Climate Change: the Fish Notice

One of the most pernicious arguments from climate deniers is that “a few degrees” doesn’t have much of an effect. After all, if you raise the temperature of the room you’re sitting in by a “mere” 1°C (1.8°F), you might not even notice.

Nature notices. The fish notice.

The Gulf of Maine includes Atlantic ocean waters along the coast of much of New England and part of Canada, stretching from Cape Cod in Massachusetts to the southernmost tip of Nova Scotia. From ocean heat content data we know that the water in that region has been warming rapidly of late:


For a long time, cod was a mainstay of the fishing industry. But cod numbers have been declining, so it became necessary to limit catches in order to allow the population to rebound. Unfortunately, the plan didn’t work so well — because just as it was implemented, ocean warming undermined those efforts. An NPR report tells the story well:

Cod was once so plentiful in New England that legend had it you could walk across the local waters by stepping on the backs of the fish.

Now, though, this tasty species is in such trouble there that cod fishing is practically shut down.

And scientists say it looks like rapid warming in the Gulf of Maine explains why regulators’ recent efforts to help the cod while allowing fishing were a failure.

“Year after year, as they looked at the population, they realized that there were fewer cod than they expected there to be,” says Andrew Pershing, an oceanographer at the Gulf of Maine Research Institute. “They thought that they should be rebuilding, but they were actually declining.”

At the same time the cod were mysteriously failing to rebound, he says, strange things were happening on the shores of Maine. People were finding seahorses, which almost never go that far north.

“We had squid we don’t normally find here,” recalls Pershing, “we had species like black sea bass that are normally found around Long Island that were hanging out in the lobster traps here in Maine.”

These oddities were happening because the Gulf of Maine was warming. In the journal Science, Pershing and his colleagues say the warming was also hurting the cod — and managers didn’t take it into account when setting their fishing quotas. That means even if people didn’t exceed their quotas, too much cod got taken.

“In really warm years, every female cod produces fewer babies than we would expect, and we also see that the young fish are less likely to survive and become adults,” says Pershing.

Ecosystems all around the world are warming up due to global climate change, says Pershing, but the Gulf of Maine is ahead of the curve. Over the past decade, it’s warmed faster than 99.9 percent of the global ocean.

“That happened so fast that the people that were managing this very important fishery were not able to keep up with the changes,” he says.

Now that we know of the impact of ocean warming, further steps can be taken. But even if they work as planned, things won’t be like they were before; the ocean waters will remain warmer.

But Pershing says rebuilding will look different in 2020 than it would in 1990.

“Even with the lowest warming that we could find out of any of the climate model runs, we still end up with a population that’s only about a half of what the population should have had in the 1990s,” says Pershing. “We’re headed for a Gulf of Maine where there still should be cod, but where there will be fewer cod than there used to be. They will be a much smaller part of this ecosystem than they were 20 years ago.”

New England isn’t the only part of the U.S.A. already impacted by climate change. The Pacific Northwest has also felt the pain:

The line I like most from that video is: “So anyone who claims that this massive coal project is about jobs, had better learn how to subtract.”

Climate change is destructive — already. It costs money, it costs property, it costs jobs, even livelihoods — already. Who pays for those costs? It isn’t the fossil-fuel industry. It’s you and me.

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10 responses to “Climate Change: the Fish Notice

  1. I wrote about this last February and presented it to our county supervisors citing Pershing’s paper

    Tonight I will present the state of corals and the Trump Legacy. It will be published in the same paper.

    Best regards


  2. Last time we visited Newfoundland we came across an ocean sunfish (mola) basking on the surface of Trinity Bay, on the northeast coast of the island. Although they are found in temperate waters, NF is well west of the Gulf Stream and it was just after iceberg season, the last grounded berg having melted away the week before we visited. Molas mainly feed on jellyfish, which we also saw in abundance. Yes, the fish have noticed.

  3. One of my advisors, Carl Walters from UBC, had done a great deal of work on fisheries. He was fairly caustic regarding fishery managers who set quotas based on public opinion rather than what the scientists were recommending. Reductions were recommended but managers would either not reduce or would only do a small reduction. Fisheries worsened so complete bans were recommended, but managers just reduced quotas. Finally fisheries collapsed completely and only then were bans put in place, and even then managers kept trying to do limited open catch seasons. He’d get going on a rant and then turn it into a whole lesson complete with graphs, model outputs, papers to read. Second semester was all case studies and easily one of the more fascinating courses (first semester was modelling and population dynamics which was rather difficult….his TA said that he was now just beginning to grasp the material after 6 yrs of TAing).

  4. Sunfish have been common summer visitors now for a number of years in Trinity and Conception bays where I sail. (Ever gone thru Baccalieu Tickle in westerly/sou’westerly high winds? Interesting experiences to be had there.)

    Jellyfish blooms have been common both for reasons of higher temps (surface temps well offshore up to 20C are common enough in late Aug) and for reasons of environmental degradation. Late June/early Jul temps when you must have been around are usually below 10C.

    Actually, the cod here are finally, finally, finally coming back after decades of fishery closures and it seems to me anecdotally the blooms are a bit down the last 2 years or so.

    • Some schools of bluefin tuna are coming back to Conception Bay now as well after pretty much a half century hiatus of limited sightings. Amazing creatures–huge creatures–to see when they are hunting shoals of bait fish. Which fits into tamino’s thesis here.

      Hope it lasts.

    • The jellyfish blooms might be responsible for the appearance of molas, which feed on them. Of course, you’d expect an association between environmental conditions that increase blooms and attract moles, i.e. the warmer waters might attract moles, but their survival will be because the bloom is there.

      There are huge changes taking place in Monterey Bay, too, where they’re being studied in excruciating detail by NOAA, Monterey Bay Aquarium Research Institute, Moss Landing Marine Labs (CSU grad school), and Hopkins Research Station (Stanford).

  5. Another sea temp story 0.8C sea temp chnage has allowed tropical fish into the waters off Northern NSW and decimated the kelp forests, changing the ecology and it’s happening worldwide apparently.

  6. If you’ll excuse the off topicness – someone mentioned this alleged paper on a blog, but to me it looks like mathturbation:

    [Response: The abstract actually states “the recent CO2 increase can be considered as a lagged response to solar activity.” Is your bullshit alarm flashing red?]

    • The two reviews that are currently there are sufficiently damning that the manuscript should be filed under “Bird cage lining”, but there’s a point that bears reiterating – the stoichiometry of fossil carbon emissions is sadly lacking, and in a paper making the assertions that this one does one wonders (not) why…

    • Oops, thanks, I was so busy trying to work out the word flim flam that I forgot the most basic. Ah well, I already pointed the person who mentioned it to realclimate. I hope the ‘paper’ gets canned.