A very unscientific answer to the question “Why do salmon jump?” was good enough to garner First Place in the Best Humor category of the 2016 Alaska Press Club Awards. Dick Shellhorn photo

I was shooting the breeze with a local gill netter a couple weeks ago, and he mentioned that there didn’t seem to be many “jumpers” this year. Marv Van den Broek, retired hardware expert who spends as many hours out in his bright orange 40-year-old C-Dory as he does gathering firewood, agreed.

Most salmon catchers would assume this means there aren’t many salmon around.

But wait. The commercial guy, who likes to move from the Flats to the Sound midway through the season, mentioned he made several sets at Port Chalmers, picking up a couple hundred pinks each time, without seeing a single jumper. 

Which led to the question, “Why do fish jump?” Or in this case, not jump.

A common theory floating around town is that this year’s top layer of water is so warm the fish are running deeper, and don’t want to go through a sauna to leap with joy. Hmm.

I was going to ask Alaska Department of Fish & Game biologists for their insight, but Buddy Janson, down at Whiskey Ridge Trading, said not to bother: “Back when I was seining with my dad, jumpers coming into a set always meant we had fish. The question was always how many. One time I asked a fish biologist how many fish we could expect from each jumper. His answer: one.” 


So, there you go. And there I went, deciding this might be worth some research. 

My buddy Randy Bruce told me Sig Gildness told him it was so they could see where they were going. 

I ran into dentist Gilbert Urata, who also fishes commercially, at the Post Office. He said the same thing. I said, now I know why you are a University of Oregon graduate. I’m an Oregon State Beaver, and we have this thing going.   

Can you imagine a humpy going airborne near Knowles Head, diving back down, and telling her school mates: “Oops. We’re way off target. Take a U-turn. The AFK Hatchery is way back there.” 

Note I wrote “her.”  A young secretary working for Bert Adams at the Native Village of Eyak heard us discussing this topic and chipped in: “My dad told me only the females jumped.” 

“Why, to get the males excited?” I said.

“He didn’t say why,” she replied. 

Perhaps it is to shake the eggs loose from their skeins prior to spawning, was a theory others offered. If so, why are they jumping out beyond the Cape? That means there is going to be a whole lot of loose eggs before they reach their spawning grounds, which of course we have already decided they spot by jumping.

Back in the days of seining with Captain Olaf Gildness, we would watch an occasional humpy jump over the cork line after we had “pursed up.” Olaf had number of favorite theories, including “to catch a fish, you need to think like a fish.” Try that sometime. A salmon has a brain about the size of a pea.

I countered with Darwin’s Theory of Natural Selection. “See that fish that jumped over the corks? It’s going to survive, while it’s fellow non-jumpers won’t. Someday you’re going to make a set, and after you close it, every fish will jump over the corks.”    

Now that’s jumping with a purpose. Olaf just shook his head. He was a great guy to fish with.

Computers make deep research into this conundrum easy, yet just because someone writes results in black and white doesn’t necessarily make it any truer, although it makes something else deeper. 

Sample findings:  1. They may be jumping to clean parasites or sea lice from gills or scales. 2. They jump as a side effect of increased and rapid hormonal changes. (Just ask any teenager about that one.) 3. Jumping results from agitation or stress, a behavior used by fish farmers to determine if something is wrong with their stock.  

Sport fishermen, who are arriving in their annual migration to line the banks of Ibeck Creek in search of coho, have a whole different perspective. My favorite is: “Salmon jump because they don’t have a middle finger.” Obviously, this postulate was developed by a chronically unsuccessful angler. Worry not, Buddy at Whiskey Ridge Trading can line you up with secret surefire lure. 

Any coho that makes it through that maze of flies, spinners, and eggs deserves to leap for joy.

And that is as a good an answer as any. More than one researcher suggested fish jump just to have fun. A salmon’s life is short. Why not enjoy it? 

Finally, perhaps the most honest statement, confided by a few brave souls: No one knows for sure why salmon periodically jump.