“Bike salmon” are cyclists who “swim upstream” (like salmon) by going the wrong way on a one-way street. “Bike salmon” also refers to riders who go the wrong way on two-ways streets.
 
The term “bike salmon” has been cited in print since at least April 2008, when it was popularized on the blog Bike Snob NYC.
 
   
Bike Snob NYC
WEDNESDAY, APRIL 30, 2008
It’s All In the Details: How to be Fast on a Fixed-Gear
(...)
Ride The Right Way
Bike salmon are the new wheel-suckers, and now that the weather is nice and all the vanity bikes have come out of mothballs I feel like a rolling sample sale in that I’m constantly being mobbed head-on by fashionistas. I’m not sure when it became mandatory for fixed-gear riders to go against traffic all the time and I’m not sure where it came from.
   
Spokejunkies Trailhead Chatter
Fatty McBastard
Posted 21 June 2008 - 12:01 PM
What drives me nuts are Kids and some adults who ride on the wrong side of the road. Maybe the adults are DUI drunks who have lost their driving privledges. Nothing more annoying than riding along and look up there is some jerk heading right you. I always yell “Your on the wrong side of the road a$$hole.” Its their parents fault - bad advice. Remember the rule - Ride with / walk against.
 
I hate bike salmon. I end up playing chicken with one of these retards at least once a week.
 
Faster Mustache
Submitted by paul h on Sat, 08/30/2008 - 11:13.
wuss. i say make it a bike salmon race
   
Bike Forums
jeebusaurousrex
09-22-08, 01:13 PM
I’ve noted that bike salmon are usually delivery guys, but bike LANE salmon are newbie cruisers.
     
Bike Commuters 
Bob
December 21st, 2008 at 23:36
More bicycle advocacy groups along with their members and “lone riders” need to start speaking out on a national level.
“Bike salmon” that’s funny.
 
Bike Snob NYC
WEDNESDAY, MAY 13, 2009
Smoked Salmon: Lock Your Bike, Don’t Lox It
Since yesterday’s PSA was a resounding success (despite the fact that even I went “commando” today in the fender department) I’ve decided to create another one. Unlike fender use, which is really something that doesn’t affect other cyclists unless they’re riding right behind you, this new PSA targets a group of riders who are a menace to us all. I am referring of course to those directionally-challenged irritants known as “bike salmon.”
   
Steamboats Are Ruining Everything
BIKE SALMON: OMEN OR HARBINGER?
Posted by Caleb Crain on Monday, 20 July 2009 at 01:38 PM
(...)
Gradually I became hoity-toity about my righteous biking. I glared at cyclists who came at me the wrong way down a one-way street and began to refer to such transgressors by a moniker that blogger Bike Snob NYC invented for them: “bike salmon.” I shook my head at cyclists who insisted on riding on the side of the street opposite the bike lane. I clucked my tongue at cyclists who didn’t even bother to slow down at busy intersections.
   
Bike Hacks
03/17/2010
Dictionary of Bike Commuter Slang
(...)
The Bike Salmon: Complete credit goes to Bike Snob NYC. This is when a rider “swims up stream” by riding the wrong way down a one way street.
(...)
COMMENTS
A Bike Salmon doesn’t just ride against the flow on one-way streets, the term more often refers to a rider on the wrong side of a two-way street.

I’ve had a couple of Ninja Salmon (same thing, in the dark with no lights) nearly take me out on my morning commute.
Posted by: John Pitts | 07/18/2011 at 03:53 AM
 
StreetsBlog
Monday, April 19, 2010
The Persistence of Bike Salmon
by Sarah Goodyear
Over the weekend on CommuteOrlando Blog, Keri McCaffrey posted a video showing a bicyclist riding in the wrong direction on a Florida street. After pointing out how this might have ended badly for the rider, she poses the question “Why do they do this?”:
 
The Guardian (UK)
How to stop ‘salmoning’, scourge of NYC’s bike lanes
People riding the wrong way in New York’s bike lanes are a serious nuisance. But what to do about it?
Posted by Matt Seaton
Tuesday 13 November 2012 11.45 EST
What to do about “salmoning”?
 
This is the question that’s come to obsess me. If you haven’t come across the expression before, it refers to people who use bike lanes the wrong way – because, like salmon, they’re swimming against the stream. Unlike fishy salmon, however, which we sincerely hope reach their spawning grounds and restock our rivers and oceans with their wonderful pink-fleshed progeny, cycling “salmon” are a total social nuisance.