barotrauma studies
I have seen on Fisheries NT facebook page an article on a barotrauma study on golden snapper. Interesting read and I have tried to cut and paste the link and text herr but my phone isnt allowing me to. If someone else can great - do it please.
Its finding are that survival rates for reef fish from deeper than 10 metres are significantly reduced when released (using a weight, not vented).
There is an interesting comment attached putting forward an argument for purely bag limits for these fish, not size limits. Basically saying that as soon as you catch your bag limit you stop fishing. Ie keep what you catch no matter how small. Argument is that less of the bigger breeders would be dragged up, released and die anyway.
Have a read and post your thoughts.
Would be interested if WA Fisheries are doing similiar studies?
Fish! HARD!
Versus
Posts: 918
Date Joined: 06/03/09
http://www.youtube.com/watch
http://www.youtube.com/watch?v=C-1n4YZNaSY
Yep think it was on here about a year ago. Different fish react differently, i've heard there's basically 2 types of swim bladders, one is better at dealing with barotrauma and the other type isn't (don't quote me on that i haven't looked into it). Would be good to know more, as you say no point releasing fish that will die anyway.
Versus
Posts: 918
Date Joined: 06/03/09
Another, this one from
Another, this one from Queensland
http://www.youtube.com/watch?v=wzHbZ_5UGMU
Notorious
Posts: 914
Date Joined: 23/02/12
Many people on here dont like
Many people on here dont like the thought of them actually damaging vital fish stocks such as Dhufish via barotrauma. I have raised the point before after people brag of catching 10 Dhu and releasing 8 like they're some sort of hero. Little do they know whether their released fish survive the next couple hours after they dissapear to the bottom.
https://www.facebook.com/groups/174055815943047/?fref=nf
randall df223
Posts: 6454
Date Joined: 08/08/11
I think the idea of bag only
I think the idea of bag only limits needs discussion. Makes sense to me to catch one or two and then stop, rather than catch 8 before the one you are allowed to keep only for those 8 not to survive???
Policing it is an issue??? How do we stop the dishonest ones who would discard a smaller fish for a larger one???? Dont know, but they're probsbly alreasy breaking the current laws.
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sunshine
Posts: 2555
Date Joined: 03/03/09
But as I understand it tagged dhuies
And hence released dhuies - have been recaught regularly so the survival rate appears at least better than one might expect. Upgrading concerns me - crazy really as a smallish dhuie flesh flavour and texture is far superior to a big one - I even prefer pinkies provided they are FRESH - note the capitals for a feed the same day but question how well they freeze even with vac systems
Another reason I fish lighter than many, takes longer to get them up through the water column and hence arguably less baro sustained
Wazo
Posts: 84
Date Joined: 12/06/08
catch limit of 4
Catch limit of 4 Dhuies....pack up and go home....thats a fair days fishing......or catch 25 Dhuies....keep 2 ....kill 9-10 with Barotrauma and go home thinking alls good.
The logic doesn't make sense with current limits and science.
It takes a lot of effort to bring a fish up carefully enough, not to mention new deckies who skull drag before you can stop them....it only takes a couple of metres and the fish are shot.
Not a fan of catch n release with demersals....just get your fish on the boat and head home...everyone wins...especially the fish.
Yewiefish85
Posts: 780
Date Joined: 02/01/11
I personally believe there
I personally believe there should be bag limits only on certain species with even larger penalties for those who exceed the bag limits, as for barotrauma damage to released fish, i believe that Paul G in the past has posted about his tagging effort on dhufish that have shown obvious signs of barotrauma
Wazo
Posts: 84
Date Joined: 12/06/08
Paul G top fisho
Paul fishes better than anyone and works hard to protect the fish....he's ex pro and knows his stuff.
Joe dirt skull drags and leaves the fish in bad shape. Even on my best day I still get caught out.
Dhuies dont release well...we all know that
chris raff
Posts: 3257
Date Joined: 09/02/10
Good subject worthy of
Good subject worthy of discussion , thinking bag limit would be better option myself .. I realise bring them up slow , release weight etc but survival is still not 100% . Not much worse a feeling than seeing a just under dhu or snapper floating back past your boat after doing all you could to minimise the trauma . Commonsense would say add it to your bag but the law as it stands would punish you . Definitely think it should be seriously considered .
“Intelligence is like a four-wheel drive. It only allows you to get stuck in more remote places.”
carnarvonite
Posts: 8627
Date Joined: 24/07/07
Release weights
IMO, All release weights do is take the fish out of view so you think you are doing the right thing but have no proof to show for it. Piercing the air bladder allows infection, even if done by a pro and take a bit longer than the release weight to kill the fish.
Catch your tally the try something different, go to small gear and chase whiting, troll for pelagics anything but bottom bouncing where you are going to kill more fish.
There is no way to stop greedy pricks upsizing their catch, we hear quite a bit of it during the Carnarfin fishing comp that runs for a week with daily weigh ins and the ability to stay out for as long as you like. The new daily weights are broadcast each day and if you have one that isn't going to beat it, over the side it goes so you still have the chance to get a bigger one.
hezzy
Posts: 1519
Date Joined: 27/11/09
wazo & john completely agree
wazo & john completely agree with you both , im not a fan of demersal release either
I still think even with all best care and attention , released survival rate is pretty low in most cases , they just disappear out of sight to die a slow death more often than not ,
and yes it shites me to tears to see people post up reports of how many dhuies they have kept on catching and then released way past their bag limit like it was some kind of special feat
many use small successes like paul g,s to justify there sheer selfishness and arrogance ,
it also really irks me to see how many of these numnuts on fishing shows also handle fish , just while they blabber on to the camera for self glory ,
if they where serious they would advise peeps to only catch the fish they want to eat , then move off to something else or go home ,
lots of older blokes get blamed for rape and pillage , but its across all ages imho bragging on social media has gone into overdrive
hezzy
OFW 11
evil flourishes when good men do nothing
randall df223
Posts: 6454
Date Joined: 08/08/11
On the laptop now so I'll try
On the laptop now so I'll try and post the link to the article
https://www.facebook.com/photo.php?v=554964647926246
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randall df223
Posts: 6454
Date Joined: 08/08/11
the comment that caught my
the comment that caught my attention was by Stephen mcgovern
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randall df223
Posts: 6454
Date Joined: 08/08/11
Interestingly, it seems
Interestingly, it seems Fisheries NT have not imposed size limits on reef fish for this very reason. Seems to be a completely different way of thinking and management up in the NT?
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carnarvonite
Posts: 8627
Date Joined: 24/07/07
Mulloway
Love to see what the successful release of mulloway in over 25 metres of water isn't, they have a very fine bladder unlike dhufish and it usually has a tear in it even if you bring them up slowly and for someone like me who doesn't like them its a shame because using 2 hooks on a rig means you have caught your bag limit of something you don't want in one drop.
squidder
Posts: 457
Date Joined: 03/09/10
Upsizing
is always going to be the driving force with most anglers and when some hear a bragging session on what's getting caught over the two way, ego's take over.
As for mulloway I personally have released quite a few in 30mts of water. In saying that a lot have shown to be swimming at various depths, some being only 5mtrs from the surface, others mid water and so on.
They appear to be very lively and do not get lifted out of the water and swim off with haste. In saying that no one knows if they survive as they are not tagged.
I might add these fish are caught on light gear.
Ben Derecki
Posts: 1926
Date Joined: 10/10/07
Bit of bagging going on
Bit of bagging going on without any data in support of the bagging. Does anyone have actual info on it or are we all just talking gut feel / 'I think'?
randall df223
Posts: 6454
Date Joined: 08/08/11
It would be good to know if
It would be good to know if similar studies have been done locally? I think as has been pointed out, different species cope better upon release. Going back to the comments on the original facebook post by NT Fisheries, someone claims that red emperor release well. I dont know if the science supports that or not. I think I'll do some research into what WA Fisheries has done.
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Ben Derecki
Posts: 1926
Date Joined: 10/10/07
Starter?
http://www.fish.wa.gov.au/Documents/research_reports/frr191.pdf
crasny1
Posts: 6986
Date Joined: 16/10/08
Why havent a formal study been done in WA?
That I am aware off. Im not talking tag recaptures. It would be interesting for fisheries to "hire" the submarine escape training facility on Garden Island or similar deep structure and do some formal scientific studies. Obviously not easy to do but proof like this would make me feel alot better about C&R.
I do think no size but bag limit would be a fantastic idea. I personally dont like the idea of trying to De-barotrauma a dhu, even with release weight. Problem would be if you caught one off those very pretty but very small juvy Dhu's. Hardly worth keeping them!!!
"I would like to die on Mars. Just not on impact!!" _ Elon Musk
Seaquest
Posts: 1132
Date Joined: 22/10/09
A study has been done but
A study has been done but its methods were debatable. Read the above documents that Ben has posted. Cages where used to keep the dhuies in after release. Some people believe the cages had more to do with the bad survival rate than the barotrauma.
I personally hardly ever use a release weight to release fish. If the processes of catching and releasing is done correctly most fish will swim out of your hands by themselves. I think more education is needed in the releasing of dhuies. There is more to it than just sending them back down on a release weight.
Toby Roe
Posts: 118
Date Joined: 01/02/10
If you are worried about
If you are worried about C&R deaths you could always come spearfishing! Zero bycatch
crasny1
Posts: 6986
Date Joined: 16/10/08
Use to Toby
But a confrontation with a Great White that chased me on a wave windsurfing board and tried to bite it spooked me. I dont want to become the flesh that was hanging from its top set of choppers. It certainly needed some dental floss!!!
"I would like to die on Mars. Just not on impact!!" _ Elon Musk
randall df223
Posts: 6454
Date Joined: 08/08/11
How do you measure the size
How do you measure the size of a fish when its metres away underwater being viewed though a light refracting mask , before you put a spear through it? And I'm not taking the piss, I really have often wondered about that?
Fish! HARD!
Toby Roe
Posts: 118
Date Joined: 01/02/10
Randall,Just err on the side
Randall,
Just err on the side of caution. You would normally start spearing smaller easier fish like flatheads etc. and so can get a pretty good feel. The good thing about spearing is that you can C&R a fish without disturbing it and I much prefer to return from a day out spearing with no fish than line fishing.
Sulo
Posts: 256
Date Joined: 13/08/11
The NT study and the WA study
The NT study and the WA study were certainly more akin to fish torture than survival research.
There is some more GOOD research coming out of NSW, (pinkies and mulloway) I have read it however it is not publicly available yet unfortunately. The author did just send me a copy of some research from QLD which was done on what would have to be the WA Dhufishes closest relative, the pearl perch. Here is an abstract from the paper, however having just read the paper they did use cages however it seems with greater success than previous researchers (WA) due to the sizing... 1.9m compared to 0.75m.
Post-release survival of line-caught pearl perch (Glaucosoma scapulare) was assessed via field experiments where fish were angled using methods similar to those used by commercial, recreational and charter fishers. One hundred and eighty-three individuals were caught during four experiments, of which >91% survived up to three days post-capture. Hook location was found to be the best predictor of survival, with the survival of throat- or stomach-hooked pearl perch significantly (P < 0.05) lower than those hooked in either the mouth or lip. Post-release survival was similar for both legal (≥35 cm) and sub-legal (<35 cm) pearl perch, while those individuals showing no signs of barotrauma were more likely to survive in the short term. Examination of the swim bladders in the laboratory, combined with observations in the field, revealed that swim bladders rupture during ascent from depth allowing swim bladder gases to escape into the gut cavity. As angled fish approach the surface, the alimentary tract ruptures near the anus allowing swim bladder gases to escape the gut cavity. As a result, very few pearl perch exhibit barotrauma symptoms and no barotrauma mitigation strategies were recommended. The results of this study show that pearl perch are relatively resilient to catch-and-release suggesting that post-release mortality would not contribute significantly to total fishing mortality. We recommend the use of circle hooks, fished actively on tight lines, combined with minimal handling in order to maximise the post-release survival of pearl perch.
Taken from here http://dx.doi.org/10.1016/j.fishres.2013.12.005
Certainly the number of tagged recaptures of Dhu fish would suggest they do survive OK, as to whether people should be catching and releasing these fish from deeper waters for the pure hell of it I guess is a moral question that each angler needs to ask themselves. However having confidence that a released fish has a relatively good chance of survival is a bit more comforting for anyone releasing undersize fish, lets also face it with a boat limit of 2 there are plenty of times when legal specimens need to be returned also.
Personally I have had large Dhufish that I have considered dead at the side of the boat on a release weight going down to the bottom just about rip the release weight rod out of my hands once getting down to 30m.
randall df223
Posts: 6454
Date Joined: 08/08/11
Interesting.
Interesting.
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Batty
Posts: 348
Date Joined: 24/11/10
Releasing Barbel in the UK
When releasing Barbel, a very hard fighting river fish in England we were sometimes having to hold them for over 5-10 mins before they would recover. We learnt that after,the fight was over and the fish was in the net to leave it in the water for a minute or two to get its breath back, then after unhooking/ weighing photo etc they would swim away strongly.
This doesn't help with barotrauma but If your going to release your fish you'll find they have more strength. Imagine running 500m as if your life depended on it then stick your head in a bucket of water and see how you feel !!
Lifes a game but fishing is serious !!!
Sulo
Posts: 256
Date Joined: 13/08/11
With barotrauma the more time
With barotrauma the more time at the surface being held in a net or getting the release weight ready, photos etc the more likely the fish is going to die.
The old treatment for divers with barotrauma was to send them back down to depth as quickly as possible with as much air as possible. Disolving the bubbles back into the blood at depth and reducing pressure on organs as quickly as possible is the critical factor. Landing nets should be ready to go as should release weights and cameras if pics are required.
lame
Posts: 315
Date Joined: 20/01/10
old WA stats
http://www.recfishwest.org.au/images/PDF/Westag%20in%202012-13.pdf