FISH BEHAVIOUR:

[CEO]

Fish Behaviour, is one of the topics to be explored on the ABC's CATALYST program, at 8pm THURSDAY 12 th April. Could be worth a look. Someone might like to post a summary for those who, like me, won't be able to see it, because of meeting commitments! If we can educate the fish, it will make them easier or harder to catch.

[CEO]

                                                     
                                                            WELL?  Who saw the show and what did you think of it?

[CEO]

FISH BEHAVIOUR:  Dr Graham Phillips presented the show and introduced Dr Culum Brown, (Macquarie University) a behavioural ecologist, as the "Fish Whisperer."
There are 32,000+, fish species across the world and we know little of their ecology or biology. Three quarters of the world's fish stocks are at risk of collapse from overfishing, claims Dr Graham Phillips, the presenter. 50 tonnes of fresh fish cross the floor of the Sydney Fish Market every day. So if we want fish in the future, we must give them a fighting chance.
  Dr Culum Brown, claims little fish in the school, learn from the bigger and older fish. He cited the Cod fishery of the North Atlantic, as an example. When that fishery collapsed, the younger, smaller Cod, lost the ability to migrate to one of their annual haunts.
  He is doing research with aquarium bred freshwater, Rainbow Fish, and claims fish have social lives and a rapid rate of learning. Also, fish reared in hatcheries, can be taught a response to predators, or a trawl net.
  Callum Brown asserts training fish, before releasing, is the key to their survival in the wild. Matt Taylor, (Mulloway Man) estimates 50% of the Mulloway fingerlings (80 - 150mm) he releases, die before reaching maturity.
  Brown claims trained Rainbow Fish can remember a learned response for up to one year. He says their responses come from watching and learning, which he calls "cultural learning." This "cultural learning," is lost however, if the big old fish, are taken out of the school.
                                                        YOUR COMMENTS & OBSERVATIONS ARE WELCOME.

[billfisher]

It gives credence to Dr Aylings obsevation on coral trout on the GBR and the concept of catchability. He found when closed reefs were open to fishing the trout were 4x easier to catch than on the fished reefs, even though underwater observations showed that there numbers were the same.

Most of us have seen this with fish swimming around a popular wharf that are almost impossible to catch, or the good catches to be had mid week or after prolonged periods of bad weather.

[CEO]

     THEORY:                Therefore the obvious tactic  is to fish with a different local bait or lure. I had a sensational Bass session this summer using an old green rubber Flopy! (1970's) My mate at the other end of the canoe, had much less success using a current subsurface lure, bright, shiny and vividly coloured. The same lure thousands of other Bass fishers would have been using last summer, because it was new on the market! My theory is that these Bass, to 2kg, had never seen a Flopy before. They hadn't "learned" about it. And I'm sure it was quite a "painless" experience for them! So, while it seems some fish may learn in a controlled environment, some fishers are even slower to learn! Just ask my mate!

[CEO]

  The notes on the ABC Show were compiled by my wife, while I was out.  So I apologise for any erorrs in transcription!

[CEO]

Did anyone catch the alleged problem with the Cod fishery in the Northern Hemisphere? Why they lost the ability to migrate and where to?

[CEO]

  Was this show a scientific comparison of apples and oranges? It seems they made a lot of untested inferences to me! What do others think?

[CEO]

 QUESTION:  Why do some fish swim in schools or shoals? This is a serious question, NOT a joke! What do you reckon? There must be a biological reason. Let's have your ideas and theories.

[CEO]

  AND why do the bait schools swim north? Ditto for the Sea Mullet schools, which are already schooling up in the estuaries, on the South Coast our members tell us. Any ideas, theories or fishy tales?

[billfisher]

I watched the show on fish behaviour. In the case of the Newfoundland Cod they were saying that too many larger fish were caught. Since juvenile fish learn their behaviour from the larger and older fish the collective memory of the species has been lost and the fish do not migrate to their old grounds.

Regarding schooling it does protect them from predation. There are other benefits as well such as increased reproductive success, helps fish find food (more eyes on the lookout) and makes swimming easier (less drag as each fish swims in the wake of the one ahead).

[CEO]

Now I know why our highways are so busy. Less drag! And I always found driving to Sydney a real drag! (Just joking!) Thanks Billfisher. Makes scientific and biological sense.

[The Rubber Grub]

Schooling fish, simply safety in numbers and reproduction, I thought this was common knowledge.  Fish in the middle of a school have less a chance of being eaten than those on the fringe.  Sure there are other benefits as mentioned in other replies.  Most times on the water I see evidence of this on the sounder.  Scattered bait suddenly ball or sit hard on the bottom and I get excited, sometimes disappointed when a seal or dolphin revels itself or like the other day when my mate landed the jew that scared the bait shitless.

I caught the show and note some cynicism (I may be wrong) in some of the replies below.  Yes, he used rainbow fish for the study, however I believe similar results would be obtained regardless of species.  Some years back I caught a doco on migratory birds raised by humans that had to be taught migrate, it was not innate to them. (I think this also transpired into a movie).  Same goes for hand raised animals, if to be released into the wild they need be taught to hunt.  Remove humans above the age of 18 from the world (along with all text, dvd's etc) and what kind of a world would we have in 20 years?  I suggest vastly different from what would have been otherwise.  I know I have learnt much from my elders.

Reproduction I feel is innate (no one taught me anyway), however, if we don't have the right area, location or for the female sex the right mood, we (most) don't drop our pants in public and do the naughty boy.  Do impoundment bass do the dirty despite not having the conditions to reproduce?  I know that they school at times when in the wild they would be doing the dirty.  Having never killed a fat female impoundment bass I don't know if they roe up, however, I believe they do having pulled smaller males from a deep school that have been spilling milt.  Though they don't reproduce as they don't have the right area / brackish conditions to do so.  It could be similar for the Newfoundland Cod not being in their breading grounds.

Cheers
TRG

Post script. My mate has just informed me that impoundment bass do roe up

[maniak]

Hello Rubber Grub,
                          I agree with your summation. In my experience working with Bass, yes they do roe up in impoundments and will also spawn in these impoundents however, if the water is not of suitable salinity levels the the eggs if fertilised will simply die.These particular fish were kept in saltwater ponds. It would be interesting if anyone has caught a roed bass in a freshwater impoundment. In other words Bass may not need saltwater to spawn but it is essiential for egg survival. This would seem to support the theory that Bass were originally a saltwater species which have adapted to the freshwater environment relatively recently on the evolutionery scale.
                      Bass could also be brought into roe and milt by manipulationg temperature and daylight length in an artificial environment ie temperature / light controlled coolrooms similiar to the way chickens are manipulated to achieve higher egg production.
Regards
Maniak