Soniferous Fish of SEQ

[Slider]

Can add queenfish, yellowtailed and black kingfish to the list of soniferous fish.

Greg, I'm no gamefisherman and I haven't heard of 'prey wash' - or is that the use of water being sprayed on the surface to keep pelagics on the chew?

Fishhunter, I've always believed the pen is mightier than the sword, but there are times ...

Bondy, I am speaking with a couple of marine scientists at UQ at the moment who are showing appropriate interest. Not many tailor being caught here at the moment, but I expect that to change fairly soon. That keg is still in the garage too.

Was pleasing to read research being conducted in Western Australia into yellowtailed kingies - the researchers were using hydrophones to assess spawning locations by listening for their 'mating calls'.

[bondy99]

Slider, good to hear.

I'm also at UQ, can you pm the marine scientists, I may know of them.

Send me your addy with phone number and I'll come up.
Cheers, bondy

[caster226]

every year since i joined this site you post the same old thing. always the same info about fish vocalisations. never really sourcing it to the people that actually did the various studies. presenting it as as though it could be your research. maybe drop the name of a few scientists you have emailed. then you make assumptions well beyond those studies that you present as fact. you ignore or attack anyone that disagrees. then fan the anti netter fires on your unproven guesswork. you then go on to try and sell your homemade lures. am i worng with where this is heading again. so which one of us has an agenda.

[Slider]

Everybody knows my agenda caster so there's not much point in trying to hide it.
I periodically write these things on Ausfish due to the fact that new members sign up here every day who have never heard this stuff before and who on learning about these things may become my allies in assisting me to alter inshore netting practices - sorry for that, but you don't have to read my posts. It is apparent that even long term members of this site find this material to be very interesting - and it is fascinating that fish behave the way they do.

If you think I am fabricating all of this, perhaps you could do some research of your own and check up on me - you have a computer. But I suspect that the content of the research papers would be above your level of understanding and your experience level is obviously such that you wouldn't be able to correlate that content with the things that people all around the world are noticing when they are fishing in netted areas. If you are as expert as you say you are, then I greatly doubt that you would be dismissing my assertions as readily as you are. And it is a bit hard to take you seriously when you can't offer anything at all that might bring into question these assertions. The reality is that nobody has yet been able to offer anything that realistically questions these assertions - for very good reasons. To say "that's bullshit", which is effectively all that has been presented so far, isn't really of any value to anyone.

So tell me, which part of what I am saying isn't right?

That fish vocalise alarm signals and release alarm chemicals?

That fish develop (learn) antipredator behaviour to any predator that might kill them?

That fish swim away from a predator that might kill them?

That schreckstoff causes fish to stay away from an area known to hold predators?

That nets are a fish's ultimate predator?

That fish populations bounce back when netting is banned in an area whilst rec fishing continues?

I can prove beyond reasonable doubt that all those things are indeed the case.

When I have completed my proposal for the creation of Rec Fishing Havens for Cooloola and Fraser and it is released for all to see, there will be references for every single piece of research that I quote. The paper I produce would be a worthless document without those references. You, caster, will have the opportunity then to offer whatever feedback you desire on the content of that proposal. So unless you can come up with something constructive to add to this thread as others are doing, then go and talk nonsense elsewhere.

[Slider]

Sorry Greg, I overlooked responding to the bit about shark pingers - was busy dealing with trivial matters.

To my way of thinking there is no reason at all why the pingers wouldn't be effective in repelling sharks and cetaceans and probably fish - though I don't know much about this scenario. It must have taken an awful lot of trial and error though to establish what sounds annoy the animals sufficiently to repel them. Especially when you consider that the Japanese very successfully draw dolphins into a certain bay by banging iron bars against the side of iron boats - you'd think that would annoy them. I suppose curiosity of the animal is a factor in that regard.

An interesting thing I saw repeated several times at Sandy Cape the other week that I can't recall seeing before - when a net was shot next to Breaksea Spit for whiting, a number of sharks of differing species would turn up 10 or 15 minutes later in feeding mode. They would head directly to where the net had been shot, but because the fish were either on the beach or the fish that hadn't been netted had bolted to the hills, there was nothing for them to feed on - though the hammerheads don't seem to mind the stingrays that aren't spooked by the net.
It would be likely and logical, that the sharks have heard the alarm vocalisations of the netted fish which has functioned as an attractant. Vibrations of the panicked fish in the net is probably also a factor. Similarly, when offshore fishing and a good red emperor is hooked (for example) the bronzies or tigers suddenly turn up to relieve you of the red. Always seems to be the reds they come for and it can be assumed that is due to vocalisations of the hooked fish and their preference for the species. They don't seem to like cobia as much despite cobes being very vocal and every pig fish seems to make it to the surface without any probs. Of course sharks are scavengers who don't mind a free feed and I strongly suspect that they are these days drawn to the sound of boats. They know that there will be chum and 'prone' fish available when they get there. I also think that this is a factor when the subject of shark populations comes up and boaties claim that there are heaps of sharks out there cause they always see them when fishing offshore.

[caster226]

im just spinning my wheels as you are never going to give straight answer. you just keep hiding behind other peoples research. the personal attacks i expected but i wont tolerate whats probably one of your cronies suggesting i be hunted down and assaulted. ive never claimed to be an expert on any subject in my life. in nearly 50 years of fishing both recreationally and a good portion of that was in the charter and tackle industry i have fished a lot of the coasts of west aussie qld and central and northern nsw. so yeah i have a bit of experince in a few fishing styles. but i guess that doesnt qualify me to answer any questions by your measure. so its time to take my bat ball and offensive posts and leave you with it. its not worth risking violence to try and share my knowledge.

[Slider]

Specify a straight question and I'll provide a straight answer. I would also like to know how I can 'hide' behind other people's research when I'm the one that is bringing it to the attention of everyone. If this helps - the other people whose research I am 'hiding' behind is that of the likes of - Brian Wisenden, Doug Chivers, Patrice Brehmer, Thomas Holmes, Mark McCormick, Milton Suboski, Maud Ferrari, Smith and Mowbray, Donald Baltz, Rodney Rountree, Culum Brown, Kurt Schaefer, Douglas Mann, Joseph Luczkovich, John hayes and Roger Young, Carl safina and Joanna Burger, Jan Smith, Mark Abrahams, Mary Louise Keefe, Mark Collins, and there are many more that I couldn't be bothered putting up. For a start caster, google Brian Wisenden and have a look at his research.

Btw - fishfeeder and I do not know each other and the statement that you would be 'risking violence to try and share my knowledge' is laughable - and I did laugh. Also, I don't have 'cronies' - I have many supporters who believe in what I do and have noticed the same things about nets that I have, or have seen the stock depletion first hand and are aware that something needs to be done about that soon - from Karumba to Cooktown to Cooloongatta. They know that my motivations are genuine, there are no hidden agendas, I aim to benefit recreational fishing and conservation of species is central to the whole deal. But you think caster that I have a vested interest somewhere don't you - what, may I ask do you believe that interest to be?

[Horse]

Caster226, you obviously do not agree with Lindsays point of view. Thats fine, its a free world but rather than snipe at a thread why not put your thoughts together and start a thread putting forward your opinions and the justification behind it.

[HeadBanger]

Ignore him, Slider. I am very much appreciating the information given here, and the more I read about it, the more and more interesting it becomes. And when looking back through the thread, the majority of posters are appreciating the information as well. Keep the info coming!

Cheers,
Kaidon

[NorthC]

Slider,

Very interested in your hypothesis for a variety of reasons.

But for the time being I am interested in your interpretation of how your hypothesis reconciles with annual migrations and feeding frenzies observed each year in south east Queensland (and many other places) where masses upon masses of pilchards and anchovies are balled up against the coastline and "lunched" on repeatedly by piscivorous predators over many days. This is an amazing spectacle, yet there is no obvious flight response or area abandonment by these species in reaction to this event. Based on your hypothesis, audible alarm and/or chemical alarm cues would be abundant and these bait fish should be fleeing these areas with some haste?

Thanks
Andrew

[FishHunter]

im just spinning my wheels as you are never going to give straight answer. you just keep hiding behind other peoples research. the personal attacks i expected but i wont tolerate whats probably one of your cronies suggesting i be hunted down and assaulted. ive never claimed to be an expert on any subject in my life. in nearly 50 years of fishing both recreationally and a good portion of that was in the charter and tackle industry i have fished a lot of the coasts of west aussie qld and central and northern nsw. so yeah i have a bit of experince in a few fishing styles. but i guess that doesnt qualify me to answer any questions by your measure. so its time to take my bat ball and offensive posts and leave you with it. its not worth risking violence to try and share my knowledge.

Caster I dont know slider from a bar of soap I was posting my reaction and feelings to people like you, deal with it.

[Slider]

My apologies to Fishfeeder - it was Fishhunter I meant in my last post. And thanks Fishhunter for helping to clarify.

Northc - thank you for raising that very good point and I'll do my best to provide an adequate response.

Antipredator behaviour by fishes is not a cut and dried case of abandonning a location as soon as a predator threatens. They would be in a constant state of avoidance behaviour if this was the case. 'Risk assessment' by the fish/school occurs - weighing up the benefits associated with avoidance vs the requirement for that fish/school to feed and breed. The pilchards or anchovy are generally inshore in large shoals for spawning purposes and to abandon the area altogether prior to fertilisation of eggs is of greater detriment to their species than to stay and POSSIBLY be eaten. In saying that, there is definite avoidance behaviour displayed by the baitfish when being predated upon by the pelagics and sharks. The individual fish within the school swim more tightly together and they move away from predators on a local scale as much as they possibly can. On completion of spawning - they're out of there.

The question should also be asked - how long does it take anchovy and pilchards to spawn?

It doesn't take days - is the answer. The reason why these schools appear to be present for days is that it is not the same fish schools that we are seeing each day. Just like many other species such as tailor for instance, schools will move into the same location to spawn as schools before them due to idyllic spawning conditions existing in that location, communication between schools that lets incoming schools know where they are and the benefits associated with having massive quantities of eggs and milt from different schools in the same location which creates maximum recruitment ability and across different gene pools.
Has anyone noticed that these spectacles of inshore baitfish shoals seems always to occur in calm conditions. This is due to the fact that calm conditions causes for there to be minimal current and minimal dispersal of eggs and milt.

And as opposed to nets which take out entire schools in one fell swoop, individual predators, even if in large numbers, will only make a proportionately small indent in the baitfish population - one pilchard/anchovy at a time - and will not prevent successful spawning as would a net. Fish species that have a life history of being netted, see nets as so much of a threat in this regard that they take extraordinary measures to avoid the threat that they have learned that nets pose.

The next question is - how do the pelagics and sharks know they are there?

As indicated by man's ability to attract fish (pelagics in particular) by the use of sound, the predatory species, as do the dolphins, listen for the vocalisations of their prey in order to locate them. If this wasn't the case, the predators would be wandering aimlessly around the ocean in the hope of locating prey which would be so inefficient as to render their species extinct. And the predators love it when the bait is shoaled up inshore as this provides them with the ability to herd them against the shoreline where they can't escape. The pilchards and anchovy don't really want to be in the surf zone as that isn't their choice of spawning location and renders them more vulnerable to predation. They want to be just offshore where currents are minimal and also wave action so as to provide the best possible chance of fertilisation occurring. They end up in the surf because the predators have herded them there which is an indication of avoidance measures in itself. But pelagics are mostly day time feeders and the anchovy and pilchards are mostly night time spawners, so they don't stay in the surf zone and do get their opportunity to spawn.
Of course, the audible and chemical alarm cues that are released by the pilchards/anchovy, acts as an attractant for more predators to arrive on the scene to predate on the bait. This is unfortunate for the baitfish, but this is the trade off that has evolved with the benefits associated with releasing alarm cues outweighing the negatives. However, the jury is still somewhat out on the evolution of alarm cues.

I'll make the point at this stage that it is becoming increasingly apparent that predatory species are not being drawn to spawning schools of anchovy and pilchards inshore as they used to. I have witnessed on several occasions in the last few years when massive shoals have been a stones throw from the beach for days but with no predators in attendance other than MAYBE a couple of sharks, a small school of small mac tuna/tailor or the odd dolphin. Whether this is due to netting or population depletion of the predatory species, I couldn't say. But it is cause for concern.

Now when nets are involved in targeting commercial quantities of fish, they are targeting spawning aggregations - as a rule. These fish, whilst taking extraordinary avoidance measures, must also assess risk. Therefore, they will avoid the area initially, but must arrive at a suitable spawning location quickly or waste the eggs and milt within. So when it would seem logical that they should head offshore for the term of their natural life in order to avoid the beach haulers, they can't, or recruitment would plummet to extinction levels. They must spawn inshore and that coincidentally (not) is where their predominant food source exists. Evolution over millions of years has seen this scenario and pretty well every other ecosystem dynamic, develop in similar fashions. So the species that are targeted by beach haulers will do their best to avoid the nets via learned predatory responses, but at the end of the day must revisit the inshore area where they are potentially vulnerable to "predators" in order to feed and breed. Mullet are a prime example of this situation in that they are demonstrating a tendency to leave the estuary in a directly offshore direction when they once turned immediately left on the eastern seaboard and right on the western. The mullet come back to shore at some point to the north of the estuary to spawn and this year it was more than 25km north after exiting the Noosa River.

However, it would seem that a species can arrive at a point of population decline through overfishing that they will actually alter their migrations to avoid the nets - which is what the mullet are trying unsuccessfully to do. Tailor have been demonstrating this behaviour for several years now with a demonstrated offshore migration that never used to occur. This is particularly the case with mature fish which of all species have demonstrated an earlier and more substantial flight/avoidance behaviour than smaller, younger fish due to learned predatory response. Offshore spawning results in serious ramifications to both the fertilisation of eggs in that spawning is occurring in locations less conducive to successful fertilisation and the ability of larvae to actually reach an estuary where they must spend the first 12 months of their lives. This means that smaller, younger fish become the predominant spawners inshore with the average size of tailor per age now known to be smaller than it once was resulting. This I suspect is caused by younger tailor having less robust eggs than mature tailor, though the actual reason is unknown.

'Risk assessment' is an aspect of research into chemical alarm signals with a number of papers dealing with this scenario with definite outcomes to the experiments in this regard conducted.

And we thought that they were all just gold fish swimming around and around. I think it is extraordinary that fish have these abilities and it has been one hell of a ride for me in discovering that this should be the case. I might point out that much of the above has never been written about before and are largely my own conclusions based on the existing related research into the various circumstances involved and my own observations.

[Slider]

I'll take this a step further because it's not just fish that are involved in this issue.

Every angler is aware that when searching for predatory fish, that to find the birds (terns, gannets) is to find the fish. The reason why this is true is due to the fact that the seabirds are entirely reliant on the predator fish to herd the baitfish to the ocean surface where they can be accessed by the terns, gannets, shearwaters, albatross, frigates, boobies etc. Without the predator fish the seabirds starve irrespective of how healthy baitfish stocks are. Terns in particular need the predator fish, because unlike gannets that can dive from heights and swim and catch prey in shallow/ish water, the terns don't dive and take their prey from the surface.
Terns tend to roost at river mouths where exposed sand banks and built up sand provide a suitable roosting location. Unfortunately for the terns, pretty well every river mouth in SEQ is netted from 400m to the north of the estuary. The netting causes area avoidance by the predator species which can be in tens of kilometres from the estuary mouth. This then requires the terns to fly greater distances to feed than they historically have had to. This compromises not only the ability of the terns to feed themselves, but also their ability to feed their chicks. This is not only due to the distance for them to reach the predatory fish, but also the fact that they can't feed multiple times per day and rest between fishing ventures due to the distance required for each fishing venture. For migratory terns that need to 'fatten up' prior to embarking on migrations to northern Asia, this loss of feeding ability causes greater mortality rates of terns during migrations.
Dolphins are also affected by netting for similar reasons. Dolphins that habitually inhabit inshore areas find that their food source is not always present inshore and are forced to move offshore or to wherever the prey species have gone. Turtles are dramatically affected due to their mating usually occurring in inshore areas and nesting of course on the beaches. These energy consuming activities require sustenance that is derived from fish that aren't necessarily where they are supposed to be.
So if netting in itself affects seabirds, dolphins and turtles, then netting in combination with fish stock depletion is a double whammy that inevitably leads to population declines irrespective of whatever other measures are put in place to reduce their mortality rates associated with commercial nets and shark nets.

[Slider]

This might be of some value from an angling perspective:

While chemical alarm cues are a trigger for conspecifics (same species as the fish emitting the alarm) and heterospecifics (other species that are preyed on by the same species) to avoid the area that they smell the chemical, that same chemical is naturally an attractant of natural predators of that species. So, if, for instance you are using lures to target barramundi, you could 'lace' the lure with a prey chemical to add to the efficiency of the lure. This could be done by perhaps adhering a piece of mullet skin to the lure or soaking the lure in a bucket that has dead and damaged mullet in it. These mullet would have to be freshly dead as the chemical has a 'shelf life' and the skin of the mullet must be damaged in order for the chemical to be most effective. It can be expected though that if soaking the lure, that the chemical would wash off the lure very quickly and it might be something that would need to be done prior to each cast. Plastics might be more effective in this regard, but it is up to the imagination as to how one could adapt this to a given circumstance and lure type. However, I must state that the killing of baitfish for this purpose alone is not something I can condone, but if the baitfish is used as bait as well, then I guess we'd all feel better about it.

Also, if using livies for bait, then to leave a bucket with holes in it with the livies in it, in the water beside the boat, would allow alarm vocalisations to penetrate the water and draw the barra to the area being fished. Similarly, the bucket (with holes) that has freshly dead and damaged mullet in it that is being used to soak the lure being used, was left in the water beside the boat, then the chemicals would penetrate into the water and also draw barra from downstream into the area being fished.

These methods of course can be adapted to suit the target species and the type of baits available.

Further, if you are using lures or bait and are catching fish, then it is possible that the chemical that is released by these fish during the fight can remain on the lure or hook/s. Therefore it might be adviseable to rinse the lure/hooks after each landing to ensure the chemical isn't still present on the next cast and consequently spook the fish you are trying to catch.

On lacing the lure with chemical alarm - another method of extracting the chemical for use at a later date would be to freeze the water that is in a bucket in which the baitfish have been damaged and thaw as required.

To give some idea of how much skin of the baitfish is needed to be effective in spooking or attracting - 1 square cm of skin can permeate 56000 litres of water and be detectable by fish and elicit a response. At that rate it easy to understand how a few tonne of damaged fish in a net can permeate the volumes of water required to spook fish over quite a large area.

[Slider]

In a similar vein, it has been demonstrated to work that putting a mobile phone in a waterproof container, dropping it over the side of the boat and making it ring, will attract reef fish. Perhaps an electric toothbrush would be a more cost effective method of achieving a similar result or even an aerator.