The Search for Megalops
“You Don’t Need to Be A Scientist To Report”
Tim Visel – The Sound School, New Haven, CT
The 2020 Blue Crab Season
View All Megalops Program Reports on the Blue Crab Forum™,
Northeast Crabbing Resources Thread
Megalops # 3 –July 15, 2020
This is a delayed report.• A Note from Tim Visel
• 2019 Connecticut Blue Crab Season Ends with Snow
• A Strange Blue Crab Season
• The Polar Vortex – The NAO
• The Blue Crab and Sulfide Diebacks
• US Fish & Wildlife Conference of 1947
A Note from Tim Visel
I did not miss shoveling snow last year; the sudden temperature drops in November of 34 degrees Fahrenheit did concern me. I thought such cold would allow the formation of sea ice, but just as quickly, the cold air then moderated, leading the way for many Hudson Bay lows, storms that had their centers pass to the west of Connecticut pulling Gulf Stream warm air ahead of them. We had more rain than snow, and overall a mild winter. We did have a few cold outbreaks including records being broken and one late in May, but they did not last. Water temperatures actually rose as the winter went to spring. It was a cool but not cold period so the
first observations of small crabs were not a surprise, the number of small crabs however, was. These small crabs not only survived, but also survived in large numbers along the coast. It was like 2010. The first reports noted the numbers of small crabs. Observations of small crabs increased in May and by June swarmed crab lines. The report of Indian River June 20th NE Crabbing Report's posted on June 25, 2020, would be a typical early June report with so many crabs just short of five inches one shed could produce a good year, two sheds a great year; the 2010 crab season had three sheds.
If these crabs did shed including the adults, the percentage of white belly versus rusty crabs would change. Last year adult crabs gave the appearance that they stopped shedding, but when cooked, often had a pre molt shell forming beneath that was clearly evident. Warm days would create the conditions for an early shed and the ratio between short to legals may dramatically change. Thank you for your reports, every observation is important as we learn more about the Connecticut blue crab. I respond to all emails at
[email protected]See you at the docks.
Blue Chip
Blue Crab Populations Dwindle as Snow and Cold Returns to New England Post 2011
The Connecticut 2019 Blue Crab Season ended with flurries and a snowstorm. Cooler water returned to Long Island Sound. Since 2011-2012, blue crabbing in the snow – that almost happened last year, at least you could try. Colder weather has returned to New England as the last decade has seen some record snowfalls. In the last two years our winters have been much milder with little snow; last fall at first, very mild, then cold.
The October water temperatures were in the high fifties (2019) when a series of low-pressure systems with strong winds ended the late fall catches on December 6, central Long Island Sound water temperatures were a cool 44°F. The return of cooler winters that seem to go into “spring” recently has had an impact on the blue crabs last season- the season length has collapsed, the crabs arrived at Essex Town Dock in September, some 90 days later than 2010, and several Connecticut blue crabbers described the blue crab season as “strange” or “weird”, and it was compared to these just a few years ago (see Blue Crabs IMEP 71-B, posted August 16 on the Blue Crab Forum ™. Fishing Eeling and Oystering thread. Megalops Report #3 posted at the opening day of the Connecticut Blue Crab (May 1) had cool temperatures and a very wet spring. A delay in rising water temperatures is thought to have reduced long Island Sounds’ “Dead Zone”, a bank of low to no oxygen waters that grew in size during the extremely warm 1990s. (In 1998, CT only had about an inch of snow all winter), but these changes appear to be natural and climate pattern related, the NAO – the Northeast Atlantic Oscillation, something that was mentioned to me on Cape Cod 40 years ago that is just now being discussed. A natural cycle that has influenced Long Island Sound fisheries and those of New England, it certainly appears to be the same pattern for lobsters as die-offs were reported in 1792 to 1810, 1898 to 1905 and 1998 to 2005; three times in 300 years. (See IMEP #71 posted on the Blue Crab Forum™ on July 31, 2019, New England Lobsters Make a Comeback, 1912 to 1872, Fishing, Eelgrass and Oystering thread) We also have two cycles for the blue crab; which coincide with positive NAO phases, the blue crab explosion of 1898 to 1912, and 1998 to 2012, one century apart; if significant changes happen, it will be the lessoning of cold periods between the warm with great instability between the two.
The NAO climate feature is discussed in depth on the North Caroline climate website. The impacts of the NAO appear to be significant for shellfish as coastal energy (storm frequency and strength) has a direct New England immediate result is now a flurry of papers that point to the NAO or other climate, indices for natural cycles of sea water – fish life changes.
For many years-- decades, it wasn’t a popular stance to write about natural cycles, as it would almost immediately lead to intense discussions about climate change. That has been an unfortunate stifling impact upon the study of natural science changes (as recorded in fisheries). For example, when lobsters died-off in 1998, very few articles mentioned that this happened a century ago, even though every New England state including New York then built lobster hatcheries.
In fact, it was largely the fishing community that kept mentioning the natural science aspect as fish and shellfish “cycles” and the most responsive species to such cycles is the blue crab, my view. It lives in areas subject to intense heating/cooling impacts of heavy rains (acid pH conditions) and drought. They were closest to the resources, made direct observations and kept records of catches. It was unfortunate that natural science was cast aside, but some researchers have realized the value of “fisher comments” and have set to work to reexamine beliefs and values about habitat policy of energy and temperature models. Natural science research however, has languished for decades. (See Kenneth W. Able – 2016, Natural History, An Approach Whose Time Has Come, Passed And Needs to Be Resurrected. Journal of Marine Science, Vol. 73, Issue 9.) The fishing community in time will receive some recognition here in contrast to models. Natural science research languished for decades with a focus upon human impacts.
Long Island Sound temperatures, fisher observations and the NAO – variability call its association with the ridge-trough dipole and tropical modes of the sea surface.
NAO Habitat Impacts
The association of the NAO to shellfish (also frequently mentioned by shellfishers as cycles) was recently discussed in a NOAA publication in 2018.
See October 25, 2018, Press Release “Commercial Shellfish Landings Decline Likely Linked to Environmental Factors- Not Overfishing,” contact Shelley Dawick, from the press release from that paper is: “A major change to the bivalve habitats occurred when the North Atlantic Oscillation (NAO) index switched from negative during about 1950 to 1980, when winter temperatures were relatively cool, to positive, resulting in warmer winter temperatures from about 1982 until about 2003,” Mackenzie said, “We suggest that this climate shift affected the bivalves and their associated biota enough to cause the declines.”
“In the past, declines in bivalve mollusks have often been attributed to overfishing,” said Clyde Mackenzie, a shellfish researcher at NOAA Fisheries’ James J. Howard Marine Sciences Laboratory in Sandy Hook, NJ and lead author of the study. “We tried to understand the true causes of the declines, and after a lot of research and interviews with shell fishermen, shellfish constables, and others, we suggest that habitat degradation from a variety of environmental factors, not overfishing, is the primary reason.”
It certainly did represent a major funding or policy stream effort to quote a frequent phrase, “global warming sucked all the oxygen from the room” – there was very little funding or research effort left – for natural cycles and that is just obvious by the absence of opposing views and papers.
Ken Able, who recently retired from Rutgers University, mentions this natural science dilemma in a paper titled, “Natural History! An Approach Whose Time Has Come, Passed and Needs to be Resurrected”. ICECS Journal of Marine Science, Vol 73. #9 September 10, 2016 pages 2150 to 2155. The article mentions a shift from natural history (See Mervin Roberts’ questions about bias in long term surveys 1985, The Tide Marsh Guide to Fishes).
And mentions a tendency to construct complicated mathematical models (the number of models here soared in recent years) that attempt to close the box on natural features that most likely cannot be boxed. (Data points outside of this box are frequently termed “outliners”) from Able “2016,” is this statement: “The development of our understanding of fish and other marine fauna, including my own over several decades, has proceeded from basic natural history to ecology and evolution, but we often need to return to natural history to address deficiencies in our attempts to manage fisheries conserve habitats and model ecosystems.”
Most of the climate models related to fisheries have large habitat knowledge bias as they rely on single base data assemblages. For example, rainfall tends to both change salinity and pH – (acid rain) and temperature can change dissolved oxygen levels and species biological stress. In fact, if you have attempted to read (and at times perhaps gain helpful information from these models and at times and felt that there must be large gaps in science knowledge in your past, do not anguish! These models often create their own language and terms, and in my experience can overlap – consider this quote from a very recent paper titled, “Long Island Sound Temperature Variability And Its Association With The Ridges-Trough Dipode And Tropical Modes Of Sea Surface Temperature Variability.” Ocean Science 15, 161-178, 2019 and I realize this is out of context but regarding Long Island Sound recent cold events – review the following statement: “The onset and mature phases of LIS cold events were shown to coincide with central Pacific El Nino events, whereas the termination of LIS cold events was shown to possibly coincide with canonical El Nino events or El Nino events that are a mixture of eastern and central Pacific El Nino flavors.”
These papers are not really for the general public, but they are frequently referenced or quoted for public policy makers.
Now contrast basically the same statement in a paper titled, “The Record Breaking Cold Temperatures During The Winter Of 2009-2010 In The Northern Hemisphere (Wong, Livand Lee – Atmosphere science Vol. II, Issue 3, 2010.)
“In this study, we show that the record-breaking cold temperatures from North American to Europe and Asia during the period of 28 December, 2009 to 13 January, 2010 are associated with extremely negative values of the North Atlantic Oscillation (NAO) index which produces northerly surface wind anomalies and cause the southward direction of the cold Artic air. It is speculated that if the downward trend of the NAO continues, more frequent cold outbreaks and more snow are likely in the coming years.” (The increase in snowfalls did in fact happen, T. Visel.)
That was almost a decade ago and only recently have fishery researchers looked at the impact of the NAO? The NAO has been studied for over a century?
These references point to a specific and known climate features, but one that until recently lacked natural history. The possible explanation of very hot then very cold climate periods in New England’s recent climate history. The omission of natural history, for example, is confirmed by the absence of reports that contain information on previous lobster die-offs in Long Island Sound past the 1998 die-off. Lobsters had died off in 1898 and basically in the same geographic region, and it seems before in 1792 to 1810. The 1898 lobster die-off led to the establishment of six lobster hatcheries with the one at Wickford, RI, the most advanced and created the nation’s first larval aquaculture upweller. (See Can We Rebuild Our Lobster Fishery – A Capstone Project Proposal, September 2009 to October 2012 – Tim Visel, The Sound School, 39 pages. And “Lobster Die-off of 1898 and The Great Heat, IMEP #6 posted February 24, 2014, Blue Crab Forum™ IMEP #6 Sound School Capstone Proposal, Wickford Lobster Hatchery and Upweller System (completed in 1900).
Although the southern New England states experienced a lobster failure between 1898 to 1905 and had constructed lobster hatcheries little if any of this historical (natural science) fisheries or climate aspect was brought forward and mentioned in the more recent lobster die-off a century later. In addition, the increase of blue crabs detailed in Rhode Island state reports after the 1898 lobster die-off was not mentioned or the same surge of blue crabs in the same geographical area post 1998.
As blue crabs surged here (just as if they had done before), the history of blue crab catches was not reported and it’s just not Rhode Island, however my effort here is not to single out a single state or group for science research omissions, but to show how large the missing observance of natural science is today in resource decisions. In some reports of the 1800s, it looks like another possible die-off had occurred as US Field Army officers’ complaints that the cost of feeding British prisoners lobsters (War of 1812) had increased and that lobsters were no longer cheap prisoner food (At one time, lobster was only the food of the poor, and reconsidered a subpar meal, so you if had to have lobsters delivered to your back door so neighbors would not see that you ate them.) The period of 1792 to 1810 is looked at another species reversal in New England. It is important to note that the 1770s have had been hot, in fact leading agricultural leaders at the time had urged the planting of Mulberry trees in an effort to create a silkworm thread industry in Connecticut. Colder weather and multiday blizzards soon collapsed this agricultural effort in the 1830s, but reminders still exist from 250 years ago. Today a section of Guilford is still called “Mulberry Point” as a reference to when mulberry tree groves were planted there.
If a third lobster die-off is confirmed, 1792 to 1810, and some references seem to support that, it would help explain other species reversals that followed each of them, black sea bass in Maine, tarpon being caught in Narragansett Bay and the rise of bluefish after hot periods on Nantucket.
A Strange Blue Crab Season?
That was some of the comments made and posted to the Blue Crab Forum™- it was a strange year compared to others in Connecticut. If you expected the same “calendar”, the seasons were different this year, and reflected in shifts in farm and fish seasons. Our climate had shifted to one containing more powerful storms and cooler temperatures. Even the most persistent weather watchers now mention the difference, we are in a period of rapid change, a transitional change in the NAO.-the Northeast Atlantic Oscillation this appears to be why so many comments last year that this blue crab season was different, then just a few years ago, it just was the opposite.
All July and August 2019, I watched and waited for the blue crabs to appear at Essex, as with many other shore crabbers. In 2009 and 2010, blue crabs were plentiful here, perhaps a better word would be extremely abundant. In just one tide, four lines could easily fill a 5-gallon pail of adult crabs, sometimes two pails, but last year, 2019, if you covered the bottom of a 5-gallon pail that was “good”. Blue crabs did finally arrive at Essex, the end of September about 100 days later than just a few years ago. “And, the best places to crab was in “salty rivers,” lagoons that do not have large freshwater inputs. Some rivers that have large watershed and greater freshwater flows had very low numbers of crabs.
And, it was difficult to assess habitats; some peat rivers – rivers that have extensive salt meadows and few or no oysters, are “acid rivers” with acid rain and leaf tannin. These waters are generally acidic and poor crabbing in them. Crabs like the oyster habitats both calcium shell builders and if oysters can live that is a good indication the blue crab can live also. Salinity barriers also impact forage as well; when our waters warmed in the 2000s, oyster sets in the shallow increased and so did the blue crab, so also silversides in drought. Blue crabs were extremely abundant in these shallows, even at times mixed with lily pads; it was hot and a lack of rainfall allowed salty alkaline seawater to move right into the tidal interface and blue crabs followed. Some reports mentioned hard blue crabs swimming among lily pads as freshwater plants started to die-off from salt. An excellent report is on the Internet titled, “Back Bay, Currituck Sound Data Report – Introduction and Vegetation studies 1858-1964. And it reviews the changes in vegetation from natural storms including changes in salinity. Some of the spots in Connecticut that are usually peat or acid rivers had crabs during a period of low rainfall. Peat rivers or creeks were largely absent tidal driven sand and often are bottoms plant debris filled –from stems and leaves, and usually soft bottoms.
The spring was very cool and wet, holding water temperatures below that of just a decade ago. The crabs in high salinity pockets stayed in them as habitat expansion and movement was delayed months into the fall. Blue crabs were found in Essex the end of September versus 2010, when crabbing was good in June, a 2010 June 1st report on the Blue Crab Forum™ reports a catch of one bushel of crab in Old Lyme with a water temperature report of 68 to 70 degrees. It would be the end of August before these temperatures were surpassed, about 90 days later last year. In 2010, the farm growing season got an early start as well. Guided by warm soil germination temperatures. Our weather pattern has changed and tending to be cooler and more rain, it’s easy to forget this spring was so wet some Connecticut fields had to be replanted twice. A June 5, 2019 Wall Street Journal reported that June 2018 to 2019 were the twelve wettest months on record, delayed planting on millions of acres (when water delays or prevents replanting the crop acreage is declared a loss for crop insurance.) In October of 2018, a NOAA Press Release headline read, “Commercial Shellfish Landings Decline Likely Linked to Environmental Factors, Not Overfishing.” (Contact person Shelly Dawicki, - see the Polar Vortex Section).
This season was very different even from just a few years ago. One of the indicators is how our blue crab population is aging, they are literally turning “grey,” as they age. They are turning to different colors “rusty,” perhaps they have stopped shedding. Water temperatures are warm, almost hot, in Connecticut in the late 2000s, blue crabs shed almost constantly. Their shells were bright white with sharp blue claws. That is not the same today – often crabs show brown stains, fouling growths and even a small barnacle.
In some blue crab growth studies (C.W. Leffler, Marine Biology, May 1972 Vol. 14 issue 2, page 104-110) crabs kept at high temperatures 34° C to 27° Celsius or 93.2°F to 80.6°F growth was faster and growth increases per molt, were smaller. Colder temperatures slowed growth. (This was a study conducted in laboratory conditions). This has happened here, and the blue crab gave us a natural science experiment on a tremendous scale, as waters warmed from a positive NAO phase so did blue crab growths. Crabs were shedding constantly and yellow face or rusty crabs rare or unknown. This changed with a huge movement of blue crabs to the east and the difference in shell appearance, striking. (See Megalops report sent 8/22/12, waves of crabs moving both east and west); Up until then the coastal populations were a new shell of a brilliant white belly and sharp blue color claws. The appearance of these hard shell crabs was very different and with the help of blue crabbers was able to map the eastern appearance of them, as catches surged when the “yellow face” crabs arrived. When you crabbed in 2012, it was easy to pick out the yellow faced crabs, but by 2016, “rusty” crabs started to dominate the catch pails. Now going on ten years later, rusty and yellow face crabs make up to 80 to 90 percent of the catch the past few years. Clean, white belly crabs have declined so much they can be considered a minor part of the catch – and I believe growth has slowed or even stopped. These “rusty” crabs have extremely hard shells, very similar to those “old” hard shell lobsters we would catch in the 1960s, dark red, white molar teeth (claws) barnacles or even small mussels on them from time to time. These lobsters looked old, not the bright red to green new shell lobsters.
I think the same thing has happened here with Long Island Sound blue crabs, these crabs here stopped shedding- and most of the rusty crabs are around seven to seven and a half inches spike tip to spike tip. If they shed, we may see some eight and nine inch crabs.
While most blue crab studies give an age range of the blue crab at 5 to 8 years, but I think we need to change that. Blue crabs in pockets of suitable habitat can perhaps live but do not shed. It is perhaps the solar heating of marsh waters that gives these areas a longer season and continue to hold crabs. Most blue crab studies point to slower growth in colder temps. (It is recognized that a blue crab in Florida waters takes about a year to reach legal size; five inches while many Chesapeake reports mention 18 months.)
For the past three years, I have noticed good numbers of three to four inches crabs that I predicted would shed and reach legal size and increase the catches as they had done in the past, but they have appeared to stop growing also. They are also becoming hard, as well direct observations of 3-inch crabs in the oysters, Indian, and Black Hall Rivers, 2019 Blue Crab season they now appear “rusty.” So how old are these crabs?
That has been a research question for me for 50 years, because crabs shed their shells; aging is difficult to determine. They can move, sometimes miles, and finally as mentioned above, growth appears to be very temperature dependent. A cooler part of the coast could show smaller same age crabs as those in warmer areas, even within the same estuary. We may need to expand the age of blue crabs to 8 years or even to 12 years, or perhaps more? As our recent winters have been cooler and snow-filled, the age question of how long blue crabs can live maybe answered here at the northern habitat edge of them.
The Polar Vortex – The NAO
The climate fluctuations past the massive glacial melt freezing New England of its once thick ice sheet appear cyclic and were like features of the circumpolar vortex as described by Hurd C. Willett in a 1953 book Harvard University Press, titled Cambridge “Climate Change Evidence, Causes and Effects”, edited by Harlow Shapley. Hurd Willett’s chapter titled, Atmospheric Circulation, which starts on page 51 has this segment: “The cycle is one of alternate expansion and contraction of the circumpolar vortex with equatorward or pole ward displacement of the prevailing storm tracks.” And provides explanation of climate shifts: “Periods of contraction of the circumpolar vortex (now known as the positive NAO phase) are marked by those characteristics particularly in the higher latitudes-“ and “periods of expansion of the circumpolar vortex tend to the cool in the middle latitudes” – today recognized as a negative phase of the NAO.
Another feature of this polar vortex is the creation of blocking weather patterns as the vortex intensifies, it tends to block “regular” weather patterns. Shifts in the phases and location of the Vortex also was described by Willett as periods of unequal solar heating of the atmosphere, resulting in blocking weather patterns.
Hurd Willet describes these blocking weather patterns, a powerful vortex (as seen during this latest transition from a long NAO positive phase to a more recent and severe shift to the negative phase post 2010- Tim Visel) as ridge that “blocks” storm systems.
The peak frequency of polar anticyclogensis of the extreme blocking type that occurs during water of increasing solar activity) primarily wet the major sunspot maximum, is almost exclusively a phenomena of the North American continent, and not of the Asiatic.”
The research about climate change in the 1950s first acknowledged the lag time between land and sea cooling; the sea is an enormous heat sink, and a moderating influence long ago noticed by coastal farmers. Water can moderate climate and impact transitions of fish species here in New England. Conover in the same book, “Climate Change” also cites Hurd Willett’s work on page 229.
“In general, it can be said that the global temperature trends have been upward from about 1885 to at least 1940, with an indication, at least over New England, that the rising trend has decreased over the past 10 to 20 years. Since 1885, the amount of rise has been about 2°F in winter and less than 1°F for the year. The greatest rises have occurred in winter over the Arctic, exceeding 6°F in the 1917 to 1937 period.”
And further-
“Observational evidence shows that the warming of northern waters lags behind the warming of the atmosphere.” Willett believes that the primary causes of the most significant changes of temperature in the Northern Hemisphere, in terms of the general circulation pattern lie in the position and intensity of the winter polar anticyclone over Eurasia and North America.”
This “lag” in water temperature extends the habitat capacity of warm water species (such as the blue crab in Long Island Sound). When it turns sharply colder – when the continental temperatures cool. This happened in 2010 when the NAO dropped to some of the largest negative readings since the 1950s (source NOAA Climate Prediction Center).
A NAO press release stated about the NAO– Combined landings between 1980 and 2010 dropped by 85 percent, bringing scallops, oysters, quahogs, and soft-shell clams.
“Warming ocean temperatures associated (see Mackenzie and Tarnowski, 2018)with a positive shift in the North Atlantic Oscillation (NAO) which led to habitat degradation including increased predation, are the key reasons for the decline of these four species in estuaries and bays from Maine to North Carolina.
The NAO is an irregular fluctuation of atmospheric pressure over the North Atlantic Ocean that impacts both weather and climate, especially in the winter and early spring in eastern North America and Europe. Shifts in the NAO affect the timing of species’ reproduction, growth and availability of phytoplankton for food, and predator-prey relationships, all of which contribute to species abundance. The findings appear in Marine Fisheries Review.
“In the past, declines in bivalve mollusks have often been attributed to overfishing,” said Clyde Mackenzie, a shellfish researcher at NOAA Fisheries’ James J. Howard Marine Sciences Laboratory in Sandy Hook, NJ and lead author of the study. “We tried to understand the true causes of the decline, and after a lot of research and interview with shell fishermen, shellfish constables, and others, we suggest that habitat degradation from a variety of environmental factors, not overfishing, is the primary reason.”
The information in the Mackenzie – Tarnowski report is very much needed and long overdue. This is something that inshore fishers have mentioned before, it is cycles. But the background research for the cyclic rise and fall of fisheries was close to over a century ago. These cycles were a part of climate research conducted by Hurd Curtis Willett of Massachusetts Institute of Technology and later by Harry Van Loon.
In 2004, Hans Von Storch, a well-known German climate researcher with two colleagues George Kiladis and Roland Madden, organized an interview with Dr. Van Loon, who was hired by Hurd Willett to work at MIT in 1951. D. Van Loon did much of the research about the NAO in the 1950s and 1960s.
This interview features the earlier discussions of polar waves and fronts that provided pathways for cold air to reach the tropics and for very warm air from the tropics to influence temperate zones. American Institute of Physics, Oral history interviews – this section contains “Interview that offer unique insights into the lives, works and personalities of modern scientists.” Interview Harry Van Loon; Interview location: Boulder, Colorado; interview date, September 4, 2004.
Interview Harry Van Loon, 2004 Transcript from the meeting-
Page 24 – How would you then understand that both the Antarctic and Artic Oscillations have received very little attention: “If I really get into this, I will have to insult people that I like. But let me just say just as Clinton’s people said, “It is the economy, stupid.” It is the waves stupid, both into northern and in the southern hemisphere the north Atlantic Oscillation is part of a long wave pattern and you cannot disregard that, so few people take the time to go beyond to see what has been done before on a topic that I deal with.”
“They would have found, for example, the older Defant in 1925, wrote on excellent paper on the NAO, but even now, they don’t refer to it.”
(The history of the NAO in fact, goes back to the Viking seafaring culture and the colonization of Greenland in 985 (Mallet, 2013 Polar Lows In The Northern Hemisphere Influence Of The Large-Scale Environment, Its Variability And Its Changes With Climate Change.)
Harry Van Loon worked for Hurd Willett in 1951 at MIT.
From the Interview with Harry Van Loon, Hans von Storch, al. Kiladsk and R. Madden. Interview tropical September 4, 2004 in Boulder Colorado, USA ISSN # 03441-9629
Harry Van Loon responds to questions concerning anthropogenic (manmade) climate changes at the very end of this 2004 interview Pgs. 29-31
(Harry Van Loon published more than 50 papers on the Northeast Atlantic NAO. – T. Visel)
Question: It seems that you have not engaged in what people call anthropogenic climate change research.
H. Van Loon: “No, I haven’t…”
Question: Did you ever, in your career communicated with the public, with the media or with policymakers?
H. Van Loon: “Not much, I remember an occasion when I was called by Reader’s Digest some years ago. They were going to have an issue on sun and climate. He asked me, “What do you think of anthropogenic global warming?” I said you know, “If you had called me twenty years ago, you would have asked me ‘what do you think of global cooling?’”
He said, “Yes, in those days I wrote a book called, ‘The Cooling’”. (Note from Tim Visel, It appears much of Harry Van Loon’s work was based on his observations).
H. Van Loon: “Don’t forget, I was born at one end of the NAO, and lived for 26 years at its receiving end. Some of the correlations with Copenhagen are the highest.” Pg. 23)
‘So, I said to Readers Digest, “Now you can write one called ‘the Warming’ and you will be just as right. Climate changes all time scales. Because the change happens on our watch doesn’t necessarily mean we are responsible.’”
Question: What do you think is the role of people who are called very often by the media and who are actually influencing the public opinion. You have not participated in this debate with the public. On the other hand, the public deserves some, needs to have a few people like you.
H. Van Loon: “The public deserves reliable, proper information on policies, science, health etc. But it is not so that everybody who has a strong faith in an issue is necessarily the one to give the public information. He or she may be very biased because of their conviction or faith in this issue. Best how do you sort them out? They have to be able to say, ‘I don’t know.’”
Question: How would you do that? How would we do that? Your have the opinion. Some people do better than others, how do you judge that?
H. Van Loon: “I refer to Plato who said, don’t ever give power to those with power. Give it to those who don’t want power because they will do their duty and then they will relinquish the power.”
H. Van Loon concludes: “Also, don’t let those who are keen to be in the limelight be the ones who tell the public what ‘they’ believe is going on.”
But this situation and opinion for Natural Science research has improved little, my view-Tim Visel. I attended the Maine Fishermen’s Forum (2016) a few years ago which featured several presentations about global warming and climate change, when featured increases in the Gulf of Maine, water temperature and a huge increase in the lobster fishery – a positive NAO. I listened carefully as some of the presentations were very good, but kept waiting for mention of a previous century ago warm up; the lobster die-off in the south and increases in Maine, from the sessions I attended no mention of Maine’s Lobster history was made. No mention of cycles of warming and cooling, just a focus upon human impacts (which can be quite substantial. I agree,) however, without any fisheries history, a bias so powerful that it overwhelmed any other possible explanation – my view. During one of the breaks I mentioned, the NAO to one of the weather forecasters who was part of a panel discussion on climate change- if that could be a part of the discussion. The response was “I can’t talk about this”, which left me wondering if it was from lack of knowledge or lack of permission and he then quickly walked away.
But the last three years more and more researchers are looking at the NAO – something Dr. Van Loon had and researchers before him including Alfred Defant in 1925.
Albert Joseph Maria Defant was a meteorologist climatologist and one of the founders of the field of physical oceanography. His career was interrupted by World War II, and his research on large scale atmospheric circulation was first published in the 1920s. This paper titled (1921) “Die Zirkulation der Atmosphäre in der gemäßigten Breite der Erde” Georgiafiska Annder 3 209-266 or The Circulation of the Atmosphere in The Temperate Latitude of the Earth.
In 1926, he became lead scientist for the oceanographic expedition collect the German Meteor Expedition and with multidisciplinary cruises experienced the research areas of chemistry, biology and geology. He was to write about how winds could influence surface ocean waters. Defant’s identification of three major large scale-modes including one he termed the North Atlantic Oscillation or the “NAO” for short. Defant’s works are being reexamined today- See “Defant’s work on North Atlantic Climate Variability Revised” – February 2008, Stefan Bionnimann.
This is where an opportunity exists to bring natural science back, by combining other disciplines and utilizing historic fishery records that respond to climate patterns. In my previous posts, I suggested for heat, oysters and the blue crab, for cold, lobsters and the bay scallop, one short lived, one much longer; this will tend to even out the sharp responses to extremes.
Numerous reports research projects about climate patterns are underway on important factor which shows a possible decline in bias is the mention of natural cycles of seafood long mentioned by fisheries influenced by climate. The 2018 NOAA-NAO paper is an excellent start. My view – Tim Visel.
The Blue Crab and Sulfide Diebacks in New England
The 2000s were a time of declining eelgrass, but from what I witnessed on the Cape, in the 1980s, a surge in waterfowl, especially black ducks had loosened eelgrass in search of shellfish seed in the shallows. An abundance of waterfowl and “open winters” had happened in Cape Cod and I recall strong discussions about this with the MSOA – The Massachusetts Shellfish Officers Association at the time. The waterfowl was impacting both shellfish and sea birds it seemed, were especially fond of small clams and scallops, puddling the shallows and uprooting large amounts of eelgrass in the process.
When I worked on the Cape, this was a huge issue with the Massachusetts Shellfish Officers Association and I recalled conversations with George Souza and Burke Limeburner, shellfish officers about this growing problem. I had never witnessed such shellfish bed damage from waterfowl in Connecticut. In shallow water in Green Pond, Falmouth you could see hundreds of depressions working in eelgrass in areas next to it. See Journal of Field Ornithology - general notes, summer pages 240-241 (1981).
Much of the hard clam seed was in or near these worked banks. It looked very similar to plunge holes used in soft shell clam hydraulic “tests”. An enormous eelgrass wrack developed along the shore from the waterfowl, as Mr. Hammond said, “the result of open winters”. Some discussions on the Cape were mentioned as to control waterfowl, as both the bacteria wastes in shallow water could be clearly seen, and bacteria clinging to eelgrass roots (some waterfowl such as black ducks, feasted on them) could easily pass into the water column. Some areas on the Cape were closed to shellfish thought to be from this fecal impact, bacteria from birds. Bacteria thrived under eelgrass (as in all grasses) and waterfowl uprooted organics mixed among its roots, exposing at time, sulfide stained grey sands – (Personal observations Tim Visel, Cape Cod 1981-1983). Some had blamed blue crabs for those depressions and the decline of bay scallops. I had seen what waterfowl could do to eelgrass, but it was difficult to imagine so many crabs doing the same thing to eelgrass or scallops. However, it was the blue crab connection to marsh that I found confusing – in all the times I had spent crabbing, I had never seen blue crabs attempting to move to eelgrass to feed. I wondered how an adult blue crab could hold a bay scallop in its claws crushing it as food. I have seen blue crabs feasting upon small soft shell clams and crushing small quahogs in Paines Creek, Dennis, Mass. (see IMEP #59A, posted August 5, 2016. which describes an incredible set of quahogs in this creek).
I looked to more climate and soil explanation for both the eelgrass and salt marsh diebacks. This was a time period in which the public attention was being focused upon seafood declines: lobsters, winter flounder and bay scallops- the staple crops of New England cold weather species – all were in sharp decline and overfishing was frequently mentioned. On the other hand, oyster sets were increasing, as were bluefish and the blue crab. I then started to think about habitat health, and the impact of temperature and energy upon habitats and the species that dispensed upon them. No one it seemed had mentioned “under fishing.” The increase of soft bottoms as I had experienced in Tom’s Creek was increasing the marine compost of sapropel was also now happening on the Cape.
A century ago, a noted botanist George Nicholls, of Torrey Canyon Botanical Club noted the presence of sapropel and deepening depressions in salt marshes (salt Pannes). This is from 1920 at the end of 40-year period of heat and few storms discovered what native Americans knew – oysters had been prevalent before, and shells and shell bases were covered with marsh and organic peat in huge deposits in areas near rivers. The largest and perhaps the most studied are the shell middens of Maines’ Damariscotta River. In which distinct layers of shell and organic humus were reported. These humus layers were likely sulfide rich Sapropels.
In the years after the southern marsh die back studies, 1990s, the same sulfide “dieback” impact would be seen in northern salt marshes as the heat continued to build and our waters become warm and hot at times. Sulfide is a known plant poison and in heat, the biochemistry of Sapropels produce it. The salt marsh dieback noticed in southern marshes has happened here, a loss of plant vigor, necrotic black spots and fungal diseases (the same process also is now linked to eelgrass fungal/sulfide rings) sulfide browning and then plant death. This similar dieback occurred in Germany when heat and drought impacted forest soils, increasing sulfides in soils and causing tree stunting, leaf and needle drops and weakening of tree crown vigor. This situation at first was attributed to human pollution that caused soil/sulfide levels, but in fact the greatest sulfate impact was found to be natural, a prolonged drought known as the German forest Waldsterben controversy.
In Southern New England, the increase of the purple marsh crab was looked at for causing salt marsh dieback. An excess of the purple marsh crab which cuts plant tissue as part of its life history, encouraging fungal growth and borrows deep into salt marsh peat for habitat but as in the case in southern saltmarsh die-offs, the die-off of New England salt marshes was also linked that recreational fishing which had “released” from predation these crabs and from human disruption of predator-prey relationships including harvest of blue crabs. (See IMEP #76, posted May 28, 2020).
A paper titled “Role of Crab Herbivore in Die-off of New England Salt Marshes- Authors Mark D. Bertness, Christine Holdridge and Andrew H. Altieri (Brown University) published in Conservation Biology, Volume 23, No 3, pages 672-679 contains these sections, including the blue crab fishery:
“Since a documented population crash in 1994, tautog abundances have failed to recover in Massachusetts (King et al. 2007), and this severe reduction in tautog coincides with the accelerating impacts of Sesarma detected in our aerial image analysis. Similar to tautog, Black-crowned Night Herons (Nycticorax nycticorax) have been historically abundant intertidal forages on Cape Cod, but a recent census indicates their populations have declined over 50% in the past few decades.”
“ The current northern range limit of blue crabs is associated with the thermal boundary at Cape Cod (Williams 1984), which suggests that their control of Sesarma could expand to the die-off marshes in eastern Cape Cod if their distribution moves to higher latitudes with climate change, as has been the case with other shallow water marine species.”
“Our work contributes to mounting evidence that human activities are triggering consumer-driven die-offs that are pushing salt marsh ecosystems toward collapse by affecting the plant species that build and maintain them.”
I wondered how many snails, blue crabs would need to eat, and the shell was small and crabs did frequent the marsh edge, but never observed them feeding in it. But experiments in southern waters supported that blue crabs ate these snails and kept populations low and preventing salt marshes from being devoured by an army of “locust-like” snails in southern marshes In northern marshes it was suggested such as tautaug kept purple marsh crabs in check. But could this be just a cycle, in 2012, the year the blue crab peaked here, the Chesapeake Bay are also saw blue crabs surge. When oxygen poor waters and sapropel increased blue crabs did better (Waters with the surge in blue crabs got a D+).
The Examiner, Washington DC
Crab Population Rebounds to Strongest Level in 19 Years
April 19, 2012
“Annapolis, Maryland’s blue crab population reached its healthiest mark in 19 years, Gov. Martin O’Malley announced Thursday, as one of the state’s signature resources recovers from record low populations just a few years ago.
The Chesapeake Bay’s blue crab population climbed 66 percent from 2011 to an estimated 764 million crabs this winter, according to the Maryland Department of Natural Resources.
The state will now set its sights on maintaining the population while fishermen try to get flexibility to increase their hauls. Larry Simns, then president of the Maryland Watermen’s Association, said he’s grateful for the work scientists have spearheaded alongside Maryland fishermen.
“If you give Mother Nature a chance, she’ll bring everything back full circle,” Simns said.
The announcement comes days after a report card issued by the University of Maryland’s Center for Environmental Science gave the Chesapeake Bay a D+ for its heavy concentration of sediments and dead zones – areas of the Bay where algae growth reduces oxygen levels.”
Pg. 38
US fish & Wildlife Service Staff Meets In 1947- The Biology Survey
During World War II, fisheries had market stability, fishers obtained fuel and engines as fish was “A Fighting Food”; food producers had important roles with war effort. Price supports kept increases in catch from large price drops critical to inshore fishers. Uncle Sam bought the fish to present increased supply to price collapse. That was to change dramatically in the post war etc. This was to impact the nation’s fishing managers as well.
The war was now over, and key members of the Fish and Wildlife Service gathered in Washington, DC to decide the fate of fisheries study in the US. Important to this effort, called the Conference of Division of Fishery Biology, really did not fit the new post war mission- a recognition of Interior’s Fish and Wildlife Service. A key individual in the Conference was Dr. Cottam, who already directed a huge research effort with Audubon into eelgrass and forage grasses for waterfowl post the 1930s die-off of eelgrass. The conference held in Washington DC, January 27 to 31, 1947 and apparently Dr. Cottam had a role on page 4 of the meeting minutes has this sentence:
“The presentation of this plan was in line with the earlier statements of both Dr. Cottam and Mr. Higgins, that divisional reorganization, delayed several years by the war, was overdue.”
For those involved in near shore fisheries research and history will recognize some of the attendees—George A. Rounsefell, Paul Galtsoff, James Gutsell and Victor Loosonoff and Eugene Sorbes of the Leetown Fish Laboratory in West Virginia; all were in attendance.
The blue crab was mentioned in the conference in a section that reviews weather declines in fisheries was in fact overfishing or due to natural causes. See Appendix: the report states climate rather than reproduction capacity giving the abundance, not fishers. This division of “opinion” was to follow the fisheries research effort from founding of the US Fish Commission in 1871. Even the first director of the US Fish Commission, Spencer Baird had mentioned this division in 1877, a period of cold which followed a warmer period. Near shore fisheries had declined and in a 1877 in his speech at the international commission held at Halifax Spencer- Baird gives us the species of concern in 1877, my comments in brackets [Tim Visel]
“While it is probably that the supply of fish on the outer banks and in the deep sea, away from the coast, [deeper water less subject to rapid change – Tim Visel] is as great as that of former years, a lamentable falling off is to be appreciated in the capture of anadromous fish, such as shad, salmon, the alewife. [largely impacted by heat and drought, Tim Visel] as well as of many species belonging immediately to the coast, such as the striped bass, the scup, and other fish. [also impacted by temperature and change in primary forage species- T. Visel] and stating, “The status of fish in the sea is very largely determined by the question of temperature.”
And further, to highlight the reversals in abundance Baird includes in his speech natural fluctuations and those caused by man and he changes in fisheries, as recorded by catches.
A question that still remains today for migratory species and species that have next to land, what is natural and what has been caused by our activities and changes in shore species, in our area the decline of reef fishes, the dramatic decline of Tautog and the incredible increase of Black Sea Bass. The increase and decrease of shore fisheries is often found in the fisheries literature, especially the first shore fisheries not depended upon commerce or commercial markets. They are mentioned to as cycles – complex themselves as climate can influence forage, predators and the habitat quality and quantity of nursery habitats.
In 1877, US Fish Commissioner Spencer Baird gave a stern warning about concentrating too much emphasis upon man's actions, from Paul Galtsoff, History of Woods Hole Circular 145, Washington, D.C., May 25, 1962. Spencer Baird’s address to the 1877 Halifax Convention:
“Fortunately, it is believed the (commercial fisheries, Tim Visel) are capable of remedy by proper legislation and protection, artificial propagation, etc., and that we may look forward in the distant future to a very considerable return to the farmer, very desirable state and condition of the fisheries…(and then later) the status of fish in the sea is very largely determined by the question of temperature” (see the Search for Megalops, Megalops #1, March 1, 2019, posted March 11, 2019 on the Blue Crab Forum™ Northeast Crabbing Resources). As early as the first 1871 the US Fish Commission Reports, he mentions climate changes directly, but not using today’s terms, but in the terminology a century ago. From Galtsoff 1962, Spencer Baird lists the reasons for the decrease of summer shore fishery of the south side of Massachusetts and Rhode Island (This is a period of extreme cold – T. Visel) as,
1) Decrease or disappearance of the food of commercial fisheries;
2) Migration of fish is to other localities -See “what happens when the fish move north and fishermen don't.”
3) Epidemic diseases in peculiar atmospheric agencies such as heat , cold, etc. (This is the rise in Vibrio infections in the climate cycle of the North Atlantic Oscillation NAO - Tim Visel).
4) Destruction by other fisheries (see the outbreaks of starfish and the oyster industry - Tim Visel).
5) Man's activities resulting in the pollution of water, in overfishing and the use of improper apparatus. (Renew escape panels an escape fence in the trap, trawl and pot fisheries. - Tim Visel) Reports on the conditions of the sea fisheries of the south coast of New England: In 1871, Spencer Baird mentions sulfide events and disease, as #3 above page XXII,
“Thirdly, disease or atmosphere agencies, the question of epidemic diseases among fisheries is sometimes suggested by finding large numbers are coming ashore, at times with and at others without any assignable course. Occasionally this may be referred to volcanic exhalations, which charge the water with Sulphuretted hydrogen gas or other noxious substances and have produced death.”
Paul Galtsoff, History of Woods’ Hole, Circular 145, Washington DC May 25, 1962.
Much of the conference proceedings were about the nation’s fisheries and trends. The rises of some species and the sudden declines in others. Much of the same “opinions” about the rise and fall of fisheries still occur seven decades after Baird’s 1877 speech.
Appendix 1
The Problem for Models – Climate Cycles and The Blue CrabBy the 1940s United States Fish and Wildlife researchers had apparently come to conclude that natural factors, not catches, had come to define the changes in blue crab abundance especially in Chesapeake Bay. Fish and Wildlife Service Conference of the Division of Fishery Biology January 27 to 31, 1947 Conference Proceedings Issued March 1947, fisheries management titled “Ecology Utilization and Management of Marine Fisheries,” Paul S. Galtsoff – The American of Eastern Oyster in 1964, James Gutsell The Natural History of the Bay Scallop 1930, and Victor Loosenoff, who connected oyster spat fails to climate cycles in 1967 and Eugene Sorber, head of the fish laboratory in Leetown, West Virginia) on page 27 contains this section:
“The blue crab of Chesapeake Bay exhibits wide variations in abundance that cause large losses to the industry. Restrictions on the catching of adult egg-bearing crabs did not remedy this condition. Research has just discovered that those variations in abundance are caused by changes in the survival of young crabs rather than by the number of eggs spawned. This survival is influenced chiefly by stream flow, especially in the James River, there is a very promising prospect that further studies of the manner in which crab survival is influenced by those flows that make it possible to raise the average abundance of crabs in the Chesapeake Bay through regulating stream flows by means of flood control and power dams now proposed by the Corps of Engineers. The reimposing of restrictions on the catching of egg-bearing crabs which was popularly advocated would have cost the fishermen nearly a million dollars a year without increasing the supply of crabs.”
(Flows in rivers are influenced by the NAO – Tim Visel).
Appendix 2
Natural History – A Time To Revisit?Kenneth W. Able – 2016, Natural History, An Approach Whose Time Has Come, Passed And Needs to Be Resurrected. Journal of Marine Science, Vol. 73, Issue 9. ICES Journal of Marine Science- September/October, 2016, Pages 2150-2155. Published: 22 April 2016.
“This resurrection of natural history is still needed because of the complex life history of fish, and many other marine fauna, and the lack of appreciation of shifting baselines in marine environments. These inadequacies are especially evident when we try to address the effects of human influences, e.g. fishing, urbanization, and climate change relative to fisheries management and conservation. A solution lies in the rebirth of natural history studies, especially at “places” such as marine field stations. Long-term monitoring especially continues to provide critical insights. All these approaches are limited by inadequate appreciation and, as a result, funding. The solutions are largely site and investigation specific but would be enhanced by a greater appreciation of the advantages of comprehensive, long-term studies in natural environments, especially regarding the increasing worldwide emphasis on conservation and habitat restoration.”
