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Nic
04-09-2008, 11:38 AM
I originally put this post in another section but I thought I would re-post it here, as it applies to both fresh and salt. It is in reference to whether large fish that are held vertically for a photo can die even after they swim away, apparently none the worse for the experience.

Bill Sawynok from Infofish says the DPI has performed a study on this. During the study, one set of large fish was held vertically and another set was held horizontally (these were barra, I believe). Then both groups of fish were released into holding tanks.

The mortality rate for vertically-held fish was 100%. X-rays showed that some had vertebrae that had come apart, and all had suffered significant internal damage. Surprisingly, the fish didn't die within hours or days -- it actually took several weeks for them to die. I hadn't expected that; presumably it takes a while for their damaged organs to eventually fail.

I guess these sort of injuries make sense really, as fish haven't evolved organs that can withstand the full brunt of their body weight, unbouyed by water. They have never needed to.

If your fish is too heavy for you to support with both hands, it can help if you sit down and bear some of the fish's weight on your lap. Alternatively you can hold the fish in the water and get your mate to take a photo from further up the boat. You see plenty of magazine photos of happy anglers holding large Murray cod, barra etc. in the water in that way. I reckon those kind of pics look great.

I'm sure many of you already hold your fish correctly, but if anyone would like more info there are some helpful tips here: http://www.info-fish.net/releasefish/

Cheers!

the gecko
04-09-2008, 12:15 PM
Thanks Nic, thats good research. I knew support was important, but I didnt know it was 100% mortality rate. So that means we should never weigh a fish by the jaw, unless we are gonna keep it? It doesnt look good for lipgrippers with built in scales.

Wetting down the brag mat is another good tip for improving release rates.

cheers
Andrew

Nic
04-09-2008, 12:26 PM
That's a good point about the brag mat Gecko.

Funny you should mention the lipgrips with in-built scales -- the fellow who imports Bogagrips actually feels pretty worried that people might be using it to weigh fish before release. He is keen for people to only use that function when the fish is to be kept.

My other half says he's seen a photo of a sling designed for weighing fish. It sounds pretty good to me. Does anybody know more about this?

Didley
04-09-2008, 12:33 PM
Nic, Great post, Thanks.
I don't weigh my fish but if I did, I'd zero the scales with the landing net attached and weigh in the net, saves handling the fish at all.

jim_bream
04-09-2008, 01:15 PM
Nic,
check either this month's BnB or Qld Fishing Monthly - I've seen it recently but just can't remember where! (Gettin olddddddd)
Jimbo

Nic
04-09-2008, 02:01 PM
Nic,
check either this month's BnB or Qld Fishing Monthly - I've seen it recently but just can't remember where! (Gettin olddddddd)
Jimbo

Ah yes, here it is -- p120 of the September issue of Qld Fishing Monthly. Thanks Jim!

The stretcher is a simple DIY job but looks pretty effective. Not a weighing tool but it still looks like a good handling tool for long and heavy fish. Here's a pic I dug up. :)

Scott nthQld
04-09-2008, 02:12 PM
even that sling could be easily modified to use with a scale, then you'd just subtract the weight of the sling. A few peices of heavy cord would do the trick.

samson
04-09-2008, 02:37 PM
People hype on about the damage it does which is correct as you can clearly hear vertibrae crack when fish are held vertically but they only talk about big fish as far as i'm concerned there is no difference between large or small fish held this way as organs,vertibra and gill latches are all proportionate to the size of fish making size irrellivent it just seems worse when holding heavier bigger specimens but i'm sure small fish suffer the same damage.

reidy
04-09-2008, 03:00 PM
Thats a very interesting point,never crossed my mind i must addmit but the logic is quite relevent heavy weight +gravity =dislocated vertebrae/broken spinal cord
Next time i think about lifting verticaly im going stop and have another look.
Top post
Cheers
Reidy

TonyM
04-09-2008, 03:51 PM
Thanks Nic,

It's always a worry to see big fish hanging by the lip, and it's fantastic to see the message is getting spread more and more nowadays.

The sling sounds like a good idea - the way these impoundment fish are going we're just about going to need a hoist fitted to the boat to lift them!

I agree that the photos of the fish in the water are great - probably the best bet once you've allready got a pic or two of big fish for bragging rights.

Cheers
Tony

fleety77
04-09-2008, 04:14 PM
cheers for the tip, will remember it if and when i catch a monster..........or any fish for that matter

DR
04-09-2008, 04:19 PM
Good stuff Nic..
i was told many years ago that this was a problem for fish, the example that was used was to look at old pics of sharks on gantrys held up by the tail, all their guts drops down near the head & sometimes actually has bits hanging out of their mouths. They are not meant to be in that position without water to support them..

SgBFish
04-09-2008, 04:30 PM
Nic that for that tip.

What is the current thinking on hook removal? For lip hooks I tend to remove but anything deeper into the fish I tend to cut the line as close to the hook as possible in the hope the fish dislodges it itself.

Is there any research on this topic.

Cheers,
Scott

Atriplex
04-09-2008, 04:46 PM
Very interesting. Thanks for that.

Presumably that would also mean that poling fish out of the water (lifting the fish up vertically with the fish still connected to the rod) would have the same effect. Along with lifting a fish vertically with a gaff.

Lucky_Phill
04-09-2008, 04:49 PM
Thanks Nic,

I read about this some time ago and it went into details and even stated ' growth ' lengths of fish lifted by the jaws, before and after. Amazing difference and was surely pointing towards the separation of vertebrae.

I am wondering, although am pretty sure, that this same effect will happen on Spottie mackerel. There are times when Spotties are in huge numbers and ' light gear ' is brought out to have some ' sport '. Bringing the fish on board, either by hauling them with the ' leader ' or a small gaff under the jaw, could probably have the same , vertebrae separating effect. I think my system will change to a landing net..... or " in water release ".

Cheers Phill

Nic
04-09-2008, 05:19 PM
What is the current thinking on hook removal? For lip hooks I tend to remove but anything deeper into the fish I tend to cut the line as close to the hook as possible in the hope the fish dislodges it itself.
Is there any research on this topic.


Good question... I remember reading a study investigating the mortality rates of lip-hooked and gut-hooked fish. The species they used was sand flathead and they experimented with net-caught fish, lip-hooked fish and gut-hooked fish.

I don't think any lip-hooked fish died; more fish died from being caught in a net and not hooked at all! Many fish hooked in the gills or gut died though, particularly in those cases where the hook caused bleeding. Not removing the hook did improve survival rates somewhat, but it still wasn't as good as those of lip-hooked fish.

The study strongly recommended using circle hooks, with angler surveys showing that catch rates on circles were just as high as those on J hooks. If you simply must use a conventional hook, the researchers said, at least keep the line tight to reduce the chances of the fish swallowing the hook.

I quite like using circle hooks myself, as they tend to be quick and easy to remove.

Hope this helps!

Nic

tunaticer
04-09-2008, 05:40 PM
Nic that for that tip.

What is the current thinking on hook removal? For lip hooks I tend to remove but anything deeper into the fish I tend to cut the line as close to the hook as possible in the hope the fish dislodges it itself.

Is there any research on this topic.

Cheers,
Scott

G'day Scott,

A few months ago I either watched a dvd or read in some fishing research documents about clipping lines close to hooks and survival rates.
They placed freshly caught snapper into a holding pen similar to what they use in SA for raising tuna in and compared results for both a close clip to the hook, leaving 150mm of leader material hanging from the mouth and removing the hook from the rear of the fishes mouth.

Results showed that leaving 6 inches of line hanging from the mouth of the fish resulted in almost all hooks being shed within a few days and a low mortality rate. Clipping lines close to the hooks let most hooks remain embedded in the mouth and after several weeks infection had taken hold and most fish died soon after. Removal of hooks was about a 50-50 affair.



On lifting fish and especially larger fish I believe that it is very dangerous to the fish in almost any manner. Fishes organs, blood vessels bone structure, muscle design all revolves around being nearly weightless in water. A fish laying on its side on the deck of a boat will have its attaching tissues being subjected to probably in excess of 50 times the mass that they normally will face underwater. At the very least its got to feel like badly pulled muscles to them as they lay on the deck, let alone being lifted unsupported.

Personally I remove the hook from any large fish i do not want to take whilst it is still in the water beside the boat. Failing that i cut the line leaving a good amount outside the mouth.

Jack.

the gecko
04-09-2008, 07:18 PM
I also read that study, they said leaving 6in of line out of the fishes mouth was better than leaving just a clipped hook in the gut.

Nic
04-09-2008, 08:50 PM
Thanks Tunaticer, I'll remember that. Do you know why it works?

Barrykrocker
05-09-2008, 01:14 AM
good info in this thread

jim_bream
05-09-2008, 07:45 AM
I always realease my fish in the water..... usually just as I'm about to slide the net under em or after I see it's going to be a PB!!!!

TonyM
05-09-2008, 08:14 AM
Thanks Tunaticer, I'll remember that. Do you know why it works?

My memory is a shocker, however I think it has something to do with the longer tag left on the hook means less chance of it getting in the way when the fish are feeding.

i.e. A shorter tag could obstruct them from swallowing food as it could get stuck halfway down.

Cheers
Tony

nigelr
05-09-2008, 09:56 AM
Thanks for an excellent, thought provoking post Nic.
Should be made a 'sticky' this one, I reckon.
Makes me glad that, at this point in my life at least, I'm not a 'sport' fisher............
Cheers.

the gecko
05-09-2008, 12:19 PM
Hi Nic,
Heres the full article on leaving a length of leader for gut hooks, that I copied from an american bass forum.It recommends leaving 18in of trace, if you cant remove the gut hook safely. This helps keep the hook from interfering with the fishes eating.

Hooks In or Out?
by Ralph Manns
"Getting the word out on hook removal. Those of us who try to share the findings of scientific study with non-scientists are often frustrated. It seems very difficult to get the word out. We write about some important discovery, but find anglers, particularly the influential professional bass anglers, either don't read the new information or dismiss the new scientific insights because they conflict with beliefs the anglers already hold.
Professional and TV anglers aren't the only ones to be slow in learning and applying the latest "word" from scientists. Biologists, particularly state fisheries workers are too busy with their own assigned tasks to read all of the literature produced by other scientists. They continue to advise anglers to handle fish using outmoded procedures.

The recommendation that anglers cut the leader close to the hook when bass are "deep-hooked" is a good example. It is hard to find a publication on catch-and-release (C&R) techniques that doesn't pass on this poor advice. Yet, recent research on release techniques strongly suggests there is a better way.

Some years ago, Doug Hannon noted that most magazine articles and state publications recommend leaving hooks in bass and other fish to "rust" out. He claimed that hooks don't rust fast enough, even in salt water; and suggested that the shank of a hook pointing up the throat of a bass acts like a lever or trap door that prevents swallowing. Bass can die of starvation while waiting for normal body processes to eject the hook. Food coming down a bass' throat will bypass a hook-shank, IF the shank lies tightly against the side of the throat where the barb is lodged. However, if the shank protrudes into the throat, food coming down can push the shank across the esophagus, blocking it. Deep-hooked bass may even feel pain as the food rotates the barb and regurgitate the food. Recently, Hannon's observations have been scientifically verified. John Foster, Recreational Fisheries Coordinator for the Maryland Department of Natural Resources, studied striped bass at Chesapeake Bay. His researchers held throat-hooked stripers between 16- and 28-inches long for observation in half-strength seawater so that hooks had ample opportunity to rust away. Size 1/0 and 2/0 stainless steel, bronzed, nickel, tin and tin-cadmium hooks were hooked in the top of each fish's esophagus, with an 18-inch length of line connected to the hook.

After four months, 78 percent of the hooks were still imbedded. Cadmium coated hooks poisoned 20 percent of the fish, and production of these hooks has been stopped. Bronzed hooks were less likely (70%) to be retained than tin-cadmium (80%), nickel (83%), or stainless steel (100%) hooks.

In a second test, the line was clipped at the eye of the hook, as advised by most existing C&R guides. One-hundred percent of the stainless hooks were again retained, while 56 percent of tin, 76 percent of bronze, 84 percent of tin-cadmium, and 88 percent of nickel hooks remained. Fish mortality was greater when all line was trimmed. Foster theorized that the lengths of line hanging from a fish's mouth kept the hook-shank flat against the side of the esophagus and allowed food to pass. Without the line, food could move the hook and close the throat.

Hooks rusted slowly in stages, and the bend and barb became smaller very gradually. Stripers formed scar tissue around imbedded hook points, a typical reaction of body tissue to foreign matter. Foster noted, however, that once the tough scar tissue formed, hooks became more, not less, difficult to remove. Months after fish were hooked, infections sometimes developed around points, causing some deaths.

Based on his research, Foster recommended anglers carefully remove even deeply imbedded hooks. If the hook can not be removed, then it seems better to leave about 18 inches of line attached. Perhaps, someday, these findings will reach C&R anglers, the biologists who are researching C&R and publish C&R guidelines, and TV anglers who teach by their example.

Another good idea is to carry strong wire-cutting pliers. Cur off protruding barbs in the throat and the hook shank falls free easily.

Texas researchers recently compared the mortality of largemouth bass hooked with live bait and artificial lures. Their main finding: "there is no biological justification to regulate use of live bait to catch bass" has been widely publicized. Other findings may help anglers make appropriate adjustments in technique.

In two separate tests, largemouth bass in a private water were landed by TPWD anglers using Carolina-rigged scented plastic worms, crankbaits with multiple treble hooks, and live carp fished with either a Carolina rig or a float. To simulate normal fishing conditions, anglers with different levels of expertise were used.

While fishing with floats, anglers were instructed to delay hooksets until floats went completely under, simulating the way typical amateur anglers fish with unattended rods. Under all other conditions, anglers were to strike immediately upon feeling a hit. Captured bass were immediately examined to identify hook-related injuries. When bass were hooked deep in the throat, the line was cut and hook left in place. (TPWD did not identify whether the cut was made in the traditional way near the hook, or with line remaining outside the fish's mouth.) Bass were then kept in a large holding net over a 72-hour observation period to determine short-term mortality rates. Sixty bass were taken using each method. Tests were made in August, when water was warm and stress and mortality are normally high.

The average mortality under these worst-case conditions was 22 percent. Carolina rigs with scented worms caused the highest mortality, followed by live carp used under floats, crankbaits, and Carolina-rigged carp minnows.

TPWD biologists concluded that the timing of the hookset appeared more critical than the type of bait used in the determination of short-term death rates. The data show bass hooked in the throat had poor survival odds. Evidently, largemouth bass took both lures and live bait fully into their mouths almost immediately. The bass pros' advice to strike without delay is important to reduce fish mortality. Angling techniques that delay hooksets should be avoided.

Carolina-rig and worm combos likely killed more fish because the loose-floating leader prevented immediate detection of some strikes and flavored worms are easily swallowed or held in the back of a bass' mouth. Eighteen percent of bass taken on rigs with worms were throat-hooked.

In contrast, Carolina rigs with live bait and live baits under floats caused less mortality, likely because live preyfish are often held in a bass' mouth for a few seconds, killed, and turned to be swallowed headfirst. This gives anglers a few seconds more to detect hits before baits are ingested. The decision to delay hits when live baits were used with floats and to strike immediately with Carolina-rigged baits likely caused the different mortality rates of these two techniques. Nevertheless, 10 percent of bass hooked on Carolina-rigged live baits were hooked in the esophagus.

It is no surprise that crankbaits are less likely to be swallowed, as their artificial nature is immediately detectable to fish. When fisheries are managed primarily for C&R or trophy bass production, it may be appropriate to ban use of multiple rods to reduce delayed hooksets, or to limit lures to items unlikely to be swallowed. In any case, C&R sportsmen will want to avoid techniques that delay hooksets, like fishing with unattended rods.

The TPWD study showed that bass hooked in the tongue and esophagus had about a 50 percent chance of dying, while bass hooked in the lips mouth, jaw, roof of mouth had 25 percent or less mortality. Interestingly, only 12.5 percent of gill hooked fish died. This finding suggests anglers who kill and eat or mount gill-damaged bass because "they are unlikely to live" are in error.

TPWD also compared the survival of bass when they were bleeding and when leaders were cut and hooks left in the fish. Removing hooks improved bass survival when bass were not bleeding. But there was little difference in mortality when bass were bleeding or hooks were left in the fish.

Anglers practicing C&R rather than to eat bass might note these findings. Fish caught with only superficial wounds are likely to survive release. Small, deeply-hooked and bleeding bass likely should be eaten, rather than released to die later. But lunker bass are so valuable that they should be immediately released, even if they are bleeding or deeply-hooked. Remove the hook if possible. Leave an 18-inch leader if you can not remove the hook."

cheers
Andrew

Ps- sorry to hijack your excellent post nic, I hope this is also interesting to some.

Nic
05-09-2008, 02:29 PM
That's excellent info Gecko, thank you!

I guess the lessons are:

- Try to strike quickly to avoid gut hooking fish
- If you do gut hook a fish, keep it and eat it - particularly if the hook has caused bleeding
- If you can't keep the fish, try to use wire cutters to snip off the barb
- If that's not feasible, leave 18" of leader hanging from the fish's mouth.

I reckon circle hooks are great to use as well, where possible, as they nearly always lip-hook the fish. We often use them to nose-rig jerkbaits on paternosters.

I didn't know it took so long for fish to shed embedded hooks. 83% of nickel hooks still embedded after four months isn't very encouraging. Still, I guess if we try to do everything else right, it's not likely we'll have to leave hooks in very often.

SgBFish
05-09-2008, 08:03 PM
That's excellent info Gecko, thank you!

I guess the lessons are:

- Try to strike quickly to avoid gut hooking fish
- If you do gut hook a fish, keep it and eat it - particularly if the hook has caused bleeding
- If you can't keep the fish, try to use wire cutters to snip off the barb
- If that's not feasible, leave 18" of leader hanging from the fish's mouth.

I reckon circle hooks are great to use as well, where possible, as they nearly always lip-hook the fish. We often use them to nose-rig jerkbaits on paternosters.

I didn't know it took so long for fish to shed embedded hooks. 83% of nickel hooks still embedded after four months isn't very encouraging. Still, I guess if we try to do everything else right, it's not likely we'll have to leave hooks in very often.

Nic, great summary.

I think this type of research is very important. I would have thought hooks rusted faster than that. There is alot to be said for putting more iron in hooks that the average punter uses and the promotion of circle hooks.

Scott

Colo77
05-09-2008, 08:16 PM
People hype on about the damage it does which is correct as you can clearly hear vertibrae crack when fish are held vertically but they only talk about big fish as far as i'm concerned there is no difference between large or small fish held this way as organs,vertibra and gill latches are all proportionate to the size of fish making size irrellivent it just seems worse when holding heavier bigger specimens but i'm sure small fish suffer the same damage.

I'm with you there. Any fish intended to be released be it a 100mm spangle perch or a 1300mm barra deserve the same handling practice. I cringe every time I see a fish held vertically.

As for hook removal, if it can't be removed relatively easily with a pair of pliers, cut it off & get that fish back in the drink where it belongs. buggering around with deep set hooks will only damage the fish in 1 way or another.

That's my 2c worth.

Cheers Colo

P.S. Good post Nic

Colo77
05-09-2008, 08:35 PM
Great info guys. My reply above was after reading only the first page of this post. But I've learnt few more great tips for fish friendly handling techniques.
Might have to keep a decent pair of side cutters in my tackle bag for future use.

Thanks again.

Colo

tunaticer
05-09-2008, 08:54 PM
Similar report to what I read/viewed Gecko. The one I came across was an Australian study involving snapper specifically and I think it was down in Spencer Gulf.

Results were very similar to these results though.

Jack.