You referenced two pages from Vol 1. of OR. Here is the copy of the OR I'm looking at, pages 333 and 334 - Link That doesn't say what you say it says.
I found the text that PeaRidge cited here: http://ebooks.library.cornell.edu/cgi/t/text/pageviewer-idx?c=moawar;cc=moawar;idno=waro0001;node=waro0001%3A2;view=image;seq=353;size=100;page=root
I also found this on that page:
“We still labored on the 13th strengthening our position, and at night threw out sentinels beyond the glacis. Men stood at the guns as on the night previous. Night very dark and rainy. On the night of the 13th a body of some ten men were discovered evidently reconnoitering. A shot was fired by them, which was returned by the sergeant. They then retreated. Nothing more could be seen of the party that night.”
It wasn’t an organized assault upon the fort and it wasn’t the US firing upon enemy combatants. It especially wasn’t significant or first blood.
Union troops walked into abandoned Ft. Pickens on Jan. 8. Later that evening, local men attempted the same. OR records reported that Union Troops initiated alarms, and the men left.
We're the "alarms" gunfire?
The next meeting between the Union Navy and locals was on the evening of the 12th when a party of four locals approached the fort to speak of Naval occupancy withdrawal. See pg 337.
Again, no seizure.
The next communique between the principles was from Florida official William Chase who “begged” Union officials to turn over the forts without bloodshed.
See page 338.
Hardly seizure.
The civility of the Florida officials continued despite this:
“By the eve of the Civil War, the small force of U.S. troops assigned to Pensacola Bay were quartered at Barrancas Post. Forts Pickens
and McRee were occupied by caretakers.
“It is a little known fact that the first shots of the Civil War were actually fired on the drawbridge of Fort Barrancas on January 8, 1861, more than three months before the Confederate bombardment of Fort Sumter.
“Concerned over the secession movement in the Southern states and aware of rumors that state troops were preparing to move on the post, Lieutenant Adam J. Slemmer, thecommander of Fort Barrancas, posted a sergeant's guard in the fort and placed his men on high alert. The guards observed shadowy figures on the drawbridge and confronted them. When the intruders failed to identify themselves, the U.S. soldiers fired a volley at them.” ExploreSouthernHistory.com
The OR reports another similar event five days later. See page 337.