The decision focused on the “agricultural practice exception” set forth in 50 C.F.R. § 20.21(i)(1).
In short, although the parties and the district court erroneously believed the exception was relevant to the charges, the error was harmless.
If you have a case about "duck baiting," you should read this opinion.
Otherwise, here is some helpful language for raising new issues on appeal:
We apply a ‘general rule’ against entertaining arguments on appeal that were not presented or developed before the district court.” But we have discretion to reach waived issues, and we exercise that discretion in three circumstances: (1) “in the ‘exceptional’ case in which review is necessary to prevent a miscarriage of justice or to preserve the integrity of the judicial process”; (2) “when a new issue arises while appeal is pending because of a change in the law”; and (3) “when the issue presented is purely one of law and either does not depend on the factual record developed below, or the pertinent record has been fully developed.”