Meaning of “over-fishing” - Learner’s Dictionary

over-fishing

noun [ U ] uk us /ˌəʊvəˈfɪʃɪŋ/

the problem of catching so many fish in a part of the sea that there are not many fish left there:

low fish stocks caused by over-fishing

(Definition of “over-fishing” from the Cambridge Learner’s Dictionary © Cambridge University Press)