Good Friend of mine who did research on nuke plant cooling systems subjected marine invertebrates and salmonids to varying degrees of exposure to chlorine. The chlorine was used to keep growth of algae etc. from plugging the cooling lines that kept the reactor cores from getting too hot. One interesting thing that came about was the gross deformites in most of the off springs the salmon looked just like the one in the picture, the shiner perch from Sequim Bay were the worst or best display of abnormal development.
Some years later we were at the Seattle Aquarium and saw a whole returning run of these freaks at a little show and tell hatchery the aquarium folks were operating my bio friend theorized that in so much as there was no creek around there they were using city water and the filters were not capable of getting all the chlorine filtered out thereby creating the same enviroment that she had back on Sequim Bay in the mid seventies.
I have caught a few of these blunt nosed fellows as far to the north and west as Sitka Sound and have always figured that chlorine had a hand in the development of these little dolphin heads.