| The reproductive tract of many fish is specialized to produce extremely large numbers of gametes which are expelled into the surrounding environment. In most teleosts, fertilization and embryologic development occur outside the body (Although a few species do bear live young after development within a parent). Many gametes are needed to make up for the lower chance of fertilization, and the loss of developing embryos due to predation. Gamete production is often seasonal, and the size of the gonads may increase greatly during the spawning period to produce the required number of of sperm and ova. |
