Swim Bladder Deflation

[Horse]

After having trouble releasing a big Cod last week I thought it might be a good idea to brush up on how to deflate a swim bladder. Has anyone got any good info on the best tools for the job and what techniques work best.
The other option is to use the downrigger and a release mechanism

[peterbo3]

You can use any small sharp object to deflate the bladder but I think that the fish needs to be towed beside the boat to get water over the gills. That is when lip gaffing helps. The fish will be in shock after being dragged up & will not swim away on it's own power even if the bladder is deflated.
Drag it alongside the boat at low revs & it will often come good.

[deepfried]

I was watching IFish this morning and they used a release weight made with snapper leads tied to an upside down hook. Also have seen that method used on samson fish in WA during my regular TV fishing show sundays. I think studies have shown that puncturing the swim bladder is not that good for them.

[sleepygreg]

I cant see how puncturing the swim bladder can be good for them long term. I may be wrong, but I have heard and seen this method used, and still doubt its long term benefit for the individual fish. How does the fish re-inflate its swim bladder when its back down at its normal depth to compensate for water pressure (thats what swim bladders are for, so I am told). I think there are many more questions than answers here. Where is the underwater research with the deep releasing of fish via the weighted hook method (as opposed to the above water reaearch - where the fish doesnt float to the surface so it worked rationale). Not doubting this method - just would like to see the data - if anyone could post links it would be much appreciated.

Cheers
Greg

[Lovey80]

I never liked the idea of peircing the bladder. As stated above it can't be good long term. Getting them back to depth as fast as possible can be the only real viable solution IMO. The down rigger with the clip around the lips is the best solution I have heard. I rarely bring my rigger anymore but will start again in the future.

Cheers chris

[Jeremy]

Couple of useful links below. Think I remember Smithy saying he used the reef pick on big cod last time this came up??

http://www2.dpi.qld.gov.au/fishweb/13049.html
http://www.recfishwest.org.au/ReleaseWeight.htm

Jeremy

[Swindells]

Great links Jeremy.

[Cheech]

I cant see how puncturing the swim bladder can be good for them long term. I may be wrong, but I have heard and seen this method used, and still doubt its long term benefit for the individual fish. How does the fish re-inflate its swim bladder when its back down at its normal depth to compensate for water pressure (thats what swim bladders are for, so I am told). I think there are many more questions than answers here. Where is the underwater research with the deep releasing of fish via the weighted hook method (as opposed to the above water reaearch - where the fish doesnt float to the surface so it worked rationale). Not doubting this method - just would like to see the data - if anyone could post links it would be much appreciated.

Cheers
Greg

I agree. I think that puncturing the bladder is more about us feeling better, not the fish feeling better. Probably just enables them to swim down and be out of our sight before they die.

[Noelm]

not all that sure that attaching a big weight and sending them down in very quick time is any better than deflating the air bladder with a knife, either way I guess the fish has got more chance of living than in an esky!

[Jeremy]

deflating the air bladder with a knife

don't remember anyone advocating using a knife to deflate the swim bladder.

If you are going to deflate the bladder, use a tubular needle or at least a sharp clean thin object such as a bait needle.

Jeremy

[honda900]

swim bladder deflation is an interesting subject,

We (Australian Govt) tend to follow the americans like sheep so i presume it will be about 5 years before we start to follow their lead on this subject, by law they must carry and use a venting tool.

http://sero.nmfs.noaa.gov/sf/pdfs/FB...ule%20v2-1.pdf

Venting procedure.
http://www.flseagrant.org/program_ar...eries/venting/

Regards
HOnda.

[435_Mark]

The link below is to the fact sheet that summarises the best ways to relieve barotrauma. There are a heap of fact sheets on the recfish research website that Jeremy put up the link to. Basically the research found that venting did increase survival on those species that were particularly susceptible to barotrauma. In the "Gently does it. Releasing Tropical Reef Fish" fact sheet the survival of saddletail snapper (large mouth nannigai) went from 44% to 60% when they vented them.

One of the best methods for getting smaller fish back down is the "coucombs" listed on the second page of the pdf at the link below. For big fish like large cod the "shot release" (barbless hook with an attached lead weight) works well. You usually have to add a bit more weight to your shot release to get them back down though.


http://publisher.onepixel.com.au/doc...&documentid=47

[435_Mark]

Whoops!! Link to the rest of the research fact sheets.

http://www.recfishingresearch.org/re...h_survival.asp

[Lovey80]

not all that sure that attaching a big weight and sending them down in very quick time is any better than deflating the air bladder with a knife, either way I guess the fish has got more chance of living than in an esky!

Why so mate? The bladder expanded because the pressure around it was reducued rapidly, i figure if the pressure of the depths is reasserted on the bladder surely the bladder has to deflate-problems solved without injuring the fish?? Am i missing something?

Cheers

Chris

[finding_time]

It is the first 10 m that is critical, if you get the fish down 10m it will stay down, The swim bladder will be double the size on the surface than it was at 10m down regardless of the depth from which it came. I use my reef pick with 5m of chain and 5m of rope which is tied to the gunnel at the back of the boat, just place one of the hooks in the jaw and let go. Rate of decent does not matter and will have no effect on barotrauma it's the rate of accent which will cause an issue but you have already stuffed that by the time you work out you have a cod on the line!
One day at the Bannana Gutters off Round Hill we caughty around 10 large cod , using the above method all stayed down and i pressume swam away!

Ian