The live aquatic bait ban in effect at Baltimore City's three reservoirs will be modified to allow the use of state-certified, zebra mussel-free bait, Mayor Kurt. L. Schmoke announced yesterday.

Live bait had been banned to protect the reservoirs from accidental introduction of zebra mussels, which can attach to live bait. The inch-long shellfish multiplies rapidly and has clogged large water intake structures.

Now if you use live aquatic bait, you must have a receipt from a state-certified bait shop in your possession, dated no more than 48 hours from purchase. For a copy of the regulation, a list of state-certified bait dealers and/or certification forms, call the Department of Natural Resources, (410) 974-3061.