The Next Species: The Future of Evolution in the Aftermath of Man (16 page)

Climate change is the chief suspect in this developing tragedy. Warmer ocean waters hold less oxygen, and a warmer climate generates less wind to oxygenate surface waters. The result is a more stratified ocean with a surface layer of warm water riding on cooler, denser water, which impedes the mixing of oxygen. In addition, shrinking ice at the poles may be slowing deep-ocean circulation, which brings oxygenated waters to the deep waters of the Pacific and Atlantic Oceans.

During that Permian extinction 250 million years ago, increased atmospheric CO
₂
warmed the planet, which stripped the ocean of its oxygen and wiped out more than 90 percent of the creatures in the sea.
Oxygen deprivation was a major source of extinction during the Cretaceous extinction as well.

Bigeye tuna, swordfish, and sharks can dive to the top of the oxygen minimum zone, but few finfish can go into it for any length of time. Sperm whales, elephant seals, and some sea turtles are among the best penetrators of this zone, but it takes serious adaptations to withstand the pressure and the lack of oxygen. For the few that can, the upper boundary of the oxygen minimum zone is a hidden treasure
where life abounds.

To show the extent of change that has occurred over the last half century, Gilly likes to refer to descriptions by the author John Steinbeck and the marine biologist Ed Ricketts, who in 1940 took a trip around the Baja Peninsula into the Gulf of California surveying the marine life. Steinbeck wrote a book about the journey, called
The Log from the Sea of Cortez
—the Sea of Cortez being the more traditional, more romantic name for the Gulf—describing his trip with Ricketts and a crew of fishermen from Monterey, California. Steinbeck had featured Ricketts, who made a living at his lab on Cannery Row by preserving specimens of marine life and selling them to schools for use in biology laboratories, in two of his novels,
Cannery Row
and
Sweet Thursday
.

The purpose of the Steinbeck/Ricketts expedition in 1940 was to collect samples in the tide pools along the shores of the Gulf of California over a six-week tour. The group left Cannery Row in Monterey at a time when Hitler was invading Denmark and moving up toward Norway and “there was no telling when the invasion of England might begin,” wrote Steinbeck. But they put
the world’s drama in their rearview mirror, and boarded the
Western Flyer
, a chartered sardine boat, heading for Baja California, Mexico.

Three days later, they eyed the lighthouse at Cabo San Lucas, at the southern tip of the peninsula, and at about 10 p.m. they rounded the cape and entered the dark harbor. Except for the lighthouse, there were no lights in the harbor. Today, Cabo San Lucas is a full-blown mega-resort, with lights that stay on all night. Then it was a sleepy little village where it took Steinbeck and Ricketts all day to find the authorities in order to get their visas stamped.

The first Mexican town Steinbeck described at length in
The Log from the Sea of Cortez
was La Paz, a large port around the southern tip of Baja coming from the Pacific. I visited La Paz last summer and witnessed the various efforts being made to compensate local fishermen
for the reduced catches they and their hungry families are encountering.

Frank Hurd is the science director of Olazul, a group of American and Mexican scientists and innovators working with local fishing communities to develop sustainable systems of aquaculture as an alternative to depleting overfished stocks. Hurd invited me to see his version of an offshore, semimobile aquaculture pen. One morning before dawn we drove out from the city to a fish camp on the northern shores of La Paz where Hurd and his associates had been testing a spherical pen, 277 cubic yards (212 cubic meters) in volume, about three miles offshore. Hurd said Gulf currents could flush out the wastes and bring in nutrients and oxygen for the shrimp he was testing. The structure was made from recycled and reinforced polyethylene timbers wrapped in coated steel mesh netting “built to withstand the occasional hurricane that rolls up the Mexican shoreline during the summer and early fall,” said Hurd.

In his book, Steinbeck had described on their Sea of Cortez journey how they
trolled a couple of lines off the back of their boat and were pretty much able to keep themselves in finfish such as yellowfin tuna, skipjack, Mexican sierra, red snapper, and barracuda the whole trip. Hurd said that the local fishermen in La Paz described similar catches in the old days but today try to make a living selling trigger fish, sand bass, bonito, mackerel, and other species that were considered trash fish back in Steinbeck’s time.

The Sea of Cortez that Steinbeck investigated over seventy years ago is not the same body of water that Gilly and his crew motored to in 2004. In his log, Steinbeck described marlin and swordfish frequently leaping out of the ocean into the air and dancing across the surface of the water. The scientist described seeing only a couple of small squid on his entire six-week excursion in the Gulf of California. And there was nothing that resembled a Humboldt squid.

Gilly also spent some time looking through historical records for
sightings of Humboldt squid. There were isolated reports in the scientific literature going back to 1938, but no reports of large numbers until commercial fishing for them commenced in the late 1970s. He queried a number of old fishermen in the Gulf, and none of them remembered sighting the squid before that. Humboldt squid were absent in the natural history of the Gulf written by early Jesuit missionaries. James Colnett, an officer of the British Royal Navy, saw no Humboldt squid in the area south of Cabo San Lucas in 1793–94, though he described squid “of four or five feet in length” at the surface off the Galápagos Islands. “But that’s a far way off,” said Gilly.
The squid must have migrated to the Gulf of California since Colnett’s time, but details of the move are lacking.

Humboldt squid appear to have evolved in the southeastern Pacific where El Niño events warm the surface waters of the ocean every four to twelve years, creating unusual global weather patterns. Changes in the Humboldt squid fishery mirror changes in El Niño–driven weather. Though Gilly and his associates measured high concentrations of squid in the central Gulf in 2012, they had moved away from the shore and their sizes had decreased. Gilly thought an earlier El Niño event in 2009–2010 led to the animals’ accelerated sexual maturity, what he called an even more radical live-fast-die-young life strategy in the face of an uncertain future.

Humboldt squid have two tentacles that can reach out and grab prey and eight arms to envelope them. The squid can attain eight feet in total length (mantle plus tentacles). They use their tentacles and arms to subdue prey and their razor-sharp parrotlike beaks to tear them apart. They are some of the fiercest of the cephalopods, a group of animals that includes squid, cuttlefish, and octopus.

Humboldt squid are also famously cannibalistic. Unai Markaida, a marine biologist at El Colegio de la Frontera Sur in Campeche, Mexico, studied prey items of 533 Humboldt squid and found evidence of other Humboldt squid in 26 percent of their stomachs. Fishermen who pursue the Humboldt squid tell scientists that once squid are hooked, other squid start attacking and eating the fishermen’s
catch. The fishermen have to pull their catches in fast to avoid these voracious attacks.

The Humboldt squid is particularly fast and propels itself through the ocean as if by jet engine. It draws water into its mantle and then ejects it through a spout like a rocket. All squid have the ability to change color quickly, some imitating patterns, even textures of sandy bottoms or rocky reefs. Humboldt squid lack this patterning capacity but are able to switch back and forth from maroon to ivory, pulsing like a strobe. The capability to communicate through color change is quite profound for a creature that is related to the snail. According to Gilly, “There’s jitter [vibration], variation, and change in the frequency between two squid. It’s highly unlikely this isn’t some kind of communication.”

Up to four million Humboldt squid hang out in the Sea of Cortez near Santa Rosalía at about one thousand feet (three hundred meters) during daylight near the shelf where the bottom starts falling off sharply, but move up at night when the deep-scattering layer moves up as well. It’s then that the fishermen initiate their attack. Hauling up a squid that can weigh up to a hundred pounds by hand lines is a rough job at night, particularly when the average price for cleaned squid is less than ten cents a pound (0.5 kilos).

One winter day, I caught up with Bill Gilly at the Hopkins Marine Lab on Cannery Row, next to the Monterey Bay Aquarium. People claim there are differences but also a lot of similarities between Gilly and Ed Ricketts, who accompanied Steinbeck on his journey to the Sea of Cortez.

Ricketts’s lab on Cannery Row was a hangout for authors, illustrious locals, and street people. Gilly’s lab is more of a gathering place for assorted Stanford students. Ricketts, according to Steinbeck, lived across from the local house of prostitution but never visited the house after dark unless he’d run out of beer and the stores were closed. Gilly lives next to the Monterey Bay Aquarium and goes there frequently.
In Steinbeck’s eulogy he said Ricketts “loved to drink just about anything.” Gilly would admit only to enjoying the occasional beer. Their greatest similarities are that Gilly, like Ricketts, is a biologist who loves Monterey, Baja, and the Gulf of California and likes to laugh.

When Gilly announced his plan to retrace Steinbeck and Ricketts’s 1940 voyage through the waters and intertidal zones of the Gulf of California, he received a surprising call of support when the owner of North Coast Brewing Company called and offered his services. “You know those guys drank a lot of beer on that trip,” he said. “And I’m the man that can help you with that.” Gilly reacted with a smile.

Gilly and his team arrived at the boat on their date of departure and found two shrink-wrapped pallets of beer with a sign on it that said
FOR DOCTOR GILLY
. Inside the shrink-wrap were seventy-two cases. “It was the most beer I’ve ever seen outside of a Princeton reunion I once attended,” laughed Gilly when he told me the tale.

In the end, Gilly and his crew drank only about 1,242 beers. Steinbeck and his crew drank 2,160 beers. “And they did that with a smaller crew and a shorter trip,” said Gilly in awe.

There were other differences in the two expeditions that were not as lighthearted. At the various intertidal zones that Steinbeck and Ricketts visited, the author repeatedly used expressions like spiny-skinned starfish in “great numbers,” and “knots” of brittle stars, but Gilly’s team did not observe a great number of either at any of the tide pools they witnessed.

Steinbeck and Ricketts
encountered “huge” conches and whelks (large sea snails and their shells) at several sites and a great number of large
Turbo
snails (shaped like a turbine). Gilly’s crew found only small living specimens of conches and
Turbo
at just a few sites, and dead whelk shells at one. In 1936, William Beebe, an American naturalist, explorer, and marine biologist, found a beach just north of Bahía Concepción—about midway up the eastern shore of the Baja—that was what he called “a conchologist’s paradise,” with shells “of amazing size and a host of species.” Tellingly, Gilly’s crew found a dramatic decline
in all these species.

One of the greatest and most disturbing changes in the Gulf is in the “pelagic,” or open-ocean, predatory finfish that inhabit the upper portion of the water column and aren’t associated with the shore or the bottom. Although Gilly and company traveled at the same time of year, using the same type of boat, and for about the same duration as the Steinbeck adventure, they witnessed
a greatly changed community of open-ocean fish.

Steinbeck and Ricketts wrote, “We could see the splashing of great schools of tuna in the distance, where they beat the water to spray.” The pair also saw marlin, sailfish, and swordfish, but Gilly’s team sighted few of these.

Gilly’s team did catch sierra mackerel and yellowtail, but neither fish was of the same size or in the same numbers as Steinbeck and Ricketts had reported.

Steinbeck and Ricketts got a look into the future, though they didn’t realize it at the time, when they boarded a shrimp trawler off Guaymas on the mainland side of the Gulf and witnessed the unintended consequences of the fish species that came up with each net. Though the fishermen tried to separate the shrimp from the rest of the catch and tossed back the unwanted fish, most of these died belly-up in the water. Today shrimp trawling is recognized as the single most ecologically damaging activity in the Gulf.

Sharks, particularly the enormous schools of hammerheads that once circled the sunken islands, or seamounts, in the middle of the Gulf, have declined in size and number. The same is true with manta rays: they have been replaced with smaller mobula rays than the ones seen by Steinbeck and Ricketts. Steinbeck wrote of the attempted landing of a number of huge manta rays, but the rays always broke the line, even when it was three inches thick. And Steinbeck and Ricketts noted several other species of squid but not Humboldt.

Though Gilly never saw the abundance of marine life that Steinbeck had witnessed, he found his own vision
when he got to San Pedro Mártir Island, an area known for hosting many sperm whales. Since sperm whales eat Humboldt squid, Gilly figured there must be a lot
of squid, and this was the reason for taking this detour, which had not been a part of Steinbeck’s journey. He was looking for baby Humboldt squid, something nobody had ever found in the Gulf. Satellite data had told him there was an intense tidal upwelling event (tides bringing the rich waters of the deep up toward the sea surface), and he guessed that the forward edge of this rich marine zone might harbor tiny squid larvae. On his second net tow, he found two baby squid a quarter of an inch long. But there was more.

It was a place where “all the life was, plankton, fish, squid, and whales,” reported Gilly. The biologist and his team were greeted by a nonstop squid review, with Humboldt squid darting in toward the boat and flashing their underbellies in attempts to lure small schooling fish near the surface. The show continued until after midnight.