Monday, February 10, 2014

2014 Connecticut Blue Crab Special Report #2

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 - The Sound School
Items of Interest to Blue Crabbers
The Search for Megalops Special Program Report #2-2014
February 2014
Habitat Questions about Sapropel, Blue Crabs and Climate Change
Marine habitat succession happens underwater as well
Winter Sulfide levels can kill- Fish and Blue crabs
Some of the problems about marine habitat succession are that it is both long term and happens out of sight.  It is also an area that is under studied and rarely presented to fishery managers or fishers for that matter.  I planned a small habitat succession experiment on land in my backyard to illustrate this point.  Two years ago this spring I purposely stopped mowing (read application of energy) a small section of our backyard lawn.  Many neighbors cut and mow their lawns on a schedule that rivals any transportation routine and apply fertilizer (which I do not) so my experiment with the loss of energy soon became a concern to a neighbor last year who offered to cut down this habitat experiment twice.  But I explained that my lawn mower was a “miniature hurricane” and that the loss of energy quickly caused land habitat succession to be very visible (which it was) but the loss of energy in the marine environment on sub tidal habitats is hard to understand and see.  He seemed puzzled and left shaking his head. 
All summer long small trees spouted, and weeds grew tall and a couple of times he would discuss it looking at it as he mow his lawn to a fine level of smoothness only to see a patch of golden rod and young black locust trees sprout amid wild plants blooming a few feet away.  Again the offer was made this spring to cut down this “wild tangle” but again I declined.  It’s quite noticeable now, I agreed but wanted some pictures – “It will be gone by Christmas,” he seemed okay with that.  That was the point --habitat succession on land was quite noticeable and that in just two years it was something that people could see.  Marine habitat succession of sub tidal areas is hard to see and takes much longer than land.  And when marine succession occurs it’s mostly plants and shellfish that define the habitat quality change and you can see them also as catches but succession in marine habitat types is even more difficult.  That it can take decades.  In sub tidal areas important habitat indicators is of the bottom itself, which is even more difficult to ascertain.  Most of the cove and bay bottoms in Connecticut the last two decades have become softer and often muck filled. It is often referred to as a negative habitat change from fishers.  The soft eelgrass Sapropel bottoms are damaging to winter flounder and shellfish in high heat but do seem to improve blue crabs habitat quality.  Additional research is needed for habitat quality of soft Sapropel bottoms however that would require additional funds. 
There is just not a lot of grant money available for “muck studies” it just doesn’t cry out for research priorities.  Sadly, although Sapropel formation might be the best indicator we have for climate change for Long Island Sound and apparently it has been almost completely overlooked.  But marine habitat succession has profound ramifications for coastal life today especially the history of it, the temperature and energy conditions related to it, impacts to navigation, shoreline erosion, estuarine ecology, habitat quality and finally fisheries abundance.  Most recently those areas do have a responsive research community post Irene and Sandy, but when it comes to marine habitat succession we largely missed the boat. That ship set sail in the late 1970s and with it a negative “NAO” as climate pattern that is also frequently “overlooked” (Megalops report # 1, January 2014).
Bottom sediment quality is so elusive, because it is difficult to see compared to land habitat succession.  That is what is of interest now is we had a second Great Heat (1974 to 2008); since 2008 the temperatures have dropped and energy levels significantly increased for New England thanks for a negative NAO – the North Atlantic Oscillation.  The NAO after being positive for so long turned sharply negative in 2011.  A negative NAO is associated with increased storm activity and cold polar air sinking for south into the middle US. (Megalops Special Report #1, March 26, 2013)
At the beginning of the last century The Great Heat 1880-1920 lobster populations crashed and blue crabs increased.  After 1984 blue crabs started to increase and lobsters crashed again.  In 1931 the climate and energy levels reversed and lead to the cooler and stormier 1950s and 1960s.  Could 2011 have been our 1931?  It is still early to say that but one of the indicators could be climate in the 1920s, blue crab populations began to drop, a series of colder winters was thought to have ruined the blue crab habitat quality, Megalops sets then came too late for blue crabs to survive increasingly long winters but the stormy weather improved conditions for kelp forests and lobsters slowly recovered.  The bay scallops who became practically extinct from southern New England waters in 1920s had reproduction success—improve and  “came back” sometimes suddenly to the amazement and delight of coastal fishers who rejoiced to see an old friend return, it had been a long time.  The NAO turned sharply negative in 1950 – it was the age of the bay scallop and quahog.  Oysters declined to level not seen since the 1870s.  But something also occurred:  bottoms released sulfides stored during long hot periods killing fish and blue crabs in winter.  Sometimes habitat succession is not liked by us when it happens and winter “kills” became common in the 1950s (Megalops Program Report #1, April 17, 2013). Winter kills became common after 1930 in coastal salt ponds.
Habitat Succession Turns Violent 1931 to 1950
To coastal property owners however the 1950s and 1960s there was nothing to rejoice about, while bay scallop production would rise to historic production highs in Niantic, many coastal residents there were busy repairing seawalls, and supported new federal efforts at “flood and erosion control “with local” boards now forming in many municipalities.  The Northeast Atlantic Oscillation appears to be a natural cycle event and it had turned sharply negative.  It is not a new climate event-- the “Polar Vortex” has been mentioned recently in some weather forecasts, but the vortex is a feature of the North Atlantic Oscillation (NAO) but does not directly cause it.  Its presence has been known for quite awhile.  In a book titled “Climate Change,” Harlow Sharpley, Editor (Harvard University Press), Hurd C. Willett describes the “circumpolar vortex” on page 56 and reviews its presence, but it’s quickly recognized today by its large horseshoe shape storm track across the middle United States, drought often on the left side while increased rain or snow on the right – our side of this horse shoe shape storm track.
“The Cycle is one of alternate expansion and construction of the circumpolar vortex with equator ward or pole ward displacement of the prevailing storm tracks.   Periods of expansion of the circumpolar vortex tend to be cool in middle latitudes, accompanied by increased rainfall in lower middle latitudes and decreased rainfall in the highest latitudes.”  Periods of contraction of the circumpolar vortex are marked by warm characteristics particularly in the higher latitude.”  (1953)
First impacted water bodies then were shallow and often had restricted flushing – tidal restrictions.  As such they had increased residence periods for nitrogen locked up in organic matter – compost.  As energy levels decreased (storm intensity/frequently) it built up and then rotted.  In the absence of oxygen, bacteria thrived, consuming organic matter while releasing hydrogen sulfide gas.  When that happened, bay bottoms turned black.  Coastal residents a century ago watched this also happen and they did one of the few things they could do restore the energy and this was accomplished on a limited scale – coastal dredging by horse drawn scoops.
The previous period of warmth 1880-1920 saw bay bottoms turn soft and black.  Oyster sets were huge, blue crabs became abundant.  Black mayonnaise more aptly termed “fresh Sapropel” grew thick creating deep deposits. After 1931, temperatures dropped and storm intensity increased. The built up Sapropel deposits were washed from coves and bays and with it the byproduct of high heat low oxygen reduction by bacteria, sulfides.  At times sulfides could and did kill fish especially under thick ice. These events became known as winter kill.
In the 1940s, ice returned to New England’s salt ponds; duck hunters who enjoyed “open” winters before now saw conditions become colder.  Thick ice formed on salt ponds, in areas of tidal flow winter ice scour increased re-suspending these Sapropel deposits and with it sulfide fish kills, termed black water deaths.  (*Black water is rarely used today although some old aquarium texts still mention it). Sulfide is extremely toxic to fish, effectively blocking oxygen exchange in the gill tissue itself, it binds so completely that even in the presence of oxygen, and fish perish quickly.  Fish simply cannot access the oxygen and flee.  In the transition years, winter fish kills on Cape Cod increased along with colder temperatures came a sudden increase in storm frequency and storm intensity.  Coastal coves with shallow narrow connections to the sea often became blocked with ice and subject to winter sulfide kills.  Coves can also become blocked by storms and coastal residents a century ago would use oxen and horse teams to unblock them. They would do this because this habitat succession threatened valuable herring/alewife runs, seine fisheries and shellfish.
A fish kill (striped bass) happened a few weeks ago in the Black Hall River in the Old Lyme; The Black Hall had been one of the areas that had overwintering blue crabs survive and the past three years one of the first areas to report blue crab catches.  No doubt a thin layer of Black mayonnaise in oxygen helps blue crabs, but deep layers contain high amounts of sulfide and can kill blue crabs as well as fish.  One of the signals of declining habitat quality for blue crabs is the reports of such winter kills.  (Megalops Program Report #1, April 17, 2013).
The buildup of Sapropel (black mayonnaise) has happened here before and a few accounts have survived a local habitat history that describes hard bottom habitat transitions to soft ones.
One of these accounts describes Quiambaug Cove in Stonington. Edgar P. Farnell wrote to me in June 1987 as part of an investigation of increasing Sapropel (Black Mayonnaise) in Quiambaug Cove, Stonington and comments by eastern CT winter flounder fishers.  I was working for the University of Connecticut at the time. Winter flounder fishers reported that heavy muck was now covering once productive winter flounder habitats and those changes had occurred after 1974 when the Negative NAO turned positive to warming temperatures in bringing Southern New England.  This increasing warm temperatures naturally lowered oxygen levels and small coves were some of the first impacted water bodies; they were shallow and often had restricted flushing- tidal restrictions. As such, they had increased residence periods for nitrogen locked in organic matter – compost mostly leaves.  As energy levels decreased (storm intensity/frequency) and temperature increased this created natural anoxic conditions. Organic matter accumulated quickly and then rotted forming Sapropel.  In the absence of oxygen bacterial reduction process, sulfate reducing bacteria thrives, continuing consuming organic matter while releasing hydrogen sulfide gas.  When that happened, bay bottoms turned black.  Coastal residents a century ago watched this also happen and they did one of the few things they could do – restore the energy to increase flushing and this was accomplished on a limited scale, by dredging – salt pond and cove inlets.
The letter that Mr. Farnell wrote to me encompasses those features of coastal salt ponds a century ago is included below,
Dear Mr. Visel:
Mr. Frank Rich has advised me that you are considering improving the tidal flow in Quiambaug Cove.
The buildup of much and heavy vegetation is more of a concern. It certainly has had an effect on the Cove as a whole including clams, oysters, crabs, fish and mussels. When the Filter Plant was built many years ago, the north end of the Cove increased the buildup of heavy mud that has continued for many years.
When my father (deceased 1972) was young, he recalled that every spring landowners along the cove would use a team of oxen and plow to dredge the Cove every year between the bridges at a perigee tide. This, no doubt, improved the tidal flow, because when I was a boy, the Cove had little of the muck which now prevails.
I thought my Father’s recollection might be of help in validating your forecast that dredging the area between the bridges would have a dramatic effect on the quality of sea life within the Cove.
Very truly yours,
Edgar P. Farnell
(June 30, 1987)
In cold weather as ice built up frequently cold water sulfide kills happened naturally and there was nothing coastal land owners could do except wait for spring.  They didn’t like this habitat succession and sought to correct tidal exchange problems themselves and therefore the recent public policy dilemma over climate changes – how much is “us” and how much is “natural.” 
Did a stormy colder period follow a relatively warm period (1880-1920) as coastal storms then were few as compared to the storm filled 1950s and 1960s?  What were the habitat conditions, did they succeed like terrestrial ones, or could hurricanes in the marine environment be the equivalent of land forest fires and quicken habitat succession?  It is natural to see blue crab populations and lobster populations reverse in our area subject to changes in temperature and energy levels, and if so how many times before could such decreases in some species provide clues for another? 
These are some of the questions that come up with a long term environmental fisheries history review that places Mother Nature, with equal footing (a legal term would say standing) as to our involvement?  Is it over fishing or a declining habitat quality?  Is shoreline erosion something we should just expect during negative NAOS.  This is a huge issue for the environmental community, coastal landowners, fishers and the public.  This is why the habitat questions remain, the oyster industry grew to an enormous size during The Great Heat (1880-1920) during a time of an unprecedented period of coastal pollution?  The Connecticut Lobster fishery failed after pollution controls amid excellent conservation and resource management laws.  At the turn of the century (1900), bay scallops collapsed in southern New England but in 1876 Greenwich, CT would have the largest bay scallop fishery – during this brutal cold and stormy period.  In 1876 most of New England ports would be locked in heavy ice by December, but bay scallop fisheries in 1878, two years later would be huge?  Blue crabs were extremely scarce in 1878, but Noank, Connecticut became New England’s lobster capital, and four decades later only to be the site of a lobster hatchery to help replenish small lobsters for a failed lobster fishery but was now the site of now a growing blue crab fishery?  These events are recorded in the fishery statistics for our region.
These species all appear to reverse – In conjunction with habitat quality either being reduced or rebuilt by the negative or positive phases of the North Atlantic Oscillation (NAO). The NAO is one of the most studied and recognized climate patterns in the world.
If you follow the negative and positive phases of the NAO, years later you mirror catches of fish and shellfish. A positive NAO warm few storms certain species thrive, a negative NAO, cold and stormy, the same could be said for other species.
This spring could be the difference for blue crab habitat quality – another long cool spring could mean a late Megalops set – again. This would be the second negative NAO winter in a row for blue crabs.
In the 1950s and 1960s two or three cold springs was often reflected in decreased catches of blue crabs. We might be seeing the first habitat succession changes now in a long cyclic process.  These changes could improve lobster habitat quality years from now.
The species to watch --adult lobsters returning to western  Long Island Sound better  winter flounder recruitment in eastern Connecticut and bay scallops increasing to our north.  That would signal a possible habitat reversal.  The climate pattern to watch is the NAO – a sharp negative phase coincided with a steep drop in blue crab populations in southern New England 50 years ago. A habitat succession process that soon favored lobsters not blue crabs; it could happen again.  Reports of winter kill blue crabs would be important after the ice leaves in a few weeks.
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.

Monday, February 3, 2014

2014 Connecticut Blue Crab Special Report #1

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 - The Sound School
Items of Interest to Blue Crabbers
The Search for Megalops Special Program Report #1-2014
January 2014

  • Year Four of Study: Climate & Temperature Influences Habitat    Quality
  • Climate, Energy and Habitat Quality Comments
  • Thank you for past support and comments
The 2010 blue crab season seems very distant now, the catches of blue crabs from the Connecticut River were hard for me to believe; I still have pictures of my son Willard’s best trip, a cooler and two five gallon buckets filled to the brim on my office wall as a reminder. He had made his point – over 200 crabs!

I had not experienced anything like that growing up in Madison in the 1960s; lobsters were abundant then not blue crabs.

My research into the impacts of climate and energy to fin and shellfish populations were well under way again as I had rejoined the Long Island Sound Study Habitat Restoration Committee in 2005.  In 2010, the surge of blue crabs was not just a one day occurrence; blue crabs were everywhere and in large numbers. Several New England Regional media reports labeled it “New England’s Blue Crab Explosion.”  It was.

The blue crab increase came at an unusual additional time; lobsters in Long Island Sound were dying at the same time blue crabs were increasing.   For centuries biologists and resource managers had combined lobsters and crabs as a single reporting catch landing or statistical reporting area.  An easy mistake; they each had shells, crawled mostly, and had claws. Their larval stages were hard to tell apart (Megalops) and seemed to be caught using similar baits. For lobsters and blue crabs in Southern New England they may share the same habitats, it’s just at very different times--the tale of two different habitat qualities in the same place, a habitat history.

At first, it was difficult to believe the blue crab catches made in the Connecticut River in 2010.  In the 1960s, a day’s catch of a dozen blue crabs from Tom’s Creek, Madison was a great catch. In 2010, if you didn’t have 12 crabs in an hour something was wrong.

Environmental fisheries history (combines long term climate, and energy, with fisher reports and catch landing statistics) as a way to investigate habitat quality is just now being recognized as an area of importance.  I always wanted to see if what some fishers reported in Connecticut historically was region wide; did fishers also see the same habitat changes that I saw or experienced the same thing I did growing up in Connecticut?  The answer to that now is “yes” for the time period I witnessed.

While crabbing in the 1960s, I had no idea that lobsters had died off in Connecticut sixty years before at the same time blue crabs also then became abundant.  The experiences I had access to were the ones I could see…that was all.

Thanks to the Massachusetts Office of Coastal Zone Management and the Town of Chatham, Massachusetts for the latest report recently posted titled, “The Study of the Marine Resources of Pleasant Bay,” Fiske et al. 1967 contains an interesting section regarding blue crabs as a series of colder winters caused blue crabs to decline across Southern New England – fishers and fishery managers were curious why- important enough even then to deserve a mention.

“No significant bait or edible crab fishery exists in the bay; however, an unconfirmed report by the Harwich Shellfish Officer suggested that a few blue claw crabs (Callinectes sapidus) were taken by family fishermen in the area of Muddy Creek, Harwich. It should be noted that during the 12-month sampling period biologists did not capture or observe any blue claw crabs in the estuary. During the course of interviews, many local fishermen expressed concern over the disappearance of blue claw crabs in the bay. In recent years, there have been similar reports from many areas along the southern shore of Massachusetts. The cause for the general decline of this species in Massachusetts is unknown. Until recently, many bays and tidal rivers supported substantial family fishing for these edible crabs. Since this species appears to be in marked decline, specific investigation should be conducted to find the cause of this decline and to determine possible methods of rehabilitating the crab stocks.”

Also, during the same time period, Westport River, Massachusetts blue crabbers were asking the same questions: What wasn’t known and what a retired Chatham oyster grower, John Hammond described to me as a habitat war – two species fighting for the same habitat, but in that case, it was eelgrass overrunning and ruining quahogs setting beds.[1]  In this case it was a long general decline between blue crabs and increase of lobsters.  And when you look at regional data, Narragansett Bay experienced the same decline. Regionally lobster catches were improving 1930-1960 while blue crab catches were failing, especially in the Buzzard’s Bay area of Massachusetts.

Blue Claw Crabs- The Westport River (Massachusetts) Report

The Westport River is one of the few areas on the south shore of Massachusetts where blue claw crabs (Callinectes sapidus) still occur in numbers sufficient to support a family fishery. The blue claw crab is a species which was formerly abundant on the south shore of Massachusetts but has been declining in numbers for at least the last decade. Such decline has also been observed in waters south of Massachusetts. Jeffries (1966) noted that the blue crab began to decline in Rhode Island in the mid-1930's and that by 1938 they had diminished to the point that it was no longer profitable to fish for them commercially.

The cause of the decline of this crab in our waters is unknown. Practically no investigative work has been conducted relative to the blue crab and its ecology in Massachusetts. Such work should be initiated in an attempt to determine the cause of the decline of this resource and management practices needed to restore it to its former abundance.

That is why the Massachusetts-based (Blue Crab Forum) response May 30, 2013 from Masspi was pure gold to me; he had also seen similar habitat changes in Buzzards Bay; his comments were especially appreciated and helpful (Special Report #2, May 30, 2013).


Climate and Energy and Habitat Quality

So what does all of this mean for the spring blue crab 2014 season? At least one thing is for certain: we should know early (by April 15) if the Fall Megalops survived, they should be about an inch and noticeable on shellfish beds. Early December reports mentioned adult blue crabs still feeding in deep holes in eastern CT Rivers, but the North Atlantic Oscillation still remains negative with a slight storm track to the east. The deep horseshoe storm track so dominant last winter is shallower but still providing polar air to rush south and warmer air with moisture shifting to the northeast increasing snow packs.

In terms of environmental history, the period from 2004 to 2014 resembles the 1931 to 1939 period. Colder winters and increased storm intensity, bay scallops have started to return (again to the north) and winter flounder recruitment showing some signs of recovery. 1931-1939 saw also the end of huge offshore eelgrass meadows and the emergence of a kelp/cobblestone habitat in more open waters.  Eelgrass habitats seem to be a key habitat indicator for climate reversals, and part of a long term pattern governed by heat and low energy periods. It is during these same periods (high heat, low energy) that blue crabs also do so well, but bay scallops and lobsters do not.

In the 1950s, when cold and powerful storms eliminated much of the eelgrass populations, New England’s kelp/cobblestone habitat increased and bay scallop landings soared.  If kelp/cobblestone habitat significantly improves, that would indicate a species reversal within a decade, a possible return of the colder preferring lobster, not the blue crab.  Kelp/cobblestone habitat in Southern New England is critical to lobster recruitment when it declined in the 1980s, it predicted a lobster habitat quality decline, and the increase in Sapropel in the 1980s predicted the increase in blue crab habitat quality.  We just didn’t realize it at the time not having the benefits of “habitat histories.”

We have excellent records for the oyster industry with important temperature observations that can assist in this effort.  The change in temperature and energy levels was not instantaneous – rather slowly as climate conditions changed and impacts to shellfish species were reflected years later.  After many years of no oyster sets, by 1941 New England oyster farmers were already starting to look very carefully at water temperatures.  Gordon Sweet of New Haven, Connecticut who wrote extensively about the need to conserve oyster sets was beginning to have second thoughts.  In his October 1941 paper titled “Oyster Conservation in Connecticut” Mr. Sweet introduced a new concept for explaining the dramatic oyster harvest declines as now  climatic factors.  On page 591 (Geographical Review Vol. 31 #3, Oct. 1941) is found this footnote with mentions about “habitat” and “a new balance.”

“The colder the waters, the less prolific the oysters and the more difficult their survival.  The progressive contraction south of the northern limit of habitat was apparently due to human exploitation plus marginal environment.  Another hypothesis would be our coastal waters are colder than they were 300 years ago but the writer has no data to support this suggestion.  Recent investigations under taken by the State of Maine indicate that the rehabilitation (restoration) of their oyster beds is not feasible owing principally to low water temperatures which practically inhibit the spawning of Ostrea (crassostrea) virginica.  This contraction has proceeded south to Long Island Sound were a new balance has been established.”

 It was going to get worse: “the new normal” (a new balance) a term used often today was to continue to constrict oyster habitat quality back to warmer coves and rivers.  Victor Loosanoff would in the 1960s record multiple years of set failures between 1940 and 1965 – sets often did occur but in October and November and did not survive the winter as they came too late (George McNeil, personal communications 1980s).

In Dr. Loosanoff’s 1966 paper “Time and Intensity of Setting of the Oyster, Crassostrea virginica.  In Long Island Sound (Biological Bulletin Vol. 130 #2 pages 211-227, April 1966 US Bureau of Commercial Fisheries Biological Laboratory Milford, CT (now NOAA NMFS) he mentioned that in the 1940s, 1950s and 1960s, cooler waters had pushed 10 year set dates, from July (considered “normal”) into much later August and even September.  In the late 1960s sets of October (1956) were recorded which arrived too late to survive.  Oyster sets did occur it was just they occurred late because of cold springs and cooler spring waters.  In his summary he concluded that “during the 25 year period 1937-61 has shown that the larvae of advanced stages were never extremely common.”  This was in stark contrast to the 1880 to 1920 period--oyster sets came “early” and were often intense.

In fact, the Connecticut Oyster Industry grew quickly first in the 1850s by first importing millions of bushels Chesapeake Bay seed oysters from southern – warmer waters.  Significant offshore of recruitment was almost unknown here in outer Long Island Sound – at that time oysters could grow here but oyster growers still need “southern plants.”  Henry C. Rowe in his paper titled “The Oyster Industry of Connecticut” (History of Connecticut, N. G. Osborn, Editor, Vol. 4, The State’s History Company, New York, 156 Fifth Avenue, 1925) mentions extraordinary industry growth between 1880-1890 at the beginning of The Great Heat, a period of tremendous warmth and few storms 1880-1920.  The largest Connecticut oyster set in this period would occur in 1899 the year of extreme high heat and the year southern New England lobsters died.

It was as Mr. Rowe during this early warming period who was the first to commit resources to shell planting in deeper waters much too risky during the turbulent 1870s.  He would soon become the largest Connecticut oyster grower.  His business would also suffer the largest declines in the colder 1930s.  After 1954 (the same year of a large quahog sets on Cape Cod) oyster sets failed or came too late to survive.  That also occurred on the Cape Cod, a Survey Report, Pleasant Bay, Dept. of the Army Corps of Engineers, November 1968 – has this section on page 18.

“In early May 1966 The Chatham, Massachusetts shellfish officer planted seed oysters in Crows Pond.  Local interests desire to revive the oyster industry in the bay and are concerned with the future water temperature of the bay.” 

And what were most damaging to an oyster grower were three bad sets in a row that would drive down blue crab harvests as well.  One cold year and late Megalops would lessen catches but not eliminate them.  Three cold years in a row would sharply reduce blue crabs – as they present in four sizes; four cold years in a row would be devastating as these winters also contained strong storms.  Late blue crab sets wouldn’t be large enough to survive the long winter; we just need to look at catch landings and a weather feature called a North Atlantic Oscillation to see how oysters and blue crabs respond to this fluctuation.

Oysters and blue crabs over time appear to share similar habitat/landing trends.  When oyster populations were high, so were blue crabs and later they both declined together.  John Hammond, the oyster grower from Chatham with whom I would meet many years later, attended a public hearing held August 27, 1964 regarding the Pleasant Bay Army Corps report for dredging a new inlet; he supported the project but cautioned “on the adverse effects of cold water entering through (the) inlet on shellfish.”

By 1964 the huge blue crab populations were memories on Cape Cod but still questioned in the State Marine Fisheries Pleasant Bay report written in 1967.

Fishers in Narragansett Bay also noticed the decline, as the number of Northeast storms increased and gale duration lengthened; two notable gales April 20-22, 1940 (Logan Airport) and November 28-30, 1940 (Logan Airport) winds were at gale force for 31 hours, the second storm totaling 53 hours (Pleasant Bay Report 1968).  These winters gales were devastating to blue crabs.  Adult blue crabs dislodged from hibernation were often cast up on Southern New England shores and quickly consumed by seagulls.  The decline of blue crabs coincided with the decline in oysters.  From the millions of bushels of oysters from Narragansett Bay cultured during The Great Heat only would yield only 3,000 bushels in 1959 in the middle of the last North Atlantic Oscillation.

Fishery managers across Massachusetts also noticed the regional decline in blue crabs.  In a 1968 study of Waquoit Bay eel pond Massachusetts Division of Marine Fisheries) is found this (pg 32) section “The Blue 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.  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 the species in Massachusetts in unknown.”

What wasn’t known was the climatic feature of the NAO – a negative NAO represents that horseshoe shaped storm track so prevalent the last two winters.  A weak or negative NAO allows the sub polar jet to dip way south cooling inshore waters on the Eastern Seaboard.  A cool spring (often cold) results and summers may often be hot but warm waters peak too late for oysters and blue crabs.  That is why over catch landings history in our area blue crab abundance also occurs during a high period of oyster abundance. 

But the Northeast Atlantic Oscillation would prove disastrous for the oyster industry as the Icelandic low became less defined and weak (a negative phase) colder air dipped far to the south in Florida in a classic horseshoe shaped pattern and allowed cold polar air to dip well into the middle states.  This pushed warm and moist air to the Northeast, and low pressure systems riding north along this horseshoe shaped storm track became the dreaded Nor’easters, when an oscillation of the low allowed the storm track to move east providing increased snowfall and northeast gales; a movement to the west produced the Hudson Valley lows with strong southwest gates.  It was the snow melt from these heavy snowfalls that was to provide cooler Long Island Sound waters and therefore delayed oyster sets and now apparently blue crabs Megalops sets.

We have the oyster set data from the Fish and Wildlife Service and can compare it to the NOAA National Weather Service Climate Prediction Center NAO conditions from the 1950s to the present.  While Victor Loosanoff was recording poor to complete oyster set failures the NAO was exhibiting a strong negative phase.  Spring waters were cooler and delayed oyster setting or provided late weak “waves.”  Although spring temperatures did warm quickly some springs in the 1950s and 1960s, but that only increased to cool water as melted snow and ice water further north drained and actually cooled Long Island Sound waters.  As oyster sets declined so did the blue crabs.  But to really drive down blue crabs’ populations one snow filled winter would not do it, it would take three in a row – a late Megalops set would not survive cold and storm filled winters – they could occur it would be just too late to provide recruitment of 1” to 2” and possible 3 to 4 inch sizes.  After three to four years fishers run out of legal size crabs as blue crab abundance would then suddenly collapse – giving rise to the situation “some great years and then none” which I experienced myself growing up in Madison, CT blue crabbing in the 1960s.

During this time Southern New England Fishery managers (and fishers for that matter) noticed the decline of oysters and blue crabs.  The NAO was negative and turned positive in 1971.  In 1972 after 20 years of poor or little oyster sets here we got a good one, the NAO in 1971 had suddenly turned positive and would turn sharply positive in 1980.  Now that we have good climate history records we can look back and look at the decline of oysters and blue crabs during this period and examine any patterns but I don’t need to do this NOAA has already identified this period.  A positive NAO – favored oysters and blue crabs a negative NAO did not.  We can obtain the climate history from the NOAA Climate Prediction Center itself.

“The winter time NAO* also exhibits significant multi decade variability (Harrell 1955, Chelliah and Bell 2005).  For example, the negative phase of the NOA dominated the circulation form the mid 1950s through the 1978-79 winters.  During this 24 year interval, there were four prominent periods of at least three years in which the negative phase was dominant and the positive phase was notably absent.  In fact, during the entire period the positive phase was observed in the seasonal mean only three times, and it never appeared in two consecutive years.” 

This aspect would tend to restrict Megalops sets and devastated the oyster sets – that is the habitat history.  And what did the NAO negative summers look like?  They were often accompanied by the most powerful hurricanes following the same basic horseshoe shape storm track.  In 1954 between August 30 and September 12 two powerful hurricanes hit Connecticut, Carol and Edna, making September 1954 one of the toughest “shoreline months” in decades.  The NAO in August 1954 was record breaking negative 2.57 1955 another bad hurricane season was only slightly – less negative.  In 2010 the NAO turned sharply negative.  For those who recall last March (see special Report #1 March 26) the NAO was a negative 2.09 as last year’s Megalops set did came “much later.” (Special Report #6, October 24, 2013).

One of the problems of determining habitat quality and fisheries abundance in terms of climate changes has been the exclusion of historical fisheries data in helping determine cycles or patterns.  Although the NAO has been known for decades it is rarely mentioned as a significant existing climate change event or weather pattern affecting the State of Connecticut.  From historical fisheries research the NAO should have been not only included but highlighted.  Does habitat/finfish surveys indicate the impact of the 1950s/1960s cold water NAO – they most certainly do.  In one of the longest benthic surveys in Connecticut – is of New Haven Harbor.  Cooler water temperatures favored an increase in lobsters even in the summer months perplexing the study authors (1981).  In 2005, Paula Daddio, an Aquaculture Science teacher here at The Sound School loaned me her copy of a 1981 – New Haven Ecological Studies – prepared for the United Illuminating Company by Normandeau Associates.  It contains life histories of winter flounder and lobsters recorded abundance from habitat quality conditions immediately often the last negative NAO – 1974-75.  As such it provides a unique (and perhaps unparalleled) opportunity to examine relative abundance for lobsters and blue crabs reversing in New Haven Harbor.  It has been a tremendous resource in reviewing the 1998 die off of lobsters and resurgence in blue crabs.  Under the negative NAO habitat quality declined for blue crabs and increased for lobsters - this long term study supports that conclusion and mentions the rise of lobsters on pg 69, as habitat quality improved in the 1970s and 1980s so did the relative abundance of lobsters in New Haven Harbor, from page 1969.

“Lobsters (Homarus americanus) have shown a notable increase in catch abundance during recent years (Table 4.6-4).  From 1974 through 1977 catches ranged from 80 to 150 individuals per year, while in 1978-1980 catches ranged from 225 to 525 individuals per year.  Increased numbers were reflected in an increased rank of abundance during the later period (i.e., from 8th to 13th during 1974-1977, to 5th during 1978-1980) (Table 4.6-3).  In addition to higher catch abundances, lobsters were occasionally abundant during mid-summer; the period in previous years when densities typically declined.  Summary Report Supplement 1977-1980, prepared for The United Illuminating Company, New Haven, Connecticut, New Haven Harbor Ecological Studies 1981, NAI Normandeau Associates, Inc.”      

Blue crabs were so scarce then they were too few to count or include as prevalent, not even making the top 30. 

In 2010, I estimated New Haven Harbor held millions of blue crabs and lobsters had become “rare.”  A species reversal of enormous significance when compared to climate and energy change we now know as the “NAO.” 
But who are the first ones to see these habitat changes – fishers- that is why habitat observations are so important. The US Weather Service was one of the first federal agencies to recognize the importance of numerous observations in order to make weather predictions – Can we make similar habitat predictions?  Yes, I believe we have all the habitat indicators necessary to do that over time.
So I want to thank all the crabbers that reported them last year. Much thanks also to the International Blue Crab Blog™ for posting Megalops newsletters; The Blue Crab Forum™ continues to archive all reports and that has been extremely helpful in rechecking observations/reports. Connecticut Fish Talk™ continues to post the Megalops and IMEP Habitat Newsletters as well.
I was also pleased with the three  Sound School student reports this past year and look for more this coming season. Thanks for your continued interest and support.
Looking forward to the 2014 blue crab year.
Tim Visel

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.

[1] Anyone interested in environmental fisheries history with reference to habitat quality for finfish and shellfish species, this study is a must read. Thank you Town of Chatham for making the Pleasant Bay Report available: The State of Massachusetts commissioned a series of monographs regarding Marine Resources of the state which include over 20 such reports. They are very valuable to documenting habitat histories.
* The first identification of this climate feature can be traced to Nathaniel Bowditch 1802 - American Practical Navigator that detailed a strong Icelandic low tended to pull polar air towards it with low pressure storms, he termed it “the graveyard of Atlantic Storms.”