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BlueChip

The 2018 Blue Crab Season
The Search for Megalops

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Tim Visel
The Sound School, New Haven, CT 06519
April 30, 2018

The 2018 Blue Crab Season
Comment & Outlook
Report #1

It is never a good sign when writing up the season forecast two weeks from the season opening to watch it snow. I am writing this report in Rockport, ME and snow piles still exist here on April 15th. While I was visiting a favorite bookstore in Camden, ME and upon exiting, it was snowing. I was headed to look at the glass eel fykes set at the harbor head where a mill falls enters Camden Harbor. A series of Nor’easters had hit New England in March, and March left not like a lamb, but like a wolf. April does not seem any better. I am finishing this report in West Virginia and arrived via the Poconos with heavy snow squalls between Wilkes Barre, PA and Harrisburg, PA on April 17th in the afternoon. Even Charles Town, West Virginia had snow pellets as I arrived.

Warmer weather is yet to arrive to a spring that has broken snow and temperature records. Seawater in Long Island Sound is in the low 40’s and mixing of Sound waters have been helped by a series of strong Nor’easters that also turned nature’s composts in shallow waters. Colder water is generally clear, allowing sunlight to grow plants submerged vegetation (algal strains) and ultraviolet light to kill bacteria. Colder water contains less bacteria and slows bacterial growth – things generally considered “good” for us from our experience with food spoilage, but these things are not good for the blue crab. The blue crab in northern waters increased when it was hot (bacteria multiplies quickly) storms were fewer and less severe and waters “cloudy” with dense algal strains termed “brown tides.” In the very hot summers from 1998 to 2010, blue crab populations soared here, reaching levels not seen in New England in a century. These last three winters have changed blue crab catches in New England; they are later in the season, lower and now consisting of “rusty” or “yellow face” crabs, extremely hard shells that look like they have not shed in several seasons.

It is possible the yellow golden stain or yellow face is similar to that of human tooth stains, may be the result of stannic sulfide. It is thought that low pH causes denaturing of proteins (the shell) or bacterial action of bacteria with ferric sulfide. This is the result of chromogenic bacteria. This species of bacteria (Actinomyies) is responsible for the yellows of human teeth, and they have a similar sulfide connection.

It is thought that low pH of humus and large acidic oak leaf deposits causes denaturation of shell proteins or bacterial action in conjunction with ferric sulfide. There appears to be a sulfide connection and metal involvement, stannic sulfide is also known as Tin sulfide and has a yellow color. The rusting, perhaps from tannins the stain of tea of this perhaps “oak leaf tea” those crabs, which live in the rivers and hibernates in areas of high tannin inputs.

Crabs that live in more saline waters in sand and eelgrass, which have saltwater fouling organisms, such as sponge, barnacles and hydroids. I recall when I first started the Megalops newsletter a veteran crabber emailed me saying these are river crabs able to live in fresh water for most of their life cycle. I did not fully understand what the information was about until I started to look at other crab fisheries in other parts of the world, which raises the question, do we have more than on “blue crab” here? That was the information in the email that some crabs have adapted to rivers and needed very small amounts of chloride. With so much exchange of bilge water and the length of time megalops can survive and hibernate poses an interesting question.

Do we have a subspecies that lives longer and mostly in the rivers? I had a chance to look into this question over the winter and discovered that early blue crab researchers had the same questions, that crabs with unique morphological appearances overlapped in range and, no doubt, had adapted to particular habitats and climates, salinities and temperatures.

Two Species – One Prefers Rivers?

Some blue crabbers may notice a different scientific name for the blue crab Callinectes hastatus to Callinectes sapidus. This occurred in 1896 by Mary Jane Rathbun, a noted authority on crustaceans working for the U.S. Fish Commission. Before that time, the blue crab scientific name was hastatus and not sapidus. In fact, there are several species that look almost identical.

Earlier Albert Ordway (1863) described nine species of Callinectes, including Callinectes hastatus (beautiful swimming spear carrier), but was changed to sapidus meaning savory, a term that continues today. Rathbun also described a very similar blue crab subspecies C. acutidens (sharp teeth) for this crab is found in Central and South America. Because hastatus had been used for decades, it took decades for sapidus to be used in many older scientific reports. On a couple of occasions, I had noticed a slight difference in our blue crabs, especially the claws. They were smaller and shaped differently, we might (not confirmed) have another species of blue crabs: a blue crab from Central America.

Torben Rick et al 2015 – Journal of Archeological Science 55 (2015), pg. 42-45: A study of Native American shell middens not only revealed that blue crab was an important source of food for Native Americans but perhaps a marker for Callinectes similus, a species of blue crabs found in warmer waters, showing possible range expansion over time. In a genetic study of the blue crab in the Western South Atlantic, Ana Luiza Figueiredo Lacerda et al (April 11, 2016) estimated that the blue crab of Brazil had a megalopa phase of 31 to 69 days – long enough to support larval stages to remain viable on ocean transit. These crabs appear to have a larger shell and smaller claws.

Callinectes ascutidens, Boschi (1964), has a shape and number of frontal teeth – male gonopod – morphology is slightly different from sapidus – the species that we associate with our blue “crabs” here in Connecticut. For those crabbers who noticed the tremendous movement of blue crabs from the Housatonic River in August of 2011 following the tropical rains from tropical storm Lee, the claws were much smaller and at times different body shaped (See notice sent out to the Megalops mailing list on Wednesday, August 22, 2012). “These crabs have a very different appearance and don’t resemble the bright white/blue shells of spring or summer. These crabs might be several years old, perhaps the 2006 and 2009 megalops set survivors.”

In researching the history for blue crabs, I learned of many species, about 30 species for the blue crab, exist worldwide. Some look very similar to our blue crab while some are much larger and have a different shell and claw shape and colors. But the different species do overlap and the blue crab of Central America prefers rivers. In fact, many reports in the literature seem to be increasing, regarding the findings of blue crabs living in freshwater (or nearly so), even sometimes lakes. I will continue to look at this potential in the near future.

I then recalled the mass movement of blue crabs from the Housatonic River in 2011. They, in fact, looked different and put out a notice on August 22, 2012, detailing that they looked very different. The largest issue, perhaps, that those “rusty” and “yellow face” crabs have very hard shells and appear not to have shed for several years – my view.

A Colder – Cooler Climate Cycle

The later and often cold weather/delayed seasons have reduced catches but also made recruitment less apparent. We may now only get our megalops from areas to our south carried north by the gulfstream. Researchers have found viable blue crab megalops off the coast of Ireland, but these climates are just too cold for the blue crab. Winds have also changed more northerly, and suggests that larval forms that did mature here in Long Island waters found themselves in deeper water surrounded by large numbers of black sea bass. The hot summers eight years ago brought back “torch lighting” blue crabs in a different format – not torches or lanterns of the 1890’s, but powerful “eyeball” battery operated headlamps that searched for dormant crabs late at night. It is the oxygen minimum that occurs around 2:00 a.m. to 3:00 a.m., photosynthesis stops, and algae perish then sink to the bottom and bacteria decompose this organic “food.” Oxygen levels bottom out while sulfides now rise, producing the “smelly summer marsh gas of August.” Blue crabs leave the bottom at night, move towards the surface for a little surface oxygen or just remain dormant, conserving what little oxygen remains in their blood. Late night blue crabbers in 2011 after found thousands of blue crabs clinging on pilings sometimes as many as 10 to 20 crabs per piling (observations of Westbrook, CT – Tim Visel) on still hot nights, frequently associated with “bad smells” as hydrogen sulfide leaves the water to the discomfort of many coastal residents. It is in these conditions that blue crabs thrive, up to a point to a massive bacterial sulfide event. Purging sulfide is very toxic to most “oxygen sea life” can drive blue crabs from the water – the so-called “Blue Crab Jubilee.” Now that has changed for the northern blue crab. Colder water is now filled with oxygen, waves from the storms have “turned” nature’s compost – humus on the surface, and sapropel below, and changed the bacterial spectrum from ammonia producers to those that now produce nitrate, a far less toxic nitrogen compound that, in fact, cold water algae need. In heat, bacteria that can live in it “purge” ammonia, the ammonia that brown tide algal strains need. In cold, nitrate dominates and those algal are the preferred nitrogen for the “good” or nutritious algal that shellfish need. In the 1950’s and 1960’s, a cold/nitrate Long Island Sound produced large quantities of chlorella. In the 1990’s and 2000’s, it was the brown low nutrition brown algal species. Even though the water was filled with brown algae, shellfish still starved.

In the colder 1950’s and 1960’s, nitrate, a key algae nitrogen nutrient, was at times “limiting” in Long Island Sound, which is a scientific term that describes a shortfall or deficit - there was not enough. It may be difficult for some to believe that at one time sewage treatment plants were not so much discouraged – actually at times praised for providing a “new” source of nitrate. These views are found in the fisheries literature when in the colder 1950’s and 1960’s, algal strains ran out of nitrate and the blue crabbing then nowhere near the crabbing here of the 1900’s. In 1950s, researchers such as Gordon A. Riley, termed Long Island Sound even as nitrogen limited. That was in years when cold seawater slowed bacteria growth, and in doing so, reduced levels of nitrate. It is the nitrate that each spring provides for a “bloom” of algae that feeds shellfish that also have gone the winter without much food and why shellfish here store glycogen as food reserve each fall. Change the nitrate levels or their availability (time) and the consequences can be enormous. Most of that change is climate related, and in more recent times, we have strived to remove nitrate from waters and not increase it. Timing can be huge habitat factor in our coastal waters and the concept of habitat clocks the timing of when several relationships combine to favor or hurt a species. Perhaps the best habitat clock we have is the record of eastern oyster sets, the ability of oyster larvae to survive long enough to set on a clean surface in mid summer and obtain enough algae to prepare it for the long winter without food. If the set occurs in late fall, chances are these young oysters will starve before spring. They just won’t have enough time to store food before temperatures drop below 47oF. The oysters may have spawned “spat,” matured to veligers and set heavy upon surfaces (mostly shells or rocks), but very few survive. The 1898 oyster set was said to be heavy but a late season hurricane called the “Portland Gale” buried these young oysters with silt – particles of rock “flour” surrounded by a bacterial mucus that suffocated them. The set could be huge but subject to natural “clocks,” mostly temperature and energy. None of it could survive if these “clocks” were not aligned.

The Blue Crab Explosion 1998-2011

We can examine this “clock aspect” from looking at our recent surge in blue crabs – megalops sets came in early summer and gave these crabs time to shed into legal size before fall, our winters were mild and at times even warm with temperatures in the 70’s. From 1972 to 2011, almost four decades, our waters warmed, and with the low oxygen, at times brown tides, and almost a near absence of hurricanes, blue crab populations increased and soon filled the buckets for a new generation of blue crabbers who had countless hours of fun with simple gear of a string, piece of chicken and a net (or trap) to catch the blue crab. And the catches, at one time, were large and in the shallows, putting this delicious crustacean within reach to thousands of recreational fishers from the shore and then the climate changed; but this has happened before.

The Ice Famines and The Great Heat 1880-1920

The ice business was a huge industry in the 1890’s. Ice was very valuable in keeping food cool and slowed bacterial waste of food. In the warm months, the iceman came with huge metal pincers, holding a large block of ice for the icebox, which was the name that described an insulated sometimes, ornate box in which food was kept cool by ice. By the 1950’s, the term “icebox” was replaced with the term “refrigerator.” If you use or know the term “icebox,” you, like myself, were born in the 1950’s. After that time, “plug in” electric refrigerators kept food cool and even frozen. A revolution occurred in the ice industry as people no longer needed a small door in the pantry for the ice to be delivered. They could now make it themselves.

So it is difficult to imagine the value of ice when almost every home cannot, at times, make its own. But that was not the case in the 1890’s, as our climate warmed, New England suffered “ice famines” – a low supply of ice made prices rise. Ice hoarding was subject to public shame and a New York Times article dated July 11, 1911 titled, Eleven Dead In Pittsburg Ice Famine Draws Worse and Suffering Is Great.”

The ice business was a large commercial industry and the February issue (1900) of Ice and Refrigeration mentions on page 125 both the ice famine conditions and the very warm conditions of New England at the time. Under a section titled “Ice Harvesting” can be found these sections:

“The winter has been mild, and especially characterized by the absence of snow, there is still ample time for wintry weather – the most severe cold of 1899 came in February …”

“In Maine, there is enough ice held over since last winter to prevent an ice famine, even should the harvest fail [It would southern New England would produce small amounts of ice – Tim Visel] some 300,00 tons of last year’s crop being reported as still remaining in the Kennebec houses, and in the Penobscot houses about 150,000 tons … ”

Also, under the New York ice report is found this statement:

“From no other state were such loud complaints heard of poor ice, no ice or little ice, as from the Empire State. At [the] Catskills, people were digging in the gardens after Christmas.”

At this time, the falls were very warm, and around the middle of January, the “cold” arrived but it was just too late. The waters did not cool fast enough by the time the waters were cold for ice; sun angle and daily temperatures eliminated ice formation. During the 1880-1920 period, ice famines accelerated the construction and development of mechanical ice formation – the ice plants would replace the icehouses. In this climate, small fields, shallow ponds were shut to produce thin “pond ice.” Today, only those who study this climate period would know of “ice famines” or the value of ice during these very mild winters. However, the blue crab, then was great only to continue to rise to 1912-1914.

The future decline of “natural ice” as an industry was already beginning. In 1900, the magazine under a section titled “Newplants and Improvements” dozens of cities were building “ice machines” in the Connecticut section (pg. 128): including New Haven, CT.

“New Haven – Lee & Hoyt, cold storage warehousemen have recently equipped their warehouse with an Allen ice machine.”

And …

“South Norwalk – Plans have been matured for the organization of a company with 50,000 capital to erect and operate a plant for the manufacture of ice.”

The release of electric refrigerators in the 1920’s would doom the ice industry and the “icebox” and the iceman. By the 1940s, the term iceman was relegated to the pages of history. So was the large catches of the Blue Crab.

The ice famines were over, but a colder New England climate with more northwesterly winds meant doom for the Blue Crab. Here in the historical fishers’ literature, the great blue crab habitat expansion- the term that Rhode Island Fishery managers called the “crab question” now retreated to the last areas of habitat suitability - the warmer salt ponds.

Much has changed from the last century and we have created habitats of refuge for the blue crab – dredged channels. These are next to shallows – the creeks and salt marsh peat that absorb heat in the spring. Look to these shallows to have the first feeding blue crabs. The dredged channels provide the over winter habitat, the dredged basins (or deep salt ponds) the food, the marshes and shallow creeks provide the warm water. Look to these areas for the first catches of the 2018 blue crab season.

Have a safe and productive fishing season.
Blue Chip

All crab and crab habitat observations are important as we learn more about them. Send comments or questions to Tim.Visel@new-haven.k12.ct.us