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How to Tell a Male Salmon From a Female

It's very difficult to distinguish between male and female salmon before the fish reach maturity. As they mature, they begin to develop in different ways and you can find clues in everything from jaw and fin size to forehead shape to color. The easiest way to tell a male salmon from a female is a side-by-side comparison, as the differences are most notable when judged against another salmon. Outside of that, the only foolproof way is to cut open the fish and examine it.

Instructions

- 1
  Look at the snouts of the salmon. Mature males have a distinct hook, called a kype, while females do not. Look at the teeth as well -- males tend to have longer teeth than females.
- 2
  Compare the head sizes of the salmon. Males have longer, larger heads than female salmon. Male salmon heads sometimes look disproportionately large for their body.
- 3
  Check for a hump along the back of the salmon. Pink salmon males develop this hump, while females do not.
- 4
  Look for clues with the adipose fin -- the fin located between the tail and dorsal fin. A mature male salmon's adipose fin is very large, sometimes several times larger than a female of the same age.
- 5
  Compare the foreheads of the salmon. Female salmon have rounded foreheads, while males have concave sloping foreheads.
- 6
  Check for signs of color. Depending on the variety, male salmon will develop bright red spots or turn bright bronze or copper. Female salmon keep a monochromatic body color into maturity.

Animals & Science