I think we can consider this an example of implicit valuation of natural resources.
On Wednesday the U.S. Supreme Court lifted restrictions on the use of sonar in Navy training exercises off the coast of California. Here are some links to the story:
Los Angeles Times
and some background information by the Natural Resources Defense Council.
This is a case of two public goods: national defense and marine species, with the former being a pure public good and the latter a common property resource. By ruling in favor of allowing sonar for training purposes, the Court has essentially said that the potential to save human lives is more important than the potential to save marine mammals.
This is implicitly placing a value on marine mammals, no?