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 http://linux.maritimeaquarium.org/blog/  and later News 8 WX Edge http://wxedge.com/articles/20130510monitoring_the_ups_downs_of_blue_crabs

 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 http://www.bluecrab.info/forum/index.php  and the Blue Crab Blog site of Dr. Matt Ogburn http://bluecrabblog.blogspot.com/  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 36ยบ 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: S10@climate.ncsu.edu) 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!

 

Tim

 

Email your blue crab reports to: tim.visel@new-haven.k12.ct.us

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 susan.weber@new-haven.k12.ct.us

 

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.

Thursday, May 16, 2013

Maryland Female Crab Harvest to be Reduced 20-40%

Maryland Department of Natural Resources has is reducing the female crab harvest by 20-40% effective today in an attempt to increase reproduction. This move is in response to the low crab population estimate from the 2013 Baywide Winter Dredge Survey (see survey results here). Read more about the proposed harvest changes in Maryland and Virginia at the Baltimore Sun.

The proposed harvest restrictions are somewhat counter-intuitive due to the significant increase in female abundance this year over 2012 Winter Dredge Survey estimates. It is not terribly surprising that juvenile abundance was low this year given the small number of females recorded in 2012. What would have happened if females had been given more protection in 2012 when their numbers were very low? Could the 2013 juvenile year-class have been bigger if the proposed protections for females had been enacted last year?

2013 Connecticut Blue Crab Report #2

From Tim Visel of 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 Program Report #2 Blue Crab Year

  • Southern crabbers receive poor survey news
  • Climate patterns continues for another 60 days
  • Watch for Megalops “waves”
  • Energy events transition habitats
  • It’s not over, three opportunities for rebuilding stocks
  • A blue crab report from the field
  • Blue claw crabs in Barnegat Bay, New Jersey
 

May 15, 2013

Southern crabbers receive poor survey news –

Two days after the first program report for Connecticut Blue Crabbers Chesapeake Bay crabbers also received grim news.  On April 19th Virginia and Maryland released the results of a Chesapeake Bay wide winter dredge Blue Crab survey – both showed huge drops in the number of estimated sub legal blue crabs.  The winter dredge survey looks at the number of adult hibernating crabs and the number of young crabs estimated to shed into the fishery (Legal size) within 6 months.  It can also provide an estimate of the numbering over wintering female blue crabs that could potentially spawn.  The winter dredge survey is conducted by both states and combined in the late 1980s as a cooperative study.

The 2010 and 2012 Chesapeake Bay blue crab years were very high (similar to CT reports) but took a dip in 2011 – also similar to Connecticut catches but the results in 2013 look grim, back to 2006 levels.  The winter dredge survey reported that much of the small year one crabs (2 inches) suffered a loss of nearly a half billion crabs.  That year class seems to have taken a large hit, perhaps signifying a habitat “event.” 

The 2013 Chesapeake Blue Crab fisheries may face catch limits, but it is far too early to predict the full impact of the survey but early indications do not support higher than average catches.  One of the factors acknowledged in the report is a growing awareness of the predator/prey relationship of red drum.
Number of Over Wintering Female Blue Crabs Holds Hope

The only glimmer of good news from the Chesapeake survey was an increase in the number of over wintering female blue crabs that recorded an increase of 95 million to 147 million (Marine Resources Commission Commonwealth of Virginia Press Release, April 19, 2013).  That stock has the potential to provide an immense Megalops capacity and this section is a quote from the release.

 

“Adult females are the cornerstones of the joint Virginia-Maryland stock rebuilding program that began in 2008, when a fisheries management framework was established to conserve adult females because they can spawn an average of three million new crabs each brood and release about three broods per year.”

 

Enhancing the population of female crabs was enacted with a prohibition of Virginia’s winter dredge fishery in 2008.  Many reports mention that the Chesapeake Blue Crab season is off to a slow start, but warmer temperatures could change that.

Climate Pattern Continues for Another 60 Days


Latest information for New England shows cold air will remain in place over central Canada influencing our weather for at least another two months.  New England can expect cooler temperatures and drier conditions, then turning sharply warmer.  The horseshoe storm pattern typical in North Atlantic Oscillation periods shows no sign of moving signaling a coastal low storm track that should make us in Connecticut uneasy – it’s this horseshoe shaped storm track that historically ushered in powerful coastal storms and Northeasters up the New England seaboard.  Colder air this spring could bring devastating results to already a less than certain Connecticut blue crab season.  Without a quick sharp rise in water temperatures we may face losses similar to those reported for the Chesapeake.  Many crabbers feel in fact, we may have already lost the over wintering adults.  As of May 3rd no reports of blue crabs have come, most of the same time as last year had one or two reports every week.  It’s still early yet for a complete prediction but the next few weeks are critical.

Watch for Megalops “Waves”

One of the features of blue crabs larvae mentioned in earlier reports is it ability when faced with colder temperatures to suspend post Megalops development – some accounts claim for up to four months.  So some of the last reproductive Connecticut larvae crabs may have survived the winter and we should see those “star” crabs on or before June 15th.  A second wave of Megalops from a 2013 reproductive cycle should appear July 30th to August 15th.  This is of course depends upon habitat quality, and the Hurricane Sandy.

The impact of bottom disturbance is thought to be significant upon hibernating adult crabs, seeking muck bottoms adults often will find eelgrass in soft bottoms and borrow in and wait the cold temperatures living on stored fat reserves from the summer.  A strong storm can rip up the soft bottom and eelgrass exposing the crabs to a whole host of predator species, conch, and starfish but perhaps the most aggressive is the Blackfish (Tautog) which will punch the crabs back with its teeth breaking its shell.  A Guilford fisher from the 1960s used to trawl near Kimberly Reef Long Island Sound for winter flounder who described it once to me as Connecticut’s Blue Crab graveyard – an area between Faulkner’s Island and Kimberly Reef where blue crabs would try to find soft protected bottom for the winter – only to be pulled out of the mud by Northeasters providing a feast for conch and starfish (Mr. Walston personal communication).  Catches of winter flounder by trawl nets would yield two the three bushel of large blue crabs until February or March after that Mr. Walston claimed “they were all dead.”  Some people living in the Guilford area may recall this older eastern rig trawler with trawl nets by the Guilford Sluice dock in the 1960s.  Although the adults would benefit from a mild and calm winter severe cold and storms were devastating to the adults as recorded in the areas north of Connecticut.  For the smallest reproductive life stage in shallow water – with bivalve shell litter and vegetation it might be different.  It is possible for the reproductive size to survive this energy appearing as a wave of Megalops from the hibernating Zoea stage.  This would occur as a wave of Megalops in the spring as a “carryover” from the previous summer productive cycle.  To make it they would need to be in shallow protected areas such as salt ponds.

Where to look for the first Megalops this year could be in some of the salt ponds in the Bridgeport/Fairfield region which have reported incredible Megalops sets in 2009 and 2010.  A big question here and its asked frequently is the impact of not only cold temperatures but also of bottom disturbance – upon the very small Megalops.  The truth of the matter is we just don’t know – we have two indicators to consider temperature and energy so it will be difficult to be certain about each.

Energy Events Transition Habitats


The energy pathway of storms and of course Sandy now is the largest question.  The energy of Sandy for sub-tidal marine habitats is similar to the habitat changing impacts of terrestrial forest fires.  Only in this case it is rare to have a series of devastating forest fires on the same land – there is just not enough fuel to support them but in the marine environment that is not the case – energy events happen in cycles and history tell us that a series of hurricanes in the same or similar geographic region can in fact happen – in fact the 1950 hurricane season here in New England had three Hurricanes Able, Dog and George all with similar storm tracks.

If the energy events come in a quick series habitats did not have time to re-stabilize and if combined with changes in temperatures they “reverse.”  We have seen a series of habitat reversals in Connecticut the past two centuries and with each a change in species.  (See Blue Crabs and Climate Change Report # 11, July 27, 2011 and Blue Crabs and Climate Change 8/2/2012).  The habitats had not fully re-stabilized from Irene but the eastern and central blue crab seasons were good, last year now have had two very powerful hurricanes (now Sandy) and habitats have started to reverse – the buildup of muck (Sapropel) appears to be lessening and firmer bay bottoms now appear to be holding larger amounts of juvenile winter flounder.  It’s still too early to make a call about blue crab populations in general, but the 2013 season could help answer the energy question also.  It looks like the cold has perhaps dealt a blow to the post Megalops stage, the question is still open on the impact of energy on the Megalops sets themselves – the largest question is year 2 class the 3 to 4 inch range, if they were able to survive this energy in the shallows.

It’s Not Over – Three Opportunities for Rebuilding Stocks


One of the first studies to identify a spring wave of Megalops after a winter season was a 1965 study of the Blue Crabs in Texas by William More.

In this study a significant Megalops stage was found in Texas bays during February/March then August to October and two district waves of Megalops were reported.  Other researchers were also identifying this spring and summer sets – perhaps as a survival mechanism and also two years or two reproductive cycles (successful waves) combined to enhance a single season total catch.  The reproductive success safety could also then be spread over two years despite poor conditions in one.  “Seasonal patterns of availability, based on the occurrence of Megalops in plankton samples taken in Gulf passes to major bays, varied from bay to bay (Table 2).  Megalops were present in the samples during all months, but the largest catches were recorded in spring and summer.  Similar availability patterns were reported in Louisiana by Darnell (1959) Pg 218” – A Study of The Blue Crab in Texas William R. More (1965).

If the spring Megalops was lost a summer set is still very possible – if both sets are lost than a very poor season results.  It is possible than Connecticut native Megalops set could have survived the long winter and be visible as star crabs in June.  If not then surviving females (if in large numbers) could provide star crabs in August.

The third opportunity is a transported Megalops set from the Chesapeake Bay itself – pre Megalops that gets carried from the bay and hitches a ride on Gulf Stream currents and prevailing winds, deflected into northern areas in midsummer.  This has been thought to be a major influence in our Connecticut fishery and to the Cape and Islands further north.  So we have three chances for a Megalops set this summer, one significant set should be noticeable by August.

A Blue Crab Report from the “Field”


As vocational educators and institutions we strive to have young people experience “real world situations” in educational formats.  For the marine environment that involves “boots on” field work and in this case a small blue crab study.  Two Sound School students who attend from Cheshire Connecticut conducted such a study for blue crabs while on vacation last summer, and Cole London wrote up this experience for our newsletter.

Field work (an old agriculture term) can be its own challenge, changing weather, biting insects, the unpredictable equipment failures, etc but this case science can also be enjoyable and a “work” experience at the same time.

Perhaps a Capstone Project in a few years? 

Thanks for the article – Tim Visel

 

Blue Claw Crabs in the Barnegat Bay, New Jersey By Cole B. London

     My Megalops Study for blue claw crabs was completed in the Barnegat bay in the Town of Seaside Park, New Jersey.  Seaside Park is located on the barrier island named Island Beach.  In the State of New Jersey a legal “keeper” blue claw crab for non-commercial use is 4.5 inches from point to point.

     The water depth of the bay varied from a low tide of three to five feet and a high tide of six to eight feet.  This study began on August 7, 2012 and ended on September 3, 2012.  The purpose of the study was to examine and record the characteristics of the blue crab population.  There were a total of 160 hard shell crabs caught, 0 soft shells.  There were 22 females and 36 males caught which measured 4.5 inches or larger from point to point.  The remaining 102 blue crabs were less than 4.4 inches from point to point; many of these were much smaller as in 3.4 inches or less.  There was no sponge crabs caught. 

     I went out in a 20 foot runabout using four sided wire traps to catch crabs in a habitat of vegetation during the daytime in sun and overcast skies.  I also crabbed from a pier using the traps, drop lines and a net.  The habitat of the pier had some vegetation but was mostly muddy/sandy habitat.  The traps were purchased and the drop lines were assembled from wood, white cord and a metal clip.    The bait was mainly bunker which was purchased frozen and cut into three sections then clipped in the bottom of the trap and clipped to the drop line.  On a few occasions chicken was used.   I did not notice that the crabs liked on bait type over the other.  I did notice that the crabs did not like the bait frozen or even cold, warm and oily seemed to be the attraction. 

     The conditions were varied throughout, sunny, cloudy, windy, choppy, at night with or without moonlight.  The pier had overhead illumination.  Day time catches ere smaller in the quantity of crabs and the larger crabs were caught in a vegetated habitat.  Large quantity catches were in the high tide, maybe because there was more room for them to swim or move around and be seen.  The small crabs, 3.5 inches or less were abundant in the PM.  They definitely were attracted to the overhead illumination and to a flashlight beam which made them easy to scoop up in the net, no drop line required.  The trap would yield multiple catches at one time because they could not escape once the line was pulled and the trap closed.  With the drop line only one at a time was caught.  This was done slowly and carefully so the crab would not feel the movement and release the bait and jump off before I could reach it with the net and scoop it up.  

     I made 17 trips crabbing which resulted in a total catch of 160 blue claw crabs.  About 65% of the catch was less than 4.5 inches point to point.  The largest was a female of 6.5 inches point to point and the larger; keeper crabs were caught mainly in a habitat of vegetation.  The water temps ranged from a low of 71 to a high of 78 degrees.  Catch quantity did not seem to be impacted by water temperature and the catch was varied at all temps.  The catches in quantity and size increased from August 25th to September 3rd.  The best catch was from the pier on August 25 in the clear PM where I caught seven crabs 4.5 inches or larger and 22 smaller.  It was the best because these seven were the most caught of that size during any one session.  Bigger crabs were caught at night overall and there were less day light hours at the end of August.  I definitely caught more crabs in the PM.  All crabs were treated respectfully and returned safely to their habitats.  Cole London, Sound School   

Some of the first bottom trawl surveys should be starting soon for New Haven Harbor; we should have some additional information shortly.

All reports of surviving Blue Crabs are significant, but it’s still very early to predict the entire season.

If you observe any blue crabs this spring (even dead ones) send in a report.  All observations are helpful.  June is a busy month for us at Sound School but hope to get one report out before graduation, see you at the Docks.

Tim

Email blue crab reports to: tim.visel@new-haven.k12.ct.us

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 susan.weber@new-haven.k12.ct.us

The Sound School is a Regional High School Agriculture Science and Technology Center enrolling students from 23 participating Connecticut communities.

 

Wednesday, May 8, 2013

Dr. Tuck Hines, blue crab biologist, receives Washingtonian Green Award


Congratulations to Dr. Tuck Hines for winning a Green Award from the Washingtonian magazine. Read the press release here.