Abt's Golden Oportunity

[mystic shad]

We are all aware of the decline in fish stocks throughout the nation. We are all aware and agree on the damage done by professionals to our fish populations. I hope we are all aware of the damage that rec fishos have upon a fish population as well. Before anyone gets all defensive, I'm not blaming or pointing a finger.

Consider the facts, Our draconian size and limit regulations allow people to catch and kill all bream over 25cm. Common knowledge that the absence of maximum size limit nails your breeding stock. Some aren't aware that this also has a major impact on the genetic variation of your stock. Basically the gene pool slowly degrades to a gene puddle.

I've fished around middle harbour & cowan for 20 odd years. In middle harbours case, I've noticed the average size of bream getting smaller and smaller. ten years ago 35cm was a reasonably common size. Today, 30cm appears to be the average size.

Just like every species, there are bigger, smaller, faster growing slower growing etc, variations in a communities gene pool. By killing the 40cm bream. people have removed the gene stock that produces bream that grow quicker or grow bigger. hence we are left with a 30cm bream that may be 7 years old. The seven year old bream that is 35cm is no longer around cos he and his genetic qualities are locally extinct .

Have you stopped to wonder why nations like Australia and New Zealand produce

exceptional athletes, scientists and other field leaders. The two main reasons are 1, good food and clean environment 2, Genetic variation.

In your ancestors country of origin, they would have married within the same village or maybe the next village. The new colonies have people from very corner of the globe and as such a very deep gene pool or In other words basic hybridisation is occuring.

The ABT has a golden oportunity to improve the genetic variations of bream stock and in turn improve the tournaments future success. If the ABT were to freight the fish in the big fish tank from the clyde to say Batemans bay, there would be a great improvement to the genetic variation of batemans bream. The same for batemans bream going to the clyde. If this was supervised responsibly with suitable safe guards to ensure pests and disease were not spread. We would all see a major improvement in the size and quantity of fish we catch and release.

Your thoughts and opinions please

[Ken A]

Interesting post.

Whether or not the gene pool is being degraded depends entirely on the best spawning size of the Bream. Some fish like Jewfish for example produce their best results when they are around the 7 to 8 kilo mark & as they grow larger they don't spawn as well producing smaller quantities of less healthy juveniles. I am only aware of this as there was a study done by CSIRO. Taking big Jews apparently has little effect on Jew stock.

Maybe its the same with Bream? Do you have any information on Bream spawning ??

[allen glover]

The flaw in this scheme is that most fish spawn offshore and not in the estuaries!! Translocation may have a short term benefit to the stocked estuary at the loss to the supplying system but come migration season its all over red rover. Best off simply practicing C&R then leaving them in the system that they are balancing. Also I dont think the couple of hundred fish taken in an abt comp is going to have any big effect on anything.

[Pukka]

The ABT has a golden oportunity to improve the genetic variations of bream stock and in turn improve the tournaments future success. If the ABT were to freight the fish in the big fish tank from the clyde to say Batemans bay, there would be a great improvement to the genetic variation of batemans bream. The same for batemans bream going to the clyde. If this was supervised responsibly with suitable safe guards to ensure pests and disease were not spread. We would all see a major improvement in the size and quantity of fish we catch and release.

Your thoughts and opinions please

33968[/snapback]

Batemans Bay is at the mouth of the Clyde River????

Did you mean transporting fish from upriver in the Clyde to downstream (Batemans Bay), because that is what a lot of competitors did.

Pukk'

[Buz]

Somehow I don't think that abt bream would be healthy enough when released to do anygood anywhere.

The reef science tank system needs a major review/overhaul, the fish at the last two Aus Opens were in terrible trouble, I doubt many would have survived.

Buz

[mystic shad]

[batemans Bay is at the mouth of the Clyde River????

Did you mean transporting fish from upriver in the Clyde to downstream (Batemans Bay), because that is what a lot of competitors did.

Pukk'

I'm a dopey git. Sorry for the typo error. Not only does it expose my typing skills it completely debases my geographic knowledge as well.

I actually meant the Clarence river or somewhere at least 300kms away (taree).

The concept is to introduce yellowfin bream "love stuff" into foreign populations in order to increase genetic variation within local stock.

Kens point relating to size and age could be a contentious point. Consider the heights and sizes of boys at the age of sexual maturity. At 14 I remember being tackled by same age guys that had beards and muscles like the hulk.

It is quite possible that a 40cm bream be the same age as a 30cm bream.

Consider the biological facts.

There are many sub species of Homo sapien. Villages and tribes over the centuries bred within their own kind. Gradually the pedigree develops and the problems associated with "in"breeding.

Early civilisations without scientific knowledge regularily donated or kidnapped young breeding girls and boys for the benefit of hybridisation. As fish stocks decrease, so does the availability of genetic variation. Isolated populations evolve to make the most of their local area. When there is a change in the ecology, the over specialised organism will fail, whereas the mongrel species will adapt to the conditions.

Did you know that the reticulated python of south east asia will happily dine on a local villager. Fortunately for us, our genetic make up has endowed us with shoulders that are two broad for the snake to get his gob around.

As I sit in front of my computer screen. I am thinking of how man will evolve to suit the office environment. Consider the liklihood of people growing even biger bums, our eyes becoming boggled and square, our legs and arms becoming shorter and toes becoming redundant as we don't walk anywhere. It motivates me to go and weed the garden.

[Grantm]

Some good points there Mystic. I know with a lot of animals this is happening, German Sheppherd dogs are a great example. Because the larger dogs say over 40 kg are renowned for hip and elbow problems and also other arthritic conditions, breeders are choosing smaller dogs to breed with with no evidence of hip problems. Therefore the average dog being breed today is around the 35 kg mark and less dogs have hip probs. Agressive dogs are also not being breed which means there are less of these guys as well.

The point is that smaller dogs are breeding therefore smaller dogs are around now. Its the gene pool thing. There is probably hundreds of exapmles of this and I dont see why Bream are any different. The big ones need to go back and I hope one day they put a maximum size limit on.

Sad thing is c&r fisho's are still in the minority. Every time im at the ramp at Parsley Bay the is people cleaning monster fish and last weekend was no different. Saw a 1 meter lizzard on the table and a huge Bream 45 plus.

I like your theory Mystic dunno if relocating fish would work or not but its worth thinking about.

[OWZAT]

G`day Fellas ,

I read on The Fisheries site that the mortality rate of the Bream In the last two Oz opens were within reasonable levels , but flathead survival rates were a bit of a disaster.

But aren`t bream a migratory species anyway ?.

And as Alan Glover says , they spawn offshore , so one could reasonably assume that not all those fish would return to the same estuary , and if thats the case , then one might also reasonably assume that those fish that did not return , would probably head off in all directions , breeding with others in various estuaries etc.

Who`s to say that bream in the Manning would/would not/ breed with bream from the Hawkesburry / Clarence / Tweed / River.

Are bream , once established in a habitat ( new or otherwise ) territorial , and only breed with the locals ?.

Do they stay in the same system once they mature , or do they head off for greener pastures , as do we grey nomads ?.

I think Rex Hunt touched on this very subject some weeks ago , but having taped it to watch later on , I taped over it and did not get to see the full story.

Have fisheries Tagged bream from say Eden , and Found them in Ballina ?.

What are the migratory habits of these fish , and what is , and how was , the formula for the size limits achieved ??.

Interesting Thread , deep , but interesting .

Mick

Edited February 28, 2005 by OWZAT

[Ken A]

Its getting more than deep its getting silly.

[Matt]

But aren`t  bream a migratory species anyway ?.

And as Alan Glover says , they spawn offshore

The Yellowfin Bream do Mick, but I think the Blacks actually spawn up river in the brackish margins and dont actually move from their parent system? Anybody confirm this?

Cheers

Windy

[mystic shad]

Oh dear, here comes an epic.

I hear your opinion of sillyness ken. Nevertheless, discussions like this play a major role in species conservation and rehabilitation. I'm very proud to say that I was responsible for panda bear steaks being removed from the black stump menu!

I was having a yarn with Tim Morgan at the boat show last year. He mentioned that yellafin spawn at the mouths of the estuary. I can't remember what time of year. My Jedi Master said that heading into autumn is the usual time and they move to spawning sites on the full moon. He also mentioned that they have mini spawns around the full moon as well. This may explain the countless groups of 4 or 5 bream I noticed on the weekend. they were more content swimming closer to each other in what appeared to be a lambada like dance (serious) I rarely catch bream on the full moon. Nevertheless I still plug away at it.

With the utmost respect, I dispute Allen Glovers claim regarding long distance migration on the grounds that

1, estuary species that frequent close to coastal areas.

2, There is no need for them to venture much further than 1 estuary to the next.

The liklihood of sydney harbour sub species venturing to hawksbury is high but I doubt much further. Regardless, this would all depend on the prevailing seasonal currents.

3. Larger adult yellafin appear to take residence within a particular area. By that I don't mean 1 snag. They may visit the same snag daily during the tide flow then move to a hole later etc.

4. Considering the fish is very shy and has a strong desire to be in cover. Large migration would be folly.

5. I have seen very large schools of juveniles when diving close to the coast. a hundred or so 15cm bream with their faces rummaging through the gravel, with no regard for predators. Safe to assume that by the time they reach maturity, the population would be a handful. Personally I have never caught a bream from the ocean that exceeds 32cm. The muscletone and beautiful colour of an ocean bream speak for themselves.

6. They have quite a long lifespan. All creatures that have longevity are generally cunning, reclusive, and congregate in small communities. As such it would be quite rare to see all of an estuaries bream population gather for a giant orgy. Me thinks they are a little more discreet than the sexual antics of flathead.

My jedimaster also commented on the interhybridisation of blackbream to yellafin. this may explain the notion that some monsters rarely move around.

Perhaps we have 3 sub species of bream, Pure yellafin frequenting estuary and mouths to the sea. Silver bream that inhabits the coastline and visits the estuary on holidays. Black bream that are purely estuary only.

If this is the case then interhybridisation is certainly a possibility. That would then lead me to think that species like black bream could be easily bread into extinction by their ocean going cousins. NSW fisheries are considering doing research on this

I will copy this and send it to steve starling, he seems to know stuff.

[Ken A]

I hear your opinion of sillyness ken. Nevertheless, discussions like this play a major role in species conservation

Not on my site they don't. Jedimaster ? Panda Bear steaks on Black Stump menu's is a load of crap. Sub species of homo sapiens , 14 year old boys with beards !

Its a load of bullshit your carrying on with now.

The subject is bream try sticking to it.

[mystic shad]

Not on my site they don't. Jedimaster ? Panda Bear steaks on Black Stump menu's is a load of crap. Sub species of homo sapiens , 14 year old boys with beards !

Its a load of bullshit your carrying on with now.

The subject is bream try sticking to it.

34136[/snapback]

Point taken ken and I apologise for the panda bear steaks.

The Jedimaster is my fishing mentor who has the skill of arriving to the spot you've been plugging at all day and lands a monster on first cast. He's an old player who's taught me alot.

I should have said "clines" as oppposed "Sub species" of Homo sapien when i was trying to illustrate the physical modifications that occur to cope with differing environments.

I trust everyone remembers their days at high school. 14 year olds with beards sounds odd, however it's true. Some kids around the age of puberty grow much larger quicker and develop a mature body whilst many are still scrawny till 18. It's an excellent example of genetic variation.

I'm sorry for the lateral examples and if they offend. My attempts at explaining a point sometimes digress

[allen glover]

your point is flawed and simplistic

There's no evidence to say that bream populations are seperate and distinct . let alone the fact that there are simply no sub species or "clans"of bream to warrant your genetic mixing in the first place. Maybe your shrinking bream anectdote is a cause of feed availability or seasonal growth or the methods currently used attracting a smaller fish or angler abilites or pollution or commercial pressure all these are more valid arguements than a shallowing of the suposedly distinct gene pools.

Any fish that can be caught offshore is hardly exclusively esturine and thats what your arguement is based on the claim that bream dont/wont leave the system they were "born". Thats supposing again that Yfin are spawned in estuaries in the first place.

On the other hand though theres heaps of scientific and anecdotal evidence that both Yfin and black bream do annually migrate between systems . A whole commercial fishery is based around it!!!

Finally my point that the amount of positive effect that would result from translocatng fish caught by compeditors in the ABT would be so minute as to simply not justify the effort. 200 fish aint gonna make any difference. Why bother in the first place nature itself is doing it for us anyway .

Edited February 28, 2005 by allen glover

[mystic shad]

your point is flawed and simplistic

There's no evidence to say that bream populations are seperate and distinct . let alone the fact that there are simply no sub species or "clans"of bream to warrant your genetic mixing in the first place. Maybe your shrinking bream anectdote is a cause of feed availability or seasonal growth or the methods currently used attracting a smaller fish or angler abilites or pollution or commercial pressure all these are more valid arguements than a shallowing of the suposedly distinct gene pools.

Any fish that can be caught offshore is hardly exclusively esturine and thats what your arguement is based on the claim that bream dont/wont leave the system they were "born". Thats supposing again that Yfin are spawned in estuaries in the first place.

On the other hand though theres heaps of scientific and anecdotal evidence that both Yfin and black bream do annually migrate between systems . A whole commercial fishery is based around it!!!

fair points Allen.

However I never claimed that all bream are strictly estuarine. They do migrate to the offshore and coastal shoreline. But how far they migrate in the ocean is a little blurry. I have contacted a boffin who may be able to shed more light upon the subject. I relish in discussion and debate. By no means am I ever offended by anothers opinion or argument. The boffin has completed his thesis on the topic below. I hope he gets in contact with Kens website as I am sure we would have many other questions to pose.

Moore, A.S. 1998 Population structure of the yellowfin bream (Acanthopagrus australis) using mitochondrial DNA Analysis, Honours Thesis, School of Resource Science and Management, Southern Cross University.