Humanoids From the Deep

This gory, scary low-budget shocker from the Roger Corman stable concerns the battle over a salmon cannery in a Pacific Northwest town. Genetically treated salmon escape the plant and are eaten by coelacanths, who mutate into humanoid monsters with giant craniums and sharp claws. The creatures begin attacking teen couples, killing the boys and mating with the girls (in some pretty graphic monster-rape scenes). Eventually, a bunch of them create total pandemonium at the annual salmon festival.