Catch and release – facts, figures and thoughts.
  |  First Published: May 2007

The ever-increasing fishing pressure on all of our waters has made catch release an extremely important aspect of angling. For starters, abiding by size and bag limits means that returning undersize or excess fish is something we all have to do at some stage. Many anglers also put back big breeding fish these days, preferring instead to use a camera to remember the catch. When releasing fish, it makes sense to do it properly and give the fish the best possible chance at survival.

When it comes to conservation and the catch and release ethic of today’s fishing, I subscribe to the theory that if you don’t want fish to get hurt or die, then simply….don’t go fishing! This does not mean I don’t care for the welfare of the fish I put back, because I bend over backwards to return fish in the best possible condition. If I do intend to keep a fish, I will despatch it swiftly and humanely. There’s absolutely no excuse for leaving fish flapping around the bottom of an empty esky or on hot sand. Yes I’ll take photos, measure, weigh and even tag them before release but I’ve always got the welfare of the fish as priority one. Here are some thoughts on handling and returning fish successfully - plus a few myth busters on mortality after release.

Moral contemplation

I’m a big fan of fillets on the plate. I’ve been eating fish for many years and will hopefully continue to do so for many more. I’m fussy about which species I’ll invite out to dinner though. In some of the larger systems I believe rod and reel has very little impact on fish numbers. These include, for example, small flathead in the Gippsland Lakes, Australian salmon from the many kilometres of Victorian surf beaches, and trout stocked into large impoundments. Other species are so common, like yellow eye mullet, flounder, garfish and possibly whiting, that it’s hard to imagine their numbers ever being threatened. These are the fish I like to see on the plate.

There are other species however, particularly in small and enclosed systems, that I refuse to kill because it would impact too much on that particular population. Other species I’m loath to kill simply because they represent way too much fun as a sportfish. As a consequence, estuary perch, bass, bream and big flathead never make their way into my kitchen intentionally.

Thankfully there’s a growing army of anglers who now also consider these fish too precious to catch just once or twice. Others adopt a self-imposed limit and restrict their bag for the table to what they consider a more sustainable take. The huge amount of snapper coming out of Port Phillip Bay will surely be heavily monitored over the next few seasons. I hope logic will prevail and that anglers will show restraint while snapper numbers are at an all time high. Whatever your moral outlook is, it’s nice to know that anglers these days are much more aware of fragile fish stocks and sustainable angling.


Before you consider releasing fish, it’s just as important to first think about the hook up. Lure-caught fish are mostly caught in the mouth. Especially with flattened barbs, extraction of the treble hooks from the mouth is easy. On the other hand, baitfishing can see hooks being swallowed deeper into the gut. In this case removing the hook will certainly kill the fish and the only option is to cut the line outside the mouth and release the fish with the hook still in place – after all, the hook is worth only a few cents and the survival rate of fish released in this way is still high.

Don’t believe any talk about fish ‘dissolving’ hooks overnight though, or even in a few days. It can take many weeks for even plain steel hooks to rust away, and many more months for fish to pass or dislodge stainless gear. Fish are amazingly hardy though and will cope with hooks stuck in all sorts of ugly parts of their insides!

I filleted a trout once that had been gut hooked, and was in the process of passing the hook through it’s stomach wall, out of the gut cavity and right out through the belly flap. I found the hook just below the skin, probably only weeks away from being totally ejected. I was able to follow scar tissue all the way back to the stomach. Incredible stuff and it proves fish do indeed get rid of hooks. It was also interesting to see the hook was starting to break down, but still quite intact.

While on the subject of hooks, research has shown that using larger hooks decreases the number of deep-hooked fish. It makes sense to use as large a hook as possible, at least up to the point where it starts to affect your hook-up rate. In addition, using some types of hooks, such as circle hooks, also reduces the number of deep hooked fish.

Lines and rigs

I believe in fishing heavier lines than most other anglers because I really hate busting fish off. To the amazement of many, I often fish 8kg breaking strain leaders when lurefishing for so-called ‘finicky’ bream. The main reason for this is that I fish snags a lot. I don’t even own lines under 3kg and I don’t believe my catch rates suffer one bit. I’m convinced that flathead, salmon, whiting, tailor, even trout or redfin and a whole host of other fish are not put off or spooked by heavier lines.

Is it really such great sport to slowly ‘play’ out a fish on super-light lines and needlessly stress and exhaust the fish before release? Even worse, it’s a shame to continually bust fish off and leave hooks and lures stuck in them, with any amount of line trailing out behind them. I believe we should land fish quickly and take all measures not to leave terminal gear jagged in their mouths. Besides, the more quickly you get a fish landed, the sooner you’ll be hooking another!

Often anglers talk with great excitement about being bust off, shredded, or even spooled by runaway monster fish. In reality the result for the fish is a sad one when you consider it then has to swim around with a lure or hook stuck in its gob and drag maybe 50 or even 100m of line around, possibly for months on end. If you use very light lines and tend to break off a lot of fish, try using much heavier rigs and leaders. I’m sure you won’t be disappointed. I think all anglers new or old to the game will be amazed at how they can increase their catch rate by even doubling their usual breaking strain lines. As an upshot, when the fish is released it will swim off in good condition.

Handling and releasing

Provided you handle them with wet hands or a damp cloth, it doesn’t do too much harm to remove fish from the water and take your time getting a good photo. Always strive to minimise the time fish are out of the water though, especially on hot days. Removing hooks while your catch is in a net or even still in the water is a good idea. Get used to holding fish safely and confidently because you will then find putting them back so much easier.

I often see people mistreating small fish by ripping out hooks and chucking them back in the water almost in disgust. There’s no excuse for harming fish before release and kicking them back into the drink, across dirt or off a jetty. It’s just plain irresponsible. Don’t forget that the joy of landing a really big catch is only because it has survived being a small fish itself, many years ago.

Mortality myths

Finally, a few facts on fish survival rates following release. I believe many anglers think that a lot of fish die after being returned, but the scientific evidence proves otherwise. Many studies over the last few years have shown a very high percentage of returned fish survive the rigors of catch and release. This is also the case with commercial fishers, where >95% of undersized bream caught in nets survive subsequent release.

In addition, the hugely successful recapture data for tagged fish is further evidence that letting your catch go is a worthy cause. In some cases individual fish have been recaptured up to three times. Incredibly, a few fish have even been caught again just a few hours after tagging. The record, however, goes to a tagged flathead that was caught again only fifteen minutes after release! So with that example, there’s hardly any more proof needed that catch and release can be a great success.




Fisheries researcher Simon Conron and his team from the Department of Primary Industries at Queenscliff have conducted numerous studies looking at survival rates of fish following capture by recreational anglers.

Two such studies involved a total of more than 430 bream caught by rod and line by anglers in the Glenelg River. Only bream between 15-25cm (i.e. undersize) were included in the study. Hooks used were Gamakatsu, chemically-sharpened, size 4 long shanks and bait was pipi or squid. Upon capture, anglers noted the hooking location and classified it as either lip/mouth or deep (throat/gills and oesophagus/gut). Lip-hooked bream had the hook removed, but deep hooked fish had the line cut at the mouth and the hook left in place. Bream were transferred to a temporary holding cage tethered to the anglers’ boat, then ultimately to moored holding tanks where they were held for 3 days.

Results showed that almost all bream (97-99%) that were hooked in the mouth survived the experience for at least 3 days (previous studies showed that virtually all mortality occurs within 3 days of capture). Some mortality of deep hooked bream did occur, but survival rates in this case were still high at nearly 80%.

Survival rates of line-caught black bream.

% surviving

Lip/mouth hooked

Deep hooked

Trial 1



Trial 2



Since a major factor influencing fish survival was the location of hooking, Simon and his team conducted a further study investigating factors that affected the proportion of deep hooked fish. Two experienced anglers fished for three days on the Glenelg River using a variety of hook sizes. They also fished two rods each, one in a rod holder with a slack line and one hand-held with a tight line. Hooks were again chemically-sharpened long shanks, and bait this time was pod worm. After each capture, anglers simply noted the position of hooking then released the fish.

Results showed that increasing hook size clearly decreased the proportion of deep-hooked fish because it was more difficult for the fish to swallow it deeply. Fishing with a tight line also significantly reduced deep hooks because it reduced the angler’s reaction time to a bite.

Percentage of black bream deep hooked.

Hook size

Fishing technique

Tight line

Slack line










Similarly high survival rates have been shown for Victorian snapper and NSW dusky flathead. The messages are clear:

For lip-hooked fish (at least those caught in shallow water where barotrauma is not experienced) almost all will survive being caught and released provided they are handled properly.

Even deep hooked fish have a high survival rate (nearly 80%) if released with the hook in place (do not try to remove the hook from deep hooked fish).

You can reduce the number of deep hooked fish by increasing hook size and fishing with a tight line.

- Martin Auldist




Avoid playing fish for extended periods of time.

Use larger hooks or patterns such as circle hooks to reduce gut hooking.

Rather than using high carbon steel or stainless steel hooks, use bronzed or nickel coated hooks as they degrade more quickly and are more likely to be removed by deep hooked fish.

Use barbless trebles on lures.

Use a knotless landing net to land fish (knots remove scales and protective slime from fish).

Use wet hands or a wet cloth to hold fish.

Minimise handling time as much as possible, especially on hot days.

Lay the fish on a cool wet surface to remove hooks or to measure.

Use long nosed pliers to remove mouth hooks only.

For deep hooked fish, do not try to remove the hook. Cut the line outside the mouth instead and release the fish with the hook still in place.

When photographing your fish, support its body from underneath rather than suspending it by the line.

Do not hold big fish vertically by the jaw.

Place fish gently back into water - do not just throw them back.

For fish that are fatigued it may be necessary to ‘swim’ them around to promote water flow over the gills. Holding their head into the current can achieve this too.






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