Back home from the mountains
It was a golden day in Yosemite yesterday, one of those glorious mid-October pauses before the cold of November where the brilliant yellow aspen leaves flutter in a slight breeze and then drop in clusters to the ground or onto the creek surface, the sun shines warmly and low in the sky and the faintly pleasant odors of plants abound, all accompanied by auditory cues. There is no more pleasant a time to be found outside anywhere on earth. At least not for me.
Amidst the glorious spectacle of a beautiful day in a beautiful place, I observed many pairs of brook trout (Salvelinus fontinalis) spawning behavior. Note the distinctive white stripes on the three bottom fins.
Brook trout are my favorite trout for their beauty and taste, but they have been steadily displaced by rainbow trout in this area (rainbows are fine in general, but they are the pellet-fed fish of choice for 'stockers' for beer-drinking and ice-chest and chair-seated fisherman types, and somehow they got into this drainage). So on the increasingly infrequent occasions that I fish, I de-barb my hooks, release the 'brookies' and eat the rainbows, even though the brook trout taste better. My small part to preserve this beautiful species.
Trout in this size drainage at this altitude typically do not exceed 9 inches in length; a really larger one might reach 1o to 11 inches—exceptional here.
The lighter-colored gravel area (redd) is the clean gravel in which the eggs are deposited (muddy or silty areas will not do, they eggs will suffocate). This spawning pair stayed in this position by default, but the larger fish was constantly on guard against intruders (probably peripheral males), swimming out to chase them away, then always returning.
I don’t actually know which fish is the female and which is the male, but only the smaller fish in front engaged periodically in this flip-flop behavior, which I presume is a mechanical aid in releasing eggs (or sperm).
All the while, I was wishing mightily that I had brought a lens longer than 90mm, because they spook if approached too closely. And also wishing that the Leica M240 was 36 megapixels instead of 24; the crop below is 50% of actual pixels, e.g. a very small crop from the frame.
Watch a video of these brook trout. Regrettably I did not catch them doing the above.
Reader Jon L writes:
The bigger fish on the redd is generally the female. Like the human species, the males are the ones doing the stupid flopping around during the spawn.
But reader Eric S writes:
The fish doing the all the flopping around is the female (even though she's smaller); she's in the process of cutting her redd in preparation for egg depositing. The larger fish with more pronounced colors and jaw is the male; both of these are universal characteristics of salmonids (trout, salmon and in this case charr).
You're spot on with your "peripheral males" observation.
Your affinity for brook trout over rainbow trout though is misguided for the simple reason that brook trout are a major threat against native rainbow, cutthroat and golden trout populations (the native salmonids of the Mountainous West—depending on your locale). Brook trout are one of the very few salmonids that can spawn in both lakes and streams and are very adaptable in alpine environments. Further, they will almost always outcompete other species for available food sources.
Fishery biologists will almost universally agree that introducing the Brook trout to the Mountains West was a huge mistake. Your native Golden trout, especially, suffer from their introduction.
DIGLLOYD: There are no native Goldens or Cutthroat or Rainbows in this drainage or anywhere near it (Oncorhynchus mykiss aguabonita, Oncorhynchus clarkii, Oncorhynchus mykiss). So the biological 'native' point is moot along with the rest of the park, except certain areas in the Hoover Wilderness (Golden Trout) and perhaps a few other isolated areas. And, well, Brookies have that deep orange salmon flesh and just taste better. And I fished them as a youngster all over Colorado, so they appeal from memory also.
My observations in this particular creek had been that the rainbow trout population was on the rise about 10 years ago, following almost all Brook trout 20 years ago. But now the Brook Trout seem to be dominant again.