Here is the deal. It will cost you either way, because even if you take it to court and win, you will have attorney fees and court costs, along with gas and time to go up there. Whether you decide to fight this or not is more dependent on how far you will go for "principle". Admittedly, you broke the law. However, as we all know, it isn't what you've done, it's what the prosecution can prove.
First let's look at what the charge is: A misdemeanor. There is no time to be served, and a small fine. This will not go on your record as anything major. Generally speaking, there is never a criminal charge filed, it is just a civil restitution (Although, a criminal charge may be filed, in which case it is generally a Class B misdemeanor or lower.) Basically, they don't want anything but your money. If you are tight on cash, it's better to pay the fine. Fighting will cost money and take time, and ultimately in not a guarantee of success.
If you have the time and money, and feel the need to pursue it out of principle, then we can look at the particulars of the case.
What they need to prove: As a civil case, they only have to prove Preponderence of the Evidence or the Balance of Probabilities. Basically that means the prosecution has to prove it was more likely than not, a better than fifty-percent chance that it happened.
What you have on your side: You were not actually seen fishing. It would be best if the park ranger had not seen your fishing poles. You were not under oath when you made your comments to the park ranger, so you cannot be charged with perjury based solely on telling her one thing and the court another (However, if you lie to the court, then you are guilty of perjury, if they find out.)
I'm not entirely certain in this particular instance, but in general, a statement made to the park ranger would be considered hearsay in determining guilt for an offense (In this case, fishing without a license). With no physical evidence (Personal observation, fish roasting on the fire, etc) and hearsay as the only evidence for conviction, I would say the prosecution would have a slim case.
If the park ranger was attractive you could also argue that your comment was only meant to try and impress her with how "outdoorsy" you were, and that you never actually fished, but when she mentioned fishing you tried to boast up your "masculine" side in order to impress her. Not sure how that would go over, but I have seen similar arguments accepted in court, albeit not for alleged fishing without a license.
In the end, if the prosecution doesn't have any evidence, you have a good chance of it being dismissed, although if you go that route be careful, as if you lie under oath you're in a whole different world of trouble. You cannot be forced to testify against yourself. Focus on the fct that you were not caught fishing, nor was there any physical evidence. The prosecution's case rests entirely on hearsay, which is almost universally unaccepted in a courtroom. It could be argued that it falls under the admission of guilt exception, though. It really depends on the prosecution, the judge, and your lawyer![]()

