Gray tabby cat with blue collar and ID

I lost my gray tabby cat, Niko, yesterday around 3pm near the Mystic River by Main Street in Mystic, CT. He's about 9 pounds, short-haired with faint striping, and he's wearing a bright blue collar with a tiny silver bell and a small green ID tag. He has a small notch in his left ear and a white patch on his chest, and he usually responds to his name when I call him, but he can be shy around strangers. I’ve had him since he was a kitten, and losing him has me really worried; if you spot him, call or text 555-123-4567.