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Barotrauma

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    Posted: 05 Aug 2018 at 3:19pm
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Not trying to start a huge argument here but getting a bit confused.  My wife and daughters would say this is nothing unusual but they would say that.
My issue is with the differing actions and obvious opinions on the effects of barotrauma on snapper by certain well known fishing show hosts.
Watching Graeme Sinclair, he advocates that any snapper over 30cm goes in the bin because if its pulled up from more than 20 metres its probably going to die if released. There has been a bit of scientific research backing this theory.  For what its worth, its what I do.
I have however just watched a recorded show of Nicky Sindon's where she is releasing snapper pulled up (slowly) from 40 -50 metres.
Now its not rocket science that a snapper put back stands a better chance of survival than if its in a fish bin but are some simply wasting fish by putting them back so they can catch more instead of stopping when they have a limit or enough for what they want?
What do you reckon?
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Post Options Post Options   Likes (0) Likes(0)   Quote MightyBoosh Quote  Post ReplyReply Direct Link To This Post Posted: 05 Aug 2018 at 3:33pm
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I liked to believe the big snapper released from deep water survived. I don't hold this view any more based on what I've read and seen. Big snapper from deep water just don't do well. At least half of the ones I catch are blown like a hapuka, and most of the remainder are in a sorry state. I fish with light gear, so I'm not exactly hauling them up either. Even if a fish does manage to swim back down, barotrauma is just that, trauma. Tissue damage doesn't magically reverse with recompression. 

Better to keep them in my opinion and stop fishing when you have enough meat, whether that be a a limit of pannies, or one donkey. Snapper over 15lb can be a pain in the arse in Northland. I just don't want to catch the bloody things!
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Post Options Post Options   Likes (0) Likes(0)   Quote The Tamure Kid Quote  Post ReplyReply Direct Link To This Post Posted: 05 Aug 2018 at 3:35pm
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Good question.
I've been out in the Gulf workup fishing with two top charter skippers who refused to let clients try to release fish from 40-50m zones because they reckoned the chance of any kind of successful release was zero. Anything legal got kept, and we stopped fishing when the boat limit was reached.
I've yet to see anyone bring a fish up slow enough for it to have the effect of a piscatorial version of divers stopping at various depths to decompress. Anglers might slow down their winding, but it's just not the same as letting it sit at a certain depth for ages - realistically, who's going to do that?

I've also seen Matt Watson do his thing with the needle, but always wondered how that affects the fish long term - surely a swim bladder with a hole in it is never able to be used effectively by the fish again, and I imagine it's got a serious purpose for a fish?

[PS. You're brave starting this thread after the seemingly innocuous Landcruiser tow wagon one! Confused]
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Post Options Post Options   Likes (1) Likes(1)   Quote Tagit Quote  Post ReplyReply Direct Link To This Post Posted: 05 Aug 2018 at 3:37pm
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In deep water pretty much keep what is legal, especially if any sign of blown swim bladder. In shallow water I think you can be a little more selective. I have noticed many times that in deep water slowly retrieved Snapper will not blow like a fast retrieved one, but whether that actually guarantees survival I don't know. 
One comment is that even on those really busy summer days where I assume a heap of small Snapper are getting released you don't seem to see dead Snapper floating around like you might behind a trawler etc. How long does a released Snapper with barotrauma take to die and do we know what the mechanism for it's death is?
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Post Options Post Options   Likes (0) Likes(0)   Quote MightyBoosh Quote  Post ReplyReply Direct Link To This Post Posted: 05 Aug 2018 at 3:40pm
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Another observation/question. I've noticed that small snapper don't suffer anywhere near as much from decompression/barotrauma as big snapper. If anything, they are brought up faster, so you would expect the reverse to be true. Any thoughts on that?
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Post Options Post Options   Likes (0) Likes(0)   Quote Coutta Quote  Post ReplyReply Direct Link To This Post Posted: 05 Aug 2018 at 3:48pm
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[QUOTE=The Tamure Kid]Good question.
I've been out in the Gulf workup fishing with two top charter skippers who refused to let clients try to release fish from 40-50m zones because they reckoned the chance of any kind of successful release was zero. Anything legal got kept, and we stopped fishing when the boat limit was reached.
I've yet to see anyone bring a fish up slow enough for it to have the effect of a piscatorial version of divers stopping at various depths to decompress. Anglers might slow down their winding, but it's just not the same as letting it sit at a certain depth for ages - realistically, who's going to do that?

I've also seen Matt Watson do his thing with the needle, but always wondered how that affects the fish long term - surely a swim bladder with a hole in it is never able to be used effectively by the fish again, and I imagine it's got a serious purpose for a fish?

[PS. You're brave starting this thread after the seemingly innocuous Landcruiser tow wagon one! Confused]
Brave or stupid Tamure, depends who you talk to.
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Post Options Post Options   Likes (0) Likes(0)   Quote JustAnotherSpearo Quote  Post ReplyReply Direct Link To This Post Posted: 05 Aug 2018 at 4:00pm
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Definitely brave Coutta, I can't comment on this one again mainly because I only have the ability to poke holes in fish and bring them up from 25 meters and generally that is at the speed I can swim.. Yet to have a fish help me to the surface.. Funny that.

Am reading closely on this one, could be a learning curb
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Post Options Post Options   Likes (0) Likes(0)   Quote Troutzilla Quote  Post ReplyReply Direct Link To This Post Posted: 05 Aug 2018 at 4:15pm
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I tend to favour the theory that snapper pulled up from deep water won't do well if released.

However I also know from trout fishing and having caught the same large trout more than once that fish if handled well definitely do survive.

Going with that theory then I often release snapper caught softbaiting in shallow water - under 10 metres.

I guess the question then is how deep is too deep to catch snapper from and release them - while still giving them a strong chance of survival.




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Post Options Post Options   Likes (0) Likes(0)   Quote Uncle Quote  Post ReplyReply Direct Link To This Post Posted: 05 Aug 2018 at 4:25pm
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Originally posted by Troutzilla Troutzilla wrote:

...

I guess the question then is how deep is too deep to catch snapper from and release them - while still giving them a strong chance of survival.




 
...& that is the $64,000 question.

There needs to be some serious research done in this direction.

With better boats, sounders & equipment, the fish are rapidly running out of places to hide.
We need to be looking out for fish welfare now before it's too late.
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Post Options Post Options   Likes (0) Likes(0)   Quote Muppet Quote  Post ReplyReply Direct Link To This Post Posted: 05 Aug 2018 at 5:12pm
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The bigger issue is faffing with fish trying to take photo's and video's. If you are going to release it make it as quick as possible. 

If they have guts hanging out the arse and mouth its obviously knackered and not worth putting back. have mentioned this before but many times I have snapper let out gas in my landing net and they have gone back fine and that is in less than 20m. 
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Post Options Post Options   Likes (0) Likes(0)   Quote waynorth Quote  Post ReplyReply Direct Link To This Post Posted: 05 Aug 2018 at 5:17pm
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Excellent subject Coutta, and encouraging to see most posters above share your concerns. A couple of years ago I tracked down a few articles online after venting devices became available and were endorsed by some high profile fishers in both the mainstream and social media. 

The text below is copied/pasted from several of these articles - a bit lengthy but pretty consistent in the findings. The very last sentence is interesting.

Capture depth related mortality of discarded snapper (Pagrus auratus) and implications for management

John Stewart New South Wales Department of Primary Industries, Cronulla Fisheries Research Centre of Excellence

Received 9 August 2007; received in revised form 31 October 2007; accepted 2 November 2007

...capture depth had the greatest affect on short-term survival of snapper, with no mortalities observed from depths of less than 21m and ∼2% from depths of less than 30 m. Mortality of snapper increased rapidly after 30m and was ∼39% between capture depths of 30 and 44m and ∼55% between capture depths of 45 and 59 m.

Survival was also effected by fish length, with smaller fish being more likely to die.

Capture depth has a major influence on survival of fish that are discarded and there is an inverse relationship between capture depth and survival (Rummer and Bennett, 2005; St. John and Syers

Capture depth had the greatest affect on survival of snapper (Table 4). There were no mortalities of snapper from capture depths less than 21m and only three from capture depths less than 30m.

The major finding from this study is that the mortality of snapper discarded from fish traps with capture depths of greater than 30m may be high. This mortality appears to be largely attributable to capture depth and rapid depressurization during capture. Rates of mortality of more than 20% are considered problematic (Muoneke and Childress, 1994), and45% of snapper from capture depths of greater than 30m died during the present study. Most of the NSW demersal trap fishery targets snapper in waters of greater than 50m (Ferrell and Sumpton, 1997) and, given that discard rates are currently in the order of 50% the mortality of these discards is of concern. Given that 66% of all recreationally caught snapper are also discarded (Henry and Lyle, 2003) it is likely that the mortality of recreationally caught and released snapper may also be an issue.


There is a current management initiative to increase the MLL of snapper in NSW from 30 to 32 cm, but the results presented here suggest that such an increase may not fully achieve the predicted increases in yield and egg production because of high rates of discard mortality.

It has been previously demonstrated that MLLs for snapper in New Zealand may not be effective in increasing stock size if discard mortality is high (Harley et al., 2000).

Gene R. Wilde

Wilde is professor of fishery ecology at the Department of Biological Sciences, Texas Tech University, Lubbock

17 studies that assessed the potential benefits of venting in 21 fish species and 1 composite group.

The effects of venting did vary with capture depth: venting was slightly beneficial to fish captured from shallow waters, but appeared to be increasingly harmful for fish captured from progressively deeper waters.

As a captured fish is brought to surface...gases may leave solution and form bubbles (emboli) in the blood, and various tissues and organs, including the eyes, brain, heart, arteries, gills, spleen, fins, musculature, and the dermis beneath the scales.

The Australian National Strategy for the Survival of Released Line Caught Fish recently endorsed venting as has, in effect, the U.S. National Marine Fisheries Service, which now requires offshore anglers in U.S. territorial waters in the Gulf of Mexico to have venting devices in their possession.

The available information provides virtually no support for the practice of venting as a means of increasing survival of captured and released fish. This result is consistent across a variety of experimental and field study protocols, within and among various species of fish, including species captured in freshwater and in saltwater, and from various depths.

Although fish that can swim away or submerge commonly are considered to have survived catch and release, this assumption is largely untested and there is some evidence that the ability to swim away is unrelated to survival. It is, perhaps, the counterintuitive nature of this result, along with some wishful thinking, that has perpetuated the practice of venting.

However, the physiological effects of barotrauma are not remediated simply by returning the fish to its capture depth (Morrissey et al. 2005) and many barotrauma injuries are unaffected by recompression

The available evidence fails to demonstrate that venting fishes exhibiting symptoms of barotrauma promotes post-release survival. In fact, it is possible that this practice decreases survival of fish captured from deeper waters, presumably because of the greater severity of their barotrauma symptoms. Venting fish should not only be discouraged by fishery management agencies, but given the possibility that venting adversely affects survival of released fish, this practice should be prohibited, rather than mandated.


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Post Options Post Options   Likes (0) Likes(0)   Quote Steps Quote  Post ReplyReply Direct Link To This Post Posted: 05 Aug 2018 at 5:57pm
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Like you, lot of conflicting info etc.
 So this is what we do.
 If the bin is MT or close to, the 1st few.. enough for a feed for each family, goes in the bin.
 If it comes up obviously blown, check down inside the throat goes in the bin.
 Once got a feed for each family from there it is more 'sport fishing',chill out enjoy the company and day.

 I encourage others on the boat, to take their time pulling fish in, just keep that curve in the top of the rod at all times.. Enjoy the moment , fight. Be it skull drag gear or light weight gear.. Never know if a JD or something that pulls hooks, rips lips easy.
Taking ones time means less, hopefully no bloating.
 If not needed in the bin goes back if looks ok..

In saying that, sometimes all looks good yet , when return they just dont look fit.. so bin them.
 This is because have on numerous times tried hard to re energise, they sometimes even come right, then flop over, re try, flop over...
So if doesnt look fit and healthy , even thu not bloated.. in the bin.. the assumption we make, is if cant get down a few meters chances are will fail somewhere after that and the bottom.
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Post Options Post Options   Likes (0) Likes(0)   Quote Skoolinfish Quote  Post ReplyReply Direct Link To This Post Posted: 05 Aug 2018 at 6:29pm
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I could be wrong, (often am) but my understanding is that Canada is split into many territory authorities for fishing purposes, and that generally there is a maximum size for salmon, any thing under has to become a part of your daily catch no matter the size.  Either way some of their overall rules are:
release most or all of the larger ones.
8 meters is considered the cut off between deep water and shallow water.

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Post Options Post Options   Likes (0) Likes(0)   Quote pjc Quote  Post ReplyReply Direct Link To This Post Posted: 05 Aug 2018 at 7:14pm
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http://www.fishingworld.com.au/news/video-barotrauma-in-golden-snapper

Caught off Australia which shows the effects of barotrauma,some marine experts from NZ deny this,I say if legal keep it,why take the risk??
QMS is not WORKING
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Post Options Post Options   Likes (0) Likes(0)   Quote feeder Quote  Post ReplyReply Direct Link To This Post Posted: 06 Aug 2018 at 7:45am
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Catch it, if legal, eat it, leave the rest alone, mind you we fish mainly 40 metres +.
 
This has long been one of my pet subjects and have debated this many times so if you want to hear my views you can troll my past posts, out west there are plenty of big sharks, put back a fish slightly under the weather and it will get eaten.
 
Cheers 
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Post Options Post Options   Likes (0) Likes(0)   Quote Kevin.S Quote  Post ReplyReply Direct Link To This Post Posted: 06 Aug 2018 at 8:18am
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I'm going to put what is probably the complete opposite of most things said.  When we go out fishing we generally only take one or two fish, as that is all we need for a feed.  Everything else goes back.  But we don't fish anywhere near 40-50m deep.  I'm fairly sure the fish we release survive because many of the smaller fish we catch show signs of having been caught before.  We always use circle hooks and when releasing try not to touch the fish at all if possible -just grab the hook with pliers and roll it out of the corner of their mouths.

From the scientific data that Waynorth mentioned it seems that if you want to return fish then you should try not to fish deeper than 30m.
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Post Options Post Options   Likes (0) Likes(0)   Quote bazza Quote  Post ReplyReply Direct Link To This Post Posted: 06 Aug 2018 at 9:14am
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OK ..... the sentiments being expressed in this thread re release or not, whilst being very noble & should not be discouraged but am about to put the "cat amongst the pigeons" suggesting that it is incidental compared to the real problems.
 
Admittedly the statistics contained in this reply are largely hypo theoretical, nevertheless imo such an outcome is a distinct possibility therefore the comparative major total disasters listed could well happen & in the meantime we are in real danger of failing to see the "wood for the trees" by focusing on lesser issues. 
 
Righto let the rant begin ......
 
Firstly what % of the worlds total biomass of fish are likely to be affected by releasing or keeping fish caught. I daresay it could be in the region of .001 % or less.
 
Lets compare that with the potential damage that will continue to gain momentum of various forms of ocean pollution & in particular plastics.
 
Currently the world is experiencing heat waves, floods, droughts, fires & extreme degrees of freezing etc.
 
Sure it has been stated such conditions have existed before & have abated which is true but never all at the same time. However it is all very well to quote that in say 1975 the temperatures in some country or other reached a comparative high or low without acknowledging that this time around there are significant differences
that could well prevent recovery ... such as.
 
(1) Never before in history has the world had such a high population combined with a decline in the indigenous wild animal population.
 
(2) There has never been so much pollution & contamination of the oceans & waterways ... particularly plastics. The production of plastics can only continue to increase & even if we were to stop completely tomorrow it is predicted it would be over 50 yrs before the affects of current pollution would begin to wane.
 
(3) The polar ice caps are retreating at an alarming rate & other natural resources such as forests etc are also disappearing at an alarming rate.
 
(4) Already many countries that largely depended on the sea as a food source as a result of overfishing, run off of fertilisers & other factors can no longer expect to do so therefore in many instances have had to resort to piracy.
 
(5) World demand has seen an explosion of demand for a wide range of goods (eg batteries, laser printer cartridges, nuclear waste & even tallow etc. etc. cannot be effectively recycled.
 
Imagine if climate change continued & counties that have historically produced or grown food product could no longer do so how long would it be before world food supply was in dire straights ?
 
Could go on & on at the risk of being labelled a doomsday prophet however surely the possibility of such a situation occurring cannot be ignored.
 
OK try enjoy your day ... hope it has not had a damper put on it.
 
PS would love to hear others thoughts & opinions on the subject.
 
 
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Post Options Post Options   Likes (0) Likes(0)   Quote pjc Quote  Post ReplyReply Direct Link To This Post Posted: 06 Aug 2018 at 10:01am
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Bazza the question was do fish suffer from barotrauma and the answer is yes. Now it is up to the individual whether to release or keep.
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Post Options Post Options   Likes (0) Likes(0)   Quote Coutta Quote  Post ReplyReply Direct Link To This Post Posted: 06 Aug 2018 at 10:42am
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Yeah, you're right in everything you say Bazza and we always need a "Devils Advocate" in discussions such as this.  But, do the correct facts you have mentioned mean that we should just give up on what we have because we're basically ####ed anyway.  Just because there is shocking cruelty going on around the world in slaughter houses in third word countries should we really worry about a few bobby calves here at the hands of the odd person who really has no right to breath the same oxygen the rest of us use? Of course we should. The number of people killed in New Zealand as a result of domestic violence and drugs is not even a drop in the bucket when compared to those slaughtered annually in the US or Asia. Should we forget about the deaths here? Ah, no.
Just saying we should do all we can to look after what we have. 

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Post Options Post Options   Likes (0) Likes(0)   Quote Baru Quote  Post ReplyReply Direct Link To This Post Posted: 06 Aug 2018 at 7:07pm
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I got half way through writing a response in a similar vein to Bazza’s post, then initially chickened out, humanity looks at everything from a perspective of how to utilize that resource for its benefit.  If you looked at it from an ecological perspective then the ranking of most harm would be:

- Fish caught and kept (removed from ecosystem)

- Fish caught, released and dies (this is not a full loss from the ecosystem)

- Fish caught, released and survives

- No fish caught


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