Why Nets Ruin Recreational Fishing

[Slider]

It's quite simple really. As far as harvested fish are concerned, fishing nets are the most voracious predator in existence. Like any animal, fish avoid predators like their life depends on it. And like any animal, fish utilise any cues that provide information as to the whereabouts of this predator so that they can avoid it.
Sound is the most critical cue relied upon by the fish - sound of a fishing vessel or the sound the fishing gear makes, or the sounds being made by fish that are trapped in a net. Most fish vocalise and alarm vocalisations are the sound they make when trapped in a net or being pursued by a predator. A 'chorus' of alarm vocalisations made by a school of fish that is trapped in a net can travel tens of kilometres through the water at 5 times the speed of sound in air. Fish that hear such a chorus, flee the area and stay away from the region of the predator for a period of time. Quite understandable and logical really and just like a conventional predator - prey relationship.

I have witnessed tailor, mullet and dart flee a beach seine net containing only mullet that is 22kms away. I've witnessed the same thing multiple times with the net at varying distances up to 22kms. I have also witnessed mac and longtail tuna as well as spotted mackerel flee beach seine nets containing only mullet - not just a few fish, but every school of macs and tuna in Laguna Bay and within seconds of the mullet within the net showing signs of panic and quite obviously emitting alarm vocalisations. I have also been aware since the 70s that it is virtually impossible to catch fish when nets are active.

This phenomenon is not unique to any particular area. Fish flee nets no matter where in the world the net is. This is the reason why net free areas are so beneficial to recreational fishing. The lack of 'predator' cues associated with netting are an attraction to fish who can feed and breed without having to constantly adopt predator avoidance behaviour every time a net is shot in their region which is costly to their feeding and breeding pursuits and costly to the survival of their species. Increased growth rates and fecundity produces more and healthier offspring which spillover into netted regions and enhance commercial catches and increase CPUE of commercial fisheries.

The commercial sector are bitterly opposed to NFAs. But the reality is that NFAs are a benefit to commercial catches and to individual fisher viability over a longer term. Increased recreational catches as are being experienced in each of the 3 new Nth Qld NFAs, increases participation rates by local rec fishers and draws tourists from far and wide to experience the improved fishing ... as is already occurring in the 3 NQ NFAs. The environmental benefits are also substantial with seabirds, dolphins and sharks directly benefitting and a more balanced ecosystem having positive influences across the board.

Every rec fisher and any individual who cares about our marine environments should understand these facts and be demanding that governments deliver net free areas.

[Funchy]

A serious question. (and let me be clear, I am a rec fisho with conflicted views on commercial fishing but no great leaning one way or the other)

If the above is true then logically a commercial fisherman would have one net shot then either travel up to 22klms away to shoot another net or wait for the fleeing fish to return. Do you have any info on this?

Any commercial fisho's care to comment?

I only ask as I find it hard to believe commercial fishos would realistically make a living this way.

[Noelm]

Just like you have "witnessed" fish 22k away from a net running away from something, how about when Mullet crews have a haul of fish, and another school swims up the beach? That has been witnessed thousands of times, how exactly did you see a net 22k away? and then come to the conclusion, all these fish were fleeing from it?

[chris69]

May be the all the jet ski's running around are scareing the fish 22kms away,tell that theory to the salmond and herring netters in canada when all the boats are working in a group or what about a pack of sharks hearding a shcool of pillies on a beach the tuna and trevally feed right in with all the prediters you would think all the pillies would be sending out signals to alert all the other fish to stay away.

[Camhawk88]

Any journal articles to link regarding this phenomenon? Surely a major issue for fisheries management around the world so Im sure there would be significant literature on it?

[ShaneC]

Nice one slided rant mate. Got me buggered how year in, year out the fish turn up at the same places for months at a time.

You must have an amazing vantage point to witness such phenomenon. Are you an astronaut by any chance???

[Slider]

Funchy's question first - yes the netters know that they have spooked the fish when they net an area and several netters have told me as much. On Teewah Beach, for example, if a haul of mullet has been taken at the mouth of the Noosa and there are no further mullet schools about to exit the estuary to spawn (they know where the next school is in the river) they will drive at 80kph up the beach the next morning to D.I. or Rainbow to search because they know there won't be anything to net at the southern end. I used to do the same thing to try and get some fish before the pros arrived up there. One netter in particular who is now deceased, had licences to net the Noosa River and lakes (N1) a K8 to net Teewah Beach and another licence for Sandy Cape (now expired due to sunset clause). He worked the 4 areas on a cyclic basis, because every net fisher knows it is pointless to net the same area on sequential days.

Noelm - the mullet can exit the estuary to spawn at any time and be oblivious of previous nettings because they are upstream and netting can only occur a minimum of 400m north of the estuary mouth. They are not exposed to alarm signals. Even if they did receive the alarm signals, they have to exit the estuary to spawn and as every mullet fisher knows, they often hug the southern side of the estuary mouth because the mullet know of the danger to the north. This has led to fishers trying to herd the fish to the northern side of the mouth and to spotter planes to locate the schools that don't hug the northern side as they have historically done and might come in anywhere between Noosa and D.I. or even further north into the lagoon when it's formed.. The spotter planes could tell them where the school was coming into the surf. to spawn There is also the fact that the netters often only net a portion of large schools and the remainder continue northwards and remain vulnerable to netting. This has led to mullet netters teaming up so that they can shoot up to 5 or 6 nets to prevent fish fleeing, as I have repeatedly watched them do. The mullet don't just sit there waiting to be netted once the first net has been shot and if you knew anything about this situation then you would know that.
So in between mullet schools exiting the river to spawn, the netters seek out the fish (tailor, bream, tarwhine, goldens, dart) as they return to the surf after the previous netting and combined with the spawning mullet, they are/were able to net sufficient fish to make a living. The window for recs to catch fish returning to the surf is rarely longer than 48 hrs because the netters (and me) know that the fish are due back after a week or so ... well it used to be that way but not anymore because there are no fish left to return ..... to Teewah Beach at least
Because I fished every day for a hell of a lot of years, I switched on to the behaviour of spooked fish - the tailor would all of a sudden stop taking lures unexpectedly and could be seen swimming in only one direction (north or south) with other species and in a skittering manner which is highly unusual. Whenever the tailor stopped chewing and I saw skittering fish, I would drive along the beach in the opposite direction to that which the skittering fish were swimming. Every single time I would find a net on the beach with fish in it and my odometer would tell me the distance. Coincidentally, there would be no fish other than flathead caught by anyone for the following week. Happened every year for decades and not hard to work out what was going on.

Chris - the herded pilchards would emit alarm signals, but that would act as an attractant. That is how predatory fish, dolphins and sharks locate prey - they listen for it. Dolphins only use sonar when close to their prey because the fish stop audible communication when they hear dolphins. Dolphins stop audible communication when hunting close to their prey because the fish would hear them and flee if they didn't - all been studied and scientifically accepted.

Definitely a major issue for fisheries managers Camhawk and yes there has been a couple of studies related to it that are now apparently only in the memory of a few scientists. I saw one such study on the 7.30 report in relation to Pacific salmon in the 90s. Any amount of research into audible and chemical alarm signalling that tells us that if the fish didn't do what I am saying they do, then it would be very surprising indeed. I have an email from a FQ fishery biologist that states in effect that this phenomenon is occurring and Tony Ham at FQ stated to me that FQ had noticed the phenomenon in relation to Australian Salmon. He now denies that, but he knows the deal. I see that Sunfish are now stating that this phenomenon occurs also.

But seriously - why would fish not use the attributes that we know that they have and not try to avoid thousands of them being killed at a time. That simply defies ever single law of animal ecology in existence.

[Noelm]

While I am sure fish can, and do, warn each other somehow, and I am also pretty sure there will be some sort of "paper" that supports such claims (mainly written by some "green" with the mention of Sea birds and stuff) I think it is a fairly broad statement to suggest a net more than 20K away will see fish scattering in fear, by this reasoning, it would only be possible to catch one fish (by line) and when it warns the rest of the school, you will have move miles to catch another fish, wonder how things would go of the pros suggest they support net free zones, providing it also includes rec fishing too? Can't imagine it would be too well received.

[Noelm]

Jesus Slider, you are making some pretty rash "observations" there, I doubt if even a small percentage is fact, Tailor going off the bite, and driving up a beach to find a net, Mullet in rivers don't know about the nets because they are only allowed set distances from the entrance, yet they can get warned (and every other fish) for more than twenty Ks away.

[ShaneC]

Everybody who has fished has noticed a group of fish shut down. Happens constantly and for many, many reasons. You personally have an interest against commercial netting so you would naturally gravitate towards that as a simple reason for a bite to stop. I find it interesting that every time you saw fish skittering as you say in a certain direction you went driving up the beach to find a reason. You must have cracked up some kays mate as it would have happened every day you were fishing based on the fact that the netters work daily in season.

Now, and I say this purely because it makes sense. If this "phenomenon" as you describe it is real, why would you make it public knowledge?? Now the netters now where to go, somewhere within 22km away from their opposition so the fish "skitter" straight into their nets!! If you worked it out, they would have long ago and would have been doing it for decades as you say. But they dont.... You are having a lend of everyone with your own personal agendas and banging them up as fact

[Dignity]

No wonder I struggle to catch fish, somebody in the next boat has caught them and all other fish in the vicinity are avoiding my lines. My head hurts from all this information overload.

If this is what the pros have to put up with then they deserve to earn a better living.

[Camhawk88]

So that would be a no then? A study isnt worth much if it doesnt go through a peer review process and get published.
Physiological papers can tell us the sensory traits of a fish but it is a long bow to draw that because they have these sensors (tested in controlled conditions with minimal environmental interferences I'm betting) that they can explain your 'observations'.

Sorry mate, an email and a personal conversation doesnt cut it. I call bullshit.

[airlock]

now i'm not saying nets are a good thing for the fish stocks, but assuming fish warnings are as far reaching and effective as you claim then surly we wouldn't be able to pull more then one or two fish of a reef without them spooking the others, Netters would only be able to net one spot every 22k's and rotate these nets making for huge distances to travel with very little play off, it seems most of the netters don't encounter any such problems, and as we all know when the fish are on the chew you can pull them off the reef until your arms bleed regardless of long battles with the buggers.

I'd be far more worried about the removal of bait stocks in an area having a knock on effect on the areas ability to hold predatory fish for any length of time then i would be about the fish being spooked.

[robfish 1]

[QUOTE=Slider;1615819

I have witnessed tailor, mullet and dart flee a beach seine net containing only mullet that is 22kms away. I've witnessed the same thing multiple times with the net at varying distances up to 22kms. I have also witnessed mac and longtail tuna as well as spotted mackerel flee beach seine nets containing only mullet - not just a few fish, but every school of macs and tuna in Laguna Bay and within seconds of the mullet within the net showing signs of panic and quite obviously emitting alarm vocalisations. I have also been aware since the 70s that it is virtually impossible to catch fish when nets are active.

Chris - the herded pilchards would emit alarm signals, but that would act as an attractant. That is how predatory fish, dolphins and sharks locate prey - they listen for it. Dolphins only use sonar when close to their prey because the fish stop audible communication when they hear dolphins. Dolphins stop audible communication when hunting close to their prey because the fish would hear them and flee if they didn't - all been studied and scientifically accepted.

Bit of a contradiction in these two posts, Slider? On one hand you're telling us that ALL fish flee the distressed fish captured in a net, but then tell us that distress acts as an attractant to predators - are you saying that the distress of netted fish is somehow different to baitballed fish? And tailor, salmon and macks AREN"T predators?. Can't have it both ways. I'd venture to say that there's a lot of baseless assumptions in your first post, and confirmation bias makes up the balance.
I'd be happy to stand corrected, if you can point us to published papers on the topic. Until then, it's all just pish and wind from a disgruntled, fishless angler!
As a case in point, I can distinctly recall catching plenty of Snapper in PPB, when the netters were active within line of sight - surely they too, would have been swimming away in fear?

[Aussie123]

A copy of this post is going to the pool room