Notes on GBR Rezoning
23 July 2003
So called representative areas are being proposed without adequate surveys to determine if they are indeed representative and without sufficient regard to accommodation of existing patterns of usage. What is being zoned is substantially unknown1 and the effect on users given little consideration.
There has been little evaluation of existing green zones, no baseline studies made as a foundation for evaluating effectiveness of the new zones and no plan in place for surveys to monitor ongoing outcomes. Neither the effectiveness nor the consequences of the plan have been given due consideration2.
The plan does not address any threat that has been shown to exist or that is apparent in the foreseeable future. The only activity that will in fact be affected by the proposed changes is fishing and the following points should be noted:
1. No evidence of overfishing has been presented2.
2. The total commercial and recreational catch is only a very small fraction of what reefs are known to be capable of sustaining.3
3. Weather, distance and existing fisheries regulations already greatly restrict fishing.
4. Where line fishing is frequent fish become very wary and difficult to catch. Opinions of fishermen based on catches at popular fishing sites is not a reliable indicator of overfishing4.
5. There is no instance anywhere at anytime of line fishing severely depleting a fishery2, 5.
6. Extensive underwater surveys of coral trout (our most heavily fished species) show little difference between reefs closed to fishing and those which are fished6. The numbers in fact are higher in the southern more highly fished part of the reef than they are in the far north which has the least fishing.
7. DPI commercial catch statistics show no decline in either total catch or catch per boat per day as would be expected if overfishing were indeed the case7.
No take areas have proven effective only where fishing pressure is very high and breeding stocks have been reduced to low levels. Their benefit has not been demonstrated and would not be expected where substantial breeding stock is already widespread as on the GBR. The benefit from closed areas here is undemonstrated and unlikely. Wholesale adoption of closed zones without trial or evaluation under our conditions is unwarranted
The stated aim of preserving biodiversity is misleading. No threat to reef biodiversity that zoning would address has been indicated or is even suspected. No marine fish or invertebrate anywhere has ever been known to have been exterminated by humans. The heavily and destructively fished reefs of Indonesia and the Philippines in fact have maintained a biodiversity even higher than the GBR.
Complex zoning as a precautionary measure is at best dubious and may well increase risk rather than mitigate it. Future possibilities are infinite and largely unknown. Precaution can only reasonably be applied to recognizable problems with reasonable probability of becoming reality. No such problems have been identified that zoning would address. The chance an elaborate plan conceived largely in ignorance will be appropriate to preventing some unknown future problem involves worse odds than Lotto. On the other hand, concentrating existing fishing effort into a significantly smaller area with no consideration of the probable effect beforehand or plan in place to monitor it afterwards clearly does constitute a recognizable risk. It is moreover, a risk that could obviously be greatly reduced by a proper experimental approach involving trials and close monitoring before application on a large scale.
The only significant activity that will be affected by RAP will be to prohibit fishing in the green zones. No other existing or expected reef uses will be altered. Biodiversity and precautionary justifications are only rhetoric with no real effect on the reef or reef users other than fishermen. In the absence of any clearly indicated or defined detriment from current or foreseeable fishing practices and levels the proposed plan amounts to undeniable discrimination cloaked in an elaborate eco-scientific charade.
There is no crisis warranting rapid implementation of the RAP proposal and the plan will not be wasted if it’s implementation is delayed. It should be put on hold until proper evaluation and redrafting has been done and not used unless evidence of a need is apparent. Careful consideration also needs be given as to where and how the resources of GBRMPA should be focused including whether this should continue to be self determined or be subject to some form of oversight and accountability.
The following statement can be found on the GRRMPA website8: “Having the best available information for decision making is essential to high quality, scientifically based management of the Marine Park.” This is indeed essential and GBRMPA must be made to adhere to the principle in practice not just pay it lip service while building an ever more elaborate structure of regulations with no sound evidence of need or appropriateness and no attempt made to monitor or evaluate consequences or effectiveness.
Ph: 4724 5290
1 Various studies have repeatedly pointed out the inadequacy of present knowledge to properly access conditions on the GBR and recommended more comprehensive and consistent surveys and monitoring be initiated. Examples are Mapstone et al., 1998a:p. 1, Mapstone et al., 1998b:pp. 1& 47, and Mapstone et al., 1999:pp. 1& 30. The following quote from p.1 of Mapstone et al. 1999 is a telling summary.
“Closure of areas to destructive or extractive uses has gained increasing favour recently as a
strategy to achieve the conservation goals for marine environments. In most cases, however,
there has been neither the prior data nor the subsequent monitoring of area closures, and
comparable non-closed areas, to allow empirical evaluations of the area-closure management strategy. In 1975, the Great Barrier Reef Marine Park Act provided for the declaration of the Great Barrier Reef Marine Park and its management for conservation and multiple use. During the following 12 years, strategies of zoning areas of the Great Barrier Reef for different levels of use were implemented over the entire Marine Park. For none of the management sections of the Marine Park were systematic, purposeful surveys of reefs with different zoning status done at or prior to the implementation of the first term of zoning. The second zoning plan for the Cairns Section of the Marine Park came into effect in 1992. In this project we sought to gather comprehensive survey data on the status of reefs prior to the implementation of this as amended zoning plan in order to facilitate future assessments of its effectiveness.
We surveyed 50 reefs over the entire Cairns Section, including reefs with a history of closure to extractive uses such as fishing, reefs that had always been open to most uses, and reefs that were to have their zoning status changed under the as amended zoning plan. In so doing, we were also in a position to compare the status, in 1990-91, of reefs with different zoning histories, albeit in the absence of structured baseline data from before the then effective zoning period (1983-91). We surveyed six locations around the perimeter of each reef by well-established and tested underwater visual survey methods.
The results we present here do not indicate a clear, unequivocal set of patterns in abundances of several organisms related to zoning history or notional tourist use. For many taxa, no effects of either past zoning or tourist use were evident. For other taxa, the zoning-related patterns frequently depended on either where across the continental shelf we looked, on the habitat considered, or on the notional history of consistent tourist use. Patterns in abundances related to frequency of tourist use also varied with habitat, zoning status, or shelf position.
Apart from any logical considerations, our data suggest that there is only limited potential to infer effects of management strategies from simple one-off ‘before and after’ estimates of abundance or community structure. Considerable inter-annual variation in counts also suggest that simple paired surveys will be likely to produce large differences unrelated to effects of management strategy. Unequivocal inferences about the effectiveness of zoning strategies as management tools will require repeated measurements over extended periods at both managed and used reefs. Such a strategy specifically targeted at management strategy evaluation does not currently exist on the Great Barrier Reef. In the absence of such an explicit assessment and refinement approach, or formal and regular monitoring strategies targeted specifically at management strategy evaluation, interpretations of ‘status’ surveys of the type we have completed will be impaired by inadequate information and there will continue to be little empirical evidence from which to justify or refine existing management strategies.
(Highlighted text marked for emphasis by W.S. The repeated measurements recommended have not been implemented and the current rezoning plan is again being conducted largely in ignorance.)
2 Negatives cannot be logically proven but they can be disproved. Where allegation of insufficient or absent information is made it is incumbent upon GBRMPA to produce evidence to the contrary if they do not agree.
3 The current annual commercial catch of reef fishes from the GBR is about 4000 tonns and the recreational catch is estimated to be about 2000 tonns (from Williams, 2002: p.66 et seq.). With some 346,000 Km² of reef and lagoon area on the GBR the total annual catch comes to about 17 Kg per Km². Elsewhere, over a wide range of Pacific reefs, the average annual catch averages some 7700 Kg per Km² (Adams et al., 1996).
4 This is well known to fishermen and can be confirmed by numerous examples and observations of my own. Beinssen, 1989 in an unpublished report on GBRMPA funded research also states: “The catchability of many demersal fish species, notably coral trout and redthroat sweetlip, was found to be greatly decreased when their populations are subjected to fishing pressure.”
5 It is important to note that this only applies to line fisheries and the GBR reef fish fishery is only a line fishery. In a line fishery catchability (see 4 above) serves to limit overfishing.
6 The following is quoted in full from an undated web document by Dr. A. M. Ayling who has conducted extensive underwater surveys of coral trout populations over the entire GBR region. It may be seen at http://fastinternet.net.au/~rock/trout.htm
“Are Trout Overfished?
WHERE ARE ALL THE CORAL TROUT?
Or are coral trout numbers on the GBR being reduced by current levels of fishing?
Notes prepared by Dr. Tony Ayling, a private marine biological consultant not affiliated with any Government Department.
Over the past 14 years we have made extensive underwater surveys of coral trout numbers on several hundred reefs along the entire length of the Great Barrier Reef. This has included repeat surveys on some reefs over a period of more than 10 years to get some idea of the long term changes that have been taking place. We have also made counts on many of the protected reefs in the Marine Park to see if protecting them from fishing has made any difference to coral trout numbers.
We will look first at the effect of protection on coral trout numbers:
In 1986, we counted coral trout numbers on 12 reefs in the Capricorn-Bunker Group off Gladstone. Six of these reefs had been closed to fishing for an average of about 5 years, while the other six were open to fishing. Average coral trout density on the protected reefs was 57 per hectare (an hectare in an area of 100 x 100 metres), compared with 49 per hectare on the fished reefs. Although there appear to be about 15% fewer coral trout on the fished reefs, by using statistical techniques we can show that this difference is not significant as it may just have been due to the variability in the counts.
In 1991 we counted fish on a large number of reefs in the Cairns Section of the Marine Park (Dunk Island up to Lizard Island). Of these reefs, 29 were open to fishing and 18 had been closed to fishing for 7 years. Average coral trout density on the protected reefs was 33.9 fish per hectare compared to 34.6 per hectare on the fished reefs. Basically, coral trout numbers were the same on both groups of reefs.
In 1992 we made another set of counts in the Cairns Section, using five different closed reefs and five fished reefs. Once again there was no difference between the two groups of reefs, with 28.4 fish per hectare on the protected reefs and 27.8 on the fished reefs.
From these figures it is obvious that coral trout numbers have not increased on reefs that have been closed to fishing. What does this mean? There can be three different interpretations:
1. Coral trout may move around a lot between reefs, and so any extra fish on the protected reefs quickly move onto nearby open reefs and average out the numbers. However, tagging and movement studies show that while a very few coral trout do in fact move from one reef to another most of them stay on the same reef, and even on the same place of the same reef.
2. Closed reefs are not protected from fishing. It may be that fishermen are ignoring reef zoning and that enforcement levels are not high enough to prevent this happening. Recent analysis of vessel sightings by coast watch has indicated that there is probably a lot of fishing on reefs that are supposedly closed.
3. The current level of fishing on the GBR has no effect on coral trout numbers.
It is probably a combination of low effect of fishing on coral trout numbers, and illegal fishing on closed reefs, that is responsible for the lack of difference in coral trout numbers we have shown between closed and fished reefs.
If surveys on closed and fished reefs are not giving us a good idea of what is going on with coral trout numbers, perhaps the long-term counts we have done can give us a better picture.
We have counts from three reefs off Townsville (John Brewer, Lodestone and Davies) over the period from 1983 to 1994. These reefs are close to the coast and are fished by both recreational and commercial fishermen. In 1983 the average density of coral trout on these reefs was 34 per hectare, in 1989 it was 34.3 and in 1994 it was 66 per hectare.
In the Cairns Section we have counts from some reefs in 1983 and again in 1991. In 1983average density of coral trout was 22.5 per hectare and this had increased to 31.7 by 1991.
Off the Whitsundays, on the three reefs Hook, Line and Hardy, mean density of coral trout was 57 per hectare in 1984,84 in 1988 and 124 in 1994.
All these figures suggest that far from decreasing in numbers that has been a marked increase in the numbers of coral trout on the GBR over the past 10 years.
So why is it that a lot of fishermen are always talking about the good old days? Why is it that the general consensus is that there has been a drop in catch rates of coral trout over the past few decades? This apparent contradiction can be resolved if we separate catchability from numbers. Poor catches do not mean that the fish are not there, just that they are not taking the bait. Reported catch rates by commercial fishermen from experimental fishing done for scientists on protected reefs are three to four times those from fished reefs, in spite of the similar densities we have mentioned above. This indicates that naïve populations of coral trout, ie those that are not often fished, are far more catchable that exploited populations. Similar results were reported from Heron Island where catch rates were much higher on protected parts of the reef than in fished parts, but no significant density differences between the two areas could be found. It is often reported by fishermen that catches are good after a long spell of bad weather when fishing activities are restricted; the fish have become more naïve and more catchable.
Another way of looking at the effect of fishing on coral trout is to use the count figures we have from along the GBR to get some idea of the total number of trout out there, and compare this to the number taken by fishermen. The Marine Park Authority has listed about 2,500 reefs on the GBR but our counts on charts and maps of the reef area indicate that there are about 1,200 major reefs. Measurements from these maps show that the average major reef has about 500 hectares of reef slope where coral trout are common, and about 2,500 hectares of reef flat and lagoon where coral trout are not very common. Our density figures indicate that the average density of coral trout on the reef slope is about 50 per hectare, compared with about 10 per hectare in the lagoon and reef flat. Length estimations show that an average of half of these are over 38 cm long and able to be taken by fishermen. >From these figures we can calculate that there are about 30 million adult coral trout on the GBR.
These figures do not include inter-reef numbers of coral trout. There are large areas of broken ground between the true reefs that also support coral trout, and the true figure may be twice or more the 30 million we have calculated.
The Marine Park Authority and DPI have made recent estimates of the total annual catch of coral trout from the GBR of about 2 million kilograms, including both the recreational and commercial catch. Given the average size of coral trout this equates to about 3 million fish or only about 10% of the available stock.
We have also made counts of young coral trout on the reefs we have surveyed. By young coral trout I mean those that have resulted from the spawning season in the previous year. These figures show that an average of about 20% of the total coral trout on any reef are these young of the year (often called juveniles). Thus the annual input of young coral trout is equivalent to about 40% of the available stock, far higher than the annual catch of 10% of available stock.
In addition coral trout grow rapidly, the fastest growing individuals reach 30 cm long in about 12 months and most individuals are over 38 cm at the end of two years.
These figures are all rather approximate but they are based on actual records and probably give a good indication of what is happening in the fishery. On this basis it seems unlikely that the present exploitation levels of coral trout on the GBR are any threat to coral trout numbers. On the contrary is seems possible that numbers will increase, as some of our counts are already indicating.
Just remember: the number of fish that are caught does not relate to the number of fish that are there, but to how easy they are to catch.”
Ayling, 2000:p. 31 in a published report to the Queenslend Fish Management Authority again reports finding no effect of zoning on coral trout density.
7 Williams, 2002:p. 68
Adams, T.; Dalzell, P.; and Farman, R.
1996. Status of Pacific Island Coral Reef Fisheries. 8thInternational Coral Reef Symposium, Panama, 1996. pp.1-7
2000. Trends in Common Coral Trout Populations on the Great Barrier Reef. Rept. To the Queensland Fisheries Management Authority. 31 pp.
Undated. Are Trout Overfished? WHERE ARE ALL THE CORAL TROUT? Internet document at - http://fastinternet.net.au/~rock/trout.htm
1989. Heron Reef demersal reef fish movement study. Unpublished report to GBRMPA
Mapstone, B.D.: Ayling, A.M.: and Choat, J.H.
1998b. Scales and Magnitudes of Variation in Population Densities of Some Coral Reef Organisms Implications for the Design of Sampling and Monitoring Procedures. GBRMPA Research Publication 49, iv + 70 pp.
1998a. Habitat, Cross Shelf and Regional Patterns in the Distributions and Abundances of Some Coral Reef Organisms on the Northern Great Barrier Reef with Comment on the Implications for Future Monitoring. GBRMPA Research Publication 48, iv + 71 pp.
1999. A Visual Survey of Demersal Biota in the Cairns Section of the Great Barrier Reef Marine Park. GBRMPA Research Publication 60, iv + 42 pp.
2002. Queensland Fisher Resources, Current condition and recent trends 1988-2000. Qld. Dept. of Primary Industries, Information Series Q102012: pp.63-74