A lot of people (myself included) are focused on fishing for false albacore and tuna right now. However, there are still some beautiful schools of striped bass roaming around. 
I filmed these fish over a sand bar in about 8 feet of water in Cape Cod Bay on a beautifully sunny late-August afternoon. One of the most intriguing parts of this video is "flashing" striped bass behavior.
More...
I know many anglers have seen stripers "flashing" before, and I recently posted about this behavior on social media. Please click play below to see what I mean and to learn more! 
If you could not already tell, I am pretty much obsessed with capturing Cape Cod fishing scenes from above and beneath the water's surface. Who knows what we will observe and learn next!
What do you think about the behavior shown in this video? What do you think stripers are doing when they "flash"? Please let me know by commenting below!
Tight lines! 
Those are mostly immature males practicing spawning actions for later years. They do this instinctively from age 4 on in anticipation of next springs spawning season.
Now that is an interesting response! Thank you Don for sharing your thoughts.
Ryan,
What time of year was this video taken? I see the flashing mostly in June/july when the fish have sea lice. Those months coincide with time of year I sight fish for stripers in shallow water, so my information may be limited by that.
Hey Chip! This footage was filmed during the last week of August. Maybe I will do some more filming this fall to see if I can capture footage of them flashing later in the year too.
I also checked out your Angler Adventures website. Looks awesome!
Strongly suspect your first guess about the stripers is correct- they are trying to remove thing (parasites often) from their bodies. Strongly doubt they are communicating by this behavior. Request you don’t use the word”theory” unless you are absolutely correct and sure about something.
Fishing has been very slow around the Falmouth region, by there are some FA. Great pictures
Best wishes Dave
Hi Dave! Good to hear from you and I hope all is well. Thanks for sharing your insights. I hope the fishing picks up for you! I’ve actually been down in your area over the past couple of weeks chasing albies.
In the aquarium hobby there is a parasite called Ich. One of the most notable symptoms of Ich is rubbingthier bodies, twitching and darting. I would guess that it’s done to eliminate parasites.
Thanks for sharing your insight Len!