Finally, a population crash NOT blamed on global warming

From Stanford University , a realization that El Niño an La Niña play far greater roles than any global warming does in ocean populations.

IMAGE: On this year's research cruise, ship's crew member Jack Purdy hoists a hefty Humboldt squid. Ian Wilson, an undergraduate at Colorado State University, stands in the background.Squid mystery in Mexican waters unraveled by Stanford biologist and a class of students

Squid mystery in Mexican waters unraveled by Stanford biologist and a class of students

While shorter days and colder weather move many of us to hunker under the covers, researchers who spent their summers in fieldwork are more likely to be hunched over microscopes and curled over keyboards, scrutinizing samples and crunching data from their summer’s labors.

One such researcher is marine biologist William Gilly, who spent a month last summer in Mexico’s Sea of Cortez tracking the sometimes-elusive Humboldt squid. Researchers from several universities were on the voyage. Gilly is in the second year of a quest to understand the surprisingly strong impact on the squid from an El Niño weather pattern during the winter of 2009-10 and, perhaps more important, how they are faring in their recovery.

In May 2010 Gilly was in the Sea of Cortez – one of the biologically richest marine environments in the world – with a biology class of Stanford undergraduates when they discovered that the squid, usually present in such large numbers that they are a staple species of the local fishing industry, were largely missing from their usual haunts.

“There were far fewer of them than normal, they were spread out over a huge area and they were very small. But they were also sexually mature and spawning – at a ridiculously small size,” Gilly said.

“It was obvious that the squid were pretty screwed up.”

Normally Humboldt squid spawn when they are 12 to 18 months old. But the precocious little spawners Gilly and his students found were less than 6 months old and weighed all of a pound apiece, compared with the usual weight of 20 to 30 pounds at maturity. One of the larger squid species, Humboldt squid are sometimes referred to as “jumbo” or even “giant” squid.

Searching the Sea of Cortez a month later on a research cruise, Gilly and two of the students eventually found large squid in an area about 100 miles farther north than usual, near the Midriff Islands, where Gilly suspects they had migrated in search of food.

IMAGE:A researcher examines small squid on the ship’s deck. Normally Humboldt squid this size would be too immature to spawn, but in the aftermath of the 2009-2010 El Nino most…Click here for more information.

In the squids’ usual coastal habitat off Baja California, upwelling brings cold nutrient-rich water up from the deep, causing phytoplankton to bloom and marine animals of all types to congregate. The squids’ palates are particularly partial to lantern fish – a slender, silvery, pinky-finger-sized species named for the small light-emitting organs on its sides.

But during an El Niño, warm nutrient-poor tropical water from the open ocean flows into the Sea of Cortez and pushes cooler water down 150 feet or more below the surface. The usual upwelling, driven by the wind, is not strong enough to pull the cool, nutritious water back up. So the upwelling just recycles the warmer water, causing the phytoplankton population – and all the creatures that depend on it – to crash.

That crash likely sent the squid searching for better food stocks, which could have led them to the Midriff Islands, where upwelling is driven by strong tides unaffected by El Niño.

“Squid can move to an area of tidal upwelling, which remains productive during an El Niño, and continue on their merry, giant-squid lifestyle and live to spawn when they are a year and a half old,” Gilly said. Or they can move away from land into an open-ocean environment, where food is less abundant but the supply is steady, as its availability doesn’t depend on upwelling.

“It is comparatively meager fare and you will not get to be a big giant squid, so instead you reproduce when you are six inches long. It is a different strategy, but it works,” he said.

With oceanographic conditions back to normal this year, when Gilly headed down to Baja again, he expected that the squid situation would probably be normal, too. But big squid were again only found around the Midriff Islands.

While small squid were present throughout the Sea of Cortez, the little ones were larger than the year before by about 25 to 30 percent. And they were beginning to repopulate their old feeding grounds.

VIDEO:Biology Professor William Gilly talks about his research expeditions to the Sea of Cortez.Click here for more information.

Humboldt squid only live 12 to 18 months, so memories of other feeding grounds probably fade fairly quickly when the squid relocate, especially if they are only living to be 6 months old. But Gilly suspects that with each new generation, more squid may rediscover the rich lantern fish feeding grounds of their forebears and the average squid will grow a little larger.

Whether the descendants of the squids that moved north will stay in the Midriff Islands and create a new, stable squid fishery remains to be seen – as of this October, they were still there. The food brought up by the tidal upwelling is mostly krill, tiny shrimp-like creatures that are a lot smaller and probably less nutritious than lantern fish, so it takes a lot more krill to help a Humboldt squid fatten up to its full potential. It may be that a revival of the lantern fish as a food source will eventually lure most of the squid back down south, with the whole squid diaspora reunited.

Gilly credits the undergraduate students in the holistic biology class with recognizing that the changes in the size and distribution of the squid population – along with different stomach contents in the squid they sampled – were the result of an El Niño year. That was unexpected, because the usual changes that come with an El Niño had not been seen along the California coast that winter. But the phenomenon that year was centered more toward the western Pacific than normal and thus did not extend as far north.

“The students really got it right, which is very cool for undergraduates to put that together,” he said. “They convinced me that all the strange observations on squid were due to the fact that it was an El Niño year.”

During 2011, commercial squid fishing in the Sea of Cortez has been slowly picking up, but fishermen are still struggling, because with smaller squid, it takes a lot more effort to catch the same mass of saleable squid as in previous years.

Fishermen have been so concerned about the sustainability of the squid fishery that a fishermen’s cooperative orchestrated a meeting in June in Guaymas, Sonora, with scientists, government fisheries regulators and some nongovernmental fisheries conservation organizations. Gilly attended the meeting after his 2011 research voyage ended.

“It was a really good way to go about resolving a problem without waiting for the government to come and do something,” he said. “They want to have a more stable fishery, and they are taking steps to make that happen.”

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Gilly is a biology professor at Stanford’s Hopkins Marine Station. For more details of his squid-filled summer field season – including some recipes for preparing squid – see his 2011 field blog at Scientific American Expeditions. Blog posts by the students in the 2010 holistic biology class are also online.

24 thoughts on “Finally, a population crash NOT blamed on global warming

  1. “They want to have a more stable fishery, and they are taking steps to make that happen.”
    ==================

    LOL….like how?
    Since when has anything been stable……………………

  2. jeez, I think it was about 5 years ago when they were saying the Humbolts were expanding past San Francisco and were going to eat the entire Pacific Ocean. LOL

  3. PhilJourdan says:
    November 18, 2011 at 11:53 am
    The other shoe will be when they blame El Nino and la Nina on AGW. I know they will, I just do not know when they will.

    They’ve been working on that at least since 1998.

  4. “But Gilly suspects that with each new generation, more squid may rediscover the rich lantern fish feeding grounds of their forebears and the average squid will grow a little larger.”

    I thought Global Warming was going to make species smaller??
    Gosh.. without Global Warming, these squids could be HUGE!

  5. I’m really sorry, but…

    so instead you reproduce when you are six inches long.

    just struck me as funny…

    Anyway… this is a new level of honesty in this type of reporting. Instead of assuming the problem is man-made and decrying the plight of the poor innocent sea creatures, it appears to actually be saying “we looked for a mechanism for what is happening, and here’s a possibility”. I remember that from the old days, it was called Science.

  6. Many organisms have evolved mechinisms such as this, to deal with enviromental variations cause by these natural, but poorly understood cycles. BTW, oranisms don’t evolve stratages to deal with change unless that change is normal.

  7. That can’t be right. Species are supposed to go extinct when there are changes to their environment, not just up and adapt. Didn’t they read the script?

  8. From Stanford University , a realization that El Niño an La Niña play far greater roles than any global warming does in ocean populations
    —————-
    Interesting story but the basic principles are not surprising.
    The population changes in the sardine fisheries off south america are the poster child for el niño.

    El niño is a powerful effect that produces significant regional changes that overwhelm any global warming changes. But it’s not global.

    When the global warming changes start to become comparable to cyclical el niño changes sometime in the future, then things will get interesting.

  9. DesertYote said:
    November 18, 2011 at 1:56 pm
    Many organisms have evolved mechanisms such as this, to deal with environmental variations cause by these natural, but poorly understood cycles. BTW, organisms don’t evolve stratagies to deal with change unless that change is normal.
    ———————————————
    Some animals even change sex to deal with environmental conditions (sequential hermaphrodites), eg: parrotfish, slipper shell gastropod, clownfish, wrasses, Iberian newt, axolotl salamander, Chaz Bono.

  10. If anyone here needs a greater understanding of the matter maybe a good old read of the Theory Of Evolution by by whatshisname. No, not Attenbrough, you know, Darwin.

  11. Back during the last El Nino much was being made of the Humbolt’s northerly march-there
    was some talk on the Oregon coast of a fishery,,,,,

  12. Fishing for salmon in Sept. 2009 in Puget Sound up at Sekui, Washington everyone was catching +15 pound Humbolt squids. I caught a couple. Humbolt squid are never up there – certainly not in those numbers.

  13. They say when it comes to spawning it’s not the size of the squid that matters.

    Or something like that…

  14. Well they obviously didn’t find the mother lode of BIG Humbolts.

    Biggest one I have caught so far; they are great fun on a fly rod, would put that one they have the on the boat to shame.

    I dredged it up from 600 feet down just to test the lifting power of a special fly rod, that was built for me. It was seven feet long stretched out like they have that one, and weighed in at 25 kilos. They get up to 100 pounds or so, when ther is plenty of food around. Mine had eyes about eight inches in diameter.

    No I obviously didn’t cast a fly to get it down 600 feet. Just tied on a two ounce regular squid jij, to drag the line to the bottom. Squid hit the jig about two seconds after I gave the jig a first twitch, and when I finally got it to the surface, there were eight more of them free swimming with it waiting to grab the jig, if mine dropped it. Totally beautiful they are when free swimming and flickering neon colors all over their skin. Mine was wearing his totally pissed off red coloring, and it proceded to fire about a two gallon aimed water shot at each of the three of us in the boat. Luckily he missed the camera my son was shooting with; but we all got soaked.

    Yes we did let it go; the Pangero didn’t want to have anything to do with it. They are totally evil, and a ten pounder can easily outpull a swimmer; even in scuba gear, and reag you to the bottom, where the big ones will eat you. the suckers aren’t like those on an octopus, they actually have claws (or teeth all around the rim, and can rip you up, even without using their beak.

    And they don’t flit around like butterflies, like you see the sea arrow squid doing in the Cousteau films. When they decide to haul A***, they jet along with a continuous wave drive, inhaling, and exhaling at the same time.

    But five to eight pounders are a better eating size; so we don’t ever kill the monsters. And of course they ARE cannibals.
    Ooh the big one was taken off Loreto Mexico (Baja), abour two thirds of the way from thr beach to the near point of Isla Carmen, in July 2008.

  15. Excellent piece of research. Should open a few eyes and channels for exploring the resilient manner in which ocean species “manage” their response to food supplies and habitat changes.

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