tuna?

I used to be a sushi chef so I heard a lot of differing points of view regarding tuna. As far as the mercury levels go it really depends on the time of year and where the tuna is coming from. Are you eating canned tuna or fresh? I've heard that canned tuna can have high levels of mercury but that's just hearsay haven't seen any documentation on it.

I am a tuna guy too this is off of wikipedia :Canned tuna is a prominent component in many weight trainers' diets, as it is high in protein and easily prepared.
Tuna is an oily fish, and therefore contains a high amount of Vitamin D. A can of tuna in oil contains about the Adequate Intake (AI) of the US Dietary Reference Intake of vitamin D for infants, children, men, and women aged 19–50 - 200 IU.
Canned tuna can also be a good source of omega-3 fatty acids. It sometimes contains over 300 milligrams (0.011 oz) per serving.[37]
[edit]Mercury levels
See also: Mercury in fish
Mercury content in tuna can vary widely. For instance, testing by Rutgers University found that a can of StarKist had 10 times more mercury than another can of exactly the same kind of tuna. This has prompted a Rutgers University scientist whose staff conducted the mercury analysis to say, "That's one of the reasons pregnant women have to be really careful ... If you happen to get a couple or three cans in the high range at a critical period when you are pregnant, it would not be good." Among those calling for improved warnings about mercury in tuna is the American Medical Association, which adopted a policy that physicians should help make their patients more aware of the potential risks.[38]
A study published in 2008 found that mercury distribution in tuna meat is inversely related to the lipid content, suggesting that the lipid concentration within edible tuna tissues has a diluting effect on mercury content.[39] These findings suggest that choosing to consume a type of tuna that has a relatively higher natural fat content may help reduce the amount of mercury intake, compared to consuming tuna with a low fat content.
A website called mercuryfacts.org which is run by an industry-sponsored group called the Center for Consumer Freedom which doesn't release the name of its contributors claims the health risks of methylmercury in tuna might be dampened by the selenium found in tuna,[40] although the mechanism and effect of this still is largely unknown.[41]
Due to their high position in the food chain and the subsequent accumulation of heavy metals from their diet, mercury levels can be high in larger species such as bluefin and albacore.
In 2009 a California appeals court upheld a ruling that canned tuna does not need warning labels as the methylmercury is naturally occurring.[42]
In March 2004 the United States FDA issued guidelines recommending that pregnant women, nursing mothers, and children limit their intake of tuna and other predatory fish.[43]
The Chicago Tribune reported that some canned light tuna such as yellowfin tuna[44] is significantly higher in mercury than skipjack, and caused Consumers Union and other activist groups to advise pregnant women to refrain from consuming canned tuna.[45] This was considered extreme and thus not adopted by leading scientific and governing bodies.
The Eastern little tuna (Euthynnus affinis) has been available for decades as a low-mercury, less expensive canned tuna. However, of the five major species of canned tuna imported by the United States it is the least commercially attractive, primarily due to its dark color and more pronounced 'fishy' flavor. Its use has traditionally been restricted to institutional (non-retail) commerce.
A January 2008 investigation conducted by the New York Times found potentially dangerous levels of mercury in certain varieties of sushi tuna, reporting levels "so high that the Food and Drug Administration could take legal action to remove the fish from the market."[46]

Have ate schools and schools of the stuff no problems here

According to the EPA (See link at bottom), the primary health concern for mercury is that it has been shown to cause certain types of birth defects when ingested by pregnant women. Although it has been shown to cause an increase in tumors in mice and rats when exposed at "extremely high doses."

Personally, I go through about two cans of tuna per week and have been doing so for a year with no ill effects.

http://www.epa.gov/mercury/effects.htm