Original post made by Chris Harris(Gottheblues) on December 31, 2002
Lactic acidosis occurs when lactic acid accumulates in the blood stream at a faster rate than it can be eliminated. This buildup of lactic acid can cause muscle stiffness in a fish and make it difficult for them to swim and eventually could lead to death. In simplified terms...the longer the fish struggles and/or the excessive energy it uses, the more likely there will be a buildup of lactic acid in the muscle tissue. Fish are built for short powerful bursts of energy and are not equipped for long periods of energy overdrawn. Spawning salmon eventually die of a buildup of lactic acidosis from their extreme energy they use. Lactic acidosis is common in humans after long periods of exercise(you will feel your muscles get sore). But we are more equipped to filter out our system of unnecessary byproducts and to fully recover without any ill effects. Fish are not as lucky as us b/c their bodies are not equipped to filter it out. A smart plan when light line fishing(or any lb test of fishing for that matter) is to have a livewell system on your boat designed to house the fish for a while til it can fully recover from a long fight. A lot of the light line specialists in my area who fight a fish for over an hour or more have a pure oxygen system livewell to put the fish in. Another way to speed up the fish's recovery time is to work water through its gills before it is released. Just don't dump him in the water like he was shot out of a cannon.
Long battles are not the only way a fish can develop lactic acidosis. Studies are now suggesting that the way you fight a fish can lead to this symptom. Some experts are now suggesting that you never "load" a rod up when fighting a fish.(ie, don't hold the rod up at its highest point). Instead lower the rod tip near or in the water to create as close to a 45 degree angle on the fish. This is called "leading" by a lot of fisherman b/c the fish can be steered towards the boat without excess pressure put on the fish. Thus, the fish will exert less energy during the fight.
On a somewhat related subject. Marine biologists now conclude that Striped Bass(southerners call them Rockfish) that are released still have a mortality rate of 30%.(the fish may swim away fine but eventually die). Striped Bass expend a tremendous amount of energy appossed to other fish and it is hard for them to recover on their own sometimes.
Some people might not care about the above information but to me it is some fascinating info to read about.