There are too many pink salmon in the Pacific

There are too many pink salmon in the Pacific thumbnail

This article was originally featured on Hakai Magazine, an online publication about science and society in coastal ecosystems. Read more stories like this at hakaimagazine.com.

The Tutka Bay Lagoon Hatchery can be found at the end of an isolated estuary in southcentral Alaska’s Kachemak Bay. Accessible only by boat from the closest hub community of Homer, the hatchery is one of 30 constructed by the state to boost commercial salmon fisheries that were struggling in the 1970s. On the last day of April, I board a water taxi in the Homer harbor to visit the facility. A raging westerly wind careens across the bay as the 10-meter landing craft slams into swells the skipper describes as “sporty.”

I’m visiting the hatchery’s Ponding process, which involves the transfer of pink salmon fry from freshwater incubators in the ground to floating saltwater pen in the lagoon. This is the first step before the hatchery releases about 60 million paper clip-sized pink salmon into the ocean where they’ll disperse to feed and mature by next summer.

There are too many pink salmon in the Pacific
The Tutka Bay Lagoon Hatchery is perched on an isolated estuary off southcentral Alaska’s Kachemak Bay. Nathaniel Wilder/Hakai Magazine

Fish farms are illegal in Alaska and raise salmon to marketable size. Hatcheries exploit a salmon’s natural homing instinct to release juvenile fish to feed them and finish the growing process at sea. After that, they return to the hatchery to provide fish suitable for recreational and commercial harvests. This practice is sometimes called salmon ranching and seafood marketers often label hatchery fish “wild caught.” I want to gain an understanding of the industry, which is largely run by NGOs that are funded by the sale hatchery fish. I want to place in perspective the mounting scientific evidence that these fish are polluting marine ecosystems, where they can have an impact on everything from plankton and whales.

The tide is too low to allow the skipper to transport the boat through the narrow channel leading to the lagoon. She drops me on a beach nearby where I climb five flights up an old wooden staircase up a rocky cliff to reach a forest of tall spruce that surrounds her facility. These tall trees provide shelter from the harsh sea conditions, allowing me to hear the soft, melodious song of a kinglet, which is a small songbird with a large voice, from a high bough above my head.

There are too many pink salmon in the Pacific
Map data by ArcGIS

Josh Sawlsville is the manager at the time. He met me at the hatchery office. A hefty guy with sandy blond hair, Sawlsville got into the industry on a lark over eight years ago when he was a biology undergrad in Wisconsin and took a semester off to work as a cook at a hatchery in the heart of Alaska’s pink salmon production, Prince William Sound, about 300 kilometers northeast of Tutka. After graduating, he returned to the industry and moved from the kitchen into the fish operation. Sawlsville manages more than a dozen employees during the summer months. However, the hatchery is just emerging from the winter season when work slows down. The hatchery is tucked away among the trees and loses direct sunlight for several months.

Sawlsville and I put on rain gear and he hands me a red-bulbed headlamp to enter the dark incubation room, a cold, damp warehouse with what sounds like 100 faucets going full blast. We wander among the incubators, which are shallow tanks stacked in rows, much like shelves that line grocery aisles. The incubators are filled with salmon fry, which were born in late fall. They are about the same length as a matchstick. To keep the young fish calm and less oxygen-intensive, overhead lights are kept off. Sawlsville lends me a red light. It doesn’t bother the fish. He explains that the red light is not bothersome to the fish. However, it does pick-up flashes of silver wherever I look: in incubators; in the chest high trough where fry are placed before being flushed into the lagoon through an underground pipe; underfoot, where little fish have escaped from their tanks to die on concrete floors. It is amazing to see the scale of the effort. If all of these fish survived to maturity there would be six salmon dinners for all residents of Canada, Alaska and the United States.

There are too many pink salmon in the Pacific
Fish hatcheries in Alaska contribute almost one-quarter of the value of the state’s salmon harvests. Nathaniel Wilder / Hakai Magazine

Hatcheries are under increasing scrutiny in the Pacific Northwest because they are causing damage to wild salmon runs. Hatcheries fish, which are less successful spawners than wild salmon, stray into far-off rivers where they can interbreed and produce wild offspring that aren’t as fertile. The love affair between Alaska and industrial salmon fry production continues. Hatcheries contribute one-quarter of the value of the state’s salmon harvests, boosting commercial fisheries, propping up large-scale fish processors, and generating US $600-million in the process. They also produce fish that is a staple on the plates and freezers in Alaska. In addition to pink salmon, the Tutka facility, which is owned by the state and operated by a private organization governed primarily by commercial fishermen, annually releases around 420,000 sockeye smolts (representing less than one percent of the pink fry released). Although they are more popular than pink salmon for their flavor and ability to withstand freezing, sockeye salmon are more costly to raise in hatcheries as they require longer rearing times in freshwater tanks. When the tide permits, the lagoon is filled with pleasure boats and fishermen who lob hooks to catch mature sockeye. They are heavier than the pinks but still have gleaming silver and are returning to the hatchery. Locals also stock sockeye in a nearby whitewater creek. They use wide-mouth nets to catch enough to keep warm during the winter at the hatchery.

Despite these benefits, some are questioning whether it is logical to continue pumping salmon into the Pacific with such reckless abandon. In the decades since Alaska rushed to construct hatcheries to fill the gaps in ailing salmon runs, especially pink populations hit hard by tectonic shifts caused by a massive earthquake in Alaska in 1964, ocean conditions across the North Pacific have been a boon to pink salmon. Today, Tutka’s pink salmon fry are swimming into a very different ocean than when the facility was first built in 1978, an ocean that appears to be favoring pinks.


It’s a golden age for pink salmon in North Pacific. Across the region, there are three times more pink salmon in the ocean than there were about 50 years ago. Nearly three quarters of all salmon in the North Pacific region are pinks. Hatcheries are grabbing that bounty .

Since the 1970s, industrial production of pink salmon has exploded, and today, hatcheries in the United States, Canada, Russia, and Japan pump about 1.3 billion pink salmon fry into the Pacific each year, leading to the production of roughly 82 million adults. About 15 percent of all pinks in the ocean originate from hatcheries, topping off a population that is already at a record level of abundance. This means that there are approximately as many hatchery pink salmon than wild sockeye, and more hatchery roses than wild chum, wild chinook, or coho. Alaska accounts for the majority of this production.

Although they are the smallest Pacific salmon at less that two and a quarter kilos, pinks are a popular choice for hatchery workers due to their short life cycle. These fish are voracious feeders and fast growers, quickly bulking up to market size by increasing their weight 500 percent at sea over four months. And unlike other salmon species that spend a variable number of years in salt water–up to five years for chinook–pinks return for harvest predictably after about 18 months at sea.

There are too many pink salmon in the Pacific
Hatcheries prefer to raise pink salmon partly because their short life cycle keeps costs down. Nathaniel Wilder / Hakai Magazine

This short life span is one reason wild pink salmon thrive in today’s changing ocean environment. Their ability to reproduce at breakneck speeds allows pinks to colonize new areas quickly and recover from population declines, prospering like rats in places where other species might not. Warming conditions also alter the food chain in ways that favor wild and hatchery roses alike.

But pink salmon isn’t the only species that is thriving. There have been more salmon in North Pacific waters in recent years than at any time in the past century. And while this has been a blessing in some places–the Bristol Bay sockeye run hit a historic high last summer at more than 66 million fish–more fish in the ocean means greater competition for the next meal. As throngs of hungry salmon chase similar prey–including zooplankton, squid, and small fishsalmon are getting smaller.

Nancy Hillstrand witnessed this firsthand. Coal Point Seafood Company is owned by her. It is a seafood processing and retail outlet near the Homer harbor. I took the water taxi to the hatchery. The place bustles with activity on a summer day. Workers on the slime line skillfully fillet salmon, halibut, and commercial boats by recreational fishermen; high-end seafood such as king crab legs, scallops and smoked salmon–sells at a premium at their front counter.

Hillstrand has lived on the bay for close to 50 years. She has watched as lucrative shrimp and crab fisheries vanish, and now salmon being delivered to her processing facility are shrinking. She says, “I didn’t realize what was happening until everybody was asking for scissors.” She needed to trim the nearly-arm-long bags she had ordered for vacuum-packing salmon fillets.

There are too many pink salmon in the Pacific
Nancy Hillstrand, owner of Coal Point Seafood Company, has lived on Tutka Bay for close to 50 years. Photo courtesy of Nancy Hillstrand

More than 50 years of data have confirmed what Hillstrand observed on her processing line. While the number of salmon has shot up, the size of fish is going down: in Alaska, chinooks have shrunk the most at eight percent compared with pre-1990 sizes, and elsewhere, such as on the Columbia River where the “June hogs”–chinooks that weigh more than 35 kilograms–used to spawn each summer, mighty chinooks are a thing of the past. This is a loss for commercial fishermen and other fish-harvesters, as well as a new paradigm in fish processing, restaurants, and markets.

Now Hillstrand orders 46-centimeter bags, and she believes hatcheries are partly to blame. Hillstrand has been fighting for reform in an industry that she knows well for nearly a decade. She spent 21 years working at salmon hatcheries across the state and estimates that she single-handedly released more than one billion young salmon into the ocean. She loved the work and the years spent in Alaska’s most beautiful and remote places. She cringes when she thinks back. She says, “I never considered what it was doing for wild fish.”


Researchers know for a long time that salmon in streams and lakes compete for food. Understanding what happens in the open ocean is a different story. All natural systems can be difficult to study. However, marine habitats, which are often far away, can be frustratingly distant, and can extend over great distances, may be the most difficult. Greg Ruggerone, a salmon scientist, believes he has found a way to work around it.

In the late 1970s, Ruggerone was a young graduate student at the University of Washington, starting what would become a long career immersed in salmon and their environments. Art Gallagher was finishing his master’s thesis on pink and chum salmon in Puget Sound at the time. Gallagher wanted to know how one species affected another. He took advantage of the fact, that in odd years, millions upon millions of pinks return home to spawn, while in even years, very few do. Gallagher was able to see how chum salmon fared in relation to the rise and fall of pink numbers. This meant that fewer chum survived when there were more pinks.

There are too many pink salmon in the Pacific
Researchers have focused on the pink salmon’s effect on other species because of its biennial pattern–odd years see millions of pinks returning to spawn in rivers, and even years see relatively few. Nathaniel Wilder / Hakai Magazine

Ruggerone was intrigued by this biennial pattern in pink populations. The origin of the pattern is unknown. Its extreme location at the northern and south ends of the fish’s ranges, which traditionally extend from Washington State to just below Arctic, is where no one knows for sure. Ruggerone spent summers studying salmon on the Alaska Peninsula. He caught fish from the shore for his research and lived in an old cabin with plywood walls, which brown bears would chew through at the end of each field season. He kept the unusual pink salmon population pattern in his thoughts as he became the project leader of the University of Washington’s Alaska Salmon Program. This position lasted almost a decade.

In 2000, Ruggerone was studying scales of sockeye salmon from Bristol Bay. Fish scales, like tree rings, contain marks that indicate the fish’s age and growth rate. Ruggerone noticed a pattern of sockeye growth as he analyzed the data. It was influenced by the rise and fall in pinks that he had first learned about 20 years ago. He says, “Sure enough it just stood out.” Gallagher’s study found that the growth of Bristol Bay sockeye fell when pinks were plentiful, just like the populations of Puget Sound Chum in Gallagher’s study.

Years ago, tagged fish showed that Bristol Bay sockeye swim in the same waters as pinks coming from Japan and Russia. These pinks, like others, are much more common in odd years than even. The scales indicated that the Bristol Bay sockeye faced stiff competition from odd-year pinks. Survival data showed that young sockeye were more likely to die when there was more pink. The pink salmon from Russia and Japan had left their marks on the sockeyes returning to Alaska.

” This biennial pattern is really special,” Ruggerone states. Ruggerone says that this pattern of up-and-down in pink populations creates an ideal experimental control in North Pacific. It allows Ruggerone to see the extent of the pink fingerprint across ocean.

The fingerprint has been found on salmon runs in the Pacific. Pink numbers are a problem for Chinook from British Columbia. Coho in southeast Alaska eat less pinks when there are many. Pinks make chums from Puget Sound to Russia’s Kuril Islands eat less. In the central North Pacific, steelhead go hungry during pink boom years. On the Fraser River in British Columbia in particular, fewer young chum survive years crowded by juvenile pinks.

These are disturbing trends, but when Ruggerone and biological oceanographer Sonia Batten from the North Pacific Marine Science Organization compared 15 years of plankton data with pink salmon abundances, a more alarming pattern emerged. Batten and her team have been collecting data on the North Pacific’s smallest creatures for more than 20 years using a torpedo-shaped sampling device called an continuous plankton recording device. This device is towed behind cargo ships and tankers. During odd years, when there could be as many as 40 times more pink salmon as during even years in the waters she was studying, large zooplankton such as copepods declined, while levels of phytoplankton–food for copepods and other kinds of zooplankton–went up. It appeared that pink salmon were eating large zooplankton’s highest-value food, large zooplankton.

” “It was a very clear effect of top of food chain affecting bottom,” Batten said. She had never seen a single predator species control the abundance of plankton. Batten and Ruggerone concluded that pinks were triggering atrophic cascade where hungry fish were drastically altering the food chain.

This food chain effect may explain why researchers have observed the impact of pink salmon on mackerel, herring and mackerel. These fish eat zooplankton, and are therefore the targets of lucrative commercial harvests. The seesawing abundance and well-being of seabirds who eat small fish, which in turn gorge on the same amount of zooplankton as pinks, is also crucial. Alan Springer, an ocean researcher, has observed that seabirds produce fewer chicks when there are more pink salmon. He believes that pink salmon booms are connected to a series of wrecks that have alarm coastal communities and puzzled scientists in recent decades. He says, “They are intimately connected.”

The pink fingerprint is also showing up elsewhere. Ruggerone noticed the pink effect after just a minute of studying a graph that showed the mortality rate of endangered killer whales off British Columbia, Washington. He says, “It’s still mindboggling for many people.” These killer whales don’t eat pink salmon and the decline in chinook salmon, which is the preferred prey of these marine mammals, can’t explain why there is a biennial pattern of whale deaths. Researchers believe that the sheer number of pink salmon–which, in this southerly part of the fish’s range, can be 45 times more numerous in odd years–could be disrupting killer whales as they hunt for dwindling chinook.

But, what is the ecological impact of the millions of pink salmon hatcheries releasing into the North Pacific? Brendan Connors is a fisheries scientist at Fisheries and Oceans Canada. He wanted to investigate the differences between wild and industrially produced pinks. Connors worked as a fishing guide in Haida Gwaii while completing university. He used single-action reels to catch chinook and coho. He dove into researching salmon interactions at sea after the Fraser River sockeye run collapsed catastrophically in 2009.

There are too many pink salmon in the Pacific
The ecological fallout of the billions of pink salmon released into the North Pacific by hatcheries has some scientists worried. Nathaniel Wilder / Hakai Magazine

Connors, his team and others focused on the question of hatchery pinks’ effect on sockeye populations. They reviewed data from 47 sockeye populations that enter the ocean from waterways in British Columbia to the Bering Sea, which represent nearly all of the North American sockeye runs. Warming temperatures have helped to boost wild sockeye populations in the northern part, such as Bristol Bay. This has offset the negative effects of pink competition. But in the southern part of their range, hatchery pinks alone have reduced sockeye survival by about 15 percent. Connors explains that if the pink salmon hatchery production was stopped, sockeye populations on the Fraser, some of which are in danger of extinction, would have a better chance of recovery.

” We often think of the ocean in terms of being a vast, endless place.” Connor said. “This work really challenges these simple assumptions.” Ruggerone and others worry that the ocean may have reached its production limit in some parts of the North Pacific during high-pink years. Any new fish will only take away a portion of the biological pie.

Hillstrand knows this. A few years back, she and a state biologist cut open a pink salmon belly to find seven sidestripe shrimp. The shrimp were worth $7 and the fish less than one dollar. She says, “We’re replacing fisheries, but everyone is kinda in denial.”


Ruggerone and Hillstrand agree that it’s time for us to look at the big picture. In Alaska, swimming against the current can be a dangerous thing. Leon Shaul, a retired state biologist knows this. Shaul’s nearly four decades of research into coho salmon in southeast Alaska revealed that pinks were making the coho, which was once the target of valuable sport and commercial fisheries, smaller. Managers did not take to Shaul’s concerns. He says that “nearly nobody is willing to take a look at the policy level.” The state’s highest decision-making levels are infused with hatchery culture, including Alaska’s newly appointed director of commercial fisheries, Sam Rabung. Sam Rabung has spent most of his career in hatchery, working his way up from technician to many leadership positions. The hatcheries are supported by deep-pocketed seafood processors like Trident Seafoods and Peter Pan Seafood Company, who rely on hatcheries to provide one-third of their pinks’ value. These hatchery fish are used to make canned salmon and roe. Frozen head-and-gutted fish is also exported to China and other countries and returned to the US as vacuum-sealed fillets and burgers. The politically powerful processing industry has openly called for an increase in hatchery production. Shaul claims that questioning the industrial production in Alaska of salmon fry is like slandering Iowa corn.

In the coming years, Connors states that as pinks migrate northward to claim new streams, the North Pacific will continue changing rapidly due to climate change. This will make it harder to predict the future. Last year, Alaska and Russia had the largest pink salmon harvests in almost a century, despite salmon runs in many other regions. The fishermen of Norton Sound, Alaska’s northwest coast, saw the lowest chum harvest for nearly two decades. Meanwhile, processing companies, including one from outside the region, stepped in to make a profit from the burgeoning pink salmon run. Last summer, pinks that are likely to be descendants of fish from Russian hatcheries at the Barents Sea inundated waterways in Norway and Scotland. These countries view them as an invasive species that could pose a threat to native Atlantic salmon runs.

There are too many pink salmon in the Pacific
As the climate changes and the water warms, the ocean habitat may become even more friendly to pink salmon compared with other species. Nathaniel Wilder / Hakai Magazine

Connors and Ruggerone believe that it will require international discussions between Pacific salmon-producing countries to address the problem. It is not clear who will host such conversations and then take action. The North Pacific Anadromous Fish Commission, which is comprised of representatives from the United States, Canada and Russia, has been addressing the issue. But while the commission, which was formed to regulate high-seas fishing, has the authority to enforce the ban on drift netting more than 370 kilometers from any shore, it has no formal role in setting policy for other activities–such as hatchery production–that might threaten salmon runs. All scientists disagree that the North Pacific has too much fish. Even though other scientists have raised red flags for decades now, discussions about the issue are only beginning at the NPAFC.

On this last leg of the hatchery tour I follow Sawlsville over the rocky shore to where a small aluminum boat with a light-duty outboard was pulled up onto the gravel. We’ll take the boat to the floating net pen where millions of fish are being fed. They’ll be released next month in a series high tides. It’s possible that these pinks, like others, are already feeling the pressure of a crowded ocean: the average weight of pink salmon across the Pacific declined by as much as 22 percent from the early part of the 1900s to more recent years. As we walk along the rocky ground below us, Sawlsville asks me about the possibility that the Pacific might have too many salmon. He states that he believes that the ocean has limits but asks, “Are we really messing up the ocean’s carrying capability?” “I don’t think so.” It’s difficult, from this protected spot, to visualize the large swells at sea and the stiff wind at sea. It’s also hard to understand how events in this small lagoon could impact the entire North Pacific. They are, however.

This article is part of “The Paradox of Salmon Hatcheriesseries.

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