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Guest Essay by Kip Hansen – 31 October 2021

While involved in an unrelated activity, I chanced upon two cartoons produced for Sea Grant Maine in 2014, six years ago.  Each of these cartoons predicts coming disaster (calamity) for Gulf of Maine fisheries.  Readers will have already guessed that the reasons for the calamity are Climate Change and Rising CO2.  The absolute worst thing about the cartoons is that they are endearingly cute.  I shudder to think of how many young minds (adult minds too) have been filled with silly and misleading information as a result.

Let’s start with this one:  A Climate Calamity In The Gulf Of Maine: The Lobster Pot Heats Up

My goodness, that was so fun – and oh so wrong.  Yes, the waters of the Gulf of Main have been warming and cooling.  But have the lobsters or the lobster fishery suffered?

Let’s check with the State of Maine Department of Marine Resources:

Despite Covid-19 and all of its economic, trade and transportation disruptions throughout 2020, and the nearly unending spate of new restrictive regulations imposed by the Federal government on Bay fisheries, Maine lobster-men (and lobster-women) still landed 100 million pounds of live lobsters worth over $400,000,000

They have been landing over 100 million plus pounds of lobsters since 2011, ten years!  That’s 1 Billion pounds of lobster.

There has certainly not been any calamity for Maine’s lobster industry.  Gulf of Maine water temperatures do not appear closely tied to lobster fishery production.  During the years of rapid water warming, lobster abundance increased dramatically – the cartoon does admit this, but goes on to project doom and gloom if . . . . . we don’t stop burning fossil fuels!

Then there is this one:

We are told that the Gulf and all its wonderful critters and those who depends on them – fishermen and clam diggers and tourists – are threatened by rising ocean temperatures and changing ocean chemistry. For chemistry, of course, they are talking about Ocean Acidification, the natural mixing of the sea and the atmosphere at the ocean’s surface.  The Gulf of Maine average sea water temperature is currently about a rather chilly 50 ºF (corrected thanks to Tom H.).   And the pH?

Note: The circle highlight is in the original image but is not mine. — kh

It is clear that pH is neither trending up or down, it is highly variable, both year-to-year and seasonally.  2018 had a range of 8.33 down to 7.85.  Other years show about a 0.24 pH unit range month-to-month, with winter months being higher, more basic, and summer months being lower, less basic (or as alarmist like to say “more acid”).   Compare April-May 2018 (light blue) to the same months in 2020 (red).

This monthly view:

While it is widely practiced, it is improper to apply the worldwide-oceans’  much-touted drop of 0.1 pH to any specific locality, in the same way it is to pretend that every place on Earth has had a rise in air temperature of 1.2 ºC.   For the Gulf of Maine, pH is all-over-the-place — daily, monthly annually and inter-annually – but generally stays within a narrow range of 7.9 to 8.3.  The same range as seen in the surface waters of the oceans around the world. 

What is the scary story about pH in the Gulf of Maine?  The cartoon claims that as the pH drops it will dissolve the shells of the clams.  Let’s see how much damage the posited drop in pH has produced on Maine’s annual Clam Landings:

Only 1,674,920 pounds worth $2,643,720.   (The 2020 data is not available on the web yet.)   Truthfully, this looks like good news to me – and oddly (or not) definitely not a calamity.

So, if we accept that irrefutable data on the harvest of lobsters and clams, it is all good news. 

There is a downside to the good news – even I will admit. 

This is the Bad News:

This graph shows the Great Collapse of the Atlantic Cod Fishery.  There was a partial collapse in the 1970s and then a catastrophic collapse in the early 1990s, from which the  cod fishery has not recovered.  The cause? 

Spectacular over-fishing – over a million tons a year for 12 years in the 1960s and early 1970s, and then, when stocks had barely recovered after the first partial collapse by the 1980s, over-fishing at a rate of 600,000 tons a year until the total collapse by 1992.

Biologists would have probably predicted a steady decline on the trend from 1982 to1989 and recommended limiting fishing – but they would have far too late to save the cod.    See the note further on about population dynamics.

If one looks at the cod graph, just the left-hand part, the sharp climb to the high peak in the early 1970s, it looks remarkably like today’s graphs of the Gulf of Maine lobster and clam landings, both of which are soaring to new heights over a single decade.  It is quite possible that Maine is pushing both lobsters and clams to the point of collapse – the same type of greedy over-fishing that collapsed the cod. 

Another example in modern times is the endlessly abundant oysters of the Chesapeake Bay.  Well, not so endlessly abundant after all:

Note: The left graph starts in 1880 while the right-hand graph starts in 1980 — a hundred years later. — kh

The world could probably get by without Maine lobsters and Quahog clams though their loss would be a real economic disaster to Maine.  We have learned to get by without the salted cod of the George’s Bank and the oysters of the Chesapeake.  The topic, however, more science-based than those two cartoons made to scare children into nagging their parents about fossil fuels, naturally leads to the question of population dynamics.  

(If you’re happy just to have viewed the cartons and read to here, you can skip the rest of this essay – unless you have a special interest in population dynamics. — kh)

A note on population dynamics

While we don’t really have a deep understanding of fisheries but we do know that  population dynamics in general are highly non-linear dynamical systems.  The most basic population dynamics formula was given by the Australian biologist Robert May as:

Xn+1 = rxn(1 – xn)

where r equals the driving parameter, the factor that causes the population to change, and xn represents the population of the species at a given time (a number between zero and one that represents the ratio of existing population to the maximum possible population, such as .75).  Changing the driving parameter, rcauses non-linear responses in the total population, as shown here, in which r  is increased from 2.7 to 4:

This diagram shows a population which, at an r of 2.7, re-stabilizes after perturbation (blue trace) then advancing through wild chaotic swings (looking cyclical but with non-repeating values) with r at 3.5 (red trace) to a total slamming up and down, even to seeming extinction, with an r of 4 (green trace).

There is another population dynamics formula:  the predator-prey model. In the real world, May’s population model and predator-prey interact – with predator-prey being a modifier of the r in May’s logistic formula. In real-world experiments, eliminating predators have resulted in unexpected results.   The results, as you can guess, have been highly non-linear. 

The Northwestern Atlantic Cod population has not entirely disappeared as the population was not confined to a single small isolated area (such as an island) but because there were wider connections to the entire Atlantic Ocean, recruitment could take place as some cod could move into the Northwestern Atlantic from elsewhere.  Nonetheless, despite reduced and limited cod fishing, the population has not yet recovered, 30 years later. “Atlantic cod fishery landings had declined from over 75 million pounds (34 million kg) in 1988 to just over 2 million pounds (0.9 million kg) in 2019 in the New England region.” [ source ]  Just 2.6% of the 1988 catch.

The same may be in store for Maine’s lobsters and clams if sensible harvest limits are not implemented – but as population dynamics are non-linear (chaotic) the future cannot be predicted. 

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Author’s Comment:

I don’t watch horror films.   Real life has enough uncertainty and plenty of unpleasant surprises as it is.

Making cartoons to scare little children is despicable.   Presenting false and misleading science information to adults is bad and damages human society.  The concept that a Noble Cause excuses the producers of this type of propaganda is an even bigger lie than those they tell.  That said, many of the people involved in the rabid climate crisis movement are well-meaning and good hearts, they have been led astray into delusion by people in whom they have had the misfortune to place their trust and been betrayed by those in whom they trusted.

I don’t celebrate Halloween either….

Thanks for reading.

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October 31, 2021