Answer: external fertilization
Step-by-step explanation:
External fertilization is the process of fertilization in which the male sperm cells fuses with the female egg cells outside the body of the female. This type of fertilization is used by the organisms which live in the water body.
The salmon is a fish species which utilizes external fertilization. In the case of salmon, the female salmon drops the eggs in the bottom of the water which are fertilized by male salmon after secreting their sperms over these eggs.