A general aviation pilot reported a NMAC during cruise. Pilot climbed; changed heading and continued.

Narrative

I was flying VFR along the shoreline at approximately 1;100 feet and broadcasting my position on the published frequency 123.025 while northbound; as instructed. Another helicopter was operating ahead of me approximately four miles north at about 600 feet and was also making position reports on the same frequency.After passing the Government Cut waypoint; my traffic advisory system generated an alert indicating traffic at the 12 o'clock position; same altitude; approximately two miles. At the same time; I observed the traffic symbol on my display.To increase separation; I initiated a climb to approximately 1;300 feet and turned right toward the ocean. As I executed this maneuver; I visually acquired Aircraft Y passing through my previous flight path with no apparent course changes. The aircraft did not appear to be monitoring or broadcasting on the local traffic advisory frequency.After the encounter; I advised other traffic on frequency 123.025 about the presence of an aircraft in the area that did not appear to be on frequency.I am submitting this report due to concern about close proximity between aircraft operating along a commonly used shoreline route and the potential safety risk when aircraft are not participating in local traffic advisories.