This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American
Editor's Note: William Gilly, a professor of biology at Stanford University's Hopkins Marine Station, embarked on new expedition this month to study jumbo squid in the Gulf of California on the National Science Foundation–funded research vessel New Horizon. This is his sixth blog post about the trip.
SEA OF CORTEZ—After the early morning reverie, undoubtedly fueled by coffee on deck and sleep deprivation (maybe three hours a night), I return to the realities of the cruise. I check the status of the squid in our animal holding system that is tirelessly maintained by Ian Wilson, a volunteer from Colorado State University. All five small squid are alive and well—they were caught last night. This is Ian's first ocean-going research cruise and part of a summer internship. We also have Elizabeth Hogan, from the Community College System of New Hampshire, who is here as a volunteer with the MATE program (Marine Advanced Technology Education) to work with Chad Waluk and Kelly Benoit-Bird's team. I hadn't known about this program before, even though it is based in my backyard in Monterey, Calif. I'm eager to learn more. It's good that students just starting out on their hopeful quest of a career in marine science can participate in cruises like this. They quickly learn that a research cruise is not a vacation. If you don't love it, you won't be coming back.
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We plow north past San Francisquito into the Salsipuedes canal that separates Isla San Lorenzo from Baja peninsula. This narrow channel is over 1,000 meters deep and supports fierce tidal currents as the upper half of the Gulf tries to drain into the lower half twice a day—and tries to fill twice a day from the southern half. It is little wonder that the racing, confused tidal surges in this area churn up deep water and bring it to the surface. This tidal upwelling of cold, nutrient-rich water makes this area, all of the Midriff Islands area really, extremely productive. Sea creatures know this, and in this region you will find many large creatures like blue whales and whale sharks as well as vast numbers of sea birds. Today a frenzy of diving pelicans greets us, but we are here searching for squid—big ones. This is the only region that held large squid during our cruise last year, and we are eager to see what this region holds now.
But high productivity in a marine environment can bring surprises other than wildlife. As we move into Bahia San Rafael the water darkens to a blood-red color, and the air temperature plummets—so much that it feels colder than inside the air-conditioned ship. We are in the midst of a vast algal bloom, a red-tide that will end up stretching at least all the way to Bahia Las Animas, twenty miles to the north, and persist for the two days that we will be here. This is the result of tidal upwelling of cold, nutrient-rich water in a hot, sunny area, and it is amazing to feel it grab you in this way. Our CTD casts in this region show that the sea surface temperature is about 10 degrees Celsius colder than it has been everywhere else so far.
Later tonight I email a colleague at NOAA back home in Pacific Grove, and he sends the official NASA image of our world in Salsipuedes a few days earlier. Satellite remote-sensing is an amazing tool that can reveal events like this anywhere in the world, and his chlorophyll map reveals peak values of 30 milligrams per cubic meter, but that appears to be as high as the NOAA scale goes. Our ship has a sensor that estimates chlorophyll in the surface water continuously, and it seldom drops below 50 all day long. Eventually it will reach 75 and stick there until the technician on board cleans it out and resets the electronics.
Soon another layer is added onto the surrealistic surface on which we float. Looking to the northeast reveals a few small islands off the northern end of San Lorenzo . But as we watch them, they grow, shrink, bridge together and merge as if they were part of a living Dali seascape—a mirage. A photograph cannot do this phenomenon justice; it is like trying to photograph a spirit. But we capture some images of change in late afternoon over 15 minutes, and in the morning, under new light, the distortion is even more disturbing.
Of course we are not the first to marvel at such a vision. Steinbeck and Ricketts describe it perfectly in Sea of Cortez (1940):
"As we moved up the Gulf, the mirage we had heard about began to distort the land. While it is worse on the Sonora coast, it is sufficiently interesting on the Peninsula to produce a heady, crazy feeling in the observer. As you pass a headland it suddenly splits off and becomes an island and then the water seems to stretch inward and pinch it to a mushroom –shaped cliff, and finally to liberate it from the earth entirely so that it hangs in the air over the water. Even a short distance offshore one cannot tell what the land really looks like. Islands too far off, according to the map, are visible; while others which should be near by cannot be seen at all until suddenly they come bursting out of the mirage. The whole surrounding land is unsubstantiated and changing.."
It is little wonder that this place of cold, red water with strong, swirling currents and disappearing islands (and often fog as well) is called Salsipuedes, which can be translated as "Leave if you can." But we must stay for now, even if one cannot tell whether the sea is red from reflection of the surrounding hills or from the microscopic algae at the base of the food chain.
Nightfall brings squid sampling, and we again collect our quota of 30 squid in about 15 minutes. This time they are all medium-sized and mostly immature. But in San Rafael we find our first large squid—a seeming monster with a 72 cm mantle length. And once again, we see that the smile is proportional to the size of the squid. But there are no small ones (<30 cm) for the experiments we are trying to carry out, so we select the smallest we can catch and put them in the temperature-controlled squid condo (each squid has its own tube with flowing seawater) for use tomorrow morning. Brad Seibel puts one in his respirometer apparatus for an overnight run. Then we clean up the squid remains and feed them to a flock of Heerman's gulls that has been patiently waiting for hours. The scene is a bit too Hitchcock for comfort.
In the morning, of course, we have a hundred trained gulls perched on the rails expecting breakfast, and they laugh heartily when we protest. Although this development could have been predicted, what I discover on checking the condition of our captive squid is totally unexpected. All three of our squid died overnight in their tubes, despite great effort to select ones that appeared to be in perfect condition. Normally squid live in this set-up for at least two days. Temperature and oxygen in the system are normal, but the squid are dead. Brad's squid also died during his experiment, again not a normal event.
Is this morality a coincidence, or is there a connection to the red-tide? Our squid system was filled with water collected from the bloom area, and it is totally recirculated. This means that the captive squid could not descend to depths below the bloom, which appears to be limited to the top 10 meters or so based on our CTD casts. Harmful algal blooms have become a hot topic, and a number of neurotoxins are known to be generated by certain species of dinoflagellates and diatoms, including saxitoxin (paratlytic shellfish poisoning), brevitoxins (neurotoxic shellfish poisoning) and domoic acid (amnesic shellfish poisoning). Undoubtedly there others waiting to be discovered, perhaps some that affect squid more than humans—in which case, it will be a long time before we know anything about them. If people get sick, the National Institute of Health pays attention, and research dollars flow. But if squid are selectively affected...well, that's a different priority.
Right now the potential effects of this algal bloom on squid are our reality, and we are left mystified. Our experiments later tonight are carried out on freshly caught squid, and we get results that are odd. Instead of reacting to a stimulus with a strong, smooth escape jet (like every squid we have tested thus far), a squid tonight responds with a jet that lasts for an abnormally long time, and our high-speed video observations show that the mantle appears to fibrillate and not relax properly. Conceivably this could reflect intoxication with some toxin associated with the red-tide, but resolving this puzzle will have to await another research effort with new funding at some future time. We file the odd results away in our "maybe one day…" folder.
A brilliant sunset, perhaps the finest of the trip thus far, is again a prelude to squid sampling after dark. Tonight, outside Bahia Las Animas, squid of all sizes are caught, from 33 cm to 60 cm mantle length. This is the only place where we have found mature squid at both extremes of this size range. Last year we also found large, mature squid here (and only here), but small squid in this region were all immature. Aging studies suggested that the large squid were 1 year old, whereas the small squid were about 6 months old—sort of the normal pattern one would expect, with small squid growing big before they mature. But now we find two size-classes of mature squid in the same place at the same time.
This is really interesting, and reinforces the idea that recovery form the 2009-2010 El Nino is still going on and that it indeed involves two paths, as proposed in the first post of this blog. It seems that some squid migrated into this productive Salsipuedes region that is buffered from El Nino by tidal upwelling , where they have continued their normal life cycle of about one year and grow to a true, jumbo size. The large squid here this year would thus be the direct offspring of last year's large squid. But most squid reacted to El Niño with precocious spawning and a six-month life cycle. That means the small, mature squid here would be the second generation to mature after the El Niño officially ended in May of 2010. But if you are a squid, there is a good chance that you are still in the recovery process from that transformative event over a year ago.
Recovery from El Niño thus appears to be a multi-generational process, and how long it will take for big squid to recolonize the former commercial fishing grounds off Santa Rosalia and Guaymas remains a huge unknown. All we know for sure is that they are not there yet. To us, it is an intellectual puzzle, but to the many families that depend on fishing, it is a much more serious matter. I wonder how they cope.
Although this place is likely to hold other secrets, we make a decision to escape the red-tides and mirages by heading back south to Isla San Pedro Martir immediately after the jigging session. And so we leave the Salsipuedes while we can.
Photo credits:
Elizabeth Hogan, MATE summer intern: Chad Waluk, Oregon State University
Diving pelicans: Ted Uyeno, Northern Arizona University
Red tide of another bloom in the Loreto area, January 2011: Susan Shillinglaw, San Jose State University Mirage of islands on north end of Isla San Lorenzo with local times indicated: W. Gilly
Red Cliffs south of Bahia Las Animas: W. Gilly
Big squid, Big smile: Ted Uyeno, Northern Arizona University
Gulls at night: Ted Uyeno, Northern Arizona University
Gulls in morning: Ted Uyeno, Northern Arizona University
Las Animas Sunset: Ted Uyeno, Northern Arizona University
Map_Post6: Google Earth, adapted by W. Gilly