The Shredder, Ultimate Burley Machine - Burley Experiment

With the Shredder now “firing on all cylinders” ( (, and the number of requests from FW Members for the burley it produces it is time to start to determine the appropriate recipe.

My observations are that the time the burley takes to dissolve in the water column varies considerably based upon the mix of fish flesh/frames to pellets/pollard, the number of times the burley is minced and the water content of the burley as it is used frozen – assuming tuna oil as a constant.  If we are ultimately going to offer the burley commercially then the mix ratio has to be right.  You want something that produces a steady stream of appropriately sized particles, but will last for a reasonable period of time.

As a scientist by training, with a High Distinction for Topics in Applies Statistics in my Honors year (I have never really admitted my geek like behavior from the 80’s), it was time to conduct an experiment.  A multi factorial analysis of variance, with the dependent variable being the burley dissolution in sea water in grams per minute, seems like the go.  Independent variables of mix ratio, mince events and water content is the starting point, which can be refined once the initial results are known.  Replicates of 4 is appropriate but if you are to test for the dependent variable in “real life” conditions the actual trip with different wind, wave and current observations is likely to confound results – use this as a factor as well.  Blah, blah, blah.  My family and friend always sledge me for over analysing things!

Anyway, I spent the day making up 750g (measured accurately) bags of burley with 2 different mix ratios, 3 different mince techniques and 2 different water contents.  2 x 3 x 2 and 4 replicates = 48 bags of 750g mass each.

Yes, it was tedious but research and development is important.  I can now go fishing with randomised 4 x 750g burley logs in the water at a time and see how they each behave, and this is the best part of the whole deal.  I know my burley works but the experiment is to evaluate what should actually be made in the future considering all of the factors. 

I still aim to have the Shore Catch burley available for purchase, in various forms (1kg, 2kg, 5kg), by the end of the year and this is all part of the process.  I look forward to reporting on results of the experiment.


Ability is what you are capable of doing. Motivation determines what you do. Attitude determines how well you do it - LH.


kirky79's picture

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Good one Mick

Tue, 2015-07-28 21:32

 Looking forward to seeing the results. 

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You have undertaken a sound approach

Tue, 2015-07-28 21:47

On paper it appears that you have a very sound methodical approach to producing a strong fish attracting berley.

Myself being of the more simpler approach to problems especially when chemistry is involved is to have a quick solution to attaining the idea mix.

We need one big dead whale washed up on the beach.Problem solved damn it. LOL

Seriously though, keep up the great work I'm sure all us F/W members are watching your endeavours with great anticipation.

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 The best part now is you

Wed, 2015-07-29 05:36

 The best part now is you have to fish to do the trials. Winning

JohnF's picture

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Ahhhhh, brings back memories

Wed, 2015-07-29 06:26

Ahhhhh, brings back memories of factorial testwork programmes I used to do in my formative years as a metallurgist......

Add in a healthy dose of OCD and the results should be good!


Boston Whaler 235 Conquest......getting the flogging it was built for.

Mick C's picture

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Ahhhhh Yes

Wed, 2015-07-29 17:30

The old OCD.  Wish I had a dollar for everytime someone described me like that.  


Ability is what you are capable of doing. Motivation determines what you do. Attitude determines how well you do it - LH.


Madmerv's picture

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Wed, 2015-07-29 06:32

 Good to see some serious research going on there.

The "real life" tests will be pretty hard to control with different conditions every day you go out. Do you plan on hanging multiple burley pots over the side for timed melt tests?  That would leave a monster trail and bring in every fish for miles so let us know where and when you are heading out..Lol

At the moment i'm doing my own burley and freezing it in PVC tubes. Pop it out and put it into a pot as needed. I find the chop on the day has the most influnce over time to melt ranging from 15min to about 1 hour. Constant side to side, or "tea bag dipping" wipes them out pretty fast.

Anyway the wife says hurry up and get it on the market as she is sick of the food processer smelling of fish.


 Sometimes when the water is quiet, you can hear the fish laughing at you !

Mick C's picture

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Melt Tests

Wed, 2015-07-29 17:42

Yes mate, multiple pots - 4 at a time.  I will try and get the conditions as similar as I can but accept that it will not be possible.  The way I have set up the design, "trips" will be built into the linear model so that the variance between trips can be looked at as well.  In this first test I really want to see which of the main factors have the most influence and then I will refine and test a bit more.

I have certainly observed that the more chop there is the faster the burley dissapates, although I have made some that is like a "block" that you have to force out irrespective of conditions and some is like a "soup" that just washes away (the main reason for looking at the mix really).  Hence I will try and minimise it through the tests and use the Minn Kota spot lock as this tends to make the boat ride the waves rather that what happens when you are tied to an anchor.

Appreciate your comments.  Cheers.  Mick  


Ability is what you are capable of doing. Motivation determines what you do. Attitude determines how well you do it - LH.


z00m's picture

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I'm happy to supply the

Wed, 2015-07-29 08:26

I'm happy to supply the research vessel and assist in the fishing part!

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What stats package will you

Wed, 2015-07-29 09:51

What stats package will you be using to assess the data Mick?

Mick C's picture

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Stats Package

Wed, 2015-07-29 17:48

I was hoping to use my old favorite GLIM, but it seems that it went out of production a long time ago.  I have only just started to have a look at what else is available and if you have any suggestions it would be appreciated.  The design is valid and relatively simple, but it is multi factorial so I will have to research the appropriate package.  It will probably take me a while to get the complete data set so there is a bit of time to research the best one I guess.  Cheers.  Mick 


Ability is what you are capable of doing. Motivation determines what you do. Attitude determines how well you do it - LH.


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Thu, 2015-07-30 07:22

you can use Minitab and set up a DOE (design of experiments)

you should be able to "download" a free copy. If you get stuck let me know I may be able to help out.

cheers, Mat

sunshine's picture

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Surely sea surface temp will impact the results

Wed, 2015-07-29 09:57

So you may need a different "blend" for summer versus winter

Mick C's picture

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Sea Temperature

Wed, 2015-07-29 17:56

Good point.  The average seasonal sea temperature change is around 5-7 degrees so the burley will defrost more quickly in summer time.  I have noticed that mix ratios and mince grade has a "significant" influence and I would like to try to get to the bottom of that first, and I don't think the water temperature change will be that great over the period of the test.

I had thought about adding salt to lower the freezing point and following your suggestion will give that a go once I get the mix ratios right.  Appreciate your comment.  Cheers.  Mick 


Ability is what you are capable of doing. Motivation determines what you do. Attitude determines how well you do it - LH.


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Binding agent

Wed, 2015-07-29 19:05

is there a product you could use to control breakdown, like a gelatine. tasteless and flavourless, but maybe not to fish?


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If you dont mind me asking

Wed, 2015-07-29 23:57

If you dont mind me asking what fish go into the mixer to make your berley?   

Looks good.


Bend over

Mick C's picture

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Total Recycling

Thu, 2015-07-30 09:43

The main ingredient for the shredder is fish frames.  We have used a whole range of different types of fish and I stockpile and freeze the frames and skins every time.  I think a mixture of fish types is good - herring, whiting, skippy, garfish, tuna, sambos and the odd demersal that isn't on the Fisheries skeletons wanted list.  Occasionally we will use whole fish, of the less desired eating quality, if the fish cannot be released due to damage when captured.  We also recycle all the old bait.  Anything with freezer burn goes in as does squid and ocky heads.  I always like to get some shell in there too so cray and prawn shells usually get added.  Any waste fish product really.  Note that we do not take and use whole fish for the sole purpose of burley.

I don't think we have contributed 1 gram of fish product to landfill since we started our burley campain.  To me, this is a real benifit of building the shredder as it can process anything we put in it. 


Ability is what you are capable of doing. Motivation determines what you do. Attitude determines how well you do it - LH.


crasny1's picture

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Mick the geek!!!Basically as

Thu, 2015-07-30 08:21

Mick the geek!!!

Basically as I see it all you are trying to check on is dissolve rates.

Any product with all that oil, fish, pollard in it IS going to attract fish.

So what you are after IMO is how long a block off various consistencies "melt" or dispurse.

I like the idea off testing it on the briney (because you are fishing off course), but mate why not make it more controlled in a tank, preferably glass so you can see the results as it happens (and dont use the pool if you have one as the Mrs might get very very agro and we all know what happens then) Sorry girls on here for that sexist comment

I am dead certain that fish will be attracted no matter what, the question is how long it does.

And yes Im a science Geek aswell, just in a different field!!!

It is one off the best ideas I have seen on here for ages mate and even though living in Mandurah will be happy to be a science assistant if you need one!!!




"I would like to die on Mars. Just not on impact!!" _ Elon Musk

Mick C's picture

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Thu, 2015-07-30 09:51

Agree regarding dissolve rates.  I did think about a very "controlled" test environment but as Sunshine points out there would be quite a bit in ensuring that the controlled environment was the same for all samples.  A large pool would be good but the ramifications would be very nasty.  The sea test also has those other benefits, and it is the environment in which it is ultimately to be used.  Yes, it will contribute variation but that will be interesting in itself. 


Ability is what you are capable of doing. Motivation determines what you do. Attitude determines how well you do it - LH.


sunshine's picture

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Neels - surely in a tank the results would be skewed

Thu, 2015-07-30 08:54

As the water temperature (enclosed body of water) would quickly reduce whereas in the real environment you have "flow" with fresh notionally warmer water passing over the dissolving blocks constantly leading to far more rapid dissolution.

The blocks that appear to be available in NZ (aka Big Angry Fush ) appear to be at least 350mm - 400mm long and 150mm diameter and their sea water temp is lower yet they only seem to last 2-2.5 hours ............

As a further observation would have thought the more oil content be it tuna or naturally within the frames being minced the quicker the melt as you cannot freeze oils

Mick C's picture

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Oil Content

Thu, 2015-07-30 10:00

We have made some 5kg blocks and they seem to last about 1.5-2.5 hours too.  I have made some mixes however where 1kg will last that long, hence the need to do a bit of research.

For the initial tests, I added fish oil because it should be in the burley, but kept it a constant for all samples.  I tend to think that the next trial will vary oil %, water % and salt % with the selected mix and mince ratio.  


Ability is what you are capable of doing. Motivation determines what you do. Attitude determines how well you do it - LH.