also, you won't see this with gars, but in looking up other fish measurement references you may come across "fork length" which is from the tip of the mouth (or whatever the anterior-most extension is) to the fork in the tail. this measurement is still used by several studies, but more and more are converting to total length.
unfortunately total length (what richard and i use) CAN be somewhat tenuous as caudal fins can be variable in nature...one just assumes that that variation isn't terribly significant in the grand scheme of measurements.--
--solomon