State officials say they will improve oversight of seafood sales in Massachusetts after the results of a Globe investigation published this week revealed widespread mislabeling at area restaurants, and few controls to protect diners from potential health risks and overpaying for fish. The Joint Committee on Consumer Protection and Professional Licensure is expected to schedule an oversight hearing on seafood substitution in the coming weeks. The Patrick administration and members of the state’s Congressional delegation - including both senators - also are reviewing the matter, and a prominent local restaurateur said he will change his menu in response to the Globe’s findings.