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 19^th 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 3^rd 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 15^th.  A second wave of Megalops from a 2013 reproductive cycle should appear July 30^th to August 15^th.  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 25^th to September 3^rd.  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.

 

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.

Winter Dredge: Female Crabs Say Recovery Still on Track

To some following the blue crab recovery, Friday’s news may have come as a shock. In 2012, the Chesapeake-wide Winter Dredge Survey estimated a record 764 million blue crabs in the Bay—the highest seen since 1991. Juvenile crab densities jumped to their highest levels ever. Then the 2013 survey saw both those numbers drop.

1.  Managers greeted the dwindling juvenile population with some depression. But those numbers may not matter as much, according to biologists Tuck Hines and Matt Ogburn of the Smithsonian Environmental Research Center. Ecologists at SERC have been tracking blue crabs for more than 30 years, almost a decade before the winter dredge survey began. Their research has revealed the population that really needs watching is the spawning females. Here is what the numbers are telling us: Female protection is working overall. The 2008 change in crab fishery management targeted protection of spawning females.  In four of the five years since then, the Winter Dredge Survey has recorded higher numbers of spawning age females compared to the period of very low levels from approximately 1994 to 2008. This indicates a positive outcome of reduced fishing pressure on female crabs.
2. To increase juvenile crabs, we need to protect their mothers. It is not surprising that the number of juveniles in the 2013 Winter Dredge Survey is very low. The number of females in 2012 that formed the spawning stock was near the same record low levels of great concern during the late 1990s and 2000-2008 and was unlikely to produce a large number of small juveniles in the 2013 Winter Dredge Survey.  This emphasizes the importance of protecting the female spawning stock. 
3. Survival matters—winter numbers alone don’t predict reproduction. The number of females in the Winter Dredge Survey provides a projection of the number of spawners in the coming summer, and into the following summer after that. But it is not a direct measure of the amount of spawning taking place. Following the Winter Dredge Survey, female crabs in Maryland need to migrate to, and in the case of juveniles over-winter in, the lower Bay before actually spawning.  In order to determine the actual amount of spawning each summer, we need a much more accurate measure of factors regulating mortality (survival) of crabs from winter to summer, including juvenile mortality and the components of the fishery in various parts of the Bay, AND their reproductive success/ output.
4. Timing and location matter. Our sampling last summer (2012) indicated that the large number of juveniles recorded in the 2012 Winter Dredge Survey did not result in large numbers of juveniles in Maryland waters of the upper Chesapeake Bay.
5. It’s too early to blame the red drum. The statement that the increase in juvenile red drum was the cause of the mortality of 2012 juveniles should be viewed with caution and skepticism.  While juvenile crabs may be important in the diet of red drum, it has not been demonstrated that predation by red drum is a major factor in regulating juvenile crab abundance. Our long-term experimental data in the upper Bay indicates that fish predation is not a major factor regulating juvenile crab survivorship, and we did not observe this type of predation in summer 2012. The biggest threat to juvenile crabs is still predation by adult crabs. The 2012 results were entirely consistent with juvenile crab mortality being directly related to numbers of large crabs.
6. We need to learn more about why females don’t reach their full spawning potential. The concern about poor reproduction of female blue crabs is a major ongoing focus of research in our laboratory.  We need to understand more about the factors regulating the production of egg sponges and the role that males play in supplying enough sperm for females to fertilize eggs during their first AND second spawning seasons.

Dr. Tuck Hines is a marine biologist with over 30 years of experience working on blue crabs in Chesapeake Bay. His research addresses broad problems of population and community ecology using long-term quantitative sampling and innovative experiments at multiple spatial and temporal scales. His studies analyze human impacts and natural change in estuarine and marine systems.

Dr. Matt Ogburn is a Postdoctoral Research Fellow at the Smithsonian Environmental Research Center and author of the Blue Crab Blog. In addition to his work in Chesapeake Bay, he has studied blue crabs in North Carolina and Georgia. His other research involves using a combination of long-term data and directed field work to study estuarine ecology, fish biology, shrimp behavior, oyster restoration, and other topics.

2013 Chesapeake Bay Crab Survey: Females increase but big decline in juveniles

The results of the 2013 Chesapeake Bay Winter Dredge Survey are in and the total population of crabs is down significantly from 2012. There's a mix of good and bad news. Female numbers are up but juveniles declined sharply from record highs last year. I'll post our thoughts on the data soon. In the meantime, here are the press releases from Maryland's Department of Natural Resources and Virginia's Marine Resources Commission. The figures below are from website for the Winter Dredge Survey at MD DNR.

2013 Connecticut Blue Crab Report 1

Here at the Smithsonian, we caught the first juvenile blue crab of the year today in our regular weekly sampling. In honor of that event, I'm bringing you the first regular report of 2013 from the Search for Megalops project in CT.

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 #1 -2013 – Blue Crab Year

April 17, 2013

 

·         The 2013 blue crab season and climate change. 2013 a key year;

·                                 The discussions surrounding habitat quality and capacity for blue crabs;

·         Could the 2013 blue crab year answer climate change habitat questions – Hurricanes and Blizzards?

·         All about Sapropel and habitat questions from western Connecticut crabbers;

·         Year class size reports are key to understanding Megalops survival – watch for year class divisions.

 

The Significance of the 2013 Blue Crab Season

As the 2013 blue crab season begins, it may be one of the most significant in 50 years. Last fall, Connecticut had an immense Megalops set, but that was quickly followed by a powerful hurricane, then numerous gales, two blizzards and a very cold winter.

Western crabbers had a poorer blue crab season (2012) with much lower crab populations, now linked to hydrogen sulfide questions, summer heat/ low oxygen and chemical concerns following a July 2011die off.  Eastern Connecticut crabbers (2012) had a good late season, believed to be populations that overwintered in the Mystic, Thames and Pawcatuck Rivers, but it was late September to October, and cut short by the powerful October Hurricane, Sandy.  Central Connecticut had overall the best crabbing 2012 and the blue crab population in the Connecticut River was again in the millions.

Conditions however could be very different in 2013 – testing some habitat indicators believed to be helping the blue crab and restricting lobsters- energy and temperature levels.

Energy levels have certainly increased since 2004 and temperatures also showing larger year to year changes – cold then hot, etc. The winters of 2010 and 2012 were some of the coldest in recent times.

As one climate period ends and another begins, it is often that such wide swings in temperature and energy levels occur.  After the long heat of 1880-1920 it was quickly followed by a hot and dry period out west; the Dust Bowl of the 1930s and 1940s. The 1950s and 1960s were colder and storm filled here in New England and recalled for numerous hurricanes which followed the New England Hurricane of 1938 and then increasingly colder winters- The North Atlantic Oscillation (coldest winter 1957).

The 2013 blue crab year will follow an unprecedented increase in energy levels (storms) and one of the coldest winters in recent memory. A habitat transition may already be in place, reports last summer included large numbers of small winter flounder in eastern CT, and Niantic Bay had a modest bay scallop season last fall.  Both species have benefited historically from lower temperatures and increased energy levels.  Many Connecticut beaches were striped of sand exposing buried cobblestones of long ago, habitat changes were sudden and in many cases severe signaling the possibilities of a significant habitat “reversal.”  The kelp cobblestone habitat has been found to be very important to juvenile lobster stages.

The 2013 blue crab year could be one of the most important observation seasons to date.  All blue crab observations are important, perhaps more so in just a few weeks. Thank you for sending your reports to me at tim.visel@new-haven.k12.ct.us – See you at the docks! Tim

The Topic of Habitat Quality and Capacity

I spoke with dozens of blue crabbers in central and eastern Connecticut last summer; many of them were just introduced to the fishery here in Connecticut.  Essex has become a popular place to crab and the late summer fishery, the last several years (except 2011) has been very strong. In fact, many visitors are shocked / surprised to see those blue plastic circular laundry tubs filled to the brim with blue crabs.  Many of the comments are from southern visitors who lived in the Chesapeake Bay area, surprised to see something “Southern” here in New England.  Last year was the same, and during blue crab banding demonstrations I spoke with some visitors who came north for lobsters but found blue crabbers instead. I suggested they continue north as Maine was having an excellent lobster year while ours (lobster population) now were at very low levels.  It’s a question of habitat quality and capacity, I responded as the habitat quality for lobsters here declined from much higher water temperatures; the habitat capacity for the blue crab improved. I didn’t need to press the point as about a dozen crabbers were fully engaged in landing blue crab after blue crab during the discussion. Last summer, you need not understand the change in blue crab habitat quality; you could see the results of it here at Essex.  Overfishing is frequently mentioned as a concern by visitors and often the exchanges that followed were more even puzzling. The blue crabs in the Connecticut River last fall found favorable habitat after the saline tidal wedge builds in late June and the runoff from spring rains subside.  The crabs that arrive then can’t withstand the fresh water flows in the spring. Those who do find deep salt water pockets (mostly dredged channels) have a chance to survive, but most crabs leaving the Connecticut River in the fall will perish - sad but true.

I was much more concerned, I explained, with a habitat failure then upon the sizes (legal size, etc) the real habitat issue is for the young.  A huge increase in adults and few stages between them is a habitat quality question, not so much overfishing. In Connecticut we have good resource regulatory provisions, such as returning egg bearing blue crabs and minimize sizes. These are good rules but do nothing to ensure habitat quality, those issues which impact habitat quality are not governed by us but by the natural world. What makes it more difficult to understand is that before a fishery collapses, the habitat capacity to sustain it collapses first.  It is a cruel irony that this situation often favors the surviving adults (they are more mobile and do not need to compete for space and food) so catch rates of adults actually increases providing a sense of security when actually none really exists.  The winter flounder collapse of the 1980s followed this pattern¹.  The huge increase in lobster production here in the early 1990s was the beginning of a region wide lobster habitat failure, and when it collapsed, the significance of juvenile mortality came into full regulatory view as landings plummeted. The fishery was not overfished, it had good management regulations the lobsters suffered from a habitat failure in Southern New England as they had a century before. It was now very warm again and with few storms habitats had changed, what was damaging to lobsters, high heat and soft bottoms would cause the largest increase in blue crabs here, also, since the last century. Lobsters and blue crabs had “reversed” abundance in Connecticut. A similar fate may now await our Connecticut blue crabs.

Could the 2013 blue crab year answer climate change habitat questions?

At the turn of the century winter flounder fishers and bay scallopers found disappointment in many Connecticut coves and bays. Following the cold and storm filled 1870s the 1880s and 1890s were much warmer and then very hot. The 1896 and 1898 heat waves in New England were record breakers for their time. Bays and coves turned black and began to smell of sulfur, the rotten egg smells so common along the shores. Besides the Blizzard of 1888, the Portland

Gale of 1898 (most likely a November hurricane) and two gales of 1903 and 1905, the 1880 to 1920 period was relatively quiet, storm free.  But with this period came heat

 

¹ (See Where Have the Winter Flounder Gone?  (Visel, 2010).  Fishers might recall catching bluefish packed with small winter flounder driven from nursery habitats in the 1980s.  Winter flounder had to flee these nursery areas and face new predator/prey relationships.

 

waves that killed hundreds of people.  National Public Radio NPR has a comprehensive report on the career of Theodore Roosevelt during The Great Heat Wave of 1896 in New York City.  The eastern CT fyke net fishery for winter flounder had largely failed by 1910 – bay scallops were practically nonexistent.

But fishers also noticed some distinct habitat changes then; eelgrass which was almost cleared completely out of the coves by the 1870s storms was back and formed huge dense monocultures (meadows), Brant feasted upon this eelgrass and populations of Brant soared as conditions now favored lush eelgrass growths. Eelgrass meadows trapped organic matter, not disturbed by storms which then rotted and turned black in high heat.  Oyster fishers at the time complained the most about these “new habitat conditions” and the first reports of ruinous black “mud” came from Great Salt Pond research in Rhode Island (1898) and the work of Rhode Island Experiment Station run by Dr. G. W. Fields. Organic matter washed into streams with manure, a dairy industry practice then and formed a slurry of rain driven organic oatmeal[1] that buried previous “hard” bottoms and now were soft and sulfur smelling which killed river oyster beds.  In the high heat this organic material started to rot and produce hydrogen sulfide, as recorded by the coastal residents who reported the “marsh stinks” the infamous rotten egg smells. That happens today also, and surprisingly Niantic Bay, Connecticut had a brush perhaps with hydrogen sulfide toxicity in August 2009. Then newscasts WTNH-New Haven contained reports of blue crabs crawling on land to escape the “low tide” Niantic Bay (River) waters with pungent smells. (Blue Crabs Picking Land Over Niantic, Friday August 7, 2009 by Jamie Muro).  I believe this to be similar to more southern crab “jubilees” when blue crabs walk ashore by the tens of thousands. The August date and very hot temperatures suggests a hydrogen sulfide toxic “event.”

When coves turned black, sulfate reduction processes accelerated and fish kills soon followed- that was the 1890s.  These conditions persisted into the 1920s (Grabau 1921).

But as oyster fishers complained about black muds lobster fishers also watched as their fishery collapsed, and the lobster die offs peaked between 1898 and 1905. Bay scallopers also were out of business, not from overfishing but because instead of cold water corraline reds algae and red weed (thought to be the real scallop grass) such as the deep water Narragansett bay scallop habitats were now covered with eelgrass and in high heat acidic conditions were lethal to bay scallop sets (dissolves shells).  But as the bay scallop, lobster and inshore winter flounder fishers saw disappointing catches, those blue crabbing, catching soft shell clams, striped bass, and those involved in oyster culture on hardened bottoms were reporting very positive increases catches couldn’t be better. And for every acre of oyster and clam shells placed on aquaculture acreage, it buffered acidic marine soils for hard shell clams while creating more habitat for winter flounder. 

The year following the Portland Gale, the Connecticut oyster set (1899) was to be the set of the century, soft shell clams set heavy on Cape Cod, blue crabbing soared region wide north even into Buzzards Bay and during this heat, striped bass grew huge.  Many Connecticut River clammers converted their skiffs into guide boats to take New York hunters duck hunting in Connecticut River marshes no longer iced in as before, and now early “hot” springs made duck hunting and turtle trapping the business of necessity not choice.  Noank, once of the center of Connecticut’s lobster fishery became a community of coastal cottages and the place to “torch light” blue crabs at night. Striped bass fishing became a popular past time for the then rich and famous. Many northern islands walking fishing “stations” were build (few storms) and the bait used to catch some of the largest stripers then that would be 2 pound lobsters or soft shell blue crabs.  Fishers and hunters were in “The Great Heat,” a period in New England’s climate history of very warm hot summers and few strong storms.   If you were to examine the lobster and blue crab fisheries today besides habitat quality indicators that are present today they will provide some answers to habitat questions asked over a century ago.  What happened to the Southern New England lobster fishery in 1898 and a century later Connecticut again has experienced a lobster die off while an amazing surge in blue crabs. Why?

These habitat changes were signaled in both cases by the fisheries noticing bottom habitat changes, the muck that covered so many estuarine bay bottoms, and produced those sulfide smells, today that muck is called Sapropel and is the largest indicator we have to habitat reversals and fishery transitions. Fishers in New England wide raised the Sapropel alarm bell in the 1980s and looking back they were correct to do so.  In one of the few case histories of this sulfur rich mud impacting fisheries could be the Long Island duck farms of the 1950s and 1960s. The appearance (or disappearance) of Sapropel may become a key indicator of climate induced habitat change. That case history is under review presently.

All About Sapropel – and Habitat Questions from Western Connecticut Crabbers

In July 2011 we had a large die off of adult blue crabs in western CT during a heavy rainstorm. It was hot; also a time of heavy West Nile reported chemical pesticide and reported application of brickets into street drains.  A large migration of crabs had already left the Housatonic River and was heading east, and western Connecticut crabbing had been excellent following another great 2010 year. After the heavy July 2011 rain event, many western crabbers noticed a significant brown coloration to the water. This brown color is linked to the breakdown of oak leaves. Tannin, an acid, is very high in oak leaves.  Some reported that the waters also “smelled” badly like sulfur. This hydrogen sulfide smell is attributed to coastal bodies of water and salt marshes in late summer when dissolved oxygen is at its lowest point. Bacterial processes in high heat and low oxygen tends to reduce organic matter (leaves) by bacterial reduction of sulfate releasing the hydrogen sulfide gas – thus the foul or rotten eggs smell. This smell (stink) was prevalent in the later stages of The Great Heat a century ago and noticed by coastal residents near marshes. That also occurs today and many coastal residents can confirm this late summer event. The rainfall may have dislodged rotting leaves increasing levels of hydrogen sulfide in tidal areas. The same areas that had been so productive for blue crabs can lead to high sulfide levels and might trigger these large late summer migrations.

Warm waters and few storms helps the blue crabs habitats but as with the lobsters, great catches are made just before a habitat crash – and the blue crabs in Connecticut might be facing a similar tipping point – an almost forgotten hydrogen sulfide toxicity in the water itself. This is due perhaps to the buildup of black sulfurous mud called Sapropel. In warm weather leaves and organic matter rots and produces Sapropel. It accumulates rapidly with few storms to wash it out it can reach several feet deep – locally it’s called Black Mayonnaise, and is often a dominant habitat type. Not too much is known about the extent of Sapropel deposits in Connecticut. Key scientists worldwide were looking at it just after The Great Heat 1880-1920, and had convened a world conference about sulfurous mud just prior to World War II. The conference (1938) papers were eventually printed in 1958 but by that time we were in the period of cold and numerous storms, the North Atlantic Oscillation.  Estuarine habitats had reversed - Sapropel deposits were washed away and from bays, coves and salt ponds, and a new habitat type, estuarine bivalve shell now became dominant. Winter flounder was enhanced by firm bottoms estuarine shell, while blue crabs which need the Sapropel to burrow into during the winter – for long hibernation periods retreated -mostly and today to rivers and dredged channels.  The onset of a habitat reversal had “helped” some species increase – up to a point. That seems to be the case with Sapropel, and now perhaps blue crabs.

In a Cape Cod study in the middle 1980s, a diverse habitat type produced the best diversity or biological richness. The observations included one quarter, hard mud, or sand, one quarter estuarine shell, one quarter vegetation, and one quarter small stones (or cobblestones) were the richest habitat areas in terms of biological diversity. When one habitat type dominated total abundance often remained about the same but diversity declined. A dominant habitat type – all yielded some organisms- except Sapropel. This habitat type tended to reduce diversity and in large deposits was vacant of most recognizable animal life forms.

Sapropel did contain eels and eelgrass together; it was felt to be important to habitat requirements of overwintering Blue Crabs who needed to hide from predators during long winter hibernation. It was, however, a limiting habitat type and in large deposits devastating to most shore life, fishers often reported accumulating leaves first - the material that creates Sapropel. Oak and Maple leaves are naturally acidic and in poorly flushed coves and bays collect and rot in summer heat. This is the material that so many kayakers experience (not pleasant and often dangerous) in shallow warm waters. When oxygen levels normally lower in warm water, this organic matter cooks – rots as terrestrial compost- but here the reduction processes create a perfect storm of habitat failings or constituents, sulfuric acid, hydrogen sulfide, ammonium and now removes all oxygen. One long time winter flounder fisher, Louis Bayer, from eastern Connecticut (1980s) watched as his favorite winter flounder habitats were covered with “black mayonnaise” and once commented to me “this stuff is bad for fish” – I quickly agreed, it was.

In some bays Sapropel has past 25% coverage to as high as 50 % to 75%. Previous core studies do show episodic events in coves that have core samples layered then mud with estuarine shell. These habitat reversals could have happened before, many times in Connecticut’s fisheries habitat “history”.

In the late 1970s Sapropel seemed to increase along with Blue Crab increases – There appears to be a habitat connection with older blue crabs which tend to seek out these soft deposits in winter, but in late summer Sapropel becomes deadly. The compost residues from Sapropel has a role in acidification of estuarine soils – bivalve shell erosion, lowering oxygen and in the presence of ammonium which fuels brown algal blooms and hydrogen sulfide a lethal one-two knockout punch to many organisms we as a society value. Sapropel is now linked to the tremendous increase in necrotic fin rot disease in winter flounder populations during the same time, and an increase in the plant nutrient ammonium which favors the harmful brown algal species (HAB).  HAB blooms have been shown to reduce bay scallop habitat quality.

As habitat quality for Blue Crabs increased, winter flounder habitat quality declined. Sapropel may even trigger mass movements of Blue Crabs by the presence of hydrogen sulfide levels in the water itself. That movement has happened the past three summers- although the 2011 “waves” were weak following a much colder winter, blue crabs could be moving to avoid hydrogen sulfide toxicity.

The movements of Blue Crabs east can be attributed to several factors but none confirmed. Several explanations exist:

1)    The movement west as with lobsters is more suited to larval recruitment and as crabs and lobsters mature, they may become habitat limited – and move east seeking greater space or habitat capacity (some of the densest blue crab sets Megalops have been in the Bridgeport/Fairfield area)

2)    Warm summer temperatures drive Blue Crabs out of rivers first from low dissolved oxygen levels and finally toxic hydrogen sulfide (late summer).

3)    Blue Crabs and lobsters appear to move toward the morning light, east as mentioned in old fish observation reports – the same is true for Bay Scallops noted to swim east in Long Island Sound before storms.

4)    Chemical contamination – possibly from West Nile treatments but the July 2011 die off of blue crabs occurred also during a heavy rain – so freshwater poisoning, chemical contamination, and low dissolved oxygen conditions may have all contributed to this die off (crabs should be tested for residue- my opinion)

5)    Hydrogen Sulfide Toxicity – this can happen in late August as rainwater flows become less, and waters warm thus holding less oxygen. In some rivers, up to 50% of flow can be sewage in the summer months. Dense accumulations (greater than 6 inches) of Sapropel shed ammonium and produce hydrogen sulfide in warm weather, therefore a sudden rain can rip into soft Sapropel deposits causing the “black water death” events (fish kills) with fish. These are mentioned by fishermen at the turn of the century. Hydrogen sulfide is highly toxic to most marine organisms and those areas poorly flushed have been known to have high hydrogen sulfide levels. This habitat impacted event associated with Sapropel has been largely missed – but one study conducted by Dr. Art Gaines of the Woods Hole Oceanographic Institution found in the Narrow River lagoons, Rhode Island, sulfide levels 10 times higher than those of the Black Sea.  That was in 1975 even before the hot period intensified in the 1990s.

 

High organic loadings can also interfere with gill respiration collapsing ionic exchanges causing high mortalities. A high rainfall therefore may be the biological trigger for such mass movements of blue crabs from river mouths to the open Sound – into a predator-prey relationship that also deserves further study.

Crabs leaving the protection of brackish waters to full salinity waters asks the question that many crabbers have also asked, realizing the predator relationship and lack of cover (not many offshore eelgrass meadows which is a natural crab  habitat type) why does this happen at all?  The presence of blackfish (tautog), blue fish and stripers alone are devastating to crabs and the ability to burrow in and hide must be reduced on cobble stone, etc. The answer to the question is they probably don’t choose to move early, they are forced to move early.  It looks like the July 2011 blue crab die-off was region wide in western, CT before the mild winter (not most likely winterkill as last March it was in the 70s).  A flood of rainwater could have dislodged Sapropel deposits and released with the (smells) tannin (brown color) hydrogen sulfide mortality (visual observations by several Megalops reporters). What we do know from the reports obtained in 2011 that crabbers that had been crabbing 20 years or more had never seen anything like this before. These observations during this weather period are extremely significant and important.

As blue crab catches increased in CT after 1998, crabbers asked why, the levels of catches today are somewhat astounding as to those in the 1950s and 1960s.  This year’s blue crab season may answer many of the above questions.

Watch for the Year Class Megalops Divisions – The next few weeks could answer many questions.

The key habitat question is for the juveniles, not so much for the adults. Key to understanding the habitat quality question as it related to blue crabs here in CT is the survival of a now native Megalops set, or the survival of a transported Megalops by currents into Long Island Sound from southern areas or both.  The simple blue crab population response is that it got hot, and that is certainly true, but the habitat question is far more complex and directly related to the increase in the Megalops survival rates here in Long Island Sound.

The 2013 blue crab year may answer many important habitat questions, a year following a hurricane and a very cold winter as compared to warm one. What to look for, the 2012 Megalops (2 inches) the 2011 Megalops now 3 to 4 inches and the remains of those incredible 2010 and 2009 Megalops sets the 5 inches and up category.

A good mixture if various size reports – multiple year classes is a positive habitat indicator. Missing “year classes” or unequal size distributions are negative indicators.  Two or more year classes “missing” in 2013 signify a habitat failure.

As in previous year’s shellfishers will most likely be the first group to report on surviving blue crabs.

Only the next few weeks will tell.

 

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.

---

² Oatmeal is an old term for unconsolidated terrestrial brown organic debris, stems, leaves, barks; dead grasses are fractions of this substance.

Maryland blue crab season opens to slow start, but warm weather is coming

The blue crab season has opened in Maryland, but cold spring temperatures will likely make for a slow start. The good news is that spring is in the air with forecasts calling for the 70's next week. Here's more from the Baltimore Sun.

Maryland's blue crab season will likely have a slow start

Cold Chesapeake Bay waters will slow this year's harvest, experts agree, but after that, nobody knows

 

March 31, 2013|By Richard Gorelick, The Baltimore Sun

 

April 1 is the official start to the blue crab harvest in Maryland. But don't reach for your mallet just yet.
"It's not time for crabs," said Jessica Borowski, a manager at Midtown BBQ and Brew. "It's too cold out."
The crabs seem to agree. The Chesapeake Bay's water temperature hasn't risen enough for the crabs to become active — and catchable.

Read the rest here.