[BlueChip]

The 2017 Blue Crab Season Start – Megalops #2, 2017
A very cool spring lingers over the Northeast as storm track moves west.
The Search for Megalops
“You Do Not Need To Be A Scientist to Report”
June 6, 2017
View all Megalops, Environment and Habitat History Posts
on The Blue Crab Forum™
Tim Visel, The Sound School, New Haven, CT 06519

On June 6th, the morning temperatures in the Connecticut Northeast hills were in the 40°s. Most low-pressure systems have moved from 200 miles east of Nantucket to the Hudson River Valley. Rains have ushered in cooler weather and Long Island water temperatures remain in the mid to high 50s. Oxygen saturation remains high and some large menhaden schools have moved into New Haven Harbor. Recent reports place the Connecticut River Shad run as good. The NAO index (Icelandic low) remains in an active state, from positive to negative, and back in almost cyclic pulses.
After many decades in a positive (warm less energy) NAO phase, the NAO index bottomed out in 2010, going to some of the most negative readings since the late 1950s. The negative phase is associated with lower temperatures, the “Polar Vortex” and stronger more frequent storms. It was also in 1958 that America’s Shad landings peaked – causing a review of cold and energy pathways into the fish habitat quality changing influence of the NAO itself? The state I believe has the best description of the NAO influencing our New England weather patterns is North Carolina (http://climate.ncsu.edu/climate/patterns/NAO.html). The timing of this habitat capacity cycle factors of the NAO – when it is negative (over time) we see a dominance in “cold water species” in Long Island Sound, in a positive phase (over time) we see that dominance reverse to those species who do better in warmth, such as the blue crab. And, the relationship between blue crabs and lobsters is now very clear: when blue crabs dominated 1998 to 2012, our lobster populations in Southern New England were very low. When lobsters dominated in our recent past, the blue crab populations were less as well as in the 1950s and 1960s. (For a color interpretation of the NAO since 1950, see NOAA Climate Prediction Center. From 1972 to 2011, this four decade period now resembles the 1880-1920 climate feature which had very similar blue crab peaks, blue crabs surged as lobster populations collapsed (IMEP #53, posted on the Blue Crab Forum™ on July 30, 2015 entitled, “Southern New England Lobster Fisheries Collapse of 1898,”) so that by 1903, New England held a lobster convention to review regulatory options for restoring lobster populations (IMEP # 62, “The New England Lobster Convention of 1903,” posted on April 6, 2017 on Blue Crab Forum™) . At the end of the turn of the century and in the 1900s, the dramatic increase of blue crabs in Narragansett Bay was termed the “crab question,” but catch statistics alone do not tell the entire story – the lobster decline in 1898 was not at first related to climate resource patterns except in New York (see appendix, “winter kill”.) In New York’s fisheries, literature we find direct references to a growing blue crab populations that had with its economic importance now surpassed lobsters. This worried New York fishery managers at the time; they had “lost” the lobster fishery and now were worried about the blue crab fishery, which according to New York fishery managers (1900s) they knew little about. They according to the fishery literature did not want a repeat of the lobster industry failure or “ruination” as it was called then. The reason New York fishery managers at the time (1900s) knew little then about blue crabs was in the very cold 1870s blue crabs were very scarce and lobsters were abundant in the shallows. Blue crabs were not considered economically important then and had therefore not been studied. That would change in the 1880-1920 period when blue crabs surged in Southern New England. It was very hot.
Climate change also altered shoreline demographics - the 1890s were brutally hot) and those who could, rushed to the shore for cool air breezes was however, not a topic for fisheries discussion. Fishers and fishery managers responded to increases and decreases in fisheries mostly as increases or decreases in human fishing effort. That is all the information they had, the concept of habitat and environmental clocks was yet to be reviewed. Increases in resources were considered really a natural event, declines viewed as unnatural, as primarily caused by our over use or because of pollution. But nature holds the governor on species change; a huge reproductive set often later results in increasing the predator species that considers this “set” as its food. This predator prey relationship was a painful habitat lesson for Long Island Sound oyster growers who now fought increasing populations of starfish (See Nantucket IMEP #58 and Marine Soil Experiment, IMEP #59A, August 5, 2016) in the cooler 1950s and 1960s. Climate heating and cooling were not addressed, but a review of the 1880-1920 period of heat and often had inshore pollution events that were sometimes “extreme” and yet blue crab and oyster sets increased? In our fisheries history oysters and blue crabs share similar habitat profiles. The 1898 oyster set in New Haven was the strongest set ever recorded (George McNeil personal communication T. Visel mid-1980s).In the late 1920s researchers were beginning to ask questions about temperature and oyster sets. In 1937 Victor Loosanoff and James B. Engle issued a report on Long Island Sound oyster setting (Bulletin #33 – Approved for publication January 10, 1939 US Dept. of the Interior – Bureau of Fisheries) include a section on the impact of temperature on spawning and food availability.
Page 218 – “At the beginning of the century rather abrupt changes in the production of oysters occurred in Long Island Sound waters. Oyster sets, instead of being heavy and regular, became lighter resulting in complete failure. During the last 37 years, heavy setting occurred only 4 or 5 times…”
And further page 253 – “In suggesting his method for predicting the time of spawning and the time and intensity of oyster setting, Prytherch (1929) offered a new and very interesting problem in the field of oyster investigation. Because the influence of temperature on all biological phenomena is undeniable, Prytherch methods are theoretically on a sound foundation.” This concept was reinforced by Gordon Sweet of New Haven, who described it as perhaps a new normal in the early 1940s, climate change was happening.
We have excellent records for the oyster industry with important temperature observations that can assist in this effort. The change in temperature and energy levels was not instantaneous – rather slowly as climate conditions changed and impacts to shellfish species were reflected years later. After many years of no oyster sets, by 1941 New England oyster farmers were already starting to look very carefully at water temperatures. Gordon Sweet of New Haven, Connecticut who wrote extensively about the need to conserve oyster sets was beginning to have second thoughts. In his October 1941 paper titled “Oyster Conservation in Connecticut” Mr. Sweet introduced a new concept for explaining the dramatic oyster harvest declines as now climatic factors. On page 591 (Geographical Review Vol. 31 #3, Oct. 1941) is found this footnote with mentions about “habitat” and “a new balance,” Sweet-1941.
“The colder the waters, the less prolific the oysters, and the more difficult their survival. The progressive contraction south of the northern limit of habitat was apparently due to human exploitation plus marginal environment. Another hypothesis would be our coastal waters are colder than they were 300 years ago but the writer has no data to support this suggestion. Recent investigations under taken by the State of Maine indicate that the rehabilitation (restoration) of their oyster beds is not feasible owing principally to low water temperatures which practically inhibit the spawning of Ostrea (crassostrea) virginica. This contraction has proceeded south to Long Island Sound were a new balance has been established.”
It was going to get worse: “the new normal” (a new balance) a term used often today was to continue to constrict oyster habitat quality back to only warmer coves, deep harbors and river mouths. In the 1960s Victor Loosanoff would later record multiple years of set failures between 1940 and 1965 – oyster sets often did occur but in October and November and did not survive the winter as they came too late (George McNeil, personal communications with Tim Visel, 1980s).
In Dr. Loosanoff’s 1966 paper “Time and Intensity of Setting of the Oyster, Crassostrea virginica. In Long Island Sound (Biological Bulletin Vol. 130 #2 pages 211-227, April 1966 US Bureau of Commercial Fisheries Biological Laboratory Milford, CT (now NOAA NMFS) he now mentioned that in the 1940s, 1950s and 1960s, cooler waters had pushed 10 year set dates, from July (considered “normal”) into much later August and even September. In the late 1960s sets of October (1956) were recorded which arrived too late to survive. Oyster sets did occur it was just they occurred late because of cold springs and cooler spring waters. In his summary he concluded that “during the 25 year period 1937-61 has shown that the larvae of advanced stages were never extremely common.” This was in stark contrast to the 1880 to 1920 period--oyster sets came “early” and were often intense.
The problem was the oyster industry thrived in the warm / hot 1890s, but in the colder 1930s oysters were not setting (except in warmer rivers), they had “retreated” to the last habitats that still fulfilled their habitat requirements. The same thing happened to the blue crabs. When it got colder in New England, Rhode Island fishery managers described that the best habitat refuges for blue crabs was in the salt ponds and rivers. They shared (oysters and blue crabs) a similar habitat history – they reversed with lobsters and bay scallops.
Summary: At the turn of the century, blue crabs soared north of Narragansett Bay as Southern New England had an inshore lobster die-off in the 1910s. This period did not reflect pollution abatement efforts, they were decades away and then it was over – the weather pattern, forage species, predators, and energy levels had all changed. Eelgrass then wasted away to be replaced by kelp /cobblestone (high energy habitats), as storm now intensified, increased and waters cooled). Blue crab and oysters declined across New England in the 1940s as lobsters and bay scallops “returned” from the colder 1870s. They now became abundant.
The impact of pollution now must be measured against natural habitat quality. The 1950s and 1960s had the Rhode Island quahog industry soar after the powerful hurricanes that re-cultivated marine soils, while oystering on a commercial level now ended. All the southern New England blue crab areas saw population declines while lobsters now increased. Blue crabbing in Connecticut was hit or miss; a very warm spring and favorable southern winds could help the blue crab, late winter snows or very cool springs, most likely hurt blue crab’s populations as the NAO phase declined for a half century (more negative).
We may be recording this now and why blue crabs may have such an important role in understanding sea food cycles. And we have had another cold spring, three in a row. All attention should be placed upon the Blue Crab Megalops sets, sign of a good blue crab season in the future.
That’s why the reports of smaller crabs (blue crabber observations) are so important. They can help predict a possible rise or fall of the blue crab again. That is also why blue crabs could become an important indicator species – its relatively short life span enables it to have the shortest cycles. Compare this to the northern quahog clam, it can live to be a century old and now appears only to set heavy three to four times a century.
While water temperatures remain relatively cool, our summer temperatures with warmer or waters the chance of a good Megalops set increases. Any reports of the smallest of blue crabs nickel-sized would be a help in predicting the 2017 blue crab season.
All blue crab observations and habitat reports are very important, thank you for any reports. I respond to all emails at: tim.visel@new-haven.k12.ct.us
See you at the docks,
Blue Chip

Appendix 1
Paulmier – The Edible Crab A Preliminary Study of its Life History and Economic Relationship 55th Annual Report of the New York State Museum
1901 pages 129-138
Crab Fishing Industries of New York
By F. C. Paulmier (indicates T. Visel insertions)
(1901 – 20 Years into The Great Heat)
“In these days, when so many reports on marine economic invertebrates (lobsters) are discussions of the great reduction in numbers (1898 lobster die off) and threatened extinction (habitat failure) of the more important forms (could include terrapins) are filled with plans for remedying this by artificial means (hatcheries), it is a relief to find one (blue crab) form at least, which in spite of being taken in great quantities, still appears to show no diminution in numbers. This is the common edible, or blue crab, which, from all accounts, is just as numerous now as it was 20 years ago.
{Lobsters and blue crabs had recently reversed in 1899 economic importance (the lobster die off 1898) and fishery managers were concerned about the potential collapse of the Blue Crab).
In spite, however of this seems immunity, which appears to depend on several factors, there is no good reason why the disturbance of natural conditions, caused by removing of thousands of crabs annually, should not in time have the same effect here that it has had on other forms, (mostly lobsters and terrapins) and its quite probable that the same story will be repeated here. It is well known fact that man never takes any thought as to the preservation of wild forms till the difficulty of obtaining them in sufficient numbers for this purposes drives him to taking measures for preserving them from extinction and for increasing their numbers. In order to do this intelligently however, some knowledge of the life history, food habits and relationship of the forms intended to be preserved must be had and it’s a strange fact that the forms of great economic importance have received little or no attention from this point of view till it became necessary to study them in order to devise means for their preservation.
The edible crab also which next to the lobster is the most important crustacean of our coasts, from an economic stand point has never received much attention, and practically nothing is accurately known of its life history and habits. On this account and on account of its being (now) the most important crustacean of New York – the catch of lobsters (New York) being very small, the writer at the request of Dr. F.J.H. Merrill, director of the New York State Museum has undertaken a study of the crab from this and from the economic point of view – page 130.
- Callinectes – hastatus –
The common edible or blue crabs ranges along the Atlantic Coast of the United States from Massachusetts south through the Gulf of Mexico to Texas. Within the limits of New York State they are exceedingly abundant in the many shallow bays along the Long Island coast and around Staten Island. Cases of this migration toward deeper water have been noticed on Long Island, where during November the crabs are seen in great numbers, going from the shallower waters of Moriches Bay out into Great South Bay and thence out into Fire Island inlet. At Bay Shore, for instances, which is almost opposite Fire Island inlet, no crabs are taken for the market during the summer, though they are reasonably abundant. During November and the early part of December 1901 much larger numbers were observed going toward the inlet and many were taken and shipped to market. This migration of the crabs depends entirely on the degree of cold. In the southern states they may remain in the shallow water throughout the entire winter. Even in the northern states, especially during a mild winter they may remain near shore in the mud and may be taken at times with clam tongs or rakes.
A cold snap, however, frequently kills considerable numbers of those in the shallow water. During the winter of 1900, according to the fishermen, a large number of these were thus “winter-killed” and were brought up in clam tongs.