A B757 'Left Engine Fuel Filter' EICAS alerted after takeoff. The aircraft returned to land while ATC declared an emergency for the flight.

Narrative

At approximately 10;000 ft; as EICAS caution message 'Left Engine Fuel Filter' appeared; I was flying the aircraft and instructed my First Officer to look up the EICAS message in the Flight Manual while I flew and handled the radios. We were level at 15;000 ft and my First Officer said that we needed to land at the nearest suitable. We were given a climb by ATC to FL230 and I said that we wanted to remain at 15;000 ft and return to ZZZ. We were experiencing no malfunctions; unusual engine readings or conditions so an emergency was not declared. We did request Runway 22L for the runway in the event any other problems arose. My First Officer handled all the communication with Dispatch; Passenger and the Flight Attendants. Approach and landing were normal with Crash Fire and Rescue awaiting us. Evidently ATC declared the emergency; however; no assistance was needed. On approach; the fuel filter light EICAS went away but remained in the Status pages. After landing; the left engine was shut down as a precaution.