Is there a difference in the actual meaning of these two sentences (average x mean)?

I'm really confused about if these two sentences actually mean the same, and if they're really interchangeable. I'm writing a scientific paper to be published in an Agronomy Journal.

"Mean fruit mass". "Average fruit mass".

Looking for both sentences, for example, on Google Scholar, the sentence "average fruit mass" hits more results, although, to me, "mean fruit mass" sounds more correct.

Appreciate any help.

This depends totally on register. Outside the maths etc domain, 'average' defaults to 'mean' and is the more usual term. But in more precisionist registers, 'mean' is a hyponym of 'average', along with 'median', 'mode', perhaps 'midmark' (and possibly other statistics of central tendency).

(answer by Edwin Ashworth, originally posted as a comment)