Never thought of it in that light Lucky Phil. If the green Zone are contributing, or reducing shark catch, its taken till now for it to be seen as a problem. I created a thread recently about shark numbers and it shocked me how widespread the problem is.
"let not he boast who puts his armor on, as he who takes it off"
Thats my point exactly Scalem. I believe its great to have places for people to fish. Especially inshore where the average family fisho can reach comfortably with his kids. The artis or wrecks i know have been consistantly producing for donkeys years. I think the bio mass can copeOriginally Posted by Scalem
"let not he boast who puts his armor on, as he who takes it off"
Interesting points of view about this old chestnut and a few things not yet considered. CPU (catch per unit of effort) for the reef fin fish commercial fleet has not improved since the GBR green zoning. On that basis alone this is a fail. The big issue, always dismissed by the RAP planners was all the evidence to the effect that for most reef fin fish species, the "spill-over effect" was a myth. The majority of target species, most particularly trout, red throat and nannygai do not "spillover". They are born and raised on a home reef and seldom migrate. This is demonstrated by a lot of evidence from various AIMS and GBRMPA studies including the long term papers of Mapstone et al. The conundrum is the direct link between "spawning recruitment" and "available habitat"...important terms. Just consider that the fastest way to get your grass to grow...is mow the lawn regularly. It is to a large degree the same with fish stocks. The fastest way to get fish to actively and successfully "recruit" is to put a stock under sufficient pressure to have plenty of "available habitat" (free suitable space and food supply). What has clearly happened in green zones...and I refer to offshore GBR zones, not inshore zones, is that reefs become "full" and fish stop "recruiting. You get a very stable population of big fish with little or no recruitment and little or no spill-over, and, at the same time, the open areas get put under increased pressure and perhaps, excessive pressure, and catches decline. There is clearly a case for zoning rotation (which won't happen due to green pressure) and there was and always was a case, supported by credible science for "split reef zoning" (50/50 green and open on the same reef to allow spill-over within the home range of a single reef and recruitment from the protected population of large fish, into the available habitat created by fishing take. Plenty of evidence that some species (NZ Snapper for example) do "spill-over" and this fishery benefits from green zones, just as there is evidence that removing some forms of commercial fishing, most particularly beam and otter board trawl improves fisheries and the rec fish havens in NSW are again testimony to this. The problem with the whole fisheries management regime is the mixed messages. Some decisions driven by credible science, some driven by political agendas which ignore science and some driven by the commercial lobby (bag limit on ribbon fish a case in point). All up no magic bullet and no quick fixes, all we could hope for is consistency and politicians of good will....as if!
KC
There are a host of issues being presented above. The big questions for me are related to the value of protected areas. In coral reef areas I can see value in closing off specific reefs if they are going to hold large populations of breeding size fish. Most coral reef fish spawning results in large numbers of pelagic eggs and larvae. This results in one reef being capable of seeding a number of reefs "downstream" up to hundreds of KMs away.
The building of artificial habitats is still a bit of a grey area. They definitely concentrate fish in one spot to make them easier to catch but many of the reefs being put in place in Queensland are primarily FADs rather than diverse and biologically sustainable areas. Dumping a barge load of gravel may be better for the overall fishery than sinking the barge itself. Maybe the solution is to fill the barge with substrate before sinking it.
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KC makes some very compelling arguments. I'm a big fan of rotating protected areas. Give the specific area time to regenerate before allowing fishing back in the area at the expense of the other area. I also like the same idea for inland rivers/creeks. Rotating creeks to give time for regeneration has to have positive results.
Democracy: Simply a system that allows the 51% to steal from the other 49%.
I think Horse has nailed it. I cant stand the thought of opening up green zones, fir the reasons he mentioned about spawning.
surely preservation of breeding fish is helping sustainability. And i dont think the commercial catch should be an indicator when discussing this. Co mercial fishing for trout is a pillage in my view,. And its proven to be unsustainable. Netting inshore is a decimating tool as well. The tonnage of fish taken in nets is unsustainable and the proof is how hard the average fisher has to work to even find fish. And before anyone thinks thats sour grapes, i personally do still catch barra around Cairns, but very few do.
"let not he boast who puts his armor on, as he who takes it off"
Odes carful with using the terms "pillage" and "unsustainable" without a bit of backup. To Horses issue about populations of breeding fish "seeding" downstream reefs, this is just not true. What the research suggests (not proves) is that a green reef with a stable population of big fish...just stop breeding. There is no natural trigger to encourage fish to spawn, so they don't. There is some evidence around this phenomenon in the northern banana prawn fishery, when the quotos were cut back to such a low level that the stock went for 2 years without a "spawning cycle" because of lack of available habitat. This is a natural trigger effect. This happens across the entire animal kingdom. In times of plenty, with plenty of feed and space, animals breed, during other times, with less space or feed, they don't. What the AIMS and Mapstone studies showed over many years is that fished reef have a higher population (albeit of a smaller size) than unfished reefs of trout and red throat. On to "Pillage" and "unsustainable"...the trout fishery is just about the perfect commercial model. They can only fish waters under 50 feet (due to mortality of fish all of more commercial value to the live trout trade) and stocks have easy access to the sanctuary of deeper water (where they are targeted by recs). No line fishery in the world is considered "unsustainable" and the numbers around the reef fin fish fishery (pre RAP) was that the combined recreational and commercial pressure accounted for approx. 3% of available biomass annually, as in of every 100 fish we collectively took 3 and the remaining 97 only had to reproduce those 3 at spawning to keep the population stable. This is I accept a simplistic argument as we don't spread our efforts across the entire biomass but the science of this fishery indicated it could stand 15% sustainabley. For discussions sake lets just say this 3% of available biomass was actually 10% of the actually targeted biomass, as in, the reefs we collectively actually fished (bear with me here) What has happened since RAP...if we consider the take has remained about the same and the areas of high fish density hard reef have been reduced by about 50% is that the take has automatically risen to 6% (or if we use the above assumption 20% and we are past the tripping point of sustainability) or there abouts and there is NO spill-over and NO recruitment or even spawning aggregations going on in green zones. See where this is going? Excessive pressure of the available stocks while a large part of the potential breeding stock think "everything is just dandy, so no need to spawn this year. There is science to back this up, papers buried in my achieves from another time and within the files of AIMS and GBRMPA, there may even be specific references to them in post I have done here years ago, when living a past life but I am over having the arguments any more. Did my bit and crashed rather than crashed through. The other chestnut to run up the flag pole is the imbalance the green zones seem to have caused. Fish populations out of what has been considered the natural kilter (sharks for example). So No, I think Green zones are a dud. A political zone, not a preservation zone. They have done nothing to enhance or even protect the fishery as a whole. Have damaged our food productivity as a nation and our employment opportunities into the future. And now, having blown the dust of my soap box, I'm going f%#@ fishin'
If lack of natural habitat suppresses spawning, why do fish readily spawn in an aquarium, even a crowded one? The biggest trigger, I suspect, is age. Every fish must age and die, and before it does, it needs to breed to keep up the population. Given maturity, sufficient health, and availability of a mate, I think that's what every fish will attempt.
Factors that determine the stable level of a population probably include food availability and number of predators. Another thing that occurs to me, is that if reefs never shared populations with other reefs, we would have different species on every reef. As the majority of species are found across wide areas, I think reefs must seed each other all the time.
Sorry back2boats, I should have been more specific...coral reef fin fish...trout & RTE are effected by this "available habitat" issue and they have not nor cannot be (at this stage) bred in captivity, even with chemical enhancement for this reason. certainly not the case with fish like barra and it is why I qualified my opening remarks that my issues are with off shore reef zoning, not inshore. I should also qualify my comment about "no line fishery being unsustainable". This should have read" single hook and hand line fishery". I am no fan of long-lines. I accept there is some minor movement between reefs, but not much (as supported by research). And you touched on food source and abundance as an issue, which it clearly is and this is not an issue in captivity as you can stock and feed in far higher density than in the wild. Anyhow...I hope a little food for thought and discussion. The boat is all loaded, forecast for tomorrow is 10 knots variable, tides are 2 days out of the neaps and I have a little reef in mind about 110k's out, well beyond the range of normal day boats so 2am in the morning I will be on the water. =)
KC
MM. Interesting KC
I am astounded there is science to prove no spill over on species like trout. ? The amount of trout I have caught on isolated bommies over a 12-24 mth period makes this a bit hard for me to believe. I should have totally fished them out by the indicators you speak of.
Also in reference to my terms pillage and unsustainable in reference to inshore barra fishing around Cairns. Can it not be possible that there would be more barra in this whole Trinity bay area year after year if netting was banned???
"let not he boast who puts his armor on, as he who takes it off"
The " spill-over " effect or lack thereof should be found on the Info-Fish website.
I will look for it over the coming days and post it up.
LP
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Fish, like humans can and do weird things, I remember in the 90's when on annual trips to North West Island there would be researchers who would generally be based at Heron but would often drop into NW, these would be various groups studying turtles (that was a most interesting experience from capture, to studying whether they were male/female -there is no way to identify them externally- to there final release), other groups studying fish habitats and movements. On one such occasion we were discussing coral trout and the researchers did say that they will move around an astounded us by telling of one that was tagged one morning and found on a reef 9kms away the next day, they couldn't say why this was so. This was unusual but then again fish can't read the rules.
The other item I remember was an article by I think it was Dr Julian Pepperell where he discussed the effects of only taking the bigger fish out of a school, (The article was in a fishing mag and I apologize in advance to Dr Pepperell if I got it wrong) if I recall it correctly, by consistently removing the larger fish from a school, the fish would as an evolutionary process breed smaller fish even when pressure is taken off them. Something to be said about upper limits as applied to a number of species.
I think he was saying it indicated it, not proved it. I also find it hard to believe. As I said, if no fish moved between reefs regularly, all reefs would have developed there own unique species (as happens in isolated islands (think Galapagos). If competition was hard, due to overpopulation on one reef, I am sure a trout would move next door to nearby reefs. I expect this would occur when they were young before establishing a territory, or after losing a territory in a battle.
It also makes sense that taking smaller fish adds to the normal attrition rate, which is already high, hence why fish spawn so many young at a time. The evolutionary response to this would be to increase the number of young at each spawning and to do it more often. The result might be more smaller fish available. I have a feeling this is an easier route than developing dwarf species.
Back from the reef. Smashing day. 5 knot variable and plenty of nice fish! Some good discussion going on here. I accept there is clearly "some" movement" across reef, but on the basis of the research, very little and it may well be just the big fish that move. From my experience almost all the trout caught in deep water (150 foot plus) are large fish. Maybe (as in a guess) these are fish being "squeezed out" of full reefs by lack of food supply but yes, wrecks, FAD's and isolated bommies do "restock". The volume of work undertaken by Mapstones team (and others) however (over some 7 years as I recall) shows little or no movement from a "home reef" (a bit like Hobbits). I don't think there are ever going to be hard and fast rules but we have the ability to at least know some of the answers. I do know that on green reefs, which were previously "open", sites of known spawning aggregations now don't actually have spawning aggregations?? I know one myself which a few of used to "hit" and always literally hundreds of trout. I have dived it as well during this time and it was amazing. In the last 2 years I have dived the same site (now a green zone) to see just normal activity. This is isolated and anecdotal but seems to support other papers I have read on the subject. I am old enough and was involved enough (and kept enough paperwork) to remember "them" telling us how great RAP was going to be...we would all be knee deep in fish, the commercial guys would catch more, everything would be rosy...sh!t I even remember 1 idiot environment minister telling us it would mitigate the effects of climate change. If one of the supposed outcomes of RAP was better fishing, then it has failed. I remain of a belief that it was a political fix, in fact I have confirmation from a very senior politician that it was a political fix, and not about conservation and NEVER about the benefit of the fishery as a whole. And with that I am back in my corner and planning my next fishing trip.
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