Pride of Bristol Bay: Spying sockeye salmon behavior

THESE ARE THE DAYS OF SALMON’S LIVES

BY BJORN DIHLE

On July 22, news broke that Bristol Bay was having its biggest sockeye salmon return since records were first kept in 1893. More than 63 million sockeye had returned to the bay’s different watersheds and fish were still running. By the time the run was complete, almost 66 million fish had returned.

A few days later, I left town to guide a natural history brown bear film shoot in Southeast Alaska. One of the sequences we were trying to get was of a bear chasing salmon underwater. We had a camera in underwater housing submerged near the base of a raging waterfall.

It could be operated from 100 yards away with an iPad. On its screen, I watched dozens of pinks and small darting and feasting Dolly Varden. In the middle of the frenzy was a salmon with a crimson body and green head – a male sockeye. It was swimming in place beneath the falls and waiting for the right moment to attempt climbing them so it could spawn in the small lake above.

Bristol Bay has the largest sockeye run – not to mention the biggest wild salmon fishery – in the world. But in Southeast Alaska, especially where I was guiding on Chichagof Island, sockeye are far and few between.

I’VE GUIDED A HANDFUL of other bear film projects on salmon streams. Some, like this one, had me in the field for a month. The main camera operator on this shoot paid homage to a spawned-out salmon by gently stroking its slimy flesh as it twitched in its final moments.

Guiding a brown bear film shoot allowed author Bjorn Dihle to spend a few days also studying Southeast Alaska sockeye and how they behave. It was quite a fascinating experience to see how these remarkable salmon act. (KRISTINE SOWL/USFWS)

Chaney loves to catch a few Bristol Bay-area rainbows besides the watershed’s iconic salmon. (TRISTON CHANEY)

A short while later, a young bear tore the fish apart and feasted on it. Rain fell heavily and often. I spent many hours alone operating the underwater camera. Bears walked by – sometimes a few yards away. Most would investigate the camera once and, seeing it was not a fish, leave it alone. A few would move the camera around.

Once, when the camera was malfunctioning, a bear shook it and it began to work again. A day after I saw the lone sockeye another crimson salmon arrived and remained in almost the exact same place below the falls.

I spent a lot of time being still, surrounded by salmon in various phases of spawning, death and decomposition. The lifecycle of the sockeye salmon I spent hours watching was very similar to that of sockeye in Bristol Bay.

The fish was born in the lake above the waterfall four or five years before. Of the five species of Pacific salmon – pink, chum, sockeye, coho and king – sockeye are the most dependent upon lakes. This makes the incredible river, lake and tundra habitat of Bristol Bay a paradise for sockeye.

On the other hand, Southeast Alaska’s topography is generally steep; its short creek systems are more ideal for pink and chum salmon.

The Chichagof sockeye’s mother had used its tail to dig out one or more redds – underwater nests – in the gravel, then laid between 2,000 and 5,000 eggs. Simultaneously, the sockeye’s father had sprayed sperm from his milt sacs onto the mother’s eggs. The eggs had an adhesive texture and stuck to the gravel and each other.

Afterward, the mother closed her nest by covering it with gravel. The father moved on and tried to fertilize other females’ eggs while the mother guarded her redds. Both were dead a week or so later – a fate all spawning salmon share.

DURING THE WINTER, THE sockeye and its brothers and sisters hatched. Called alevins, each possessed a yolk sac that sustained them until they emerged from the gravel in April or May. Now considered fry, the sockeye spent one to three years living in the lake and feeding on zooplankton and insects. There, it

Alaska Panhandle brown bears are as dependent on fishing for migrating salmon as anglers, commercial fishermen and residents of the region who fight so hard to

protect it. (JONNY ARMSTRONG)

escaped death numerous times from a host of predators.

One spring, the sockeye left freshwater and entered the ocean. Now a smolt weighing a couple ounces, it used the Earth’s magnetic field to guide it. It fed on plankton and small crustaceans – sockeye’s flesh is an orangish-red color as a result of their diet – and gained 99 percent of its 8-pound adult body weight.

After those one to three years, the sockeye began navigating back to its natal spawning grounds using its incredible sense of smell. Not all salmon return to their rearing grounds. A small percentage stray and colonize new watersheds, which is an ecologically vital way to repopulate watersheds that have been extirpated of salmon or give existing stocks new genes.

Estimates vary, but for every 1,000 sockeye that are born, one makes it home to spawn.

I recognized around 10 different bears regularly utilizing the creek on Chichagof Island. Others would come out of the woods to fish during the night. One study on Kodiak Island stated that an adult male brown bear ate 50,000 calories of salmon a day. An average sockeye contains around 4,500 calories. I watched one bear catch and consume five salmon in 20 minutes.

It may be abnormal to get attached to an individual salmon, but I found myself rooting for that sockeye. I wondered what it was waiting for. Its odds of surviving to spawn decreased each moment it hung around. Bears would leap into the hole the sockeye was waiting in and come out of the froth of whitewater with a fish in their jaws. Each time it was a pink salmon. After a bear moved on, the sockeye would return to its place beneath the falls.

AFTER THREE DAYS OF watching the sockeye, one morning it was gone. It made me think about the millions of salmon returning to Bristol Bay and how, even though the bay’s run is one of the greatest natural wonders of the world, it only took one sockeye to remind me how lucky I am to live in a world with wild salmon. Other salmon thrashed the water and prepared to leap the falls. Bears preyed upon them. Ravens, eagles and seagulls scavenged guts and tattered carcasses.

Somewhere, in the lake above, I hoped the sockeye had found a female member of its species and was preparing to spawn. ASJ

These Chichagof Island bears are hungry and on the prowl. On Kodiak Island – the heart of Alaska’s brown bear habitats – it’s estimated that adult male bruins consume 50,000 calories worth of salmon per day during the runs. (BJORN DIHLE) Editor’s note: Pride of Bristol Bay is a free column written by Bjorn Dihle and provided by its namesake, a fisherman-direct seafood marketer that specializes in delivering the highest quality of sustainably caught wild salmon from Bristol Bay to your doorstep. Go to prideofbristolbay.com for more information.