It's illegal to fish here. Didn't you see the sign over there said/saying, "No fishing--violators will be fined $4500?"

Hi,

Do both said and saying fit in the above? Thanks.
Do both said and saying fit in the above?

No. You need saying.

It's illegal to fish here. Didn't you see the sign over there saying, "No fishing - violators will be fined $4500?

Other versions are possible, however.

It's illegal to fish here. Didn't you see that the sign over there said, "No fishing - violators will be fined $4500?

It's illegal to fish here. Didn't you see the sign over there that said, "No fishing - violators will be fined $4500?

CJ
Thanks, Jim.

But isn't "that" optional in the following?

It's illegal to fish here. Didn't you see (that) the sign over there said, "No fishing - violators will be fined $4500?
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Strictly speaking it's optional, but 'see the sign' suggests a verb and its direct object, which is not the intended reading, so it's stylistically very inferior - so inferior that it should be avoided at all costs.

Did you see the sign over there? is a complete sentence in itself.

This kind of sentence - where the reader is fooled into believing that one grammatical structure is being used, but then has to backtrack and read the sentence again because his first impression was wrong - is sometimes called a 'garden path' sentence.

Similarly,

Did you hear a song on the radio yesterday was banned in Boston?

The bartender served the bourbon fell down the stairs.
Jake checked the main electricity supply had been switched off.

CJ
Both are okay grammatically, but there is a difference in tone.

"...Didn't you see the sign over there said, 'No fishing...' is belligerent and threatening. The speaker is giving the person no chance to defend his presence. This is technically a question but the speaker doesn't want an answer.

"...Didn't you see the sign over there saying, 'No fishing...' is much milder in tone. The speaker is giving the person an opportunity to explain his presence. This is actually a question wants an answer.