The AMO, Codfish, Seals and Fishermen

Only remotely related to climate change, but perhaps related to politics polluting universities, this essay floats ideas concerning our nations fisheries, and fishes for feedback from WUWT readers.

Guest essay by Caleb Shaw

When I was just a small child in the 1950’s the United States stubbornly clung to having a mere three-mile-limit, and Russian fishermen could come quite close to our shores with boats loaded with spying equipment.  They also overfished the Grand Banks and our other offshore waters with deep, bottom-churning dragnets to such a degree the codfish population crashed.  Even when the three-mile-limit was pushed far off shore, the codfish never came back.

The fishermen have taken a lot of heat for the failure of the codfish to return, and university biologists have worked hand in hand with paper-shuffling bureaucrats in Washington, far from the briny swells and crying gulls, and these lubbers tell sea-going men, men who know the sea like the back of their hands, what to do about the sea.

The fishermen have no choice but obey the bosses in high places, and their fishing has been cut back more and more.  It has not made a lick of difference.  In fact, if you wanted to use absurd logic, you could say the situation proves that the less you fish the less fish there are.  Either that or you could say that whenever Washington gets involved, things get screwed up.

In actual fact there are three main reasons the codfish population hasn’t come back, despite the fact a single mother codfish lays over a million eggs.

The first reason is that the Atlantic goes through a cycle, roughly sixty years long, called the AMO,  (Atlantic Multidecadal Oscillation,) and in a simplistic way this suggests that the best breeding conditions for a codfish only comes around every sixty years.  Right now we are back to the conditions of 1953, the year I was born.

In actual fact the shifting positions of warm water and cold water created by the AMO mean that there are different places in the North Atlantic, which, every year, may be having their peak year for breeding codfish.

You will please notice that fishermen have no control over the AMO. Even if there was a population explosion of cod, there is another harvester of cod besides fishermen:  Seals.

Seals happen to be very cute, and they started being protected when their soulful eyes touched people back in the 1970’s.  Recently their population explosion has gotten out of hand. For example, in 1994 on Muskeget Island there were 19 grey seals, and by 2011 it was difficult to count them all; there were between 3500 and 3800. The population of Grey Seals in Massachusetts alone has passed 15,000, and the population of Harbor Seals in New England has passed 100,000.  (Read More:  http://www.talkingfish.org/newengland-fisheries/booming-new-england-seal-population-creates-a-management-challenge

Even if there were only 100,000 seals in New England, if they each ate five codfish a day, that would a million codfish every two days.  That adds up pretty quickly. We are talking a sizable catch of 182.5 million codfish per year.

The seals will not obey the environmentalists who tell the fishermen to fish less, even though they owe their lives to environmentalists, for rather than fish less, the seals fish more and more.  What is especially annoying to fishermen, who are not allowed to shoot seals, is that the seals like to follow boats and steal fish right out of the nets.

Is this a return to natural conditions?  Not really, because for thousands of years, long before the “white man” came, the natural predator of seals was Native Americans.  Native Americans had really neat sea-going canoes; dugouts made of the trunks of huge white pines, and hunted for not only seals, but also whales (though likely the baby whales were preferred.)

Even the most ancient of known mound-building Native American people, the Red Paint People, who lived north of New England, had swordfish bills in their graves, and, because swordfish lack swim-bladders and sink to the bottom rather than floating to the shore, this is taken as indirect evidence that, even as long ago a ten thousand years ago, (before Stonehenge in England,) seagoing humans hunted our shores.  In other words, this may be the first time in ten thousand years seals are not hunted.

What other natural predator may have existed, ten thousand years ago, which hunted seals?  Evidence is scant, however a subspecies of polar bear may have roamed this far south, as the seas rose after the last ice age, and covered the ancient shorelines.

The only predator we are sure of is the Great White Shark.  And now that seal populations are booming, such scary sharks are becoming more common off Cape Cod.  For the first time since 1936 a swimmer was attacked, last summer.

That single attack made people think more about culling the population of seals than the suffering of hundreds of fishermen. Likely this occurred because people are greedy, and tourism brings in money, and news of swimmers being eaten by Great White Sharks is bad for business. Unfortunately, besides the tourists brought in by whale watching, there are tourists brought in by seal watching, and, because seals are cute while sharks are downright ugly, some think the Great White Sharks are the ones who ought be culled.

Perhaps we ought bring in a population of polar bears.  They are cute, and eat seals, and people feel all warm and cozy when the polar bear population goes up, and, if a few swimming tourists got eaten, well; you can’t make an omelet without breaking a few eggs.

You’ll notice nobody talks much about 182.5 million codfish getting devoured.  Why not? The answer is obvious.  Ever look a codfish in the face?  They are most definitely not cute. (Nor are most of the fishermen, whose livelihoods depend on codfish.)

I hate to sound cynical, but it seems to me a lot of the university biologists, rather than basing their conclusions on science, are basing conclusions, (which usually conclude fishermen should make less money by fishing less,) on a sort of political correctness founded upon money, votes, and, damn it all,  cuteness.

If university biologists were true scientists they would ignore all the nonsense of the non-scientific idiots ruling Washington, and study a third and likely most significant reason for the decline in codfish populations. This involves the fact that, when a mother codfish lays a million eggs, they are very tiny eggs.  In fact, for the first few weeks of a codfish’s life, codfish are basically plankton.  It is only after three or four weeks that they stop swirling about the surface, and sink to deeper depths and start behaving like a more ordinary minnow.

During the time they are plankton they are constantly growing. Many of the species of plankton about them do not grow. A tiny critter that devours countless codfish may need to turn tail a week later, because the cod it missed might turn around and eat it.

Consider the interesting computer modeling this might involve, for a geek at a university.  How often in nature does the predator become the prey?  Does a baby deer grow up to eat a mountain lion, or a baby rabbit grow up to eat foxes?  However, in the world of codfish, such is the case. What an interesting “K,” (The equilibrium constant,.) to play around with!

It just might be that the reason the Codfish population isn’t recovering is because a certain species of plankton is eating them all.  However, if only those million babies could be sheltered for only three weeks, and released, they would devour the very foe that has been depressing the codfish population, whereupon, without that foe devouring the smallest codfish, those smaller ones would also mature and eat the foe, until the foe became few and far between, and codfish populations would explode.

It should be noted that “white men” first came over here from Europe, perhaps as long ago as the 1300’s, for one risky but lucrative reason, and that reason was to fish for codfish.  There is much argument about when the fishing first started, but European fishermen certainly were sailing here before there were any “official” colonies. They had no desire to take over or start colonies, and only briefly landed here to build fires and dry their fish, before sailing back east to Europe. Why did they go to all that trouble? Because it was lucrative.  Why? Because, according to histories I’ve read, the codfish were so thick on the Grand Banks they didn’t need to use nets.  They used over-sized baskets, to dip the fish from the swarming sea.

Considering such a population boom is within the realm of possibility, and considering the good such a vast source of high-protein nourishment would be to a hungry humanity, I can only wonder over the fact not a single university smarty-pants has (as far as I know,) ever proposed a codfish hatchery.

We spend millions on hatcheries for trout and salmon, but not a penny on codfish hatcheries. We spend billions on stupid wind turbines that are counter-productive, but not a penny on a single boat for the reestablishment codfish populations.

What sort of boat?  It would be a boat designed to strip mother codfish of their million-plus eggs, milk father codfish of their sperm, keep the fertilized eggs and hatchling in a safe, predator-free environment until they were two, three or four weeks old, and then release them to the wild.  In other words: a hatchery.

I’m sure creating such a tub would involve all sorts of problems.  However isn’t that what universities are for?  To use our brilliant, young minds to solve problems?

I’m sure it would cost money, however considering the trillions spent on welfare, on unproductive losers, (on thin air,) a “mere” half billion spent building three or four small, sea-going hatcheries, and staffing them, (and many students would actually like wallowing about the Grand Banks and getting sea-sick, and do it for free,) might be an acceptable risk, as an investment.  Especially when there is at least a small chance that having actual hatcheries for codfish might restore populations to their former amazing levels.

I know young and naïve students would leap at the chance of supplying the hungry world with a huge stock of codfish, even if the scheme seemed a bit hare-brained to their pragmatic elders.

I also know these same students are sick to death of having to affix “Global Warming” to the final paragraph of each and every report, whether it be about the mating habits of nematodes, or about when dogs howl at the moon, simply to get a parking place at the college cafeteria.

Kids are not as stupid as we old geezers sometimes think, you know.

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David Riser
June 13, 2013 12:07 pm

Willis, I was originally under the impression we were discussing New England. No worries. Yes you are right in your post concerning trawling. Most likely that has a lot to do with it. That is one of the points brought out in the Case Study.

Latitude
June 13, 2013 12:17 pm

That’s my explanation of the cod collapse.
==========
There’s a lot more to it than just that Willis…
You’re heart seems to be in the right place…..
back up and first ask…why were there so many cod in the first place
….temps had more to do with it
http://www.fishlarvae.com/e/BigBang/Jordaan.pdf

vigilantfish
June 13, 2013 12:29 pm

Hi Mike,
Thanks for the info: that would be the late 1970s, then (Joe Clark was elected in 1979) as Canada was preparing for the ratification of the 200-mile EEZ (which occurred in 1982) and when ostensibly Canada had an interest in regulating and limiting foreign fishing within its extended EEZ. Very interesting….

Mike
June 13, 2013 12:46 pm

vigilantfish, it was the summer of 1979. I think the 200 mile limit came in in 1976 — it was being enforced in 1979 ergo why I was figuring out a way to determine (quickly given the computers DFO used) whether a lat/lon was inside our limit and which license area it applied to.

Editor
June 13, 2013 1:01 pm

David Riser says:
June 13, 2013 at 12:07 pm

Willis, I was originally under the impression we were discussing New England. No worries. Yes you are right in your post concerning trawling. Most likely that has a lot to do with it. That is one of the points brought out in the Case Study.

Thanks, David, and your are right about trawling being one of the points covered in the Case Study.
w.

Editor
June 13, 2013 1:15 pm

Latitude says:
June 13, 2013 at 12:17 pm

That’s my explanation of the cod collapse.
==========
There’s a lot more to it than just that Willis…
You’re heart seems to be in the right place…..
back up and first ask…why were there so many cod in the first place
….temps had more to do with it
http://www.fishlarvae.com/e/BigBang/Jordaan.pdf

IF temperature increases were the cause of the collapse, then surely we’d have seen previous collapses or at least serious drops as the temperature has varied over the centuries, and greater collapses in the southern fisheries as opposed to the northern. I don’t know of any record of those happening, although of course earlier data is more sparse.
The study is an interesting one. However, all it shows is that there are optimal thermal conditions for cod across their range, and less than optimal conditions. As the study says,

Sundby (2000) observed that recruitment tends to be better in warmer years in the cold part of the geographic range of cod and in cooler years in the warmer part of the geographic range. It appears, therefore, that although populations can exist over a fairly broad range of temperatures, highest cumulative survival occurs over a smaller range of temperatures somewhere in the middle of the species thermal range.

However, we didn’t see that pattern in the collapse. In fact, the Northern Cod, who presumably would be benefitted by a slight warming, suffered a greater drop than more southerly groups …
So while the study does show that (as with almost all oceanic creatures) there are optimum temperatures for their growth, it doesn’t say that that a temperature change was responsible for the collapse of the fishery. Instead, it says:

Changes in temperature in the wild are not usually enough to cause mortality through disruption of development (direct mortality) since sea-surface temperature anomalies typically are on the order of 4 °C (Pepin 1991).

All the best, and thanks for a most interesting study,
w.

Latitude
June 13, 2013 1:33 pm

Don’t assume that your starting point was “normal”….
…”back up and first ask…why were there so many cod in the first place”

Editor
June 13, 2013 1:37 pm

Latitude says:
June 13, 2013 at 1:33 pm

Don’t assume that your starting point was “normal”….
…”back up and first ask…why were there so many cod in the first place”

Scrap the socratic method and answer your own question, I’m not interested in playing guessing games.
w.

RT
June 13, 2013 1:53 pm

Seal was served at the first Thanksgiving. Just like all animal populations, they should be regulated by hunting.

Editor
June 13, 2013 1:56 pm

Latitude says:
June 13, 2013 at 11:23 am (Edit)

Thanks, Latitude, but sadly, you haven’t done your homework.

===
Willis, I’m not the student…I’m the teacher
…you don’t know what my profession is

Nor do I care what your profession is. If you are a teacher, you haven’t done your teacher’s homework.

Your chart does not reflect when populations increase or recover………period

You are correct that it doesn’t reflect populations directly. That’s why it’s called a graph of fish landings. These reflect fish populations, but only indirectly.
However, the precipitous drop in landings post 1968 is indisputable evidence of a drop in the population.
The big drop post 1992 is the result of the moratorium on cod fishing in parts of their range.
However, since cod fishing has remained legal in parts of their range, landings have not gone to zero. People are still out there fishing, so if there were a recovery, we would definitely expect to see it in my chart.
So yes, my chart does reflect when populations increase or recover. The problem is … they haven’t recovered. And in fact, NOAA is talking about closing the cod fishery in the Gulf of Maine. If the cod were recovering, then catches there should have recovered … but they haven’t.
And we can see that in my chart, which would show if stocks were recovering where they are still fished, but which clearly shows that that stocks have not recovered.
Period. Even if you are a teacher.
w.

Latitude
June 13, 2013 2:17 pm

Lat said: “Your chart does not reflect when populations increase or recover………period”
Willis said: “You are correct that it doesn’t reflect populations directly.”
..and you have your butt up on you shoulders right now…..why?
===========
Willis said:”However, the precipitous drop in landings post 1968 is indisputable evidence of a drop in the population.”
“The big drop post 1992 is the result of the moratorium on cod fishing in parts of their range.”
“And in fact, NOAA is talking about closing the cod fishery in the Gulf of Maine. If the cod were recovering, then catches there should have recovered … but they haven’t.”
“GULF OF MAINE COD
The Fishery
Total commercial landings in 2005 were 3,909 mt, slightly below those from 2001-2003 but approximately 139% greater than in 1999 ”
http://www.nefsc.noaa.gov/sos/spsyn/pg/cod/

Latitude
June 13, 2013 2:39 pm
Henry Bowman
June 13, 2013 3:02 pm

You write

It should be noted that “white men” first came over here from Europe, perhaps as long ago as the 1300’s, for one risky but lucrative reason, and that reason was to fish for codfish.

I think this statement is incorrect: Europeans came to North America (a) well before 1300 and (b) mostly in search of ivory, in the form of walrus tusks, as these were valuable trade items. Cod, which was quite plentiful then, was simply used for food on the voyage.
See Farley Mowat’s >a href=”http://www.amazon.com/The-Farfarers-History-North-America/dp/1616082372/ref=sr_1_11?ie=UTF8&qid=1371160608&sr=8-11&keywords=farley+mowat”>The Farfarer’s for more detail.

Rud Istvan
June 13, 2013 3:14 pm

Caleb, an enthralling essay with much food for thought as the comments show.
You might want to read Kurlansky’s recent book Cod, which is not only a history of the fishery but an exploration of the recovery efforts. One of the issues is that ‘Nature abhors a vacuum’. So the ecological niche occupied by cod is now predominated by other species, including but not limited to lobsters. Eating more lobster would help bring back cod.
Cod are an example of a complex system as rich as climate.

phlogiston
June 13, 2013 3:59 pm

Rud Istvan says:
June 13, 2013 at 3:14 pm
Caleb, an enthralling essay with much food for thought as the comments show.
You might want to read Kurlansky’s recent book Cod, which is not only a history of the fishery but an exploration of the recovery efforts. One of the issues is that ‘Nature abhors a vacuum’. So the ecological niche occupied by cod is now predominated by other species, including but not limited to lobsters. Eating more lobster would help bring back cod.
Cod are an example of a complex system as rich as climate.

Jellyfish are also occupying niches stripped of fish world-wide. They can also be cooked and eaten – apparently.

June 13, 2013 3:59 pm

I’m with Willis. Factory ships are destroying the ocean.

June 13, 2013 4:26 pm

Wow! I leave for a few hours to finish the Childcare day and get the goats, rabbits and chickens fed and out of the rain, (and also decide to heck with weeding the muddy garden,) and when I return Willis and Latitude are duking it out.
I break up fights between children under ten all day long, so I’m pretty good at it. However I don’t want to step in the middle of this one, as the fists are made of all sorts of interesting information. Go at it, men!
I would like to say that the magnitude of the decline of cod populations is clearly shown by Willis’s graph. The fact the catch could near 2 million tonnes is inconceivable to young fishermen, who live in in a time when 50,000 tonnes seems like a lot.
I see what Latitude is driving at, when he says “catch” is not the same as the “uncaught stock.” However “catch” is a solid figure, a reality, while “stock” is a theory, hidden under the surface. Perhaps sonar and other fish detectors are a lot better than I know, and “stocvk” is no longer hidden, in which case I don’t mind learning about it. However “stock” is also susceptible to the mystery of politics, and the tendency of the more greedy sort of businessmen to fudge figures. Therefore “catch” seems realer to me. I know a caught fish matters more to a hungry person than “stock,” (unless it is a fish stock in a kitchen pot, with onions, potatoes, milk, bits of salt pork, and lots of pepper.)
(Getting near dinner time, here on the east coast; can you tell?)
I really appreciate the historical insights I’m getting about how the fisheries management people could have blundered so badly.
I think returning to line-fishing would be interesting, and much better for the ecology of the sea-bottom, but fear the fishermen would go broke.
Dinner’s ready. I’ll comment more later.

Latitude
June 13, 2013 5:45 pm

and when I return Willis and Latitude are duking it out.
====
Don’t include me in on that……..
There was a major change in the way “catch” was recorded…they increased the size of the holes in the nets….that let smaller fish that were counted before as catch escape…and were not counted as catch after that
But you’re right…catch is not a solid figure.. and stock is only a theory
This is was include in the link I provided….that no one seems to have read
http://www.nefsc.noaa.gov/sos/spsyn/pg/cod/
“Gulf of Maine cod landings have generally been dominated by age 3 and 4 fish in numbers (Figure 1.3 [Fig 1.3 Data]). Representation of age 2 cod was relatively high in the early 1980s but, in response to a series of minimum mesh size increases during the 1990s, age 2 fish have gradually all but disappeared from the landings. Cod from the strong 1987 year class predominated from 1990 through 1992 but, by 1993, fish from the 1990 year class accounted for the greatest proportion of the total number landed. From 1994 through 1996, landings were dominated by age 4 cod and in 1997 age 5 fish were dominant, reflecting the higher abundance of the 1992 year class. Although traditionally low in terms of their contribution to the total landings, age 10 and 11+ fish were absent for several years during the 1990s, and numbers of age 8 and 9 fish have also been unusually low. More recently, the 1998 year class has dominated the landings at ages 3 through 6 in 2001 through 2004, respectively. As well, the proportion of cod older than age 7 has begun to increase.

Editor
June 13, 2013 6:12 pm

Latitude says:
June 13, 2013 at 2:39 pm

53rd Report
http://nefsc.noaa.gov/publications/crd/crd1203/crd1203.pdf

Thanks for that report, Latitude. Here’s the current one:
55th Report
http://www.nefmc.org/tech/cte_mtg_docs/130123/b_55th%20NE%20Regl%20SAW%20Assessment%20Summary%20Report.pdf

Willis: “And in fact, NOAA is talking about closing the cod fishery in the Gulf of Maine. If the cod were recovering, then catches there should have recovered … but they haven’t.”

“GULF OF MAINE COD
The Fishery
Total commercial landings in 2005 were 3,909 mt, slightly below those from 2001-2003 but approximately 139% greater than in 1999 ”
http://www.nefsc.noaa.gov/sos/spsyn/pg/cod/

Since I was referring to now, as in 2103, for the closure proposed by NOAA, I’m not clear what 2005 data have to do with it …
According to the 55th SAW I linked to above, dated Jan 2013, the most recent data they have is for 2011. The numbers for total removals (commercial landings + commercial discards + recreational landings + recreational discards) in the most recent three years of record looks like this:
2009: 8,400 tonnes
2010: 7,100 tonnes
2011: 6,800 tonnes
Apparently things have not improved since then given that in 2013 NOAA is talking about closing the commercial fishery.
The 55th SAW has an interesting chart.

It is, of course, subject to the usual caveat. It is what it says, total removals (catch + discards) by fleet. It is not spawning biomass, or any other measure of the cod stock.
w.

Latitude
June 13, 2013 6:40 pm

Willis, do two things…
Read the paragraph I posted….while at the same time look at that chart you posted for “total fisheries removal”…..that’s the weight of the catch
When the mesh size increased…the size of the catch “total fisheries removal”….crashed
Since then…..it’s leveled out….with the exception of the heat wave in ~1999…and again ~2006
Keep in mind the previous post I made about development of larvae….how temp dependent they are…and how long it takes to get age 2/3/4/5 fish…and if the breeders move out there’s no breeding
BTW the NOAA is always talking about closing fisheries…..that’s their job…the more they manage the bigger they are

Latitude
June 13, 2013 6:53 pm

BTW one last thing…..which won’t do one bit of good if you don’t read it 😉
There’s more to fisheries than just removing fish….
http://opensiuc.lib.siu.edu/cgi/viewcontent.cgi?article=1030&context=jcwre
…oh and BTW again….the shrimp industry has been thriving since the cod population went down…well, except for when warm water blows in there again
Isn’t that a hoot, if the shrimp business had been thriving first…..they would be complaining about the cod…LOL

June 13, 2013 6:58 pm

RE: Latitude says:
June 13, 2013 at 5:45 pm
Thanks for the link. It was last updated in 2006. Does NOAA have a more recent update?
I’ve learned a lot today, but obviously still have a ton to learn. After dinner I was reading up on Capelin, because I was intrigued by Willis’s comment that Capelin was a food for Cod but now Cod are a food for Capelin. It seemed a perfect example of the difficulty at arriving at any sort of “K,” (The equilibrium constant,) though when I discussed that in my essay I was imagining a species of plankton eating the embryonic cod, and not a small fish eating them.
In speeding through stuff about Capelin I learned Herring eat a lot of Capelin when Capelin themselves are just swimming embryos, and many times (but not always) a boom in the population of Herring will coincide with a crash in the population of Capelin. So now you have a third factor, as you try to figure out your “K.”
If you keep adding in variables I think you might find you wind up with one of those chaotic systems that has a sort of chaotic order. (After all, the beautiful spirals of a big storm or hurricane seen from space is a chaotic system.) I recall that, back in the 1980’s when the ideas about chaos theory first played around with the concept of Strange Attractors, seeing a chaotic system that switched between two different states. It was attracted to one or the other, and got stuck in one orbit or another, but occationally made a radical switch.
I don’t claim to have the slightest understanding of this chaos-theory-stuff, however, as an interested layman it was one of those bits of trivia that parks in your mind in 1986, and now it pops back in 2013, as I wonder why Codfish populations, which were “stuck” at such high levels, now seem “stuck” at such low levels. Perhaps we spun out of one attractor to another attractor. The question is, can human efforts jolt us back to the first attractor?
(Around about now the fellows who actually study chaos might be rolling their eyes.)
I think one energy that fueled the above essay was simply old-fashioned frustration. I’m frustrated because it has been twenty years since Codfish populations ( or at least “catches”) hit bottom, and we still are sitting at the bottom, despite many good and not-so-good minds working on the problem. It is a problem that would do the world a world of good to solve, because a return to the Grand Banks of yore would not double or triple our current catch of fish, but multiply it by ten or twenty. (That prospect alone might justify a return to line-fishing.)
Two posts before mine WUWT had a post about seeding the ocean with iron to capture carbon: http://wattsupwiththat.com/2013/06/12/national-laboratory-pans-ocean-carbon-sequestration-scheme/ In that post I commented (June 12, 2013 at 5:59 pm) on some population explosions I’ve seen the sea amaze me with. However the one I’d like to see most of all is a population explosion of Codfish.
Someday it will happen. All that is needed is the right combination of events. Whether these events will occur due to mankind’s efforts, or despite mankind’s efforts, is something I currently cannot foresee.

Latitude
June 13, 2013 7:09 pm

Thanks for the link. It was last updated in 2006. Does NOAA have a more recent update?
====
Why? you don’t need one….it describes what happened to the fishery and why there was a decline. Since 2006 “catch” has increased.
===========
as I wonder why Codfish populations, which were “stuck” at such high levels, now seem “stuck” at such low levels.
=========
head wall…head wall….head wall
Read the links I posted……try “historic decline” in the last one
temperature dependent….pollution….dams…..lack of food….bigger net mesh…shrimp fisheries improves

vigilantfish
June 13, 2013 7:14 pm

Caleb,
You said ‘I think returning to line-fishing would be interesting, and much better for the ecology of the sea-bottom, but fear the fishermen would go broke’.
Somehow they survived in earlier times with this less efficient technology. It’s interesting that fish became more of a delicacy in the North American diet after the collapse of the East Coast fisheries – and of course, scarcity drove up prices. Another issue is that the cost of modern technology makes the large efficient fishing vessels unaffordable to the common fishermen – they become employees of large, integrated fish processing companies. I wish it were possible for entire nations to embrace, for the sake of some level of conservation to safeguard the food supply, a lower level of technology in the fisheries. Given the apparent surveillance capabilities of Big Brother-esque governments, it might even be possible now to ensure nobody is cheating. I don’t want to sound like a Luddite, and am certainly no tree-hugger, but the combination of powerful engines, otter trawls and similar gear, and sonar, has stacked the deck against healthy-sized commercial fish populations. As far as I can tell, no one is willing to give this aspect of the problem any consideration, because efficiency is the god of modern, scientific-technological society.
Re Willis and Latitude:
I agree with Willis about what is being measured in the catch data.
The change in mesh size, afaik, was mostly effected under the International Commission for the Northwest Atlantic Fisheries – ICNAF – (which included all fisheries above Cape Cod within its purview), in the 1960s. That did not, of course, stop certain Iberian nations from putting fine mesh liners within their nets – as occurred during the turbot war between Canada and Spain and Portugal off Canadian waters in 1995.
Catch data also was seldom accurately reported, as vessel captains would hide their irregular practices or under-report by-catch when possible, so as to be able to bag or exceed their quotas. It’s very hard to estimate fish populations and dynamics in the circumstances.
Finally, as I learned long ago in fisheries biology, the escapement of undersized fish through large-size meshes was not possible once the larger fish being caught had been pushed together against the mesh or caught in the holes. (As fish became progressively smaller over time due to overfishing, this was less of an issue).
This is why mesh size was not further increased in the 1970s, as effectiveness had limitations, and international bodies like ICES, ICNAF, and later NAFO switched to Total Allowable Catches (TACs) for nations and Individual Transferrable Quotas (ITQs) for licensed fishermen (or fishers, as the PC Canadian government calls them). The latter are highly controversial among academics, as they may create private property rights to licensees, which leads to all sorts of strange situations, but does also seem to militate against overfishing in some cases.

Latitude
June 13, 2013 7:35 pm

vigilantfish
It does me no good to post links that answer all of these questions…and no one read them
Cod are like guppies and goldfish…they reproduce in the millions…their ability to reproduce is limited by food….they lost their source of food because of pollution, dams, etc
If codfish were so thick you could walk on them….they were wrecking havoc on the environment themselves..
It’s a lot easier to blame fishermen…than fix the real source of the problem….that’s the way the NOAA always fixes it….
Cod stock will rebound in minutes when they fix the real problems…….