AquAdvantage salmon anadromous GM male salmon lack reproductive success and have a reduced number of surviving offspring. GM salmon's lack of fertilization success can be attributed to nest fidelity, quivering frequency, and spawn participation. Under simulated competition environments, 94% of siring occurred by wild-type salmon, while only 5.4% was attributed to GM salmon. This advantage allows more than twice as many wild-type offspring to be produced. Other characteristics that could cause wild-type males to be chosen more frequently could be the lack of growth of the kype, the hooked jaw of a male, and red coloration on anadromous males, which demonstrates sexual
Fish jaw surface of the jaw. It is bordered below by a number of splenial bones, while the angle of the jaw is formed by a lower angular bone and a suprangular bone just above it. The inner surface of the jaw is lined by a "prearticular" bone, while the articular bone forms the articulation with the skull proper. Finally a set of three narrow "coronoid bones" lie above the prearticular bone. As the name implies, the majority of the teeth are attached to the dentary, but there are commonly also teeth on the coronoid bones, and sometimes on the prearticular as