How do they make pellets?

[cg74]

Here's a question with a scary answer:
How many pounds of fish does it make to make a pound of trout pellets?

Purely a speculative answer: A fish must be about 80% water, so about 5lb of fish to make a pound of fishmeal.
Trout pellets contain about 40% fishmeal - What with wastage etc - I'd guess at 3lb.

Am I close??

---------- Post added at 21:41 ---------- Previous post was at 21:37 ----------

and here's another question.

How many Angler's think that halibut pellets are made from halibut and that salmon pellets are made from salmon?

Doh, everyone knows halibut pellets are made from halibut, don't they?

 

[Philip]

How many Angler's think that halibut pellets are made from halibut

Of course they are not made of halibut...how ridiculous....everyone knows they are meant for catching Halibut...

---------- Post added at 22:06 ---------- Previous post was at 22:03 ----------

Here's a question with a scary answer:
How many pounds of fish does it make to make a pound of trout pellets?

I did see that somewhere and its some ridiculously huge amount of fish meal is needed to make a pellet.

Not sure if anyone still does it but there was a company in the past that would make a pellet out of any base mix you sent them.

 

[laguna]

Here's a question with a scary answer: How many pounds of fish does it make to make a pound of trout pellets?

and a more scarier question...
How many pounds of wild fish does it take to produce one pound of farmed salmon?

 

[cg74]

and a more scarier question...
How many pounds of wild fish does it take to produce one pound of farmed salmon?

Well........ Atlantic salmon have a pretty amazing food conversion rate of about 1.2-1.4 to 1. Then working on the basis my figure for the amount of fish needed to make a pound of pellets is correct - 3lb.

3lb x 1.4 = 4.2lb

But I think the answer will be heavily influenced by whoever conducted the survey and what they want it to say.

---------- Post added at 08:08 ---------- Previous post was at 08:01 ----------

Of course they are not made of halibut...how ridiculous....everyone knows they are meant for catching Halibut...

Next you'll be claiming trout and salmon pellets aren't made from trout and salmon?

 

[geoffmaynard]

and a more scarier question...
How many pounds of wild fish does it take to produce one pound of farmed salmon?

Sixteen pounds, if they are pellet fed - and they are.

 

[cg74]

Sixteen pounds, if they are pellet fed - and they are.

How was that figure ascertained?

 

[geoffmaynard]

How was that figure ascertained?

I have no idea. I simply believed the figure which was given to me by a fisheries scientist with probably more letters after his name than I can count.

 

[Philip]

next you'll be claiming trout and salmon pellets aren't made from trout and salmon?

Well of course they are... and only the best Salmon & trout filets at that !

Just like the Game anglers anglers who fish for them, you cant expect an upper class fish like a salmon to eat any old rubbish can you.:wh

 

[cg74]

I have no idea. I simply believed the figure which was given to me by a fisheries scientist with probably more letters after his name than I can count.

It goes back to the remark I made a couple of posts ago: "I think the answer will be heavily influenced by whoever conducted the survey and what they want it to say."

 

[geoffmaynard]

It goes back to the remark I made a couple of posts ago: "I think the answer will be heavily influenced by whoever conducted the survey and what they want it to say."

This wasn't just some geezer in a pub - it was arguably one of the country's leading fishery scientists. Where's Bad One when you need him? Can you back this up?

 

[cg74]

This wasn't just some geezer in a pub - it was arguably one of the country's leading fishery scientists. Where's Bad One when you need him? Can you back this up?

Back up what?

 

[geoffmaynard]

Back up what?

Your comment: "I think the answer will be heavily influenced by whoever conducted the survey and what they want it to say."
This implies (to me) that you think the report was skewed and the implication is that the results are flawed. i.e that the figure of 16 pounds is made up.
So if some other 'qualified' person verifies it you might believe it. Of course this could backfire one me and he'll say 'what a load of old tosh!'

 

[The bad one]

Geoff that's a load of Town Halls

No seriously, I don't really know, with pellet for fish.
With meat it's about 4 to 1. 4 lb of protein in to get one back.

With pellet, accepting the hoovering up of fish like caplin and other smaller uneconomic food species, a significant preportion of fish meal is offal, scales, skin and bones from the fish for food industry, which are ground up to make the meal.
As this is a waste product there would be some offsetting towards the protein budget.

 

[cg74]

Your comment: "I think the answer will be heavily influenced by whoever conducted the survey and what they want it to say."
This implies (to me) that you think the report was skewed and the implication is that the results are flawed. i.e that the figure of 16 pounds is made up.
So if some other 'qualified' person verifies it you might believe it. Of course this could backfire one me and he'll say 'what a load of old tosh!'

ALL scientific results have flaws, in the case of this example; has your mate included every (and I mean every) fishmeal processor's production figures and every (and again I mean every) salmon farmer's production figures - I'd say not. Even if he had, that then draws into question the accuracy of their data supplied.

I haven't seen the report but I know it's impossible to gain a truly accurate encompassing figure, for such a huge industry and yes it is perfectly easy to manipulate the conclusion/results made to express whatever outcome you desire. Is your friend pro or anti salmon farming?

I could go on but it's pointless as I'm sure you can see my point?

 

[geoffmaynard]

I could go on but it's pointless as I'm sure you can see my point?

I can and I agree with it to a point. But even if just taking a conservative guess at the maths, just work out how many pounds of pellet is needed to feed a farmed salmon or trout to table-ready size, then calculate how many pounds of 'waste' fish are needed to make those pellets. Is it any wonder our oceans are virtually empty?

 

[cg74]

Geoff, I agree the way we are harvesting the sea is wholly unsustainable. It's not even the most economic way. We should take a leaf out of the Americans book and harvest alien species; I'm sure signal crayfish could be turned into a useful product?

Same with river dwelling carp and catfish, also grey squirrel, mink, muntjac and rabbits.

 

[The bad one]

ALL scientific results have flaws, in the case of this example; has your mate included every (and I mean every) fishmeal processor's production figures and every (and again I mean every) salmon farmer's production figures - I'd say not. Even if he had, that then draws into question the accuracy of their data supplied.

I haven't seen the report but I know it's impossible to gain a truly accurate encompassing figure, for such a huge industry and yes it is perfectly easy to manipulate the conclusion/results made to express whatever outcome you desire. Is your friend pro or anti salmon farming?

I could go on but it's pointless as I'm sure you can see my point?

Oh if only it was as simple as you are trying to make it out.

If a credible mathematical statistical programme is used, the flaw if there is one, is always recognised by +/- 5% variation of the true figure.
When such models are created by the mathematicians the model is tested against many known quantities of stuff. Example - a known quantities of bricks. If the model when tested many, many times starts to show a deviations from the 5% either way, the model is reworked mathematically until it's back within the 5% +/- tolerance.
The models don't lie, the interpretation of what they are saying is where the lie occurs, if it occurs at all. And why there will always be disagreement about statistics....."the human interpretation of them."
Now I don't know whether there was a stat model used, which one it was and whether it was the right one to use in these circumstances, but to condemn the science based on a simplistic view is wrong, unless you can show where it's wrong. And you haven't, you've expressed an opinion without the detail of where it's wrong.

---------- Post added at 15:43 ---------- Previous post was at 15:05 ----------

Geoff, and to your question how many tonnes does it.......take?
I use this with caution as it's a Wiki answer and doesn't seem to have ref to it. 4-5 tonnes to make 1 ton of meal.

 

[cg74]

Oh if only it was as simple as you are trying to make it out.

If a credible mathematical statistical programme is used, the flaw if there is one, is always recognised by +/- 5% variation of the true figure.
When such models are created by the mathematicians the model is tested against many known quantities of stuff. Example - a known quantities of bricks. If the model when tested many, many times starts to show a deviations from the 5% either way, the model is reworked mathematically until it's back within the 5% +/- tolerance.
The models don't lie, the interpretation of what they are saying is where the lie occurs, if it occurs at all. And why there will always be disagreement about statistics....."the human interpretation of them."
Now I don't know whether there was a stat model used, which one it was and whether it was the right one to use in these circumstances, but to condemn the science based on a simplistic view is wrong, unless you can show where it's wrong. And you haven't, you've expressed an opinion without the detail of where it's wrong.

---------- Post added at 15:43 ---------- Previous post was at 15:05 ----------

Geoff, and to your question how many tonnes does it.......take?
I use this with caution as it's a Wiki answer and doesn't seem to have ref to it. 4-5 tonnes to make 1 ton of meal.

Well your added passage says it all. Geoff inticates a 16 to 1 ratio, so on that basis FCR would be 3.2 to 1.... Even the most inefficient of farms work at half that rate.

"you've expressed an opinion without the detail of where it's wrong."
Without data from every salmon farm and every fishmeal processor, the results are only an indicator and not proof.

Regards the +/- 5% tolerances allowance - I'll leave you work out the implications when combining two sets of figures (fishmeal processor and farmer).

 

[geoffmaynard]

The question seems to have morphed a bit!
If it takes, say 4lb of by-catch fish to make one pound of fishmeal pellet, and it requires say 4lb of pellet feed to produce a 2lb salmonid:
4x4=16lb

---------- Post added at 21:19 ---------- Previous post was at 21:18 ----------

Errr... I did that wrong...doh!

 

[The bad one]

Bit of info here for you lot from a programme I watched on BBC 4 about a Japanese Prof who has spent the last 40 years attempting to get Bluefin Tuna to breed in captivity. This was born out of his concerns about it increasing rarity and cost when it is caught. 20K for a fish of 300lb wholesale.
Having succeed in his quest and having scaled it up to farming them on a commercial scale it gave the figure of 10-1 10 lb of mackerel for every 1 lb of tuna produced.