EWTN Catholic Q&A
RE: 153 fishes in John 21:11
Question from Joseph Kelley on 05-30-2013:

I have read, but cannot guarantee the accuracy, that there were 153 known varieties of fish at that time. The catch then represents the apostles' mission to catch men from all nations.

Answer by Richard Geraghty on 08-18-2013:

Dear Joseph,

That interpretation seems to be a possibility.

Dr. Geraghty