When a marlin sounds

[Krabill]

We have all heard stories of big marlin "sounding" (diving very deep) and then they die. Either they sink and are lost, or are pulled up dead, or even a giant squid mite eat them.

I am wondering the science of this. I can understand that when a fish dives deep, the gas is compressed inside its swimbladder much like the BCD on a scuba diver. To remain neutral (not sink) in the water more air is needed at greater depth in either a swim bladder or a BC. The question is do the fish die first before they sink from an unknown reason? or, do they sink while alive (compressed bladder) and die of suffication because they are ram ventalators and cant get enought oxygen to their gills?

A bursting swim bladder only occurs when a fish is acclimated to depth and is rapidly brought to the surface and swim bladder over expansion occurs. (exactly like what would happen if a scuba diver held there breath from the bottom while going up and their lungs burst)

I brought up this question in my biology of fish class in college, but the teacher couldnt explain exactly.

simply put, What is causes a marlin to die when they sound???

thanks in advance to both fishermen and biologists on this one.

[fishebound]

A friend of mine, very experienced billfisherman, told me that the black marlin have a tendancy to spear themselves to the ocean floor just because they some how know that they are hooked. a little off subject but thought I'd say.

[GAW]

My intellectual theory on the physics of aspiration and the thermodynamics of the cellular effects of gas compession on tissues in Blue Marlin is: SHIP HAPPENS sometimes!!! But then again, so much for theory Catchem um up and release em the best you can.

[Capt_John]

Mostly from asphyxiation is how they seem to die from my understanding. But planing them is definately the only way to go about getting them back to the surface.

[Krabill]

Thanks to all for the answers, good thought on the plaining, I didnt know that before.

[Anthony`s Ark]

Glenn your hypothesis is almost correct concerning the thermodynamics of cellular tissue. I will only add that satuation levels of NaCl contaminating the aortic valve stem can cause permanent hybernation.

But seriously I have had two Blues sound on me. One was a rat and another was estimated at about 1000lbs. My intention was to release both fish. Both times I asked the captain to change directions on the fish imediatly. I did this for two reasons. 1. If a fish settles into a lockdown battle that means that the fish is probably comfortable in that pulling position. They could probably continue at the pressure and dept until they exhaust themselve and die or get attacked by something. The other reason is because I don't want to fight a fish all day. Both times that I requested the captain dramatically change the angle of the fight the fish skyrocketed back to the top. The idea is to make the fish uncomfortable so they change their tactics as well. Both fish were release alive and kickin.

[rbr]

The idea is to make the fish uncomfortable so they change their tactics as well. Both fish were release alive and kickin.




I wish they had a Thumbs up smiley I could put here.

Bert

[Reel Fool]

Until someone dissects (autopsy) one of these dead fish, you don't know. its all speculation & any theory is just as good as another without proof.

why they do it? careful to assume too much. until I get the chance to interview a marlin & ask them, I am assuming my own theories, but put little weight in any of them.

[seaweasel]

justin,
I think I'd rather die if I was tail raped too! Just giving ya a hard time about the spelling of that one.

Based on some tagging work we have done blues can dive pretty deep on their own, like 500 meters. But when they die...they usually keep going down and down... Mud Darts we call them. As far as the physiology of why they might die during the fight I don't know but since they have to keep moving to ram ventilate they will asphyxiate when stopped.


seaweasel

[seaweasel]

justin,
I think I'd rather die if I was tail raped too! Just giving ya a hard time about the spelling of that one.

Based on some tagging work people have done blues can dive pretty deep on their own, like 500 meters. But when they die...they usually keep going down and down... Mud Darts we call them. As far as the physiology of why they might die during the fight I don't know but since they have to keep moving to ram ventilate they will asphyxiate when stopped.


seaweasel