Return of the Sea Otter

by Todd McLeish

  The closer that Miller and others examine dead otters, the more pathogens and diseases they find. Two orphaned sea otter pups were discovered in 2014 to have a virus similar to chicken pox that causes skin lesions that result in fur loss. And the loss of fur is a great concern because, lacking a blubber layer, sea otters are likely to lose their natural insulation and become hypothermic, potentially leading to a quick death. And Miller is beginning to find an increase in mortality due to heart failure, though little is known yet about what may be causing it.

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  JUST ABOUT EVERY sea otter found dead along the California coastline eventually makes its way to Melissa Miller’s laboratory, about 250 to 300 animals each year. Most of them arrive between March and early June, with another peak in September and October, but hardly a week goes by that she doesn’t receive a couple dead otters. Sometimes they arrive by FedEx; sometimes they’re hand carried by a state park or beach employee; sometimes they arrive in bulk and in various stages of decomposition. That means that about 10 percent of the southern sea otter population turns up at her pathology lab each year, which most estimates suggest probably represents about half of the total number of southern sea otters that die annually. Those that don’t eventually make it to her necropsy table probably lived in the Big Sur area, where few people reside and where access to the coastline is limited.

  Miller, whose early career path included jobs as a sea lion trainer, tire changer, chambermaid, and field biologist, describes her present job as “a medical examiner for wildlife.” Her aim, she said, is to tell the story of every animal that arrives at her lab by not only trying to learn how it died, but also determining how it lived and how that relates to how it died. Freshly dead otters receive a full necropsy with tissue samples analyzed in great detail. But due to limited funding, those that have already begun to decompose are frozen and later thawed in batches to receive what Miller calls a “demo necropsy,” an abbreviated examination that does not include the collection and testing of tissue samples. She conducts about one hundred detailed necropsies each year, a standardized procedure that takes about four hours to complete. “I don’t care if there’s a knife sticking out of it; we’re going to do the exact same protocol all the way through the examination,” she said. That’s how she discovered that Toxoplasma was such a common source of infection in sea otters, by carefully examining every tissue of every animal for any factors that may have contributed to its death, regardless of whether a seemingly obvious cause of death was evident.

  The female otter that was on Miller’s stainless-steel table when Renay and I visited had clearly seen better days. It had been found dead of unknown causes on the shore at Palm Beach State Park in Watsonville two days earlier, and it had probably been dead at least two days before being found. Miller was determined to find out how the otter had died.

  At first glance, the animal appeared to be in good physical shape, though its belly had already begun to bloat from the gases produced during the decomposition process. Judging by the otter’s incomplete dentition, Miller said it was not yet one year old, but its eyes were bulging and blood filled, which immediately alerted Miller that it had likely experienced head trauma.

  The necropsy process was much like what we observed in Kristin Worman’s lab. But because of the otter’s bulging eyes, Miller focused on skinning, probing, and closely examining the dead otter’s head and skull for any other evidence of trauma, but none was found. No noticeable wounds were found after an examination of the animal’s pelt and torso, either, so Miller’s preliminary conclusion was that the animal’s cause of death was probably something other than a gunshot. She then cut into the otter’s body cavity. Bloated large intestines forced their way out, and very quickly the stench became overpowering—not like the smell of roadkill, an aroma I’m quite familiar with, but instead something slightly sweeter yet so potent that I repeatedly had to take a step away to blow out the putrid smells and attempt to breathe in cleaner air. I’ve observed enough dead and decomposing animals that the sight and smell of them seldom causes me to flinch, but the stench this time was overwhelming.

  After examining the otter’s major abdominal organs, Miller said the otter appeared to be in good physical shape, so trauma remained the most likely cause of death. She became even more confident of that assessment when she opened the chest cavity, unexpectedly revealing large quantities of pooled and clotted blood. “Now we know it’s trauma, probably a boat strike,” said Miller. “That would explain why it’s in otherwise good physical condition.” Using a large pair of pruning shears, she cut through the rib cage and observed even more blood, which she described as “severe hemorrhaging into the chest.” She double-checked that there were no bullet wounds or holes, and found none, but went back to look again, still with a question in her mind about whether there could be a gunshot wound.

  After another five minutes of carefully examining the inside of the pelt in the vicinity of the animal’s chest and shining the overhead lights more effectively on the animal, she finally found a minuscule hole in the fur in the vicinity of the right side of the chest. It was so small that it couldn’t have been made by typical-caliber ammunition. Instead, she considered that it may have been from a BB or shotgun pellet, perhaps a bullet fragment, or even a broken rib poking through the skin. “It’s a very subtle hole,” she said. So she made the decision to stop the procedure and do a “lead hunt” with a radiograph to determine if a bullet remained in the carcass. When the X-rays were taken, they showed a single shotgun pellet lodged just above the tenth rib (of seventeen) on the left side of the body. Based on the hole in the pelt, Miller concluded that the projectile entered on the animal’s right side, proceeded through the chest cavity, and lodged in the left side.

  Miller said it was the first time she had seen a shotgun pellet cause the death of an otter, since most pellets bounce off of their dense fur or lodge in the fur. They seldom penetrate. She still didn’t rule out that the animal had been shot and later struck in the head by a boat, but that would have to await further analysis.

  “This is not a case we’re going to solve,” she said, “because you can’t do ballistics on pellets. Without an eyewitness, the chance of finding the culprit is remote.”

  Chapter 8: Cucumbers and Geoducks

  PRINCE OF WALES ISLAND, ALASKA

  AFTER ALASKA attained statehood in 1959, it became responsible for the small sea otter populations in the state, and from 1965 to 1969, the Alaska Department of Fish and Game relocated 403 sea otters from the Aleutian Islands and Prince William Sound to six sites in Southeast Alaska: Cape Spencer (25 otters), Yakobi Island (30), Khaz Bay (194), Biorka Island (48), the Maurelle Islands (51), and the Barrier Islands (55). An unknown number was also reintroduced to Yakutat Bay just north of the region. Out of all those otters, just 106 survived the process and, along with their offspring, have spread throughout the outer coast of the region. Many continue to infiltrate the archipelago’s nooks and crannies. Those 106 otters have multiplied into more than twenty-five thousand otters, according to a 2012 survey of the area, more than eight times as many as are found in all of California and a 12 percent annual growth rate that continues unabated.

  Zac Hoyt, a doctoral student at the University of Alaska in Fairbanks, has spent nearly ten years studying the sea otter population in southern Southeast Alaska, and he has modeled the growth of the population in a variety of ways. He said that, unlike for sea otters in California and other parts of Alaska, there has been nothing to regulate the population of otters in the southeastern part of the state. Whereas sharks and killer whales are keeping the otter population in check elsewhere, the otters themselves are the apex predator in Southeast Alaska. The only limitation to the growth of the population is the availability of food, and so far there seems to be plenty. Hoyt also called Southeast Alaska’s sea otters a “closed population,” meaning that no sea otters are emigrating from other areas into the region, nor are sea otters fr
om Southeast Alaska moving elsewhere. Their population is growing entirely through their own reproduction.

  But Hoyt’s model indicates that it isn’t happening in a predictable manner. The sea otter population in southern Southeast Alaska has, in fact, grown in a herky-jerky way, with some areas experiencing rapid growth, others growing slowly and steadily, and still others seeing their once-abundant population crashing altogether. When the first organized sea otter survey of Southeast Alaska was conducted in 1975, the animals were found to have expanded their range from the initial release sites, but there wasn’t much of a build-up in the population numbers. A few otters had reached as far north as Coronation Island, off the northwest coast of Prince of Wales Island, about thirty-five miles from the Maurelle Islands release site, but most had traveled much shorter distances. The next survey, in 1983, discovered that the range expansion in that area had slowed, but the density of animals in the places they were found had grown significantly. Five years later, biologists learned that the otters were on the move again, colonizing the Bay of Pillars and Sumner Island to the north and Lulu Island to the south. Population density increased again, too, with more than five times as many otters counted than just five years previously. Subsequent surveys had similar results, with range expansions and population densities speeding up and slowing down over time.

  Some areas, however, showed unexpected results. Port Malmesbury on the west side of Kuiu Island, for instance, had the highest density of otters in all of southern Southeast Alaska in 2003, with about 470 animals recorded. But in the surveys of 2010 and 2011, when large areas of Southeast Alaska were being colonized by sea otters and otter numbers were growing rapidly, almost no otters were found in the Port Malmesbury area. And the population at Coronation Island has also experienced a significant decrease in otter numbers recently. Something appears to be limiting population growth in some areas, most likely the availability of food. “It looks like the otters may have overshot the carrying capacity that the habitat can withstand,” Hoyt said. “It’s a dynamic seen in other sea otter populations as well.” It’s having a dramatic effect on the entire ecosystem and on the economic health of the region, too.

  Like in other areas of their range, when sea otters were extirpated from Southeast Alaska during the fur trade, the species the otters preyed upon flourished, including sea urchins, Dungeness crab, and sea cucumbers. And when fishermen discovered a market in the Far East for some of those species, commercial fisheries became established. The return of sea otters to the region, which many consider a tremendous conservation success, has been met with considerable anger among the vocal fishermen, who rightly fear competing with sea otters for shellfish.

  In the 1990s, fishermen in Southeast Alaska harvested as many as four million pounds a year of red sea urchins, packaging their roe for shipment to Japan. A regional urchin management plan directed that just 6 percent of the urchins in the region be harvested each year to ensure that the fishery remained sustainable. But an unregulated commercial fishery for urchins along the Pacific coast of Russia over the last fifteen years flooded the market, and an influx of sea otters has decimated the Southeast Alaska urchin population, so the Alaska fishery is no longer as robust as it once was, declining to about half a million pounds per year in 2014. “I don’t really see the urchin fishery recovering,” said Phil Doherty, director of the Southeast Alaska Regional Dive Fisheries Association, “and the reason is the sea otters.”

  He’s right. According to Hoyt and his University of Alaska colleague Ginny Eckert, when sea otters recolonize an area, their preferred prey is red sea urchins. While Hoyt’s studies of the diet of sea otters in southern Southeast Alaska found that the animals ate sixty-eight different prey species, in the first few years after otters returned to an area, 99 percent of their diet consisted of red sea urchins. “Urchins are an amazing food for otters,” said Hoyt. “They’re easy to get, it doesn’t take them a lot of effort, they don’t have to search very hard for them, they break them open easily, and the roe provides them with a great deal of energy.” As a result, he added, about ten to fifteen years after otters move into an area, commercial fisheries for sea urchins are no longer viable.

  When the urchin fishery crashed in Southeast Alaska—like the commercial abalone fishery before it, which was wiped out due to overfishing—most of the fishermen simply shifted their focus to harvesting other species. Many switched to giant red sea cucumbers, a slow-moving, spiny slug-like creature that feeds on detritus on the seafloor. Sea cucumbers have five longitudinal muscles running along their body that fishermen slice off after harvest for sale to Japan, and the remaining skin is then dried and sold to China. Launched in 1981, the sea cucumber fishery now includes about two hundred dive fishermen in Southeast Alaska who harvest nearly 1.5 million pounds of sea cucumbers per year.

  These commercially harvested species live from the intertidal zone down to several hundred feet deep and are caught not with traditional fishing gear but simply by picking them up by hand from the seafloor or digging for them while diving beneath the surface. Which is exactly how sea otters harvest them. And the otters are much more efficient at it than people and completely unregulated.

  The sea cucumber fishery is looking like it may be the next to crash. While people, otters, and otter prey seemed to live in balance and harmony prior to the marine fur trade, that does not appear possible any longer if the prey species are targeted for commercial harvest and the otters are protected from harm. Fishermen who harvest geoducks (pronounced “gooey ducks”), the world’s largest burrowing clam, haven’t begun to feel the effects of the growing sea otter population much yet, but they know their time will come.

  Geoducks live in coastal areas of the Pacific Northwest and northward to Alaska, where they grow to about ten inches and can weigh more than seven pounds. Found buried up to three feet deep in muddy and sandy bottom habitats of bays and estuaries, they live for well over one hundred years, feeding on single-celled marine algae and other microorganisms that they filter out of the water with a siphon that can extend nearly forty inches to the surface of the seafloor.

  Dive fishing is a dangerous business, and diving for geoducks is especially hard work, which is why the sea otters haven’t had much of an impact on the fishery yet. The otters eat the easy prey first, like the urchins and sea cucumbers that live on the surface of the seafloor. But the challenging work of unearthing geoducks is worth it to the fishermen. It’s a lucrative business harvesting geoducks for sale to markets in China, Hong Kong, and Vietnam. Most fishermen earn about $75,000 per year working just one day per week for six months each year (though to enter the business they have to buy a fishing permit that cost about $90,000 in 2014). And they’re beginning to get worried about their future.

  * * *

  TO GET AN IDEA of what the dive fishermen in Southeast Alaska are facing from the influx of sea otters, I spent a morning with Kathy Peavey, a glass artist, photographer, and entrepreneur who occasionally joins her husband, Matt, on the Anne Louise, their dive-fishing vessel. When she’s not making art or serving as a deckhand, she ferries the media and others around the local waters to show them the challenges the expanding number of sea otters are creating for the fishermen in the area. I met her at North Cove Harbor in the town of Craig on Prince of Wales Island, home to the majority of the dive-fishing fleet on the island, perhaps twenty repurposed boats of various sizes and shapes.

  We slowly pulled out of the harbor, past an anonymous building where E. C. Phillips and Son buys most of the sea cucumbers and geoducks the fishermen harvest, and out into Klawock Inlet. In the summer, the inlet is usually filled with the noise and congestion of floatplanes coming and going, delivering cargo, visitors, and locals to points far and wide. We were greeted there by a small flock of rhinoceros auklets, gray seabirds with large orange beaks and white facial plumes. Peavey called them “king salmon ducks” for their propensity to show up in abundance just when the king salmon arr
ive in the region.

  Peavey said that sea otters are just beginning to move into the immediate vicinity of Craig, but not far away on the fishing grounds the animals are already competing directly with the dive fishermen. We headed south and west a few miles, past the line that delineates the boundary of the Haida tribal territory in the south from the Tlingit lands to the north, and beyond Fish Egg Island, where salmon are known to spawn, on our way to Bucareli Bay, one of several designated geoduck and sea cucumber fishing grounds in the area. According to Peavey, the site on the southeast corner of San Fernando Island was colonized the year before after the otters expanded from the west side of the island. She said the animals “ate themselves out” of their previous site—also a designated dive-fishing ground—and have moved in to Bucareli Bay. They were easy for us to find.

  The waters were surprisingly calm as we skirted the coast, but gray skies suggested that it wasn’t going to stay that way for long. As we approached Balandra Island and a large kelp bed nearby, otters began appearing nearly everywhere we looked. A group of seven otters abruptly dived nearly in unison as we approached, while a solitary individual a hundred yards away hardly took notice of us. Several others lazily sank beneath the surface to avoid the noise of our boat, and one just stared contentedly at us without moving.

  “Otters are invasive species around here; they’re the rats of the sea,” Peavey said. “It’s just like an infestation of rats in New York City. You have to eradicate them or else the humans are going to lose—to the otters, the whales, the sea lions, and the wolves. We’re going to lose our dive fisheries, and we can’t afford to.”