Marinas are easily overlooked winter hot spots. Few fishermen give them a second thought, however, rest assured—they're fish magnets. Fish gravitate to marinas because: 1) they're deep; 2) there's ample structure; and 3) there's little or no fishing pressure.
When exploring marinas focus on prominent structure. Seawalls and lone pilings offer excellent places to start your fish search. Beyond the obvious, however, search for secondary holding areas. These include structure abnormalities, like rip rap walls and dock intersections. Rip rap walls offer fish eclectic ambush opportunities on bait fish and should be fished with due diligence.
Dock intersections on the other hand, are those structural features where horizontal and vertical dock members conjoin. These provide two distinct shadow lines from which game fish can ambush prey (this in contrast to single horizontal or vertical shadow lines).
Due to the overabundance of barnacles, oysters and other razor sharp obstacles, opt for superlines or braids; fishing these on tight drags to steer fish clear of the nasties. One last note, avoid fishing anything that floats (like floating docks or boat hulls). These bob-and-weave day-in and day-out—pushing fish far, far away.