Backyard Aquaponics
A place to discuss aquaponics

We have been having discussions with some academics about the measurement of stress in fish in aquaponics/aquaculture and we cannot come up with a tried and tested method of doing so.

Anyone out there can give us some ideas please?.

WD and OH

Hi Wd
can this help ? http://edis.ifas.ufl.edu/fa005 http://www.thefishsite.com/articles/288 ... -of-stress

cheers

interesting thought..
not sure if it would apply, but i was just watching gator boys, they were working with a student that was trying to identify the difference in stress between a wild gator and one of the captured gators in the farm (they do gator shows)
here's an article on it (i would think you could do this with fish?)
http://www.thewareaglereader.com/2012/0 ... ator-boys/

Hi again
maybe this http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3276765/
and/or this http://intl-icb.oxfordjournals.org/cont ... 3/517.full
last link contain a load of refrences that might help ?

cheers

It's about pain, but as it is related... http://www.sciencedaily.com/releases/20 ... 090126.htm
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3389246

Thank you everyone for your directions. We will sit down and go through them all and report back.

WD and OH

I didn't read any of the links above... life's too short... but I can relate a couple of instances where I've seen stress affect the eating quality of fish.

Many years ago I hooked a 20kg Spanish Mackerel on a 6ft baitcaster with 6kg line... it took 45 mins to get the fish close enough to the boat to gaff... when I finally did he was stuffed, it was like realing in a Boral Besser block (cinder block)

Being such a big fish, I handed out large pieces to mates and neighbours. When I cooked it, a couple of different ways, it either curled up and/or went like rubber, it was unedible. I spoke to the others I'd given some to and they said the same.

A few months later I caught another 20kg specimen, but on a heavy 24kg trolling outfit and had him in the boat and bled in under 5 mins. He was good eating.

Also, when catching Herring sometimes I fillet the the bigger specimens and about 1 in 3 fillets will curl up and go rubbery... since the Mackerel episode I've always assumed these were the Herring that fought harder and longer.

But you don't know before you cook them which ones are going to curl up, or be rubbery, they all look and feel the same so I don't know how you would measure stress, at least in relation to eating quality.

I've noticed in smaller fish up to about 6 inches or so that they go darker when stressed, they seem to grow out of it though

http://intl-icb.oxfordjournals.org/cont ... 7.full.pdf summary (p. 521) seems interesting.

Natmaka

Just finished reading through the various publications and my brain hurts. Most of it is not for those unused to this degree of research, however there was interesting stuff there. Unless I have misread the article it seems that stress measurement is based upon the production of hormones after exposure to particular stressors, in much the same way as we produce adrenaline in response to certain stressors. Their measurements are in tiny amounts and one presumes that they must extract samples from the fish .(Which must expose them to stress).
What we are trying to establish is whether fish actually transmit some stress vibration or electronic signal that could be measured in fish tanks or ponds without handling the fish itself. If such a measure could be taken it would pick up a lot problems before things started to go wrong whether that be water quality, aggressiveness, pathogens etc.

We are still researching this.

Thanks for all the help.

WD and OH.

Barra have inbuilt stress indicators on their heads which is handy....

Hi Joel

What are the stress signs on the Barra's and are there other fish that show these signs?

Hope the weather down with you is not causing too many problems.

WD and OH

Barra have the white stripe down the front of the head.

Hi WD/OH
I hope you post any conclusions if you fine any methods that dosen't involve drawing blod/tissue samples, and a advanced lab.
I'll post this http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3276765/ to ad to your literature list.

cheers

yeah dude its sound to very difficult to justify which is handy ..