Only a month ago we were noting the conspicuous absence of any intelligible definition of campaign issues on the part of Baltimore Mayor William Donald Schaefer, who seeks to be governor. But now that is changing, even though the mayor still hasn't formally confirmed his candidacy for the Democratic nomination. Mr. Schaefer is opening up a bit, and judging from his first fuzzy comments on several important issues, he might consider closing down until he gets a better perspective.

First, there were some vague views on gun control, in which the mayor wasn't quite sure how vigorous his own city should be in curbing handgun sales. Then there was his endorsement of the return to slot machines, if only in certain parts of the state and for charity. But the worst came out the other day, when Mr. Schaefer said that two Maryland programs to help restore the Chesapeake Bay -- restrictions on development and a ban on the catching of rockfish -- might be ready for weakening in a year or two.

Talk about an issue dear to Marylanders: the state legislature just finished work on the law to curtail development in the most environmentally sensitive areas of bay shoreline. The idea is to protect the water quality as well as the wildlife in and around Maryland's valuable natural asset. Yet, even before the ink on this legislation is dry, Mayor Schaefer is saying the restrictions could be relaxed in "maybe a year or 18 months." What kind of test would that be?

The mayor's view on the rockfish moratorium is that it could be lifted "a couple of years from now," because it already appears that this endangered fish is making a comeback. Maybe so, but aside from some frustrated commercial watermen and more than a few seafood connoisseurs who miss a table favorite, no one's ready to say with certainty that the rockfish is back to harvest strength. Most state experts say that it may be 1988 before much is known about the future of the rockfish. What is known is that Marylanders take protection of the bay very seriously -- which is why Gov. Hughes and the state legislators moved on these two fronts to protect it.