Mercury in fish

 Hi everyone,

Anyone here know much about mercury in fish? What would you avoid eating too much off, I have heard that species high up in the food chain have high levels of mercury things like tuna, sharks etc. is this the case with all fish? Or is it if you have coal mines or Plants around or some chemical plants around then this could cause it.

Interested to hear more about it because some websites say to limit your fish intake to once a week

 

Thanks

Abz


Jeffree's picture

Posts: 489

Date Joined: 23/02/11

 Did a bit of biology in High

Fri, 2012-01-06 01:40

 Did a bit of biology in High school. From what i can remember, higher order consumers such as sharks, maccys, tuna etc will have more build ups of heavy metals such as mercury in thier system. 

All species of fish will have some element of mercury in their system but lower order consumers have so little mercury in their system that it will not account for much. as a higher order consumer consumes a lower order consumer, the mercury is passed on to it.

So for example a first order consumer (prawn) is eaten by a second order consumer (herring) the mercury from the prawn is passed on to the herring. Then a third order consumer (mulloway) eats the herring, the mercury from the herring is passed on to the mulloway, which also includes the mercury from the prawn. Then a 4th order consumer (shark) eats the mulloway, then the mercury from all 3 species is passed on to the shark.

so to cut it short, the higher order consumers will have a high level of mercury.

hope i havent made an idiot out of myself and this all makes sense

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sarcasm0's picture

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Date Joined: 25/06/09

Right on the mark

Tue, 2012-01-10 09:32

The reason for the buildup is because of the energy translation between primary producers and the order of consumers.  Eg Algae (primary producer) has 10 units of energy but the krill (first consumer)that eat the algae only gets one unit of the energy for the one volume of algae, the prawn who eats the krill gets 1/10th again.  Basically the krill have to eat 10 x the original algae to get the energy that the original algae had.  Same goes for the Small Fry that eat the krill and the big fry that eat the small fry.  The problem comes when the Algae has mercury or other Heavy metal toxins they pass up the chain also because the consumers have to eat at least 10 of the previous order consumer to gain the energy transfer they also pick up 10 x the poison.  So by the time the shark eats the mulloway above, its possible to have toxicity well above what is safe for consumption by humans.

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Eat more mulies and less

Fri, 2012-01-06 05:41

Eat more mulies and less sharks!

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snapper's picture

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Date Joined: 09/02/08

Nope

Fri, 2012-01-06 15:28

eat more prawns than mulies any day.

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Assassin Land Based Fishing Club Member

Posts: 9358

Date Joined: 21/02/08

No wonder your nick is

Sun, 2012-01-08 15:17

No wonder your nick is snapper.

The whole point is to eat your way down, not up, the foodchain. No one is ever going to seriously argue that eating a diet of mulies is going to expose you to mercury poisoning.

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Posts: 81

Date Joined: 08/06/11

thanks for the info, it will

Sun, 2012-01-08 15:36

thanks for the info,

 

it will be interesting to know more about fish comsumption in humans and the short and long term consequences of low and high level of mercury in humans. ill prob research and read up more on it in the coming weeks.

 

Simo_'s picture

Posts: 1843

Date Joined: 13/11/06

I just found out today I have

Mon, 2012-01-09 19:45

I just found out today I have 4 times the normal level of Mercury in me... Dunno how it happened. Doctor said I cant eat fish and have to take a shit load of pills to get rid of it.

 

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Eat a lot of macks?

Mon, 2012-01-09 20:26

Eat a lot of macks?

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Simo_'s picture

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Date Joined: 13/11/06

Nope. I haven't eaten macks

Tue, 2012-01-10 06:51

Nope. I haven't eaten macks in over a year, don't eat shark either.

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sea-kem's picture

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Date Joined: 30/11/09

Ah shit! you'll have to put

Mon, 2012-01-09 20:36

Ah shit! you'll have to put an end to all those northern fishing trips then ;)

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Date Joined: 03/01/12

The bigger the fish, higher

Mon, 2012-01-09 21:36

The bigger the fish, higher up the food chain and also longer living fish will have higher levels of mercury in them. You can always catch and release if you need a break from the offending fish in question....  :)

 

Posts: 81

Date Joined: 08/06/11

read they couldnt get rid of

Tue, 2012-01-10 08:50

read they couldnt get rid of mecury once in the body or  maybe that its hard to get rid off.. did the doctor mention of the health effects if not treated??

 

 

Simo_'s picture

Posts: 1843

Date Joined: 13/11/06

You can get rid of it, just

Tue, 2012-01-10 16:35

You can get rid of it, just takes time.

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