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 Post subject: Fish mortality
PostPosted: Wed Sep 26, 2007 11:40 am 
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As above, I am looking for evidence, ideas and comments on the mortality figures in fish after a hard run.
Obviously very C&R!
Would appreciate info/data from our UK members where an exclusive C&R policy is followed...I dont think the land owner who spends hundreds of pounds on stocking carp would be happy with a high mortality rate??!!
How would these figures translate into our Indian scenario, WRT mahseer and carp?
Indian members with experience of C&R with mahseer-your inputs are very welcome.
Would the small minority of deaths after C&R in our Indian Mahseer, affect the general mahseer population?
Yes, please do toss in arcane words like anerobic , lactic acidosis etc.
Best
Axx


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 Post subject:
PostPosted: Wed Sep 26, 2007 1:32 pm 
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In recent years, there has been an increasing trend in the release of angled game fish by the recreational fishing sector. Many sport body impose the catch and release policy to protect the depleting stock of game fish. Angler throughout the world are finding the idea of catch and release fascinating enough to follow the trend and it has become common thing to see an angler shooting the fish (off course by a camera) rather than killing the fish after a great fight.

While some of this is due to the imposition of management measures such as minimum sizes and bag limits designed to reduce mortality on immature fish, there have also been an marked changing attitudes among sport anglers and sport body. Tagging program have contributed greatly to the education of fishermen relative to fish conservation and the importance of biological study. The angler that tags and releases fish now feels a sense of contributing to causes that will enhance the fishery. Discussions about numbers of fish tagged have slowly replaced those about numbers of fish killed among the sport fishing community.

In general, fish react to the acute stress of capture, severe exercise, and handling with more exaggerated disruptions to their physiology than those seen in higher vertebrates. Nearly all species of fish have a substantial proportion of their myotomal muscle mass (80%-95%) as anaerobic white swimming muscle which reflects an ability for high work output in short bursts. Angling practices cause increased anaerobic activity, muscular fatigue, and time out of water, resulting in marked respiratory and metabolic changes. Since fish blood comprises only 3%-6% of the body weight and white muscle over 30%, changes in muscle biochemistry will be reflected strongly by the composition of the blood Therefore, the changes in various hematological parameters relative to the degree of physical exhaustion can directly affect the general health of released fish.

But can the fish survive after it is released. Little is known of the mortality associated with the release of game fish. Evidence from different studies conducted using tag and recapture method are misleading and inconclusive as the low recapture rates of tagged fishes can be attributed to tag shedding, emigration, stock size, natural mortality, and reporting failure. still the mortality associated with angling stress cannot be discounted. Studies conducted on offshore fishes released after a fight by following the fishes using ultrasonic devices for eight hour minimum shows that all fishes survive completely the psychological effects due to stress related of fight.

As of my personal experience, only one fish was found dead after the release. It was handled very badly as it fell down while taking a photograph. That is why It becomes imperative to follow the laid down procedures while handling the fish and releasing it. If you want to release a fish follow the laid down procedures and release it immediately after revival. The maximum mortality happens only due to ignorant handling like tying the fish through the gills, keeping the fish out of water for long time while taking photographs and removing the slime accumulation over the fish body again by ignorant handling. Though not an expert on this subject, it is my belief that if properly handled, almost all fishes will survive after release.

Ali :lol:


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 Post subject:
PostPosted: Wed Sep 26, 2007 2:48 pm 
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angler_ali wrote:
The maximum mortality happens only due to ignorant handling like tying the fish through the gills, keeping the fish out of water for long time while taking photographs and removing the slime accumulation over the fish body again by ignorant handling.

Ali :lol:


I agree with Ali on this... from personal observation, I've noticd that it boils down to 2 things:

1) How is the fish handled

Handling a fish in a careless manner will kill the fish due to N number of reasons, ranging from slime rub off, scale damage to the cillia of the gills getting entagled...

2) The hook set pattern

I've noticed that with the predators, some times the lure/bait is swallowed compeletely and is next to impossible to get out with a plier.. basically the hook has lodged past the opperculum... the only way to get the hook out is surgery... unfortunately, the fish never recovers from this...

sometimes it will happen that the fish "throws up" and dislodges the hook itself after having been landed... in this case too, chances are high that it will not survive because more often than not, a major blood vessle gets punctured in the process and more than anything else, the fish dies of bleeding eve if properly handled...

I can't give any figures or scientific facts on this, but at the end, if point No. 1 can be taken care of, then the cances for them surviving improve a heck of a lot!!!


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 Post subject:
PostPosted: Wed Sep 26, 2007 3:35 pm 
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Any ichthyologists on board? need some serious thought on this....
Ali, whats your point of reference for:

"...Angling practices cause increased anaerobic activity, muscular fatigue, and time out of water, resulting in marked respiratory and metabolic changes. Since fish blood comprises only 3%-6% of the body weight and white muscle over 30%, changes in muscle biochemistry will be reflected strongly by the composition of the blood Therefore, the changes in various hematological parameters relative to the degree of physical exhaustion can directly affect the general health of released fish..."

Thanks all and keep it coming.
Best
Axx


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 Post subject:
PostPosted: Wed Sep 26, 2007 4:09 pm 
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Found an article on fish mortality
http://www.acuteangling.com/Reference/C&RMortality.html

another one which deals with rainbow trout
http://www.absc.usgs.gov/research/Fishe ... elease.htm


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 Post subject:
PostPosted: Wed Sep 26, 2007 4:46 pm 
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rulerofsun wrote:


aahhh... scientific evidence to back personal observation!!! :D :D :D


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 Post subject:
PostPosted: Wed Sep 26, 2007 5:53 pm 
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Great read, so all that we've been screaming for is substantiated. Now let's wait for more inputs...


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 Post subject:
PostPosted: Wed Sep 26, 2007 7:26 pm 
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Hi rulerofsun
Thanks for the articles, they were indeed informative. I have always used light tackle for the so called 'angling pleasur'. I think the points to learn from these articles are use of heavy tackle, artificial lures, use of circle hooks for carps etc, appropriate landing net, minimum time out of water and correct removal of hook/release back in water. I believe that fish caught with float fishing techniques have a better chance of survival as compared to bottom fishing. Moreover, early strike, even at the cost of losing a fish, may also prevent hookups deep insided the throat which can occur in a delayed strike. Thanks mate, i stand more educated on the subject.
Cheers
Sualeh


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 Post subject:
PostPosted: Thu Sep 27, 2007 2:44 am 
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The shear number of repeat captures of named carp in the British angling press would indicate a very high survival rate of carp following capture and release, so long as good fish handleing practices are followed. Some of these fish not only survive but appear to thrive with recorded weights steadily increasing over many years despite several captures each season.
Barbel seem to be equally robust if handled correctly and in fact, as with the carp record, the British barbel record was eclipsed by the same fish on at least three occasions.
These are propably the two nearest British analogues for mahseer so there's every reason to believe that a successfull catch and release fishery could be sustained.

On a more pessimistic note, the hotter climate and relatively low pace of rivers like the Cauvery in the dry season mean that there is limited disolved oxygen in the water and this might increase the mortality rate.

Some specis are also more prone to death following capure. In England, pike are known to respond badly to repeated capture. They can and do get caught again and again with good handleing but handleing by an inexperienced angler can easily result in the death of the fish.


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 Post subject:
PostPosted: Thu Sep 27, 2007 2:10 pm 
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eljefe wrote:
Any ichthyologists on board? need some serious thought on this....
Ali, whats your point of reference for:


Thanks all and keep it coming.
Best
Axx


N.E. Kohler, NMFS, NEFC, pers. comm.

Bayley and Prince 1994D. Rosenthal, NMFS, SEFC, pers. comm
eviews by Wood 1991 and Milligan 1996.

Driedzic and Hochachka 1978.

Wood 1991; Ferguson and Tufts 1992.

Wells et al. 1986.

regards,

Ali


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 Post subject:
PostPosted: Fri Sep 28, 2007 12:08 pm 
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After reading a few articles i have come to a conclusion :idea: . Try to hook the fish on the lip/cheek, don’t tire the fish so that when you land its belly up. If you want to release the fish make a quick landing and an even quicker release.

Barbed or non barbed don’t make much of a difference according to some reports. It all depends if the hook has gone past the gill or not. If the hook has gone past the gill then the chances of survival is remote.

Here are a few more links to help understand:

http://seagrant.gso.uri.edu/factsheets/ ... se_fs.html

http://seagrant.gso.uri.edu/factsheets/index.html


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 Post subject:
PostPosted: Fri Sep 28, 2007 1:17 pm 
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Guys what about the natural mortality rate of fish ?
I have read somewhere that the mortality rate of the male mahseer is much higher in comparison to the female after the fish attain maturity. Ken anything similar happening to the Carp or Barbel ?
Regards
Owen


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 Post subject:
PostPosted: Tue Oct 02, 2007 5:09 pm 
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I'm not aware that there is any significant difference in mortality rates between male and female fish.
There may be a case that some females are more susceptible to becoming egg bound and dying as a result, but not sure.

If you need any detailed questions answered, try a PM to redfin, if he doesn't know, or know someone who knows, then no one knows!


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 Post subject:
PostPosted: Fri Apr 04, 2008 2:56 pm 
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Location: Bangalore
I think like all living beings fish also deserve respect............................. In India anglers dont have the right equipment to hold the fish and keep it wet while taking pictures and thats when the fish die................and also many fish are injured while extracting the hook............people talk of barbless hooks. These hooks are ok but there are more chances of loosing the fish.......................................... I have experimented and I found that .......................a single fish will take the bait several times which goes to show that it is not that painful for the fish as we used to think, if properly handeled after the catch.


The reason that angling is so popular is that, even a person who is a vegetarian and follows non voilence can indulge in this sport :D



Tim


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 Post subject:
PostPosted: Fri Apr 04, 2008 3:05 pm 
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Hi Tim

Can we see some pictures of the equipment you use to hold the fish and keep it wet?

IA


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 Post subject:
PostPosted: Fri Apr 04, 2008 3:27 pm 
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Bops,


I dont have that equipment with me, it is a carp cradle or unhooking mat if im not wrong ............................................this is one equipmet which helps protect the fish.....and reduces the chances of the fish getting hurt.



Tim


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 Post subject:
PostPosted: Fri Apr 04, 2008 5:04 pm 
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Tim, you generalized in your earlier post that anglers in India don't have the right equipment to ensure safe catch and release, before making such a comment at least ensure that you are following the same methods that you suggest. Have you ever fished with barbless hooks?

You also mentioned that fish are lost by using barbless hooks. It's a lot better if you lose a fish on a barbless hook than a barbed one. At least the fish has a very good chance of getting rid of a barbless hook.


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 Post subject:
PostPosted: Fri Apr 04, 2008 5:40 pm 
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Its unsheated ...... ouch


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 Post subject:
PostPosted: Fri Apr 04, 2008 6:34 pm 
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Image

Image

timnorris

check this before opening your mouth regards Indians


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 Post subject:
PostPosted: Sat Apr 05, 2008 1:20 pm 
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I honestly beileve that one of the biggest killer of fishing related to angling is fishing with fresh or live bait. This resulting from swallowed hooks and not many anglers will admit to it.

You will only realize this when you fish in a closed environment, some place here where I take my kids to have a go. We are normally the first ones on the scene so I get to see the boat man taking out all the dead/floating fish from the surface where almost every single one has died from a swallowed hook.

I understand that wide gap hooks helps prevent hook swallowing so some extent. One of the main reasons I do not fish live bait for fish I intend to relase is because if this.


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