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Low-flying Chinook
June 13th, 2012 05:24 pmI complained via twitter about two Chinooks -- the dual-rotor cargo helicopters -- shaking my building this morning. Naturally, when I said "low flying chinook" two people immediately thought of the salmon. So I did a little painting at lunch today.
Oncorhynchus tshawytscha subsp CH-47.
Male, freshwater phase.
The tandem rotors of this subspecies allow easier travel to shallow stream beds for spawning. With this advantage CH47 would be expected to out-breed the straight species under natural conditions, but this seems to be cancelled out by increased avian predation -- osprey can often be seen waiting by waterfalls during the spring run. In addition, lab experimentation and careful observation in situ suggest that most female Chinook actually prefer the bruised and battered males which had to swim up the falls, perhaps for their more macho appearance.
Note that the adipose fin has been replaced by the hind rotor housing. With the adipose unavailable, dorsal fin clips are used to mark hatchery fish.
Oncorhynchus tshawytscha subsp CH-47.
Male, freshwater phase.
The tandem rotors of this subspecies allow easier travel to shallow stream beds for spawning. With this advantage CH47 would be expected to out-breed the straight species under natural conditions, but this seems to be cancelled out by increased avian predation -- osprey can often be seen waiting by waterfalls during the spring run. In addition, lab experimentation and careful observation in situ suggest that most female Chinook actually prefer the bruised and battered males which had to swim up the falls, perhaps for their more macho appearance.
Note that the adipose fin has been replaced by the hind rotor housing. With the adipose unavailable, dorsal fin clips are used to mark hatchery fish.
