled.” 

In hot weather these organic accumulations can act as nitrogen sink or storage capacity. Some of these coastal storm blocking energy case histories can be found in colonial New England with examples opening of salt ponds. Salt ponds cut off from cooling ocean exchange in high heat putrefied, and fish kills were common.  These habitat changes were so quick, they were very noticeable (did not take decades to occur) and local interests acted and unblocked or “breached” them. The opening inlets that were important to local herring runs, as herring rights (alewife) were subject to public bidding and franchises.  A short case history of Quiambaug Cove was included in report #4, (July 3, 2013) that mentions the use of oxen.

The restoring of tidal energy has been a part of New England’s salt pond fisheries history. 

 What was once a small concern of the river oyster tongers of the 1930s and 1940s; tons of leaves now buried river oyster beds. As temperature warmed into the 1980s and 1990s, those leaves rotted and Sapropel formed first in the quiet coves and head waters of tidal streams. The people who noticed it first, as bad smells foul or “sour” bottoms in the marine fisheries were the quahogers, bay scallopers and winter flounder fishers. They could see habitat change over time and had vested interest in habitat quality.  No one I feel was expecting what paved streets, a renewed forest canopy and a regional leaf burning ban would have upon the Alewife fisheries. I was to witness that on Cape Cod and to the long hot period and relatively few storms that were to bring a surge of blue crabs in Connecticut not seen here since the last Great Heat.  A huge habitat reversal from the 1950s and 1960s, the age of the lobsters in Connecticut had now ended, and the age of the blue crab just lay ahead. 

Email blue crab reports to:  

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.

[1] Soft Shell Clam Habitat Creation and Associated Population Expansion Following Significant Marine Soil Cultivation/Disturbances LIS – EPA HRI Sub-Committee on Shellfish, T. Visel, April 21, 2008. A Review of Three Case Histories Following the Gale of 1898.
[2] Source---1898-1998 The Story of the Bureau of Commercial Fisheries Biological Laboratory, Woods Hole, Massachusetts. By Paul S. Galtsoff, United States Department of the Interior, Circular 145 Washington DC, May 25, 1962, Page 73.
[3] Source: Connecticut Shellfish Restoration Projects Linked to Estuarine health by Timothy c. Visel, Coordinator, The Sound School Regional Vocational Aquaculture Center, 60 So. Water Street, new Haven, CT 06519. (
A series of CT Sea Grant/Extension shellfish restoration programs for hard clam (Mercenaria mercenerica), soft clam (Mya arenaria), oyster (Crassostrea virginica), and bay scallop (Arogopectin irradians) were coordinated with local municipal shellfish commissions in the 1980s. Potential candidates for projects were identified by local environmental fisheries history, shellfish maps, natural beds and local shellfish surveys. Several restoration projects were undertaken with federal, state and local agency assistance. Results were highly site-specific; some yielded almost immediate positive results and some were complete failures
Predictions/suggestions by the local residents and resource user groups were often confirmed; therefore, their importance and contribution should not be overlooked. Environmental fishery history reviews can be an important tool in understanding the declines in shellfish production from near shore areas. As much information as possible should be obtained before attempting shellfish restoration programs. In this way, scarce shellfish restoration resources can be maximized.
”Connecticut Shellfish Restoration Projects Linked to Estuarine Health” 11:30 Plenary Concurrent Session E “Small Scale Approaches to Shellfish Restoration” – 9th International Conference on Shellfish Restoration; November 15-19, 2006, Charleston, South Carolina, USA

Friday, August 16, 2013

2013 Connecticut Blue Crab Report #7

From Tim Visel at The Search for Megalops:

The Sound School – The ISSP and

Capstone Project Proposal

     Building a Network of Citizen Monitors

The Connecticut Blue Crab Population

Habitat Study 2010-2015

  You Do Not Need To Be A Scientist To Report!

The Search for Megalops

Program Report #7

August 16, 2013

The 2013 Blue Crab Year


  • Blue Crabbing Soars in Central Connecticut
  • 2012  Megalops Set has Survived In Some Areas
  • Western Connecticut Blue Crab Habitat Failure and Recovery
  • What Happened in July 2011 Answers to Habitat Questions – Hydrogen Sulfide and Estuarine Health


Blue Crabbing Soars in CT


With tides reducing in intensity and some good weather days and nights, blue crabbing surged in central Connecticut and new eastern reports continue to be very positive. The Connecticut River fishery increased as crabs headed up river, look for the best shore crabbing at high tides and deeper holes remain very productive for boaters. The Nott Island Bay, the easterly side of the Connecticut River opposite Essex was excellent. Some 100 to 125 count catches were made during the first week of August. Catches at night however at slack water remains unpredictable, and a tremendous eel population is now present in the Connecticut River; I used Vexar™ netting bait bag material, but (August 30, 2012) even that will not prevent a poor catch. When the eels show up, crabbing is very difficult.



What is being reported is that large male crabs are moving upriver and generally the upper reaches are producing the best catches. And, at this time, I think I better take off the gloom at least for central and eastern Connecticut as this season appears to be approaching that of 2012, and has the potential to even improve beyond that. The 2012 Megalops set has appeared 60 days late and in heavy concentrations in eastern CT (May 15, 2012) and new reports in the Mystic, Thames and Pawcatuck Rivers mention a huge increase in the number of 1.5 to 2 inch crabs; these crabs should be 4 inches by December and be next year’s legal crop. I appreciate the new reporters for the Mystic, Thames and Niantic Rivers—thank you!

So, as catches now exceed 10 crabs / hour or more in central CT, the gloomy reports (March 26, 2012 and April 17, 2012) need to be changed for the central and eastern portions of the state (see next section).  The West however largely remains in the doldrums. It’s just very poor blue crabbing. Hoping to see a good Megalops set survive there in a few weeks, with New Haven to Stonington, now the place to crab. 


See you crabbing,




The 2012 Megalops Set Has Survived


Although about 60 days late (waters were very cool this spring), the 2012 Megalops survived and is present in increasing numbers in Central and Eastern Connecticut.  My spring predictions of March and April pointed to widespread winter mortality for all three years’ adults – 3 to 4 and now the Megalops set. This winter kill did not occur for adults and 3 to 4 sizes and apparently did not occur for all of the 2012 Megalops.


It just shows how resilient and tenacious blue crabs can be and my predictions of gloom premature, but let’s be honest, we had Sandy, heavy snows, several powerful coastal Nor’easters, the most snow (80 inches along the coast) since the 1950s, the huge blizzard Nemo and snow in northern New England until May. Spring water temperatures were very cool and like the Chesapeake, I feared the worst. Most recent reports from the Niantic River, Thames River and now Mystic River however show tremendous numbers of 1.5 to 2 inch crabs, next year’s legal size crabs. I don’t feel that there is enough time left in the growing season to reach 5 inches this year, but I thought the hibernation period was too long also.

With 90 days to 120 days we might need to rethink when blue crabs begin to hibernate, I thought late December, but now perhaps late January?


A big question remains in the west, once a huge producer of post Megalops blue crabs 2006 to 2011. A good set here (2013) will be a great sign as I believe as the lobster fishery before western areas produced larval blue crab stages for the central and the eastern sections. In 1980s, about a third of female sublegal lobster population in the west was “berried” or carried eggs. The larval drift for Stage 1 to Stage 3 lobsters to the east was tremendous (at that time) and species habitat carrying capacity of high density will naturally seek areas of lower density. I think the same thing can be said of western CT with the blue crab reversal after 1998. The west may be the largest supplier of Connecticut Megalops as evidenced by movements east of immature blue crabs in 2010 and early 2011. Some of the densities of small crabs reported in the Westport/Fairfield salt ponds in 2009 and 2010 were incredible. If western CT was a large Megalops supplier of the central and eastern sections, then reduced catches might be inevitable in other areas; western CT could be our blue crab nursery and why finding areas of Megalops sets so important there.  Look for the first signs of post Megalops blue crabs in sandy areas along the shore in minnow beach seines by September. Some of the best blue crab larval stages can be observed in them (August 30, 2012) and the appearance of small crabs in the west would be a very positive signal for all Connecticut blue crabbers.


Western Connecticut Blue Crab Habitat Failure and Recovery


One of the most interesting aspects of the natural ecology of embayment systems is balance, and the other is ecological voids. Nature hates a vacuum and that is true, but what takes years to happen can be gone in an instant and what happens instantly can take years to restore, in other words, we have habitat succession in the marine environment also.


One only has to look at terrestrial forest fires and marine hurricane impacts to experience this change.  But what about the habitat succession; we can’t see, we can see the impacts of beaches swept away by storms but will we see the kelp/cobble stone forests that often follow?  Forest fires are terrible events for those in its path but years later species that needed grassland habitats thrive, while those that needed the forests before decline, a balance between habitat types and the populations that need each type? Do we know enough about habitat succession and population dynamics of marine fish and shellfish in the marine environment?  No, absolutely not, we haven’t even begun to understand it or study it for that matter. We learn about marine habitat succession from fishers, as we did first about terrestrial succession from hunters. Similar to terrestrial habitat succession, (drought and high heat precedes forest fires, while rainfall signals a long term renewal of the forest). Marine habitat succession is governed also by energy and temperature.


Hunters would head to grasslands to seek species that needed that habitat, fishers head to “structure” to catch species that need it. Talk about structure to any freshwater bass fisher, and you will soon find they are keenly aware as to the value of structure to overall fishing success.


But what about blue crabbing, what made the 2006 to 2011 blue crab populations soar in western CT? What do they need, what is their habitat balance in regards to habitat succession? These are questions that need answers if we are truly to understand one of the largest habitat reversals in a century.


Did western CT blue crabbers experience something of a habitat successional event in 2011, yes I believe they did.


Hydrogen Sulfide And Its Impacts Upon Estuarine Health.


Sapropel and western CT river life systems may provide response to western CT blue crabbers. The truth of the matter is that we just don’t know much about sulfide toxicity in western CT. It is an area of research that is lacking even into today.


In many respects my response to questions from the western crabbers in 2012 is a combination of several factors low oxygen, freshwater toxicity, chemical toxicity, hydrogen sulfide toxicity and disease.


While all of these factors should be considered, I believe low oxygen/hydrogen sulfide toxicity to be the primary reason for the apparent habitat failure. Many blue crabbers pointed to the West Nile treatments and that deserves a look and I did issue a special report (Pesticides and Blue Crabs on July 24, 2012) about this, I also looked at disease and habitat life cycle stressors including oxygen and chemical factors as contributing causative disease factors, but central and eastern blue crab populations remain to my knowledge relatively disease free. So I looked at a key concern of mine the habitat impacts of high heat, low energy and high organic deposition, particularly leaves oak and maple as acidic sulfur respiration pathways leading to hydrogen sulfide buildup and fish kills.


And, as I usually do, I look at what is in print, in the historical records and current research. After researching the problem for about a year in regards to western CT rivers and harbors, I found very little written about the impact of deep deposits of organic matter (leaves).  And when pollution of rivers did grab a national attention here in the US, its focus was upon the chemical manmade aspect of non natural “polluting” substances, entering water courses not natural ones such as organics, leaves for example. A consensus upon pollution would itself contain a biased point of view, how could something “natural” also be considered a pollutant. This public policy component would initially tend to the analytical chemistry descriptions of measures for manmade substances for pollutants.


When examining the historical records it is important to recognize a resource bias in the scientific community at the turn of the century. During this period lakes were the resource of concern, still important for water powered machinery and drinking, however rivers or harbors were not high on the priority list. In fact, rivers were thought to be the best way of “receiving” factory wastes, so it was much to our repugnance a “reasonably use” of pollution policy existed.  Until well into this century, one only has to read the three hour speech to the CT Agricultural Board in 1886 about pollution which the editor of the Hartford Courant, then Mr. J. B. Olcott described walking along the Quinnebaug River with cotton soaked in glycerin stuffed into his nostrils to block out the smell from the river. Not doing so would accordingly cause one to instantly wretch. This was a common practice during this time in Connecticut unfortunately along many riverfront factory communities. Therefore, is it not surprising that some of the earliest river studies of the biological impacts of river organic matter pollution came from Europe and not from the United States. Some of the first studies are from the Baltic region, especially Germany and Poland. River fisheries were very important in Europe (fisheries, drinking water) so impacts to them were first studied and the first research on the impacts of high organic matter is from them. The first formal study of putrefied organic matter, and biological impacts upon rivers was developed by Kolkwitz and Marsson at the turn of the century. In 1909, they developed what they termed, a Saprobien system for the assessment of organic pollution, and in the 1950s, 1960s and 1970s this bias (chemical not organic pollution) for lakes and not rivers continued here in the US. In the 1930s a worldwide conference about Sapropelic formation was held and at the urging of Parker D. Trask of the US Geological Survey just prior to World War II, the paper of recent Marine Sediments was finally printed in 1955.  In 1971, H.B.N., Hynes of the University of Waterloo, Ontario, Canada, published his now famous book, “The Biology of Polluted Waters” (University of Toronto Press 1971) he mentions this bias in regards to the “well known” classifications of Saprobien System for rivers. “But perhaps well known is too strong an epithet to use because although it is widely used on the Continent, it is rarely mentioned by American or English authors.” The Saprobien System as defined at the turn of the century will be recognizable as a slightly different system for lakes today, not rivers. And the largest constituent of Sapropel in CT now appears to be leaves, and depleted oxygen (warm water) conditions – “a habitat history” or much longer cooler and then warmer periods.


The basis of this classification system is the theory that when a river system receives a tremendous load of organic matter (leaves, grasses, bark, twigs, etc) it would result in a series of “zones” of decreasingly severe conditions for plants and animals downstream. A brief description of the Saprobien System is below:


PolySaprobic – Zone of gross organic pollution organic matter with little or no dissolved oxygen and the formation of sulphides (now sulfide).


MesoSaprobic – less organic matter and grades according to the numbers of indicator life forms


OligoSaprophic – The zone of recovery where the mineralization (breakdown) of organic matter is complete and oxygen content is back to normal and a full range of plants and animals occur.


In simple terms, western Connecticut rivers and estuarine areas could now be termed PolySaprobic, favoring the condition of sulfides and extremely toxic to blue crab Megalops and adults. It is now strongly suspected in the black water deaths (largely fish kills) at the turn of the century. It is suspected that floods following years of hot stagnant conditions ripped open Sapropel deposits (black gelatin) releasing enormous quantities of sulfides causing massive fish kills, by “black water” usually accompanied by strong sulfide rotten egg” smells. Passive deposition of leaves and organic matter in coves in Eastern CT such as the North, Middle and South Coves in Essex in which oak and maple leaves have collected are good examples. Over decades in areas even 10 feet in depth have layers of leaves, the western Connecticut rivers may have received just as much organic matter by active watershed transport, organic matter from storm water, and ripped into “brown bottoms” of organic oatmeal in just a few days.


I believe that is what the western Connecticut crabbers were trying to tell me in July 2011 (see Report #12, August 2, 2011; Report #14, August 19, 2011) that heavy rain had ripped into sulfide deposits killing crabs in place. Irene may have brought down additional organic compost then followed by Sandy. The sulfides now released by these organic deposits (warm water and less oxygen favors deadly Sapropel deposits) which lower pH levels could have resulted in a western Connecticut die off of blue crabs not seen here for a century. I will also add that lower pH tendencies to increase the toxicity of insecticides as detailed in label warnings. Many insecticides have both high heat and low pH application warnings.


In simple terms, it is as if someone dumped overnight 5 feet of compost on your yard, the lawn would quickly die, you could see it, and until it is raked off, no lawn. The same thing happens in the marine environment, usually not as dramatic as floods carrying down decades of built up watershed organic matter at a time, but a gradual build up as temperature rise rot. In this case, rotting leaves may have covered valuable blue crab habitat.


In periods of cold (more oxygen in water) and frequent strong storms Sapropel accumulations “melt” away as storm activity washes it from tidal areas. Several western crabbers have asked me about Sapropel (after Report #5) and many blue crabbers have seen it, but know it best by its common name, black mayonnaise. It is also in the location of blue crab populations making its toxic impact, event (storms and hot weather) temperature related. Organic deposits with sufficient oxygen (cooler water) seems to be a good blue crab habitat type but very deep deposits in hot weather tends to be Sapropel. That explains to some extent hot weather warm water blue crab jubilees down south or here in New England late summer and the turn of the century black water deaths. One of the most notorious black water deaths from the last century occurred on Long Island, New York in Moriches Bay between July 29 and August 4, 1917. Here tens of thousands of winter flounder died and then putrefied in the heat. Although today very little is written about Sapropel itself, in Southern New England from Cape Cod to Long island, in shallow warm coves and bays, with reduced tidal exchange, it has often become a dominant habitat type. It is in hot weather Sapropel is toxic to most forms of requiring oxygen marine life and sheds ammonia, a brown algal nutrient.


This also explains how great blue crab habitats such as those in pre July 2011 habitats quickly turned deadly for blue crabs resulting in a DIP “dead in place” blue crab observed die off.


More about Sapropel and Saprobien System in later newsletters.

Email your blue crab reports to:

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.