How to recognize a buck versus hen Chinook – and sketch them both

Distinguishing male (bucks) from female (hens) salmon.
How can anyone tell the difference between male and female salmon?
The question is the same for steelhead and trout, of course, but this blog post will mostly refer to chinook salmon as an example.

Since I enjoy sketching salmon, I decided to combine a discussion of identifying makes and females (bucks and hens) while showing how I go about sketching the two. Please keep in mind, this is light entertainment, not a scientific treatise.

Here we go.

Start with an outline of the male and female Chinook.
1. Using a high-quality No. 2 pencil, I lay down the basic outline of the two salmon.
2. Notice that the male (upper fish) has a concave slope to its head.
3. The female (lower fish) has a convex slope to the top of the head.
4. These features usually cannot be identified when salmon are in the ocean, far from sexual maturity in terms of both migration-distance and time.

Stage one, get an outline of the male and female Chinook salmon.

Start with an outline of the male and female Chinook salmon.

Adipose fin size.
Check out the adipose fin on the buck. notice that the adipose on the male is more than twice the size of the female.

Snoot v.chin.
The snoot (snout) of the male is longer than the chin. the snoot and chin of females will usually be equal in length.

Body height and profile.
Although differences in these features are difficult to see from the sketch, the male will be taller than the female, in a proportional sense. If you were to look at the male and female head-on, you will see the male is both taller and narrower – the female is rounder than the male.

The Chinook sketch is evolving, with more penciled in detail.

The Chinook sketch is evolving, with more penciled in detail.

Get your salmon on the level.
I noticed that the hen in the upper sketch was tilted differently from the male, I didn’t like the effect, so I took my kneadable eraser re-sketched the body to make it more parallel to the buck. I also did some adjustments in the dorsal fins of the salmon, both in location and proportions of height and size.

Outline the tail and the ocean-phase demarcation.
I added the tail outline and the demarcation of the purple-blue of the salmon’s backs. Please note that the blue of the Chinook’s back is above the lateral line.

Where’s the vent located?
The vent of buck and hen is immediately forward of the anal fin and a little to the rear of the ventral fins.

Contrast the vent of the buck and the hen.
The male’s vent is an opening without any protruding element. In contrast, the hen has a protruding papillae that will serve the function of the ovipositor to expel eggs during spawning.

The maxillary bone is different too.
Notice that the maxillary bone of the male is larger, more prominent than that of the hen. Remember that the adipose fin of the male is also larger than that of the female.

The Chinook sketch of buck and hen progresses: add some ink.

The Chinook sketch of buck and hen progresses: add some ink.

Time to ink-in the features.
I’m adding ink with a waterproof .01 fine point pen. Note that I don’t always follow the pencil exactly – sometimes by intent, and sometimes by accident. I might try to achieve a more pleasing shape or proportion, but when I miss, I just miss and there’s no use regretting it. Art is art. Move on, unless it is such a grievous blooper that the piece needs to be tossed into the recycle bin.

Choose your paper.
I am doing my sketching work on 140 Lb. watercolor paper. It is rough and probably creates some of my wiggly lines, but I like the heft of the paper.

Add a fly to the salmon sketch.
I have begun to sketch a swing-fly below the salmon. This fly is more like we would fish for steelhead than salmon in my coastal waters, but I love these flies so ….

Are there spots on the Chinook salmon?
Yes. Chinook have spots on both upper and lower lobes of their tail, but coho salmon only have spots on the upper, never the lower lobe.

Do Chinook have spots on the dorsal fin?
Yes, Chinook have spots on their dorsal side from the tip of the tail all the way forward to the vicinity of the eye. These spots are always on the upper (dorsal) side of the Chinook, never below the lateral line. Steelhead have spots on both upper and lower lobes of the tail and also below the lateral line.

Clean up the excess pencil lines.
It is about time to get to work with that kneadable eraser to clean up the entire sketch, but we need to finish the fly first. I mention the kneadable eraser because they don’t leave streaks of pink like the erasers we had when I went to elementary school.

Chinook buck and hen sketch example: getting close.

Chinook buck and hen sketch example: getting near the end. After finishing the fly sketch I will erase the pencil so we are getting close.

Remember, none of my sketches are as good as I would wish; all of these have been a challenge and a pleasure to work on.


Finished Sketch of Chinook buck, hen, and swing fly.

Finished Sketch of Chinook buck and hen

To review – differences between male and female salmon

larger adipose fin
wider maxillary bone
snout extends past chin
the body is taller and narrower
mature bucks are darker colored

smaller adipose fin
thinner maxillary bone
snout does not extend past chin
the body is shorter and rounder
mature females can still appear to be shiny


With hope and good cheer,
Jay Nicholas – January 2021

This entry was posted in Fly Fishing Glossary, Oregon Conservation News, Oregon Salmon fly fishing. Bookmark the permalink.

1 Response to How to recognize a buck versus hen Chinook – and sketch them both

  1. sam says:

    Most excellent Jay…

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