Fished out of Venice, LA on June 19th-20th 2009, very FLAT very little wind. less than 5 knots. we caught 1 blue marlin, 1 white , and 2 sailfish.
I wouldn't say that's normal for slick ocean conditions, but it sure was nice.
HI:
On flat calm ,slick days and no wind, Raise your O/RIGGERS as HIGH as they will go.
Now drop your lures back far enough so that LITTLE LINE to your lures/bait STAYS in the water. WHY?
Don't know if the Tuna can see the disturbance of the line in the water, OR the noise of that line going thru the water, BUT this TRICK will put more fish in your boat.
INCREASE your speed when it's flat calm, that helps too.
WACKM 'N STACKM
Joseph B...aka...Ancient Mariner www.ancientmarinertackle.com
Depends on what the normal/prevailing conditions in your area are. If your area is normally rough, calm conditions can be a sign of some unusual atmospheric condition that may also affect the bite.
That being said, it's normally easier to spot surface signs when it's calm, easier to work your marks, skipper and crew fatigue is less of a factor, angler and crew reactions are not impeded by the motion of the boat, your lure selection is not restricted by the effect of wind and chop, etc... As one skipper of my acquaintance used to say - "It never gets too calm to scare me!"
Being able to fish effectively in rough conditions can be very important. When good fishing is happening in shitty conditions, crews that can do that have a great advantage over those that can't.