What are these fish doing?

[kidspot]

I was snorkeling with a friend yesterday and watched a large school of Surgeon fish in about 20ft of water "attacking" each other (see video link below) the bubbles you see are not from them going to the surface, but from the impact of them hitting each other ... anyone know what this behavior means?

http://www.kidspot.org/personal/scuba/fishfight.wmv

(right click and "save target as") it's a 360k file.

Aloha, Tim

P.S. There was no food in the water, and they continued for over 10 minutes.

 

[sasscuba]

Mating ritual? That would be my guess.:11:

 

[Charlie99]

I couldn't tell much from the video, but is it possible they were spawning? Lots of fish do a mass spawning, where multiple fish zoom upwards up off the reef and then dump eggs and sperm.

There may be a bunch of false starts and "dry runs" before the actual egg and sperm release.

 

[Diver Dennis]

I'd say spawning.

 

[rhyz]

Looking at other video clips of Surgeon fish mass spawning, I'd say thats what it is also.

 

[kidspot]

it was the oddest thing to watch as groups of 2-6 would charge each other and "HIT" hard then break away - At first we assumed there was a dead fish or some food in the water they were all after.

I didn't realize that's how some fish spawned - it reminded me of triggerfish fighting over their "turf."

 

[friscuba]

Just curious, what time of day was it? Approaching evening? I think that's the time I've heard of the mass spawnings occurring.

 

[kidspot]

3:30pm we got out just after 4pm.

 

[kidspot]

btw - here's the original video file if anyone wants to download it (6.2 mb) http://www.kidspot.org/personal/scuba/fishfight.avi

It's a little easier to see what's going on, but still pretty poor quality video.

Aloha, Tim

 

[archman]

Like others say, that's mass spawning activity. The "bubbles" you're seeing are the released egg and sperm broadcasts. Typically one female will shoot upward, with a coterie of males hot on her heels. The males' sperm release is (usually) precisely cued to coincide with the female's, which is dependent on how far *up* she wishes to go.