Fish stocks to collapse within 50 yrs

[pjw200371]

GM, nuclear power, climate change, and just about every environmental issue under the sun have strong pro and anti cheer squads.

I even read an article recently suggesting the march of cane toads across NT may be beneficial.

Now if you were pro cane toad you'd use this research to boost your case, and ignore other research, done by other equally talented people that indicate they are an environmental catastrophe.

Sorry to bang on about this, but it's an important point and appears to have been missed.

Again two scientists can have x years in the field, written hundreds of papers, but still have completely opposing viewpoints. So quoting their individual, albeit perhaps extensive experience and knowledge is pointless.

Dr Starck, Dr Peperell, et al are featured prominantly on right-wing web sites, radio shows, etc. Other scientists who strongly support exclusion zones are featured prominantly on left-wing web sites, radio shows, etc. Both have many years experience in the field, both have flaws in their research, if you choose to examine it in detail (no research is unflawed, environmental science being worse than most fields). I choose to view both extremes with skepticsm.

Having said all that: I have read Dr Starck's paper on the GBR exclusion zones, and I actually agree with much of what he says. Basically he is saying that the anthropogenic pressures on the GBR (fishing, tourism, etc) are comparitively small. This is true. However, we were originally talking about Moreton Bay. In a sense Dr Starck's arguments could even be used to support exclusion zones in Moreton Bay, given that fishing, urban and tourism pressures are orders of magnitude higher in Moreton Bay. Someone mentioned the that using a Philippines study on an Australian issue (which I didn't actually do, but anyway) is like comparing apples and oranges, Well comparing GBR to Moreton Bay is like grapes and watermelons.

Anyhow, this is the last I'll say on the subject. I've tried to be polite so far and expect the same courtesy. I may have questioned the motives of Dr Starck, Dr Peperell et al, but this is no cause for offense: they're scientists and are quite used to criticism. If they are personal friends of yours, Billfisher, I apologise, but only on those grounds.

It's clear to me some people's minds are set, and will only recognise research that supports their view. Debate is therefore pointless. For myself, I'm open to debate (the fact that I agree with much of what Dr Starck has to say regarding the GBR should indicate this) and willingly read and assimilate papers from *both sides* of the debate, or better yet, unbiased sources. There's the key, I think. It's not about 'middle ground' or 'consensus', more about unbiased views.

One thing is for sure; more research is needed. Baseline data and before/after surveys would be good, though I suspect what the data may indicate (I could be wrong , if so I'll gladly accept it) moreover I suspect if the results oppose their point of view, they will be automatically rejected by the usual suspects.

[billfisher]

Again two scientists can have x years in the field, written hundreds of papers, but still have completely opposing viewpoints. So quoting their individual, albeit perhaps extensive experience and knowledge is pointless. Not really pointless. What you have to do is separate fact from opinion. Some scientists have strong preservationist beliefs and are so likely to advocate marine parks. Others are not likely to displease their funders. Its not pointless to look at all the arguments and research and assess the relevance, how rigorous they are and whether they are supported by other studies. Anglers have a lot of solid science on their side in their case against large scale closures.

Dr Starck, Dr Peperell, et al are featured prominantly on right-wing web sites, radio shows, etc. Other scientists who strongly support exclusion zones are featured prominantly on left-wing web sites, radio shows, etc. Both have many years experience in the field, both have flaws in their research, if you choose to examine it in detail (no research is unflawed, environmental science being worse than most fields). I choose to view both extremes with skepticsm.This sounds like you are politicising science - a dangerous thing to do and only clouds the issues. Anyway I have heard Dr Starck on ABC radio. The ABC is often accused of left wing bias or as being the publicity arm of the greenies! Another flaw in your analysis is that the GBRMP was introduced by the Howard Coalition government.

Having said all that: I have read Dr Starck's paper on the GBR exclusion zones, and I actually agree with much of what he says. Basically he is saying that the anthropogenic pressures on the GBR (fishing, tourism, etc) are comparitively small. This is true. However, we were originally talking about Moreton Bay. In a sense Dr Starck's arguments could even be used to support exclusion zones in Moreton Bay, given that fishing, urban and tourism pressures are orders of magnitude higher in Moreton Bay. Someone mentioned the that using a Philippines study on an Australian issue (which I didn't actually do, but anyway) is like comparing apples and oranges, Well comparing GBR to Moreton Bay is like grapes and watermelons.
Regarding Moreton Bay being near an urban area it is not exactly pristine whether it is made a marine park or not. Being near Brisbane it obviously an important recreational area and popular with anglers. How much sense does it make to heavily restrict angling. Here in NSW it is encouraged in such areas. Estuaries such as Botany Bay and Lake Macquarie have been declared recreational only. An angling license has paid for the buy out of professionals, fish stocking and improvements such as artificial reefs. These area have become even more popular with anglers (fishing up 20%). Has all this adversly affected fish stocks? DPI surveys show that anglers catch rates for popular species in Lakes Tuross and Macquarie have gone up 100-300% and average sizes are well up too.

[grahams]

Gary Russ and Terry Hughes versus Walter Starck.....Sounds like Australia playing Iceland at Cricket. We could also throw in Peter Doherty, Ian Poiner and Russell Reichelt in the middle order, and pad up a few community groups like reefcheck and Capreef as tailenders. Not all the team have the same view, but there's a hell of lot of information, monitoring and research to develop an informed opinion. Walter Starck is highly quoted because he is one of the few scientific voices in agreement with what one stakeholder group want to hear. Walter clearly believes his point of view, it just doesn't agree with the majority of scientific research, and before you call me green I'm a long term recreational fisher in the GBR.

[billfisher]

Grahams,

I don't know if you realise that the effect of greens zones on the GBR was studied for 14 years (the Mapstone Study). It was cited by the Park advocates as evidence for for benifits of green zones before they were expanded to 33%. Unfortunately the report was witheld from publication. Now that it has come to light it can be seen that a lot of its finding actually contradict the case for large green zones.

Here are some of the comments of Dr Ayling who has also made in depth studies of the reef. I suggests, Grahams, that you might be better off brushing up on your fishing teqhniques than claiming that the fish stocks have 'degraded'!

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."

[billfisher]

Faith-based science' and all that fish

By Jim Meek

ONE OF the world's leading fisheries scientists is taking on Dalhousie University's Boris Worm – the superstar ecologist who suggested last month that the world's major fish stocks could collapse by 2048.

Ray Hilborn told me that Worm and his co-authors erred in their Science article by using fish catches as an indicator of resource collapse. "… The idea of using catch data to reflect trends in stock abundance is terribly flawed."

A professor of fisheries management at the University of Washington in Seattle, Hilborn is the lead author of several research papers – including one written under the magisterial title "State of the World's Fisheries."

Hilborn zeroes in on a recovering stock, Georges Bank haddock, to make his point that you can't use catch records to determine species health. Worm's data would show this stock has "collapsed" because of low catches. But Hilborn says Georges Bank haddock is now at the "highest level of abundance in 40 years."

Then why are catches still so low? Hilborn says U.S. regulators continue to curtail the fishing effort in the area, "having learned their lesson from 30 years ago when catches were 10 times higher" and stocks collapsed.

Hilborn and a colleague also tested's Worm's data on fish species off California. "I extracted from the same database the fish stocks off of California. About one-third (120 stocks) were 'collapsed' by Worm's definition," he said. In fact, only a "handful" of those 120 stocks are in trouble.

Hilborn is not alone in his concern about what he has called "faith-based" ecological science. One Canadian scientist told me Worm's dire prophecy was "spurious" and "without merit" because it was based on fish catches, not fish biomass. (I did interview Worm this week, and will describe his views in this space on Dec. 14.)

The Worm-Hilborn story is now part of a simmering debate within the scientific community about the alleged decline of effective "peer review" in several articles published by the journals Science and Nature. Hilborn wrote in one publication that the "peer review process has totally failed and many of these papers are being published only because the editors and selected reviewers believe in the message, or because of their potential newsworthiness."

Let's face it: The collapse of world fisheries is big news – significant enough to capture the attention of The Economist, and to grab front-page headlines in The New York Times and The Washington Post. This has in turn pushed the recent, failed effort to ban trawling on the high seas.

But what if the doomsday prophets have been exaggerating since around 1993, when – according to Hilborn – peer review started taking second place to sensationalism? Steve Ralston, a senior fishery biologist with the National Oceanic and Atmospheric Administration (NOAA), recently told a California newspaper that this issue is being driven by "enviro-sensationalism" and "an increasing 'Chicken Little' response."

[billfisher]

(Continued).

Hilborn turns the volume down on the debate, usefully, in the paper "Moving to sustainability by learning from successful fisheries," which will be published by the Swedish journal Ambio. The paper tilts away from gloom and toward optimism, noting, for instance, that well-managed stocks sometimes recover – including Pacific sardines, the "icon of 1950s collapses." In addition, fish stocks offshore affluent nations, including the United States, New Zealand and Australia, are doing relatively well.
Fishers in many poorer nations, by contrast, are overfishing as a function of that very poverty. The best remedy for this "Malthusian overfishing" may be reducing poverty and providing economic alternatives, Hilborn suggests.

He also makes an argument that amounts to heresy in some environmental circles: Trawling is justified in some areas and may even have a beneficial effect on target species (notably shrimp). Hilborn, then, doesn't endorse a United Nations ban on high seas trawling.

Instead, he suggests a UN treaty that would model high seas fisheries management on successful national fisheries. Allowable harvests would be set by independent scientists. Fleets would pay fees for access, perhaps through competitive bidding. If fees don't cover management and research costs, fisheries would be closed. And any effort would be subject to 100 per cent satellite tracking and 100 per cent observer coverage.

Easier said than done, of course.

But modelling high seas harvests on successful national fisheries seems sensible to many observers – and far sounder than a blanket ban on a single gear type. The idea, after all, is to sustain a resource AND an industry.

( jmeek@herald.ca)

Jim Meek is a freelance writer in Halifax. He also works for Bristol Communications as editor of The Inside Out Report, a quarterly journal based on public opinion research.