The Elephant Seals of Año Nuevo

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Running the gauntlet to the island in at inflatable boat, 1988. Photo: Brian Tissot

“Ok, start pounding the boat as hard as you can.”  We were in a small inflatable boat crossing the narrow, wave-filled channel between the mainland and Año Nuevo island. Thump, thump, thump, thump.

“Why?” I asked? The graduate student ferrying us across the channel glanced at us and smiled. “Well, it wakes up the big ones so they don’t attack the boat.”

The “big ones” he was referring to were bull northern elephant seals which can measure up to 16 feet and 6,000 pounds. As we motored into shallow water near the island you could see that the water was full of them, big dark shapes, some milling around, many immobile. It didn’t help to know that this was white shark city: part of the “red triangle” off California where most shark attacks occur due to lots of marine mammals. As we approached the island we saw hundreds, thousands of seals covering the beach and generating a cacophony of sounds.

As we pulled up into the beach the smaller seals backed away, the middle-sized ones hissed at us, and the large bulls ignored us. “It’s the sub-adult males you need to watch” our guide said “they get beat up by the Bulls pretty bad and have something to prove.” He smiled and took in the scene with a sense of respect and admiration. “Welcome to Año Nuevo island.”

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The island, as seen from the west looking east towards Año Nuevo Point.

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My wife in 1988, who showed amazing grace at low tides and darkness with elephant seals. We got engaged on the island. Photo: Brian Tissot

I was just there for the abalone. The year was 1987 and I was searching for a place where black abalone were largely undisturbed so I could complete my dissertation. The island  was the perfect location: isolated, difficult to access, federally protected (you need a permit to be on the island), and surrounded by seal- and shark- infested waters. During my first low tide on the island I was ecstatic: blacks were common and it was the perfect place to conduct a study. I had also just started dating my future wife and she frequently came with me. As a field biologist it was a good test of our future relationship.

To me the elephant seals became an afterthought, at least initially. As I began my surveys I discovered they carpeted the landscape, so it was difficult to do anything without running into them. Laying on my transects or blocking access to the beach we had to move slowly but deliberately and never turned our backs. Given that abalone themselves are slow, gentle creatures it added an extra sense of excitement to our work. Even big bulls, as we soon discovered, can move remarkably fast when they want to. Of course, the elephants seals were just part of the island’s story.

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Me conducting abalone research at Año Nuevo island, 1989. Photo: Susan Tissot.

Although the area was initially inhabited by the Quiroste, a group of Ohlone Indians, who lived there seasonally for thousands of years, Año Nuevo was named on January 3, in 1603 by Father Antonio de la Ascension, chaplain for the Spanish maritime explorer Don Sebastian Vizcaíno. An original Spanish land grant, the island changed hands many times before being purchased by the federal government to safeguard the burgeoning shipping industry from the foggy, rock-strewn shoreline  And over the years there were many ship wrecks on the area’s dangerous, jagged reefs. To assist in navigation a fog-whistle was installed in 1872, then a five-story light tower in 1890. Finally a substantial house to support the lighthouse keepers and their families was constructed in 1904, which is still visible today. But the pinnipeds refused to give up the island and the keeper made an official complaint in 1918 that the sea lions were overrunning his house; on one occasion a passing killer whale had frightened the seals so badly that they forced their way into every room of the house. However, despite the whistle and light a staggering number of fatalities continued to occur in the area and while crossing the seemingly innocuous channel to the island, including many close calls with researchers. Eventually the families left the island and an automatic buoy replaced the station in 1948.

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Aerial view showing shallow underwater shoals surrounding the island. Source: Google Earth.

It is an amazing place. You can feel the energy and history at multiple levels. First, every inch of the island is covered with living creatures; it is one of the most densely populated animal refuges on earth. California sea lions on the west beaches and rocky headlands, sea gulls nesting on the grassy knolls, cormorants high on the rocky outcrops, oystercatchers speckled throughout the intertidal, harbor seals with their pups in the small coves, and everywhere else, elephant seals carpeted the landscape. Collectively they created a wall of noise that alternatively sounded like a barnyard, a pig pen, a dog kennel, or a zoo. At night you could hear all sorts of sounds echoing through the old fog house which created dynamic but creepy music. The island also had a bizarre and unusual feeling to it — some might call it haunted. Just about everyone that I ever met on Año Nuevo mentioned the strange noises at night, the vivid life-like dreams, the weird feelings. I had several recurring dreams during my visits and in all of them the island was covered with people, all walking in a strange dream-like state under a moon-lit night. I even spent one night out there alone — something I don’t care to repeat. Another fairly strange place was the caretaker’s house, which was abandoned long ago. At times male California sea lions cover the island and occupy every room in the old house; doors were broken down, windows broken; molts, poop and carcasses covered the floors and the walls, stairs damaged, decaying fur in the closets and bathtubs, everywhere covered in brown stuff. It was like the scene of a bachelor party that lasted for decades. And the party continues.

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Sea lions and Elephant Seals on the beach at Año Nuevo near the old fog house. Photos: Brian Tissot.

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Male California sea lions cover the island in September, 1968. Photo: R. Peterson.

Because of all these animals focused on this one place the ecology of Año Nuevo is quite unique. All of these animals — these birds, these mammals — all forage in the Pacific and consume prey from some of the richest ecosystems on the planet. Then they come to the island to rest, to hang out, to molt, to mate, give birth, raise their young, but most of all, to poop. And poop is good, poop is energy — nitrogen, phosphorus — this is the stuff that supports food webs and creates rich food chains and huge fisheries. Because of this the Año Nuevo region is unique. Abnormally high diversity and species uncommonly abundant. Fish caught from the area are twice the size of fish caught near Monterey.

And with everything that lives in the water it is no surprise that the area is frequented by white sharks, lots of them. Año Nuevo is part of the so-called “red triangle”  — with the Farallon Islands and Bodega Bay defining the other two points — an area where 11% of all known shark attacks have occurred. The area also serves as research site for tagging white sharks as they return to the island almost every year after foraging widely across the Pacific. It is not uncommon to see large elephant seals with huge bit marks on the bodies: likely evidence of an unsuccessful shark attack.

A young elephant seal at Año Nuevo. Photo: Brian Tissot

And none benefit from Año Nuevo more than the elephant seals: the real stars of the island. Among pinnipeds (seals and sea lions) elephant seals reign supreme in superlatives: they are the deepest divers (over a mile, to 7,800 ft), spend the most time at sea (80%), are the biggest (8,800 lbs), and show the greatest sexual dimorphism (males are typically 5-6 times the size of females). You can connect a lot of these traits to their breeding behavior: big males arrive early on the island and defend large harems of females (up to several dozen) to pass on their genes to the next generation. A successful bull may sire up to 500 offspring in his lifetime. To accomplish this they need to spent up to 3 months without eating while battling it out with other big males and mating with as many females as possible. During breeding season (Dec.-Feb.) the big bulls make extraordinarily loud percolating noises to scare off rival males, which occasionally erupt into powerful fights for dominance. This is the sole function of their large, elephant-like snout. Although most fights are short-lived some battles are epic in proportion and result in bloodied and battered contestants.

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Paths of tagged elephant seals (right) from their breeding colonies along the Pacific Coast (left). Source: Costa et al., 2012.

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Geographic distribution of male and female elephant seals in the north Pacific. Source: Stewart and Huber, 1993.

But all that energy, all that sex, has to come from somewhere and that source is one of the most productive ecosystems on the planet: the deep-sea. To tap that source, elephants seals have become among the most prolific divers on the planet. Once they leave the island instruments attached to their backs have shown an amazing pattern: they spent almost 90% of their time underwater following the ocean bottom as they migrate 1500 miles to the North Pacific. The physiology if that feat is a story in itself that results from a series of specialized adaptations to aquatic life, including a reduction of metabolic rate.

Northern Elephant Seal, Piedras Blancas, San Simeon, CA 02feb2008 - photo by Michael "Mike" L. Baird http://bairdphotos.com Canon 1D Mark III w/ 600mm f/4 IS lens on tripod

Northern Elephant Seas fighting it out, Piedras Blancas, San Simeon, CA Photo by Michael “Mike” L. Baird http://bairdphotos.com

But in the north Pacific males and females separate and pursue different agendas, largely due to their different energy requirements from the disparity in size (Le Boeuf et al., 2000). Big males have to maintain their enormous bulk — and the ability to fast for long periods of time while fighting off other bulls — by acquiring massive amounts of food. To do that they take greater risks than females by exploiting rich food sources along the sea floor at 1200-1600 foot depths: primarily squid and fish. Risky because they areas they forage are closer to shore and they are more exposed to predators such as white sharks and killer whales. Females also have huge energy demands as they require the ability to nurse their babies, fast during breeding season, and survive to reproduce again. As a result, they also exploit rich food sources, but more patchy and offshore (away from predators), pelagic (mid-water) prey in the deep-sea: primarily small fishes such as lantern fish (Naito et al. 2013). These annual migrations are incredibly successful and males may gain as much as 6 lbs per day while foraging (females about  1.5 lbs/d). Clearly, elephant seals are extraordinary animals.

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Depths of dives taken by six male northern elephant seals by time of day. Source: Le Bouef et al., 2000

And now, looking back on my amazing wonderful trips to the island, most between 1987-1990, what I remember most is the energy of the place. The dazzling biological energy of the present, radiating from the birds and mammals that choose the island as part of their complex life cycles; ranging across the planet to acquire food but returning to the island to rest and breed. And the energy of the past, of all of the people who passed by here in ships but never made it to their destination. Of those that braved crossing the channel but got caught in its grips, its currents and waves, and were never allowed to leave. But most of all, I remember proposing to my wife on a cold, wind-swept October day in front of thousands of elephant seals. And 28 years later we cherish those specials days on the island and carry the energy of the place with us. Forever bound to our hearts and in our souls.

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Me helping to monitor the health of elephant seals pups on the island in 1989 with UC Santa Cruz researchers. Although only weeks old they were incredibly strong and weighed 200-400 pounds. Photo: Susan Tissot.

References:

  • Costa, D. P., G. A. Breed and P. W. Robinson. 2012. New Insights into Pelagic Migrations: Implications for Ecology and Conservation. Annual Rev. Ecol. Evol. Syst. 43:73–96
  • La Boeuf, B.J., D. E. Crocker, D. P. Costa, S. B. Blackwell, P. M. Webb and D. S. Houser. 2000. Foraging Ecology of Northern Elephant Seals. Ecological Monographs 70(3): 353-382.
  • La Boeuf, B. J. and  S. Kaza. 1981. The Natural History of Año Nuevo. The Boxwood Press. 425 pp.
  • Naito,Y., D.l P. Costa, T. Adachi, P. W. Robinson, M. Fowler and A. Takahashi. 2013. Unravelling the mysteries of a mesopelagic diet: a large apex predator specializes on small prey. Functional Ecology doi: 10.1111/1365-2435.12083.
  • Stewart, B. S. and H. R. Huber.1993. Mammalian Species: Mirounga angustirotris. 449: 1-10.

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