Mullet Jumping.

[Chimo]

Hi all

An in depth question has been raised, again, at our ranch.
Why do mullet jump in the canal?

The most jumps so far observed is 7 in a series but most are less from one to two or three.

Anyone got any ideas apart from "Its because they are happy"

Cheers
Chimo

[bondy99]

Chimo, That's a good question

Maybe a predator is chasing it or the mullet school is too thick so they need to jump.

I dont believe there has been any scientific study done to answer this as a person would need to be in the wild and watch this in situ over a lengthy period of time and I dont mean in a laboratory tank.

Maybe some one could do a PhD thesis on this.

Bondy

[Matt_Campbell]

A theory:

http://www.springerlink.com/content/w08843772m2m2928/

http://resources.metapress.com/pdf-preview.axd?code=w08843772m2m2928&size=largest

Several lines of circumstantial evidence suggest that striped mullet, Mugil cephalus, use the upper posterior portion of the pharynx for aerial respiration, the air obtained either by jumping, rolling, or holding the head above the water and moving the air into the upper pharyngeal chamber. The principle evidence is that jumping frequencies are inversely correlated with dissolved oxygen concentration, and that the pharyngobranchial organ is capable of holding gas.

[MudRiverDan]

Maybe they suck in air when feeding on the surface and this is a way of expelling it from their gullet.

Cheers

[HeadBanger]

Chimo, That's a good question

Maybe a predator is chasing it or the mullet school is too thick so they need to jump.



I've heard that if baitfish jump and 'slap' the surface when they re-enter the water, then there is not a predator chasing them, but if they re-enter cleanly, it means something is chasing them. Just something I've heard, but it definitely seems true when you can see a school of mullet in the shallows jumping about and landing on their sides with no predators around.

[bondy99]

A theory:

http://www.springerlink.com/content/w08843772m2m2928/

http://resources.metapress.com/pdf-preview.axd?code=w08843772m2m2928&size=largest

Several lines of circumstantial evidence suggest that striped mullet, Mugil cephalus, use the upper posterior portion of the pharynx for aerial respiration, the air obtained either by jumping, rolling, or holding the head above the water and moving the air into the upper pharyngeal chamber. The principle evidence is that jumping frequencies are inversely correlated with dissolved oxygen concentration, and that the pharyngobranchial organ is capable of holding gas.

G'day Matt,

I know your at the Eco Precinct near Dutton Park

Is this a tested theory or hyperbole? I would like to know if its been scientifically proven as such? I have not heard of any Honours or PhD candidates studying this , at least not at UQ

Bondy

[choppa]

other species of fish do this as well,,,, Billfish are believed to jump to knock parasites off their bodies

headbanger is also possibly on the right track,,,, as i have also heard/read something similar to this theory also,,,, fish that are excited from predators will normally break and re-enter the water without as much noise to "hopefully" not give away their location,,, and they will do this in a quicker and more spasmodic way,,,, whereas a fish "playing" will jump and re-enter in a lazy manner making more noise,,, (which in turn attracts predators,,, but fish have a limited memory span,,, so they probably forget this part)

Bondy99,,, there was something done in thesis from James Cook University ages ago,,, i forget the outcome,,, but it may be where i read something attuned to the above paragraph

choppa

[Gon Fishun]

Mating ritual. 7 jumps is the elders, 3-4 jumps is the younguns. ;D

[goat boy]

Maybe it's a hardwired biological thing to jump at all times, yes they do it to escape/distract predators, but it's just such a strong instinct they do it constantly. Much like any other animals play fight in ways they will eventually use for real, or cuddles the poodle spins around constantly before resting her posterior on a comfy cushion, In the scheme of evolutionary things, this was originally there for a purpose. ?
What about when the rays do it?

[bondy99]

Choppa,

Ok, thanks for letting me know about James Cook Uni, I have an issue with Acorbat Pro, bugger wont open any pdf files

I know fish will jump if rhey are massively schooled and not enough room to move, generally speaking , fish jump to escape predation, unless its marlin, then its jumping to shake its head in an attempt to dislodge a hook from its mouth. Very spectacular at that too.

Bondy

[ShaneC]

why do marlin free jump then Bondy????