Quote:
Originally Posted by bluesquids
Some sharks caught by hook and line have the uric acid go into the flesh because the muscles are used for a long time during the battle to tire the fish out. A good kill shot means instant lights out and better quality meat.
|
I hate to disagree, but you are confusing lactic acid, uric acid and urea.
Urea is not an acid but an organic compound produced by the kidneys that sharks use to create a condition of osmotic balance with seawater. Though urea is in urine it's not so much that sharks piss through their skin it's that sharks circulate urea through their tissues including muscles to protect them from seawater.
This works great when they are alive.
Unfortunately urea has a destabilizing effect on many enzymes, so sharks use another compound tri-methyl amine oxide to keep their enzymes balanced. Unfortunately as soon as sharks die they no longer produce the TMAO, their enzyme balance goes to shit, and at that point the urea in their body is quickly broken down into ammonia by bacteria.
Ammonia is toxic, it stinks, and it makes sharks taste bad. It also readily crosses most tissue membranes so it saturates all the tissues of a dead shark in short order.
Different sharks have different amounts of urea in their systems. Seven gills are extremely primitive they are from the Jurassic as old as the dinosaurs, and one of the oldest sharks still swimming the ocean. They have a lot of urea in their system. In fact if you cut one open you'll find that they have two ducts or hollow tubes on each side of their spinal cartilage that are filled with urea. They are much bigger in seven gills then in other more advanced sharks. On a large seven gill these tubes are about as big around as your little finger and run the length of the shark.
If you want to eat a seven gill as soon as you catch it you have to cut off it's head and tail while it's still alive, then run a hose through those ducts and flush the urea out those tubes. Otherwise the urea in them will be converted to ammonia and will contaminate all the meat in the shark.
That's the same if you hook and land it, spear it, shoot it, or throw it off the golden gate bridge. The urea is in there, and you have to get it out of there before the bacteria converts it to ammonia or the meat is worthless.
The more advanced sharks like Makos and Threshers have much less urea in their systems, that's why they are good to eat. Blues, six gills, seven gills have more urea that's why if they are not properly cared for they taste like crap and have a reputation for being bad to eat.
It's not brain surgery but it is simple chemistry.
Honestly the only reason I know about it is because I used to know an old timer commercial sharker who fished sevengills back when there was a big commercial fishery for them, and he told me all about it over a few beers.
Jim