Has there been a study done…

Has there been a study done to corroborate the claims of the commercial fisheries that the new population has been detrimental to fish populations?
Has a study been done to assess what has happened to this bird's natural predators? Perhaps this/these species need conservation.

Also, as noted in the proposal itself there is evidence to suggest the population could be declining already, which makes it seem senseless to allow us to kill more of them with no reason other than we don't like them eating the same fish we eat, and living in our trees.

This type of proposal points to a problem with our species; we don't seem to like to live in harmony with our environment. We instead prefer to dominate it.