Fish swarm taking shape of a larger fish?

"Dillon Pyron" <dmpyronINVALID@austin.rr.com> wrote in message
news:b3h6p1p9l85id7c4nedbvugcp2cjf7h5nk@4ax.com...
> Thus spake "Lee Bell" <pleebell2@bellsouth.net> :
>
>>"Buhda" <akhanna@houston.rr.com> wrote in message
>>news:KjNjf.27631$Ox.1935@tornado.texas.rr.com. ..
>>
>>>I believe that scientists have known of this phenomenon for several years
>>>now. Small fish congregating in the shape of a larger animal to
>>>discourage
>>>predators.
>>
>>I believe that this is highly unlikely. Feel free to prove me wrong.
>
> I saw it on the Web, it must be true.

That's good enough for me.

Lee

>>>A scuba friend says while diving in the Virgin Islands, they saw a
>>> school or swarm of small fish swimming in a formation making a
>>> distinct shape of a larger fish.
>>>
>>> Has anyone else ever observed this?
>>>
>>> PaulF

>>I believe that scientists have known of this phenomenon for several years
>>now. Small fish congregating in the shape of a larger animal to
>>discourage predators.
>
> I believe that this is highly unlikely. Feel free to prove me wrong.
>
> Lee

Seen it with my own eyes in Palau. A shoal of small minnowy fish which were
in constant rolling movement, forming a larger shape. Although this
obviously doesn't look exactly like a fish, it creates the illusion of a
single big 'something', moving cohesively. As a shadowy shape seen
indistinctly it was very effective, even scary.

When I got closer, I observed that each fish drops back to the 'tail' of the
shape and then swims over the top to form part of the 'nose' again. Much
like using logs to roll a big stone, taking them out at the back and placing
them at the front again.

Finding Nemo was very well observed.

Benedict.

Benedict Addis wrote:

>>>>A scuba friend says while diving in the Virgin Islands, they saw a
>>>>school or swarm of small fish swimming in a formation making a
>>>>distinct shape of a larger fish.
>>>>
>>>>Has anyone else ever observed this?
>>>>
>>>>PaulF
>
>
>>>I believe that scientists have known of this phenomenon for several years
>>>now. Small fish congregating in the shape of a larger animal to
>>>discourage predators.
>>
>>I believe that this is highly unlikely. Feel free to prove me wrong.
>>
>>Lee
>
>
> Seen it with my own eyes in Palau. A shoal of small minnowy fish which were
> in constant rolling movement, forming a larger shape. Although this
> obviously doesn't look exactly like a fish, it creates the illusion of a
> single big 'something', moving cohesively. As a shadowy shape seen
> indistinctly it was very effective, even scary.

The reason behind is, when a predator approaches, the fish
move in a way to create a void bubble in front of it's teeth.
A single fish cannot duplicate this tactic. Here the
predator just pursuits a targetting "trajectory", impossible
with a swarm.

You can observe this, standing in the reefs shallow part,
seeing the swarm from above the surface.
Throw a stone into the swarm's center and watch the fish
vanish away from the point of impact, at the same time
guarding a distinct outer shape.

Matthias