How much does a fish shrink - the answer!

[Freeeedom]

Fished close in to the reefs at Woody Point to try to get out of the westerly this morning. Picked up another decent bream, so I measured it carefully (forgot the camera again!) - came out at 39cm from nose to end of the tail. Weight was 845g.
Measured it again when I got home -about 2.5 hours after I caught it. Couldn't stretch it beyond 37cm. That's 5% shrinkage. Haven't lined the ruler up particularly well for the photo but you get the idea. If that's a ballpark figure for bream it means that a 23cm bream when caught is going to be less than 22cm when you get it home (if you keep them at that size). Personally I think the limit should be 25cm to bring us in line with NSW.
Cheers Freeeedom

[mickc]

Hi Freedom
I think you might be doing ya self a disservice , that rulers about 2 cm short of the fish's nose.
mick

[juju]

wonder if it would shrink more over more time...shows you how you could get caught back at the ramp with a "legal fish"........better just to use SPs then you dont have to worry

[Blackened]

G'day

Mickc - He mentioned he hadn't lined the ruler up too well for the photo.

Freeeedom, just to rule out a variable so to speak, did you use the same ruler?

Dave

[Damned67]

One thing to remember is temperature. Typically, constriction occurs with cooler temperatures. Is is possible then, that a fish stored on ice, will 'shrink' due to the temperature?
To avoid the temperature variable, you'd need to store the fish at the same temp as the water it was pulled from to make an accurate comparison hours later.

Anyone notice in the difference in the fitment in their wedding ring between summer and winter?

[sambos]

only the ice stored variation should count otherwise the fish will have gone off damned.your not normally going to go fishing and leave the fish stored at water temp for extended time,and then be concerned if their still of legal size.
cheers

[Freeeedom]

Hi Freedom
I think you might be doing ya self a disservice , that rulers about 2 cm short of the fish's nose.
mick

Yeah, I know it looks a bit that way Mick, but I laid the fish right on the ruler to measure it and couldn't get past 37cm. The fish was iced down straight after I measured it when I caught it, and was measured again straight off the ice. I think that probably the muscles contract, either through the cold or rigor mortis (or both) causing the shortening of the overall length.
Cheers Freeeedom

[Black_Rat]

Even people shrink ! Measure your height when you wake up and then in the afternoon I bet there is a difference

Yep, bream should be 25cm min if not 27cm min IMHO

[snagking]

only the ice stored variation should count otherwise the fish will have gone off damned.your not normally going to go fishing and leave the fish stored at water temp for extended time,and then be concerned if their still of legal size.
cheers

That's what I was thinking. But how much shrinkage is due to the cooling effect of the ice?
If it's not measured at the same temp, it's not going to be an accurate reflection due to death of the fish.
But you're right, we should take into account shrinkage due to the cooler temperature of the ice.

[disorderly]

Hi Freeeedom,

To be honest I was a bit skeptical of your original thread about shrinkage.
It just seems to be to large a change in such a short amount of time.
Now that you have confirmed this,it makes me wonder if this occurs the same with all fish or do some species shrink more than others.
I will have to check this out myself as I only measure once to check if the fish is legal.Then into the esky they go.
I also wonder if they shrink more as time goes by as I sometimes spend a day and a half at sea.
Thanks for the heads up

Scott

[paulez2]

I think you might be doing ya self a disservice , that rulers about 2 cm short of the fish's nose.

Yeah, I noticed that also. Sometimes there can also be a difference in measuring a fish in a rocking boat and having the fish flap around when just caught, or laying it on some uneven rocks to measuring it at home laying flat on the table.

Depend how many beers you have had also.

All those factors.

Maybe somebody can come up with a formula to determine the + or - errors in measuring a fish taking into account things like rocking boat, how many beers you have had or how much you may have smoked etc etc.

[BilgeBoy]

This is why I add about 3cm to each of the legal limits on my boat!

I recently caught a 35cm Squire only to be pulled up at the ramp by fisheries surveying. On their measure it was 34.5cm...WHAT THE! Luckily they were only surveying or I'd be Goooonnnne!!!

BilgeBoy

[shaman]

Speaking of shrinkage.................. Jeez it's friggin' cold tonight..........