Friday, May 31, 2013

Connecticut Blue Crab 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

Special Program Report #2

May 30, 2013

The 2013 Blue Crab Year



  • Blue Crabs as a Climate Change Indicator – The Blue Crab Question
  • Questions about Blue Crabs and Habitat Change
  • The Great Heat Destroys the Southern New England Lobster Fishery as Blue Crabs surge North into Buzzards Bay a Century Ago
  • Buzzards Bay- Coastal Features Made Warmer Temperatures Ideal for Habitat Changes for The Blue Crab
  • Our Fisheries and Climate Changes
  • What about the North Atlantic Oscillation?

Blue Crabs as a Climate Change Indicator - The Blue Crab Question


Much thanks to Norwalk’s Maritime Aquarium in Norwalk’s blog  and later News 8 WX Edge

 Extreme Weather blog for referencing blue crab climate associations (The Search for Megalops, Special Report #1 2013) and the recent increase of blue crabs in Connecticut.  Although I feel the blue crab is the primary specie indicator of warm waters here I want to include lobsters as perhaps also the best indicator of colder temperatures. 


After the blog site references several requests for more information about blue crabs and with the recent winter colder and longer, several good climate change questions also came in.  Do I feel that the blue crab increased prevalence indicates much warmer water temperatures and enhanced habitat conditions – I most certainly do, but is the recent resurgence in blue crabs unique now to Connecticut or Southern New England in general? No it is not.  This reversal between lobsters and blue crabs has happened before and not that long ago in New England’s fisheries history.  Some coastal core evidence and samples indicates this reversal between habitats that favor blue crabs and those for lobsters has happened several times before.  This identifies the habitat questions that surround climate and weather patterns of New England’s environmental changes and not so long ago fisheries history. 


Many thanks to the Blue Crab Forum  and the Blue Crab Blog site of Dr. Matt Ogburn  for cataloging Sound School Megalops reports back to the first program report in 2010.  That has made answering questions so much easier.  I appreciate those instant libraries and the ability to review past reports helps answer these recent questions.


Several of the comments I have received indicate Megalops reports have been used as reference materials in several new studies and historical information applied to other species as well.  The Massachusetts Office of Coastal Zone Management deserves special thanks as it has made available the complete Massachusetts fishery bulletin set that have yielded important information regarding blue crab fisheries from the 1950s and 1960s.  Anyone researching New England fisheries historical inshore fisheries will find them to be key reference material.


I hope that this second special 2013 report at the start of 2013 blue crab season will be of interest to both blue crabbers and to those conducting blue crab research.


See you at the docks.

Tim Visel 



Questions about Blue Crabs and Habitat Change


Much has been written about climate change and fisheries but very little about site specific habitat trends.  I focus upon the last century for blue crabs from three distinct periods New England’s Great Heat, 1880-1920, of brutal heat, the period known for harsher winters and numerous storms 1945 to 1965 and the new warm up 1974 to 2004.  The choice of blue crabs as an indicator species allows me to also look north and south into neighboring states observations and landings, especially reports from fishers.  I find that Rhode Island and Southern Massachusetts (Buzzards Bay region) experienced much of the same decline in lobsters and amazing return of blue crabs during the great heat.  The 1940s and 1950s saw winters colder and storm filled, lobsters and bay scallops thrived during those times.  When the New England’s climate moderated after the mini ice age 1870s lobsters and blue crabs reversed in abundance.  The patterns of these changes are consistent with also temperature and energy cycles.


The best sources of information for this 1880 to 1920 period are numerous United States Fish Commission reports commonly referred to as the George Goode Series - Bulletins with major selections produced from 1887 to 1902.[1]


These bulletins provide an early glimpse of the transition in habitat quality from the incredible colder 1870s – a time of immense coastal storms that plagued navigation and shipping and frightening cold temperatures which often dropped to 20 degrees below zero for days at a time.  The 1870s had several fisheries reversals, who could have expected Greenwich, Connecticut to become a center for bay scallop harvests, only to be replaced with warmer temperatures for the center for deadly malaria outbreaks.  Noank, Connecticut became famous for its lobster fisheries only to see its lobster fishery fade and see blue crabbing surge but Connecticut fishers were not alone in experiencing these species reversals.  Thanks to Jeff Granoff and Jeanette Marcucci, former educators at The Sound School who came across a series of 1870s reports of the State of Connecticut Board of Agriculture and provided them to assist with my historical climate and fisheries research.  They have proved to be invaluable and provide a critical view of Connecticut farms and farmers who also experienced this mini ice age period and recorded and the enormous toll it was taking upon terrestrial crops and especially fruit trees at that time.



While bay scallopers were loading skiffs to the sinking point off Greenwich Connecticut farmers lost most of their apple orchards.  Just how cold was it in the 1870s, Philo S. Beers then of Cheshire wrote his last article on fruit culture (passed away in January 1875) for the Agriculture Board, 8th Annual Report 1874-75.  On page 326 commenting on the dangers of hollow (Valley) apple orchards as compared to hill top orchards which largely survived this brutal cold.  This is a portion of Mr. Beers last report.


“The winter of 1873-73 was the coldest on record and the mercury sank to a lower point, according to the records kept in New Haven, than for the last one hundred years.  The mercury at my house (Cheshire) indicated, on the coldest morning, 22 degrees below zero… The north and south parts of this town (Cheshire) in the valleys the mercury sank to 36º below 0 at this time, and it was in these places that some whole orchards were killed; others on little higher ground suffered less.  I have visited many parts of this state, in the meantime, and find in all the valleys more or less loss, according to the depression of those valleys but little loss has been sustained on high ground in any portion of the state.” 


This report was not lost upon the farming community who then planted new apple trees on high ground and hilltops became common locations for them.  Fishers also were amazed by the production of bay scallops and lobsters the cold it seemed was hurting agriculture but was helping these fisheries reach new higher “landings” in New England.


That would all change in the Great Heat, which saw lobster and bay scallops landings plummet as blue crab catches and oyster sets now surged.


The Great Heat Destroys the Southern New England Lobster Fishery as Blue Crabs Surge North Into Buzzards Bay

Rhode Island officials were so concerned with the dramatic lobster reversal, reflected by collapsing landings, and the near complete die off of small lobsters (1898-1905) it became one of the first states to build a lobster hatchery (1903). At first, lobster fishers were blamed for the decline, lobster canneries also but fishers provided testimony that even the smallest of lobsters were gone, far below legal size and fishery managers finally agreed[2] Further research soon directed new England’s lobster hatcheries to focus upon Stage four – lobsters in a kelp/cobble stone habitat weak link here in Southern New England.


And while Massachusetts, Rhode Island and Connecticut and even Maine rushed to build lobster hatcheries (the one in Noank, Connecticut just passed its century mark in Aquaculture study, it continues today not as a state lobster hatchery but as a regional shellfish cooperative and shellfish hatchery) Southern New England all witnessed at times beyond explanation a dramatic rise in blue crabs.


The truth of the matter was that habitat conditions for blue crabs, deep accumulations of organic muck (Sapropel) and dense eelgrass meadows was ideal for blue crabs, the same climate conditions were killing off the lobsters.


In 1904 the State of Rhode Island commissioned a huge study about progress at the new Wickford, Rhode Island lobster hatchery (including some rare upweller aquaculture design plans) praising the work of the lobster scientists but noting the increase of crabs[3] Rhode Island by 1905 had seen its number of barrels of crabs shipped rise 100 fold. On pages 16-17 of the report contains this quote.


“The gradual development of the crab industry is also noticeable [1902 first landings which had surged in 1905]. The market for crabs is becoming better every year. Your commission believes that as the lobster experiments are now on a firm foundation, attention should be paid to the crab question which in the future will determine to become more and more important.”


The “question” about crabs was never fully explained but did follow a general discussion about landings as it seems menhaden were down also, but for the first time in several years “bluefish were taken in the upper waters of the Bay.”  It was just too soon for fishers and fishery managers for them to realize the habitat reversal that was occurring: the deep water tolerant bay scallop habitats of red microalgae in Narragansett Bay had already been displaced by expanding dense eelgrass meadows.  The productive deep water bay scallop habitats were ending.


Oysters, which during the colder 1870s retreated back to the shallow coves and rivers now set widely in the upper bay and planted oysters on firm bottoms grew quickly in the now warm and algae filled waters. The 1906 Rhode Island report went on to the report upon the Narragansett Bay Scallop fishery which for the time was rather bluntly stated on page 18: “There were no scallops in the bay.”  Bay scallops would return to Narragansett Bay only after the severe cold and shocking winters of 1921-1922 at this time The Great Heat or “hot term” was ending and New England would soon feel the full chill of the North Atlantic Oscillation still some three decades later.



Buzzards Bay – Coastal Features Made Warmer Temperatures

Ideal for Habitat Changes


The blue crab question was also being asked in northern Massachusetts – the shape and configuration of Buzzards Bay tended to collect and trap larval stages. The prevailing winds tended to concentrate larvae into the uppermost estuaries and Wareham appears to be the focal point. The increase of blue crabs from New Bedford north to Cape Cod (1905 to 1920) especially in the Buzzards Bay district (US Fish Commission Report the Crab Fisheries 1887) happened from the Acushnet River to Wareham which soon became important blue crab producing area at times producing some 40,000 blue crabs each week  (page 635). This was far different as compared to the much colder 1870s when blue crabs were scarce and did not reach commercial (catch) report or landings; it was just too cold.  That was all going to change during The Great Heat 1880-1920.  And, the climate change would soon impact fish and fishers alike. To escape the increasingly brutal and now deadly New England heat waves, summer communities were quickly established along Connecticut’s coast and those also north of Connecticut.


In one of the most chronicled histories is the establishment of the Groton Long Point shore community (1900-1915), much of the first sites was just quickly established tent platforms. The brutal summer heat also created summer communities along New England lakes and seashores. As some of the cold water fisheries failed and another enterprise replaced it- the summer trades. An entire new industry sprang up in coastal communities during The Great Heat for those seeking the cooler ocean water and shore breezes.



Our Fisheries and Climate Change


Most people when they have the term “climate change” think of more recent discussion of global warming and the negative impacts of pollution. But to fishers of the last century climate change was something else- long term changes in response to cooler and warmer temperatures. Unknown to us was the impact of coastal energy storms; fishers themselves were often surprised at coastal resource abundance, bay scallops and winter flounder surged after the stormiest and most bitter winters. During The Great Heat, winter flounder and bay scallop fisheries declined, only it seemed to be replaced by oysters and blue crabs. The length of time was too long, not years but generations, the colder and energy prevalent 1950s and 1960s followed The Great Heat and those memories lingered.  An excerpt from one of the Massachusetts Marine Fishery Bulletins which the mentions the former abundance of blue crabs in Westport, then at low levels but instead enjoying good catches of bay scallops? Fishery managers did not yet fully grasp the habitat quality implications of climate and energy, but farmers and fishers kept journals. Some of the first connections to habitat quality come from them. Fishers had long discovered habitat indicators such as eelgrass for capturing eels or winter flounder over shellfish beds in rivers. These were important habitats and fishers sought them out first to fish.


During The Great Heat 1880-1920 and the North Atlantic Oscillation 1945-1965, Southern New England experienced the second habitat reversal in a century and for inshore fish and shellfish species another reversal in abundance.


What About The North Atlantic Oscillation


The North Atlantic Oscillation has been identified for over a century. Nathaniel Bowditch mentioned it, as a grave yard of West Atlantic Ocean storms, as many of the storms coming up the east US coast seemed to be heading to Iceland. We know this today as a semi-permanent low off the west coast of Iceland, called the Icelandic low. Trapped between colder polar air and warmer ocean currents it forms a constant low pressure area that moves and periodically strengthens and weakens. The strength and position of the Icelandic low does influence our weather and climate patterns, it modifies Continental air masses and changes storm track patterns. When it is strong the Icelandic low tends to draw cold air across Canada and gives us a west to east storm track, the Alberta “Clippers” – fast, moving moisture starved lows, across Canada. When the Icelandic low is weak and ill defined, it allows cold polar air to sink far to the south into Florida-- bulging the jet stream to produce a horseshoe shaped storm pattern. Some of the most memorable blizzards have occurred during weak Icelandic low periods, 1880-1978 and numerous Northeasters fed by Gulf moisture which produced heavy New England snowfalls.


In addition to increased southern jet moisture weak Icelandic lows help energize the storms created by cold air rushing south colliding with warm air now pushed north into New England. A negative (weak Icelandic low) North Atlantic Oscillation increases the strength and frequency of storms along the eastern seaboard.


The fisheries habitat changes during these cycles are extraordinary.  Since 2007 the oscillation has turned negative[4] and few would argue that storm frequency intensifies here has now increased.  From 1950 to 1966, with a negative NAO, saw the decline of blue crabs in Southern New England, winters then were typified by cold air outbreaks.  The blue crab population dwindled from The Great Heat levels prompting the same Blue Crab “questions” often asked today with surprisingly the same explanations for the decline.


This is a section from the Fishery Bulletin for the Westport River, an area during The Great Heat that had large blue crab populations, it is very eerily the same explanations are often used today, but looking back it just got colder again. The report is from the 1970s the end of strong negative NAOs.


A Study of the Marine Resources of the Westport River is the seventh in a series of monographs initiated by the Division of Marine Fisheries in 1963.  These reports relate the extent and value of the marine resources of the major bays and estuaries in Massachusetts.  (Page 32).  (Courtesy Massachusetts Office of Coastal Zone Management).

“The blue claw crab is a species which were formerly abundant in the south shore of Massachusetts but has been declining in numbers for a t 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.  Many fishermen along the shore have expressed the belief that the loss of blue claw crabs- also fiddler crabs (UCA. spp.) is due to the careless use of pesticides in coastal areas.  While it is certainly possible that pesticides have had a detrimental effect upon crab populations no conclusive evidence has been documented in this regards.” (Page 39).


And what about Narragansett Bay and the surprising surge in Blue Crabs during The Great Heat (1880-1920), Jeffries 1966 – Chesapeake Science Vol 7 #3 fall 1966 indicates that the Rhode Island Commissioners of Inland Fisheries (1900-1914) did mention this blue crab fishery.  “Several bushels could be caught in a single morning with a baited line and dip net” (page 164) but by the 1930s as temperatures fell an energy levels increased (especially after 1938 when most of eelgrass and the Sapropel was most likely washed from coves) the commercial blue crab fishery failed.  By 1959 blue crabs were almost nonexistent and Jeffries mentions a 2 year trapping program for lobsters at the mouth of the Bay (Narragansett) which yielded only one blue crab.  In 1958 New England was experiencing a negative North Atlantic Oscillation.


It seems the question about blue crabs has been one that New Englanders have asked for a long time – centuries in fact.


The study of the North Atlantic Oscillation is critical to fully understanding our changes in fin and shellfisheries.  The state climate office of North Carolina (email: has an excellent bulletin on global patterns and the Arctic and North Atlantic Oscillation (AO and NAO) fishers, boaters and people living along the New England shore will find this information of interest. It is a great resource, readable and has clear diagrams. It is worth a look in my view. 



All reports of surviving Blue Crabs are significant, but it’s still very early to predict the entire 2013 season.  Just a few days ago Upper New York State had snow, warmer weather would help!




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] United States Commission of Fish and Fisheries, Spencer F. Board Commissioner.  The Fisheries and Fishery Industries of the United States Superintendent of the tenth census {this is the precursor of the “fish census” concept} George Brown Goode – Assistant Secretary of the Smithsonian Institution and staff of Associates Section V History and methods of the Fisheries Volume II, Washington, DC – GPO – 1887.
[2] See Connecticut Fish and Game Reports 1905 to 1920. They are being digitalized and Internet protocols by the University of California. Dozens of reports from CT lobster fishers describe the near total absence of small lobsters, describing the indications of a massive high heat habitat failure.
[3] State of Rhode Island and Providence Plantations thirty-sixth annual Report of the Commissioners of Inland Fisheries made to the General Assembly at its January Session 1906 Providence RI, E.L. Freeman and Sons, State Printers 1906.         
[4] Information regarding the North Atlantic Oscillation can be obtained from the NOAA National Weather Service Climate Prediction Center, which plots the NAO at three month intervals In 2010, the NAO was a negative 3, not seen since 1960.

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