OK Ill put in my two cents here. Think of it this way, most of the animals we choose to keep in our aquariums have evolved over the last couple million years to occupy very specialized niches in the worlds oceans. Within these niches, certain parameters are generally well maintained (dare I say better than most advanced aquarists are able to provide).
Temperature is directly linked to waters ability to retain dissolved oxygen. The warmer the water, the less dissolved oxygen can be held. We are talking in parts per million (ppm), and not 400 or 500ppm, but any where from 8 to 30ppm. Temperature may vary in a localized areas of the ocean by as much as 1.0 degree celcius daily in a common saltwater habitat, and maybe 4 or 5 degrees celcius over a year. Fish physiology allows for certain things to fluctuate in the environment such as pressure, trace elements, etc. The evolution of physostomous or physoclist gas bladders and counter-current gas exchange across gill surfaces in advanced teleost fish aid a fishes ability to maximize the amount of oxygen that can be transfered into the blood stream. Some fish can actually store oxygen in the bladder and release it into the blood stream when needed. These traits allow most fish we aquarists are interested in keeping to cope with warmer water (ie less dissolved oxygen).
Sharks on the other hand are less evolved than teleost fish, and that is fine for environments they commonly occupy in the wild. Sharks use a system of oil bouyancy in enlarged livers to control their depth in a water column instead of a gas bladder. They can't rely on additional oxygen stores from a gas bladder. Their gills aren't as efficient as a modern teleosts either, so they require an environment with more dissolved oxygen (commonly one of colder waters instead of more turbid waters) than other common marine aquarium fish. There are so many reasons why a typical aquarist should not keep sharks, but these are the main physiological reasons linking to this topic. Im sure I have forgotten many important aspects to shark physiology that would make them bad candidates for an aquarium.
Yes, large aquariums ( larger than 10,000 gallons) can meet most needs of reasonably sized sharks (>2m), their equipment, training and staff is more advanced than most aquarists.
As for the ozone generator being harmful, I am unsure of a solid answer. The ampullary of lorenzi on sharks are extremly sensitive to electrical charge in their natural environment. It's been proven that they cannot turn of the organs in the case of a system overload, hence why divers use low electrical pulses to lure in sharks and stronger ones to push them away. If I understand ozone generation correctly, it consists of turning an O2 molecule into two free radicals which then attach to floating pollutants and oxides them, then returns back to their origanl form of O2. This involves alot of negativley charges ions floating in the water or air ( 2000 neg charges ions / centimeter = that fresh smell after an electicity storm). These types of environments are found near waterfalls, electricity strikes, and crashing waves. Not common places for sharks. Will this type of environment lead to the premature death of a captured shark, i dont know..... is it healthy for the animal.... I doubt it.
Please feel free to respond to my post, I love to hear others opinions. PM me if you wish to talk further on the subject!
Cheers,
Scott
