Dissected by Dr J Floor Anthoni (2003)
The recovery of a fishery within a closed area is not disputed and indeed the fact that this happens so quickly, proves that the damage done by fishing was little. Likewise, the benefit of a marine reserve cannot be expected to be large.There is no evidence of increased egg production translating into increased recruitment to fished populations, but such effects would be impossible to detect given the small proportions of coastline protected in reserves. There is some evidence that, in marine reserves, benthic soft bottom communities have responded to protection from direct effects of fishing such as trawling and dredging.
New Zealand has over 3000km2 (twenty times the area now in marine reserves) in cable ways and ammunition dumps which have enjoyed de-facto protection as no-fishing areas, but scientists never studied their benefit to fishing, recruitment and larval production. The public sees this as a serious omission. Where is the evidence of the claim that soft bottom communities inside reserves have 'responded'?More surprising have been the indirect responses of benthic reef communities to protection from fishing. Recovery of predators such as P.auratus and J.edwardsii has allowed urchin-dominated barrens areas to revert to more highly productive kelp forests. In this way reserves have allowed us novel insights into ecosystem function as well as the pervasiveness of indirect fishing effects.
The scientific work mentioned here is the most shoddy research produced in the recent quarter century and has been rebutted extensively as being no more than a myth, worse still, it is the indirect effect of environmental degradation. Why the author keeps hammering this shows how persistent a myth can be. On the Seafriends web site visit Science Exposed and our own study, Hauraki Gulf Marine Survey 1993. The fact is that the extensive kelpbed death of 1992/93 caused subsequent death of sea urchins and an invasion of their barrens by seaweeds. The same happened also outside the marine reserve in various locations, particularly at Little Barrier Island, some 20km away.New Zealand reserves offer no direct evidence of the often-touted spillover-related enhancement of fisheries yield. However, they also show that reserves do not “lock up ” fisheries resources and at least for J.edwardsii, CPUE (Catch Per Unit Effort), yield and costs are just the same adjacent to a reserve area as in open fishing areas nearby. Thus both conservation goals are achieved at no cost to the fishery. [oops!]
Spill-over from marine reserves is one of the main myths propagated by marine scientists. Those fishing the sea know it is not true because they have extensive knowledge of where the fish roams. The above statement therefore is very important, coming from a marine scientist and backed by scientific fact. However, the author is seriously mistaken claiming that reserves do not lock up fisheries resources. What about the lost fishery inside the reserve? When 20% of the sea is locked up this way, a similar part of the total fishery is lost for future generations. One does not need to be a rocket scientist to understand this. In the case of NZ, this would amount to over $200 million per year! How is it possible to claim the last sentence? Are scientists so naive?Despite advances in fisheries management structures in New Zealand, such as the Quota Management System, significant uncertainty remains about levels of stock abundance and catch rates. This is true even for New Zealand ’s best-studied stocks, such as P.auratus. Given that even the best fisheries management systems remain demonstrably less than perfect, it seems reasonable to try and guarantee some minimum level of stock abundance by putting in place marine reserves. On balance there is ample evidence to show that positive outcomes can be provided by reserves, and little or no support for suggestions that reserves will have negative effects for both conservation and fisheries.
It is known that fisheries management is less than perfect, as knowledge attempts to catch up with discoveries of new stocks. But the QMS is guided by sincere discussion and debate between commercial and recreational fishermen (which cannot be said of marine reserves). These are the people who stand to lose from fisheries collapses. By comparison, the existing marine reserves in New Zealand have an even worse track record of failure. At least two out of three of our coastal marine reserves have failed because they are degrading from bad to worse. They do not protect the marine environment. The fact that scientists have turned a blind eye to the sea's worst enemy, land based pollution, shows how myopic scientists can be and how irrelevant their research and statements in fact are, as is also evident from this paper.
|Key words: marine reserves, recovery, spillover, export, ecological baselines, displacement of effort, snapper, spiny lobster, trophic cascades|
The idea of marine reserves, marine parks or marine protected areas (areas of sea where some or all of the normal range of extractive activities are prohibited) has existed in one form or another since the mid twentieth century. However, the level of discussion surrounding this means of protecting the marine environment has increased remarkably since about 1990. This reflects increasing levels of general environmental awareness, the high profile of such marine protected areas as the Great Barrier Reef World Heritage Area, and the gradual recognition of the scope of human impacts (particularly fishing) on marine ecosystems (Pauly et al. 1998). The public debate among those who would like to retain the status quo (Lough 2002) and those who believe in the need for the rapid and widespread implementation of new approaches, such as marine reserves (Roberts and Hawkins 2000) has taken place at many levels. At one end of this spectrum of views are scientific institutions, such as American Association for the Advancement of Science which has promoted frequent articles in journals, such as Science, discussing the benefits of marine reserves (Schmidt 1997). At the other are community meetings and local print and electronic media around the world where concerned members of the public, conservation groups and a range of commercial and recreational fishing interest groups attempt to promote what they perceive as the merits or demerits of setting aside parts of the sea.
The world has over 1200 marine parks and reserves, of which more than two out of three have failed. There exists a clique of marine reserves scientists who push the idea of marine reserves too far beyond what these can do well. In their largely opiniated articles, not backed by scientific evidence, they exaggerate on the one hand the threats from fishing and on the other hand the benefits from marine reserves. They do not distinguish between bio-geographical areas (like what applies to NZ and when) and they do not acknowledge well managed fisheries. The above mentioned articles are typical. It is an indictment of science that organisations such as AAAS do not exert sufficient criticism to separate facts from myths and fallacies. Read for instance their consensus statements.Estimates of the proportion of the sea that needs to be protected in order to maintain ecosystem function as it is now, let alone restore it to former levels, range from 10% (Turpie et al. 2000) to over 50% (Lauck et al.1998). Consequently, there is a lot at stake and all sides involved are taking the issue seriously. Ironically, one of the very factors that may make marine reserves necessary, the difficulty of directly observing the state of marine environments, also increases the difficulty of establishing the facts about their level of effectiveness, and what proportion of marine habitats should be protected. The other reason that factual argument can be difficult in this emotive debate is that many communities have no marine reserves of their own. If such reserves do exist, they may be so new or so poorly studied that it is not clear whether they have been effective (Jones et al. 1992). In the absence of relevant information, debate surrounding marine reserves can become polarised and entrenched, more a matter of faith than anything else, with different groups promoting diametrically opposed conclusions about their effectiveness (Table 1). Facts can be the first casualty, and both sides are guilty of making claims that are poorly substantiated.
One of the main problems polarising those in favour and against, is familiarity with the sea. Whereas fishermen ply the sea on a daily basis, doing controlled scientific experiments several times a day (shooting a net, setting a line), most marine reserves articles originated from scientists with very little familiarity with the sea or its ecosystems. It has indeed become fashionable to use computer models rather than studying the sea. The table below substantiates this. Note how all myths are on the pro side, the side taken by marine scientists..
|•protect fished populations [false. Fish are protected only inside MRs. Migratory fish is unprotected. Most Commercial fish is migratory and unprotected]||•fail to protect fished populations [true. MRs fail to protect fish outside. They also fail to protect migratory fish. They fail to protect nearly any fished species]|
|•protect marine habitats [false. Marine habitats are not threatened. By far most marine species are not threatened. The effect of MRs on habitat is negligible.]||•increase impacts outside reserves [true, but this argument is unrelated to the one mentioned on left.]|
|•enhance fishing through ‘spillover ’ [false. It has repeatedly been proved, in NZ and elsewhere that spillover is much less than the lost fishery]||•lock up resources [true. The potential fishery inside MRs is lost and locked up forever]|
|•export eggs and larvae [false. When large predators develop, the total output of eggs and larvae from MRs decreases. Recruitment of commercial fish outside bears no or little relationship to the amounts of eggs produced inside MRs]||•impose extra costs [true. There is the real cost of the lost fishery, which amounts to hundreds of millions of dollars in lost export revenue, and there is the additional cost of administration and enforcement]|
|•provide baselines [false. Not a single MR out of 1200 worldwide has provided a baseline]||•be irrelevant due to existing effective fisheries management system [true. MRs do nothing for the fish outside, but fisheries management does. MRs do not change our ways.]|
|MRs are urgent. [false. The situation due to fishing is not getting worse, but the threat from landbased pollution is. MRs do not protect against this.]||MRs are not urgent. [true. We must focus on the main threat, land based pollution]|
|MRs are the only way to protect biodiversity [false. Fishing does not threaten biodiversity]||MRs do little for biodiversity [true. Most species are not harmed by fishing. Biodiversity is all about viable populations of all species.]|
The above table illustrates clearly how scientists have not bothered understanding what the 'anti-reserve' skepticists say. First of all, these are NOT against marine reserves, but they want them to work and not to fail like the many failed reserves in NZ. These people do NOT say that marine reserves fail to protect fished populations inside, but they say that marine reserves do not protect or improve the fishery outside or prevent it from collapsing or protect against the more serious risks of mass mortalities, poisonous plankton, oil spills, global climate change and ozone holes. Marine reserves do not protect the fish stocks outside but fisheries regulations do!In the Australian context, marine reserves are well represented in some areas such as the Great Barrier Reef, and evidence of their effectiveness in protecting exploited tropical species is beginning to emerge (Adams et al. 2000) [The GBMP was created in 1936. How long does it take to show benefits?]. However, there is still little direct experience of marine reserves in much of the rest of the country. This is particularly true in Australia’s temperate waters, with the exception of Tasmania where a range of fish and invertebrate species have been shown to increase in size and density as a result of protection (Edgar and Barrett 1997,1999). In general, the Tasmanian results show that the effects of protection are strongest in the largest reserve at Maria Island. Newly established marine reserves in Victoria are still too young to provide useful data, and networks of reserves in other parts of Australia are still in the planning stages. Consequently the New Zealand experience of marine reserves may provide much needed clarification for the Australian situation, allowing discussion to be directed in the most constructive directions. Examples similar to those found in New Zealand are available from around the world but this paper concentrates on New Zealand because of the many cultural and ecological similarities between the two countries.
Typically, Table1 shows on the left all the myths and on the right all the truths. What makes scientists so ignorant? See also Frequently Asked Questions in the marine reserves debate on this web site.
The oldest marine reserve in New Zealand (Cape Rodney to Okakari Pt
or Leigh Marine Reserve) was established in 1976, and New Zealand now has
17 marine reserves spread around much of the country. While some very large
reserves surround remote offshore islands, less than 0.1% of the coastal
zone surrounding the main North and South Island is protected. It is important
to remember that all marine reserves in New Zealand are fully “no-take”,
with no fishing or extraction of marine organisms. This is not true in
other parts of the world where Marine Parks or Marine Protected Areas (MPAs)
often offer no protection to marine flora or fauna, or protect only a limited
number of species or areas. Typical examples can be found in the Mediterranean,
where Francour et al. (2001) found that amateur and commercial fishing
was allowed in half the MPAs in the Mediterranean, and in Florida, where
99.5% of the Florida Keys Marine Sanctuary provided no protection for any
species (Bohnsack 1997).
Reserve Effects on fished populations
“Marine reserves are loved by the public. They think it increases abundancy [sic ] of fish. Science shows it doesn't, but the public believe[s] it does” (Lough 2002).
Despite the fact that marine reserves are now widely recognized as having positive effects on the abundance and biomass of species within their boundaries (Roberts and Hawkins 2000), a perception remains in some areas that marine reserves do not work and that we must still “prove they would enhance the preservation or sustainability of marine species” (New Zealand Fishing Council 2001). There is now abundant information from New Zealand that can help to clarify this matter.
Scientists concentrated on only a few exploited species while ignoring the fate of all others. In doing so, they did not notice the devastating effects of landbased pollution. What use is a medical checkup when your fatal cancer is not detected? What use is 'abundant information' when it fails to mention the most devastating threat to the sea? When will scientists acknowledge that more than two out of three of our coastal marine reserves are not working?
In northeastern New Zealand at the Leigh Marine Reserve (Fig.1; established 1976) the recovery of Spiny Lobster Jasus edwardsii populations was dramatic, and density increased from around 8 to over 20 J.edwardsii per 500 m-2 by 1983 (MacDiarmid and Breen 1992). Unfortunately, no measurements of J.edwardsii density were made outside the reserve until much later, but they confirmed that the increase in J.edwardsii was due to a cessation of fishing (Kelly et al. 2000). By 1995 the density of the J.edwardsii population inside the Leigh Reserve was 3.95 times that of adjacent fished areas (Babcock et al. 1999), while at the nearby Tawharanui Marine Park (established 1982) the number was approximately 1.6 times greater. At another reserve in the northeast region (Hahei Marine Reserve established 1992), the number of J.edwardsii was no greater inside than outside (Kelly 2000). However, the size of J.edwardsii was greater inside all three reserves.
Look carefully at Fig2 to notice how the crayfish population suddenly collapsed between 1995 and 2000. The precise date was June-Oct 1998 when an unusually long period of mud storms drove the crayfish out. The scientific community was informed of this but did not want to believe our observations. In fact, two independent groups of scientists were working with rocklobster while remaining oblivious to a sudden decrease of 85% in their numbers! Why do scientists repeatedly fail to mention this in their publications? The Marine Laboratory of the University of Auckland sits right above the marine reserve and scientists can see the quality of the water while drinking coffee!Based on these three marine reserves of differing ages, an average rate of increase of 7.4%yr-1 was estimated (Kelly et al. 2000). The history of recovery at Leigh suggests this would be a minimum (Fig.2) with numbers increasing by over 4.5 times between 1978 and 1983 (MacDiarmid and Breen 1992). In parts of the country, where J.edwardsii recruitment is high, such as along the east coast of the North Island, the rate of increase has been even higher, increasing by 6 times after just 4 years at Te Angiangi marine reserve (established 1997, Freeman and Duffy in prep). In the Tonga Island marine reserve (established 1993) in the northern South Island, J.edwardsii has also shown significant recovery (Davidson et al. 2002) but not all reserves have shown these increases. The Te Awaatu marine reserve (est. 1993) in Fiordland had not shown a significant increase in J.edwardsii numbers after 6 years of protection (Kelly 1999). Whether this was due to its size, the nature of the fiordland habitat, seasonal factors or the continuous decline of the surrounding fishery (Starr et al. 1997) is not clear. Certainly the North Island regions support stable fisheries.
For decades we have been fed the myth that crayfish densities inside the reserve amounted to over 20 times that outside, yet the above-mentioned factor of 4 is more realistic. Why have scientists been misinforming the public for so long? Recent publications now mention a factor of 1.6, commensurate with the situation after 1998. The main message is that marine reserves do not make a major difference and marine reserves do not protect against degradation.
The quoted crayfish recovery rate of 7.4% per year is another myth. Watch Fig2 for the course of a typical recovery, which levels out after a decade. This is for the Goat Island marine reserve which is endowed with an unusual amount of good crayfish habitat. The first decade saw 400% in 10 years, followed by 0% in the next ten years, and a collapse of 85% in one year. Where does that leave the quoted 7.4% per year? The recovery rate is not only dependent on the quality of the habitat but also on the state of the fishery. Generalizations are dangerous.
Fig.1. Map of New Zealand featuring key areas and marine reserves mentioned in the text. Detail shows northeastern New Zealand which has the highest density of reserves and where most of the work on marine reserves has been conducted. Not all reserves are marked on this map.
Recovery of spiny lobster population in the Leigh marine reserve. While
no data were collected prior to protection and were only sporadic until
the mid 1990’s the increase in density is most likely due to protection
and has been observed in other reserves around the North Island. The reason
for a substantial decrease in numbers at the Leigh reserve since 1995 is
not known but has not been observed at other reserves (e.g. Hahei). Data:
Ayling 1978, McDiarmid and Breen 1992, Kelly et al. 1996, Kelly and Haggitt
2000. Triangle= time of reserve creation (1976).
The sudden decline of rocklobster was caused by prolonged mud storms between June and September 1998, which caused a massive walk-out. It is amazing and unforgivable that scientists did not notice the event and its consequences. The rock lobsters were all caught in the same year, outside the reserve. Divers and fishermen experienced record catches from the area around Leigh Harbour.
The restoration of snapper Pagrus auratus populations in marine reserves is now well documented in northeastern New Zealand. This species proved difficult for divers to census (Cole 1994) and it was not until Baited Underwater Video (BUV) census methods were employed (Willis et al. 2000) that the magnitude of their recovery could be measured (Fig.3).
The BUV is one of the worst measuring devices ever invented since it conflicts with basic principles. All measuring instruments are designed such that they cause the least influence on the quantity measured. By contrast, the BUV maximises its influence by attracting fish from afar by smell and by offering food. Such an instrument will exaggerate the quantity measured. Its linearity or one-to-one correspondence between observed and actual quantities has not been proved. Scientists have not taken the necessary precautions with the results produced with this device, results which are way out of line with those found elsewhere. The method is sensitive to the currents and hunger level of fish.A comparison of three coastal Marine reserves showed an average ratio of 14.3 times more P. auratus above the legal minimum length (270 mm) inside as opposed to outside reserves (Willis et al. 2003). For all fish, including juveniles, the reserve:Non-Reserve (R:NR) ratio varied, being 4.2 at Leigh, 2.4 at Hahei, and 2.1 at Tawharanui (not significant). The R:NR ratio for legal sized P.auratus was similar among the three reserves at the time of the study, even though the youngest reserve was 6 years old and the oldest was 23 years old. Snapper recovery therefore seems to be rapid, an impression confirmed by the increase in P.auratus numbers at the Poor Knights Islands Marine Reserve.
Scientists hail these figures without thinking about their consequences. Having 14 times more fishable snapper in a closed area means that the fishery outside teeters at less than 7% (5%?) of unexploited stock, which is not borne out by fisheries statistics. Obviously, the measuring method is seriously flawed.The Poor Knights Islands were declared a partial marine reserve in 1981. A small proportion of the area was no-take but recreational fishing, using unweighted lines, was permitted in the majority of the reserve. In October 1998 the entire reserve reverted to “no-take”. At that time there was a significant [just measurable] difference in legal P.auratus abundance between fully no-take areas of the Poor Knights and those areas with limited fishing, this difference was small in magnitude and likely to have been of limited ecological significance (Denny et al. 2002). After 3 years the number of legal-sized P.auratus had increased by 8.3 times relative to the pre-closure values (Fig.4) and were 16.6 times more abundant than in fished reference areas, where numbers of legal sized P.auratus have remained static (Denny et al. 2002). Snapper populations at the Poor Knights Islands demonstrate that while rapid recovery is possible, it is only likely to occur under fully protected, no-take conditions.
Fig3 shows how Goat Island stands out above the rest. Scientists fail to mention that Goat Island has an unusual amount of reef habitat and shelter, and that the centre of the reserve is located around an island. Fish congregate here because it offers clean water (much cleaner than 400m further inshore), currents, deep habitat close to feeding grounds and ample shelter from storms. It is an unusual place. It so happens that the other two places, Hahei and Tawharanui were also chosen because of their good qualities for diving. They too are not representative of the rest of the coast. Why do scientists fail to mention this?
Fig4 shows how quick a fishery recovers after total closure, which basically says that the ecological effect of fishing is a minor issue and so are the claimed benefits of reserves. What scientists fail to disclose is the unique situation of the Poor Knights Islands. These are located at the edge of the continental shelf, surrounded by 80-120m deep sea bottom. Snapper from a wide area around migrate on a regular basis to the only shallow warm water nearby. Thus measuring snapper densities in shallow water distorts reality and is not representative of densities in the surrounding deep sea bottom, the main extent of this reserve. To compare this oasis sanctuary with the Mokohinau Islands, is rather naive. Again no further thought is paid to the consequences of the factor 16, which implies that fish stocks elsewhere are below 5% of unexploited levels. Why are marine scientists so ignorant and naive, one may ask.Similarly, the Mimiwhangata Marine Park (established 1984) on the coast adjacent to the Poor Knights, allows only recreational spearing or fishing using unweighted lines. Despite the exclusion of commercial fishing, the abundance of legal P.auratus at Mimiwhangata was not significantly different to reference areas outside the park. In fact, mean P.auratus numbers there were lower than at any other areas, despite the recreational gear limitations and the complete absence of commercial fishing (Denny and Babcock 2002).
The Mimiwhangata Marine Park extends outward by only 100m. It is dominated by sandy beaches and much shallow sandy seabottom. There is little reef habitat. It is not policed and most people fishing there do not know that fishing rules apply.The magnitude and speed of recovery of P.auratus populations in northeastern New Zealand can probably be ascribed to two factors. Firstly, individuals of this species can display a variety of behaviours, including seasonal onshore and offshore movements (Willis et al. 2003), as well as long-term residency within restricted areas (Willis et al. 2001). It is also likely that individuals switch from one behaviour to the other, and that they show intermediate types of behaviour. The seasonal migratory behaviour means that densities of legal P.auratus inside reserves vary by 3.9 times between spring (September) and autumn
This is indeed what fishermen are seeing. The Leigh marine reserve has some large resident snapper (e.g. Mister Perfect, Panda and Monkeyface) which disappear between November and March to spawn outside the reserve. Miraculously they dodge fishing lines and nets, to reappear in April/May. This suggests that stocks of large old snapper exist outside marine reserves, experienced enough not to take the bait. The main message here is that marine reserves do little for migrating stocks, which make up the bulk of commercial fishing.Reserves in other areas that once supported significant P.auratus populations, e.g.Tonga Island marine reserve in the northern South Island, do not appear to have shown a marked recovery in P.auratus populations (Cole et al. in press). The region once supported a substantial P. auratus fishery but this has been in serious decline since 1979 when the annual catch peaked at around 3203 tons and it now less than 200t (Harley and Gilbert 2000). The yield of the fishery in the Hauraki Gulf (northeastern New Zealand) has remained at over 5000 tons per annum since the 1940s. In the case of both P.auratus and J.edwardsii, the restoration of populations in marine reserves appears to have been facilitated by the presence of adjacent healthy populations.
This is precisely what fishermen are saying. Marine reserves have very little benefit to commercial and recreational fishing. They do NOT protect fish stocks. It is much better to manage fish stocks at higher levels everywhere than to hope that locking up small areas will help.
1) the BUV exaggerates the observations. 2) there exists a large difference between spring and autumn, which could mean that fish move away or that they are more or less well fed. 3) the results from Goat Island swamp the rest because it is a special place. 4) these three reserves are all more special than the areas outside.
1) The Poor Knights are an oasis type of reserve. 2) the amount of shallow warm water is small compared to the dominant deep sea bottom. 3) fish migrate regularly from deep to shallow water, thus concentrating in the shallows, which distorts the data. 4) the BUV exaggerates. 5) recovery is fast, suggesting that the detrimental effect of fishing is small. 6) Marine reserves have little to offer. 7) controlled fishing did not affect the rest of the reserve or the enjoyment of diving there. 8) A rigidly enforced marine reserve is not better than a voluntary one.
Please note that the bottom graph was left out of the report. Why?
As can be seen, nearly all species suffered two to six-fold declines, except for sweep which have been increasing their numbers. Sweep compete with blue maomao for space but they belong to the more turbid waters along the coast. Their increase at the Poor Knights means that turbid waters have arrived there while at the same time numbers of blue maomao have declined, which is what we have observed.
The scientists who conducted this study have arbitrarily decided not to count schooling fish, so the sudden decline of blue maomao, trevally, koheru, jack mackerel, kahawai and to some extent also pink maomao, has not been recorded. One may ask how relevant such studies are when they are either incomplete or not reported properly. This is a relevant question since taxpayers paid $280,000 for this four-year study.
To put it all in perspective, children
are now learning at school that snapper increased 16-fold after fishing
was stopped at the Poor Knights!
Direct Effects on marine ecosystems: habitat recovery
“in taking an approach that wants to protect biodiversity, we'll also ensure that fish stocks are there and the bio-mass is maintained ” (S.Lee. The Dominion ,7 February 2002)
The effects of fishing at the ecosystem level are now evident worldwide and extend far beyond the target species (Pauly et al.1998). The direct effects of fishing, mainly trawling and dredging, on marine habitats are also widespread and pervasive and have been estimated to disturb areas of sea floor equivalent to the world ’s continental shelf once every two years (Watling and Norse 1998). Three dimensional habitat structure is reduced or destroyed by these forms of fishing but no-take MPAs in locations such as the Georges Bank (northwest Atlantic) have enabled recovery of this habitat structure to occur (Collie et al. 1997).
To quote the above references is more than just malicious, particularly with respect to New Zealand, where fishery management is making vast improvements. To quote that trawling disturbs the sea floor once every two years is ignoring the fact that storms do so several times each year. It is also showing ignorance of the methods of trawling, some of which cause very little disturbance.Species assemblage and habitat structure of soft bottom communities in northeastern New Zealand have also been linked to the intensity of trawling and dredging, using marine reserves as reference areas (Thrush et al. 1995, 1998). On Australia’s northwest shelf, a ban on trawling has allowed sessile macrobenthos to recover. The increase in habitat-forming species, such as gorgonians and ascidians, has been paralleled by an increase in the numbers of target fish species associated with them, such as tropical snappers and emperors (Lutjanidae, Lethrinidae; Sainsbury et al. 1998). Whether this was a direct result of the cessation of fishing, or an indirect effect of habitat structure, remains unclear [after all the above statements?]. Only long-term and large-scale experiments will tell us conclusively whether changes in habitat structure affect the productivity of commercial species.
Three dimensional habitat structures are often quoted, but do these really exist on a sandy and muddy bottom, which is the vast part of the continental shelf? Sponges and gorgoneans are associated with rocky substrate, which is what trawlers avoid. Only occasionally do trawlers bring up sponges living on low-profile rock flats in areas of current. Such places are ephemeral, often smothered by sand. Most likely these organisms are just opportunistic but unimportant.
In NZ we have vast de-facto marine reserves on the seabed in a continuous range of depths, yet no research has been done on these. No plans have been made to convert these to marine reserves. Why do scientists avoid these? What is their political motivation?
Ecological principles say that habitat structure on soft benthos is just opportunistic and ephemeral (short-lived) and of no importance to the environment.
Displacement of fishing effort
“More marine reserves could force fishers into the remaining areas, depleting stock” (A.Macfarlane, New Zealand Herald, 4 February 2002.)
Some attempts to model marine reserves have concluded that no-take areas as large as 40-80% of the available habitat may be required in order to sustain fisheries yields (Sladek Nowlis and Roberts 1998), or ecosystem integrity (Sala et al. 2002). Other models show that if fishing effort remains constant while available fished area decreases the displacement of fishing effort by no-take areas could increase the impact of fishing on unprotected areas (Parrish 1999). Thus while some areas would be less impacted by fishing, the effects would increase proportionally in other areas.
Marine Reserve scientists, in their zealous ideology, have attempted to use marine reserves as a fisheries management tool. In tropical seas where artisanal fishing cannot easily be controlled, such may be possible, although no good examples exist so far. Using computer models, these scientists have let their fantasies loose on a wide range of scenarios, all of which weakened by their underlying assumptions. The underlying problem is that a good reserve which fosters wise old fish, does not leak fish easily to the outside. But it closes the area to fishing. Thus the benefit to fishers is negative. Spill-over does not compensate for the lost fishery. If 20% of the sea is closed off, the public loses 20% of its fishery, which converts to $200M in lost exports every year. Is this our legacy to our children? For more about the 10-80% craze, read Target sizes for marine reserves.The problems foreshadowed by this model are of genuine concern, but their potential importance depends on several factors. Firstly, the proportion of coast set aside as marine reserve would have to be much larger than is seriously being proposed anywhere at present. In New Zealand, target proportions advocated by pro-reserve groups range from 10 -20%, varying from one interest-group or political party to the next. At these levels of protection, the amount of effort displaced to other areas of coast will be relatively small (Fig.5). The second condition would be the absence of effective fisheries management regimes outside protected areas. Proposals for systematic large-scale networks of marine reserves do not include dismantling existing management systems.
Indeed, fishermen go one step further by saying that marine reserves are not necessary for achieving sustainable fishing. They may be necessary for research, education and diving, but not for fisheries management. What's more, so far not one out of 1200 MPAs worldwide, including those in NZ, have proved to be of benefit to fisheries management but a temporary closure such as at the Georges Bank will work as a normal fishery management tool.In the New Zealand context, a figure of 20% representation of coastal areas in MPAs is the highest proportion currently being proposed (Green Party 2002 and Forest&Bird) and the Labour government supports a total of 10% (Department of Conservation 2002). This figure is well below that at which we would expect to see a rapid increase in displacement to unprotected areas. Furthermore, the current New Zealand Fisheries Act (1996) requires that fisheries are managed to ensure the protection of fisheries habitat as well as fished species. Consequently, fisheries management of non-reserve areas will need to account for and mitigate against undue pressure on fisheries and habitats as a result of any fishing displacement. The greater the proportion of marine reserve, the greater the need for managing human uses of non-reserve areas. To paraphrase the title of a frequently cited paper (Allison et al.1998), while fisheries managers may not agree that marine reserves are necessary for marine conservation, they understand well that reserves alone will not be sufficient. Therefore, to raise the issue of displacement of fisheries effort as a major drawback of marine reserves requires us to adopt some unrealistic positions. This would include a simultaneous enhancement of management and conservation efforts within marine reserves, and a relaxation of these efforts in fisheries management. [oops, a non-sequitur]
The consequence is that marine reserves should be managed under the Fisheries Act while the Marine Reserves Act should be abolished. This would also resolve conflicts imposed by one department on another, and of one part of society on another. Marine reserves should be created for what they do best: research, education, diving.
|Fig.5. Exploitation rate in fished areas as a function
of the proportion of the fished stock in marine reserves. The model assumes
that total catch and effort remains constant and that the fished stock
is evenly spread around all areas of coast. If this is so, the proportion
of protected stock is proportional to the protected coastline, and in order
to maintain catches, effort must go up in the remaining fished areas. (After
This graph is in fact, quite meaningless. It compares two incomparables, exploitation rate and biomass rather than reserve size. It assumes that catch and effort remain constant even though exploitation rate goes up. What the public knows intuitively, is that if you lock up 20% of the fishery, the remaining 80% of the sea cannot be fished more intensively.
Indirect Effects on marine habitats: environmental
“Certainly they are great for science, to study the sea and the relationships between a range of animals on a long term basis” (J.Nicolson, New Zealand Herald ,31 January 2002).
Because of the pervasiveness and intensity of fishing activities, it has been suggested that marine reserves offer virtually the only way of understanding what a “natural” ecosystem might be like, or of appreciating the full impacts of fishing (Dayton et al.1998). In addition to the physical damage caused by fishing, one obvious reason for this is that fishing may have directly reduced populations of some species to the point where they are no longer functionally-significant ecosystem components.
Dayton talks about environmental changes having happened so long ago that nobody can remember what the world (or sea) looked like. How frighteningly true. But he overlooks that the sea has not suffered the irreversible damage of forest logging and burning, agriculture and urbanisation. By comparison, it is still a pristine environment. No doubt, fishing will have left its mark but this can in no way be compared to what humans have done on land. Recovery in the sea happens in a matter of one decade compared with centuries for a forest. What all scientists seem to overlook is that the damage from landbased pollution has caused permanent and long-lasting change to the marine environment. Fishermen are now saying that over 40% of the coast anywhere is no longer suitable for fishing. Yet scientists choose to ignore this.Indirect effects of fishing on marine habitats are less obvious but are no less important [?]. Marine reserves in northeastern New Zealand have provided important examples of such indirect effects and the importance of reserves as environmental baselines. The first quantitative ecological descriptions of rocky reefs on the northeastern coast of New Zealand described extensive areas of urchin barrens, largely devoid of macroalgae and dominated by the grazing echinoid Evechinus chloroticus (Ayling 1978, Choat and Schiel 1982). Such barrens areas were extensive in no-take reserves, such as those at Leigh and Tawharanui, at the time of their establishment (1976 and 1982 respectively).
People who blame pervasiveness and intensity of fishing, simply demonstrate that they have little understanding of marine ecology and its energy flows. It is sad.
[Sigh] When does the author realise that the disappearance of the urchin barren zone was caused not by the beneficial effect of a marine reserve but by degradation (kelpbed death Jan 1993, urchin deaths 1993-2002, crayfish walk-out 1998)? For a complete rebuttal of these untenable claims, see Science Exposed.Urchin population structure and behaviour within the Leigh and Tawharanui reserves differed from that found in adjacent fished areas (Cole and Keuskamp 1998, Shears and Babcock 2002, 2003). More urchins adopted cryptic behaviour within reserves, sheltering among or beneath boulders. This was true even at sizes above the threshold (35-45 mm test diameter) at which they begin to graze openly on the substratum in fished areas. Populations in reserves tended to be bi-modal, with 35-45 mm size classes poorly represented, presumably due to predation.
The author and other marine scientists do not sufficiently make a distinction between the exposed north facing coast of Goat Island and the more sheltered south-east facing coast which is used for comparison. Urchins on exposed coasts stay cryptic (hidden) longer, due to wave action. This can also be seen in other places. The bi-modal (two peaks) population says that one or more year classes are missing due to mass mortality.Tethering experiments showed that small urchins were most vulnerable to predation and confirmed that predation was higher inside reserves and that at least 45% of urchin mortality was attributable to J.edwardsii (Shears and Babcock 2002). One consequence of changes in urchin behaviour and size-specific predation may be a significant time lag in the manifestation of trophic cascade effects. Decreases in urchin density and habitat transitions from barrens to kelp or algal turf were still being recorded in the Leigh reserve as recently as 2000 (Shears and Babcock 2003). These changes in habitat may in turn have indirect effects on the abundance of other organisms. For example, the density of the limpet Cellana stellifera is lower inside reserves while the density of the turban shell Cookia sulcata is higher (Shears and Babcock 2003). Experimental habitat manipulations have shown that Cellana grows and survives better in the presence of Evechinus, while the reverse is true of Cookia (Andrew and Choat 1982).
Marine reserves in New Zealand have demonstrated their potential to act as environmental baselines and ecological tools, and have enabled insights to be made into the management, productivity and ecological function of coastal ecosystems that would not otherwise have been possible. More insights are likely to be obtained from the range of more recently created marine reserves in other parts of the New Zealand, as well as Australia. These may take some time to appear if timelags, such as those seen for trophic cascade effects in northeastern New Zealand, are involved. Systems in areas where urchin barrens are present, such as the northern South Island, and the NSW coast (Andrew and O ’Neill 2000), are likely to respond with trophic cascades similar to those seen at Leigh and Tawharanui. However, there are indications that not all systems will respond in this way. For example macroalgae, not urchin barrens, dominate habitats around the majority of the New Zealand coastline (Choat and Schiel 1982) and much of temperate Australia (Prince 1995, Fowler Walker and Connell 2002, Edgar and Barrett 1997).
By being so keen to demonstrate 'effects' of marine reserves, marine researchers have missed the opportunity to learn more of the marine environment. For instance, our own observations as measured in Survey93, have largely been overlooked and ignored by scientists, even though these findings are critical to understanding the marine ecology. Science these days appears to consist of snapshots to prove an idea right, rather than following a sequence of ideas and experiments to understand how things work in the sea. Because of this, the author has missed what was really happening in the environments he studied. The fact that most of the research was funded by the Department of Conservation, did not help either. How much trust would you place in health research funded by the tobacco industry?
fishing ceased led to a transition from urchin barrens dominated by Evechinus chloroticus (a) to mixed algal assemblages
(b). Both photos are of the same site, at 5m, facing northwest from Martin’s Rock in 1993 (a), 2000 (b).
Again, no mention is made of the mass kelpbed die-off in 1993, mass urchin deaths and the crayfish walk-out of 1998.
Effects on fishing: lock-up or spillover?
“the international evidence of increases of stocks in fisheries next to established marine reserves remains indisputable” (S. Lee, The Dominion, 7 February 2002)
“What I am condemning is the objective of locking up a vast amount of perfectly good ocean in marine reserves for all time …The kaftan wearers may shout “what about spillover ”, but paua [abalone ] don ’t spillover” (E.Arron, Dive NZ June/July 2002)
“If the government is successful in locking up 10 percent of New Zealand’s fishing grounds there will be significant implications for commercial, customary [maori ] and recreational fishers”. (N.Gibbs, New Zealand Herald , 31 January, 2002)
No other concept associated with marine reserves is more controversial than that of “spillover”. Spillover implies that fish may move out of a protected area due to density-dependent effects, once the area approaches carrying capacity (Kramer and Chapman 1999). The use of this term has broadened to include any movement across a reserve boundary. Since reserves do not physically fence in fish, cross boundary movements are inevitable. Unfortunately, little is known about the scale of these movements.
The author fails to mention the concerted effort made by many scientists to measure spillover, all to no avail. It simply is not there or is too little to be of value.Because the opposing claims of those who support or oppose marine reserves hinges on this knowledge, many apparently contradictory claims can be found in the scientific literature as well as in popular media. Fishing interests generally hold the position that reserves will “lock up” fish resources, implying that fish will not cross reserve boundaries and that they will not be available to the fishery (Te Ohu Kai Moana 2001). This is often accompanied by claims that reserves will not protect fish populations because fish move too widely (Option4 2002).
This is also supported by science. Fish will move across boundaries, but not noticeably more out than in. Besides, a good reserve does not want to lose its breeding stock. The point here is that the fish species of commercial interest, roam widely and in high numbers over vast stretches of sea bottom or open sea. In order for fish to benefit, they must remain inside the reserve (be site-specific) and also of interest to fishers. Red Moki (Cheilodactylus spectabilis) is such a fish although it is not keen to take the bait but it is of little commercial interest due to its low numbers. Note in this respect that for fish to be commercially attractive, they must occur in large numbers, which requires large habitats like the flat sea bottom. On such monotonous habitats the fish do not stake out fixed territories, so they all roam about. The rocky shore habitat where fish are more resident, is too small to provide for enough commercially attractive fish.Proponents of marine reserves claim that cross boundary movements of fish (presumably combined with a longer period of growth while protected) will result in enhanced fisheries yields at some scale (Roberts et al. 2001). Given the diversity of fish species and their diverse life histories, generalisations are unwise, but this does not seem to have tempered the statements of either side [!]. While little evidence exists to support either claim, the facts that do exist tend to support the idea that reserves will enhance yields (Russ and Alcala 1996, Roberts et al. 2001). Even so, much of this evidence has been questioned because of concerns about replication or other design aspects of the studies (Hillborn 2002).
Marine reserve skeptics, please note! Finally a confession and another myth can be laid to rest, or will it?Evidence from New Zealand indicates that while reserves do not lock up resources [oops], neither do they enhance fisheries yields (Fig.7). Rather it seems that, as far as can be measured, the effects of reserves on local fisheries yields are neutral [oops, what about the lost fishery within?]. A three-year study of a lobster fishery in the Leigh region compared Catch Per Unit Effort (CPUE) and value of catch around the boundary of the Leigh marine reserve with those of two other areas in the region, Coastal Leigh and Little Barrier Island. Overall, both CPUE and value of catch were the same around the Leigh reserve boundary as they were at the two other areas (Kelly et al. 2002). This was an unexpected result since fishing adjacent to the reserve took place at the seaward boundary, 800m offshore. This is an area of sandy bottom up to 700 m from the coastal reefs where J.edwardsii makes its dens, and where fishers usually set their traps.
The author fails to mention that the marine reserve displaced crayfishermen who were then forced to place their traps at the reserve's boundaries, left, right and outward. It did not take long for them to discover that such was a waste of time, and they gradually moved to places further away.Fishing along the offshore reserve boundary began around 1985, when the reserve was nine years old. Fishers target the offshore boundaries of the reserve during the seasonal movements of J.edwardsii when they travel away from reefs onto the adjacent sand flats. The reasons for these movements are not entirely clear but they are associated with periods of increased feeding activity (Kelly et al. 1999). Jasus edwardsii can travel for several kilometers during these movements that may last for weeks. When Spiny Lobster return to the reef it is usually to the same part of the coastal reef they occupied previously and some individuals have been tracked back to the same den at which they were originally tagged (Kelly 2001). This combination of site fidelity and movement over scales similar to the dimensions of the reserve has resulted in a situation in which J.edwardsii populations are afforded a substantial degree of protection while still making a significant contribution to local commercial catches.
The outside boundaries have always been targeted, since the beginning of the marine reserve. Trawlers discovered that they could take substantial 'cashies' (crayfish for cash on the black market) in a single swoop, however, to the detriment of local craypots which also disappeared in the nets. See Lessons from Leigh for more details.The marine reserve at Leigh has protected the resident J.edwardsii population, but it has not locked it up, contrary to claims of some reserve opponents. However, the study of the J.edwardsii fishery at Leigh has shown that one of the claims of marine reserve advocates, that marine reserves increase yields, may be exaggerated. Yields of J.edwardsii are no higher adjacent to the reserve than they are at other comparable sites in the region. Overall, the fact that a positive conservation outcome has been achieved without detriment to the commercial fishery would seem to be a desirable result. [oops]
When the crayfish walked out en-masse in 1998, the cray fishers said "The reserve is finally working because the crayfish finally spill out". They had a good year and that was that.
This author is consistently wrong about 'no detriment to the commercial fishery'. What about the lost fishery inside the reserve?
|Fig.7. Lobster catch around Leigh Marine Reserve. CPUE
from three years of fishing on the offshore boundary of the Leigh Marine
Reserve and on adjacent coastlines. CPUE at each site varied from year
to year but overall did not differ among the sites adjacent to the reserve
and non-reserve sites. (after Kelly et al. 2002). White= Leigh reserve
boundary; black= coastal Leigh; shaded= Little Barrier Island.
These measurements show clearly that there is no measurable spillover from the Leigh marine reserve. It is a pity that the series was discontinued one year before the massive crayfish walkout in 1998, which demonstrates yet again that scientists are not interested in how things work but only in scoring political points. It is sad.
While no direct measures have been made of the influence of marine reserves
on catches of New Zealand fish species, at least one of them, P.auratus,
has characteristics similar to J. edwardsii that may result in a
similar balance of conservation combined with a contribution to fisheries.
A high level of site-fidelity is shown by some snapper, with home ranges
in the order of less than 300 m radius as demonstrated using visible and
acoustic tags (O ’Dor et al. 2001, Willis et al. 2001). A proportion of
individuals show a wider ranging behaviour, and acoustic tracking in the
Leigh reserve has shown that they may range over distances of more than
1 km (Egli and Babcock 2002).
Some of these tracked fish have left the reserve for periods of up to several weeks before returning. This behaviour, combined with the seasonal movement patterns of P.auratus (Crossland 1976), indicates that in addition to the conservation benefits derived from reserves [?], there is a clear potential for fish that have spent some time in a reserve to re-enter the fishery. Similar conclusions have been drawn for Blue Cod Parapercis colias based on a mark-recapture study in central New Zealand (Cole et al. 2000).
School children visiting the Leigh marine reserve enjoy the presence of some large resident snapper. They keep their fingers crossed that these legendary fish will NOT re-enter the fishery. But a reserve offers little protection.A spatially explicit model of the Hauraki Gulf Snapper fishery, incorporating movements of both fish and fishers, suggests that even with 50% of the area set aside in no-take areas, there would be virtually no impact on the yield of the fishery. Under the various scenarios explored, the influence of no-take areas on catch rates might be either positive or negative (Bentley et al. unpublished), but the magnitude of any effects was predicted to be small in relation to the overall catch. This is in agreement with the empirically derived conclusions of Kelly et al. (2002) in their small-scale study of the J.edwardsii fishery around Leigh.
Don't believe it. These models are based on untested assumptions. One needs to be naive to be impressed. See myths(6) for more admissions from marine scientists.Egg and larval export
The potential for marine reserves to contribute disproportionately large amounts of egg production is an idea widely promoted as a way that marine reserves can benefit the stock outside of reserves (Roberts 1997). Since eggs and ultimately larvae are likely to be transported out of any reserve, even though some may be retained (Jones et al. 1999), protected populations in reserves may help maintain recruitment at larger scales. There is clear evidence that areas of coastline protecting populations of commercially exploited species do indeed contribute disproportionately to egg production. Because both numbers and size of protected species increase because of protection, there is also an increase in the biomass of protected species, and egg production is proportional to biomass.
We are now entering the vagaries of egg and larval production, so keep in mind that a mature snapper produces many millions of eggs in order to reproduce itself perhaps once a year. So most of these eggs are wasted. Why?For P.auratus, egg production inside reserves is estimated to be 18 times greater inside than outside reserves, based on a study of three reserves over three years (Willis et al.2003). [oops, Fig3] Similar results have been demonstrated for J.edwardsii in northeastern New Zealand, with egg production increasing at 6.7% per year (Kelly et al. 2000). After 25 years, this rate of increase would equate to egg production 4.4 times greater inside than outside reserves (Kelly et al. 2000). [oops] In the case of P.auratus, these differences mean that a reserve covering approximately 5 km of coastline (similar to the marine reserve at Leigh) would produce a number of eggs or larvae equivalent to 90 km of coastline (Willis et al.2003) [oops]. For J.edwardsii, the equivalent length of coast could be from 22 km (Kelly et al. 2000) to 80 km (MacDiarmid and Breen 1992) depending on when the estimate was made. In principle, the relatively small no-take reserves have the potential to sustain recruitment in much larger portions of the coast.
The energy of the sun is packaged into tiny plants in the plant plankton, which are of no use to larger organisms. The whole purpose of spawn overkill is to produce food rather than offspring. Larvae of all sizes eat the phytoplankton and each other, resulting in ever larger food packages. In the end, snapper live indirectly from their own offspring. It is a method although inefficient for each, is indispensable for all. The bottom line is that egg production and reproduction are almost unrelated. So a successful spawning year bears no relationship to the size of the spawning stock or the number of eggs produced. This has also been confirmed scientifically (read the Shipp report). As can be expected, no scientific evidence has been found for protected stocks benefiting larval recruitment.
Here we have landed in the middle of unsubstantiated assertions where myths are born. 1) the BUV exaggerates fish counts. 2) the three reserves are rather special. 3) there is no evidence that snapper populations are increasing indefinitely. 4) extrapolation over 25 years is mischievous. 5) extrapolation over the entire coast, including sandy shores, is equally mischievous. 6) what happened to the previously stated presence of adjacent healthy populations? 7) the total amount of spawn mass from reserves is smaller because there is less from prey species.Stock-recruitment relationships in fished species are notoriously weak. Some fisheries scientists argue that, because of this, it is unlikely that any contribution from reserves to overall recruitment would be
Take good notice, marine reserve skeptics because for many years we have been bombarded with the opposing fallacy. Another myth laid to rest?The current proportion of marine reserves along the New Zealand coastline is less than 0.1%, just a drop in the ocean when it comes to influencing recruitment. While no evidence for such increases currently exists from marine reserves, stock-recruitment relationships have been shown in some invertebrate populations based on experimental manipulations at spatial scales (~1km) similar to most marine reserves (Prince et al. 1988). Larval export is an important issue that requires more satisfactory resolution both for conservation and the management of fisheries. In this regard, a consistent application of ecological assumptions is desirable.
Ecological principles explain why no benefit from larval export can be expected. If you want more fish, then the only methods that works is fishery management. Nothing else will.While fisheries scientists are correct to point out the weakness of stock recruitment relationships, the models of fish population dynamics on which most of their management strategies are based depend either implicitly or explicitly on the existence of the stock-recruitment relationship (Jennings et al. 2001). [oops, false] New Zealand ’s Fisheries Act (1996) requires fisheries to be managed so that they achieve “Biomass at Maximum Sustainable Yield” or Bmsy, a concept that is explicitly founded on the stock-recruitment relationship [oops, false]. It is inconsistent to deny the potential usefulness of reserves as a source of recruits while simultaneously basing “traditional” fisheries management decisions on models that rely on the stock-recruitment relationship.
The author may be a little out of his tree here. Only two paragraphs above, he explains that there is no such stock-recruitment relationship, with which ecological principles agree (for broadcast spawners). Fisheries models do not relate stock size to recruitment.The idea that marine reserves may provide insurance against recruitment overfishing in the wider stock has been used (retrospectively) as the basis for justifying the proportion of coastline that should be protected. Bohnsack et al. (2003) has suggested that proportions of between 10-20% protection [oops, Bohnsack claims 20-30%] are prudent because protection of smaller proportions of the coast requires unrealistically large compensatory increases in larval survival [oops] under overfishing conditions in unprotected areas (Fig.8).
The Bohnsack et al 2003 article makes for amusing reading, underlining precisely the woolly thinking now favoured by marine reserves scientists. Read Marine reserve target sizes to get a grip on this and also to see how much disagreement exists.Reserves as management tools: insuring against the unexpected
New Zealand was one of the first countries to implement an output- or
quota-based fisheries management system for all major commercial species.
In this approach the amount of fish that can be caught sustainably in any
area is determined and then used as the basis for setting the quota. The
Quota Management System has been praised by analysts, both within New Zealand
and overseas, as a model of how fisheries should be managed since one of
its major results has been an end to the “race for fish” (Dewees 1998).
There is no doubt that the QMS is an improvement on previous systems that
tried to control harvest levels by limiting the number of fishers, types
of gear or fishing seasons. It is argued by some that with a cap on the
total amount of fish that can be taken, there is no need for marine reserves
as a means of managing fish populations. Setting aside concerns relating
to habitat destruction and indirect effects of fishing, there is some validity
to this line of argument. However, it hinges on the crucial assumption
that the quota level is in fact set at the right level.
As has been the case with all other attempts to manage fisheries, it is becoming apparent that we do not always have perfect knowledge of fish stocks that will allow us to set quotas correctly. Even with New Zealand’s QMS, some stocks in some areas have been declining through the 1990s e.g. Stewart Island and Catlins Paua Haliotis iris (Andrew et al. 2002), Fiordland J.edwardsii (Starr et al. 1997), and Blue Cod in the northern South Island (Ministry of Fisheries 2003). Even for the P.auratus fishery in northeastern New Zealand (SNA1), major uncertainties remain surrounding total catch estimates (Boyd and Riley 2002). The P.auratus fishery in SNA1 is one of the most commercially and recreationally important inshore fisheries in New Zealand. It is also one of the best studied, yet despite this it has recently become apparent that the total P.auratus catch exceeds the total allowable catch (TAC) by 40% or over 3000 tons (Table 2). This uncertainty has major implications for the setting of TAC.
Although by no means perfect, the QMS does stop the race for fish while providing overarching control. An important element is feedback from stock assessments and catch per unit effort to set catch limits. There is room for more precautionary stock levels as more experience is gained. Each of the problems the author may raise, has its own explanation but overall, stocks are better managed than before. An enormous amount of open discussion precedes each Total Allowable Catch setting. In the last sentence, the author mentions the uncertain part the recreational fishery plays. Recent assessments (although disputed) raised the estimated recreational take by an unprecedented amount. Yet fish stocks are not worse off.Economic, demographic and technological trends indicate that the level of recreational fishing is likely to continue to grow. Given the difficulty of controlling and monitoring recreational fishing, marine reserves are likely to provide an important level of insurance against this uncertainty. They also provide a significant resource for those recreational users of the marine environment who wish to enjoy their fish alive, and in their natural habitat. Tourism based on the marine reserve at Leigh alone is estimated to bring 100,000 visitors per year, contributing substantially to the local economy (Cocklin et al.1998).
The author does not realise that some of the overfishing happened on stocks not yet in the QMS, for the purpose of establishing a high catch history on the basis of which the first quotas are handed out (for free). It is called 'catching quotas'.
The insurance argument is a well established fallacy giving peace of mind only to eco-activists, but what does it mean? The idea is that even if all else fails (goes wrong) outside, the marine reserve would still be there to seed its species in the bared areas outside. Let's check this out.
When we think about insurance, we understand that we pay a little (premium) in order to expect a large payout (indemnity) when things go wrong. But marine reserves do not protect against large scale events such as damage from hurricanes, invasions of introduced species, oil spills, mass mortalities from poisonous plankton blooms, degradation by mud and sewage and so on, because these play havoc equally inside and outside marine reserves. What about global climate change, global warming, ultraviolet irradiation, industrial pollution and acid rain? So who wants to take out such an insurance?
Since no-take marine reserves affect only fishing, they may provide an insurance for fishing-related accidents. But this only relates to fished species that are resident, which is but a very small part of the total. Who wants to take out such insurance?
Suppose a marine reserve does indeed provide the larvae to restock the outside in case of a fishing related disaster, it would take a very long period before stocks have re-established themselves, often more than ten years. During all that time, the fishery has to be discontinued. Who wants to take out such insurance, especially since better methods are readily available? Is there anybody who believes that a protected sea mount hundreds of sea miles from a damaged one will repopulate it? Obviously, the insurance argument is seriously flawed.
Marine reserves skepticists, here is another myth laid to rest. For many years we have been bombarded by the claim that the Goat Island marine reserve attracts 250,000 visitors per year (DoC repeatedly claims 300,000!). Now it is down to 100,000, and this already in 1998! We claim that visitors stayed away in droves since DoC banned the feeding of the fish (2000). Is that the cause of this sudden decline or is there more readjustment to come? When will the myth of $12M/yr or $120 per person per visit to the local economy bite the dust?
Recruitment and minimum levels of reserve protection. The logistic population
growth curve a) in which fastest growth is achieved when the population
is at about half of its maximum level (B max ) is the basis for the principle
of maximum sustainable yield (MSY).
At higher levels of biomass population growth slows due to density dependent effects on the survivorship or growth of recruits. The New Zealand Fisheries Act 1996 requires fisheries to be managed so that they are at the BMSY level b), forming the basis of setting TAC in all quota management species. In a population harvested down to Bmsy, approximately 50% of the original spawning potential (egg production) of the population would remain, but reduced egg production is expected to be compensated for by a two-fold increase in egg survival due to release from density dependent effects c).
Reducing the population to smaller and smaller fractions of its spawning potential, requires a corresponding increase in egg survival in order to maintain the original spawning potential and sustainable harvest. At levels at or below 20% of spawning potential the increases in egg survival required begin to exceed those that might be realistically expected (i.e. 5 –10 fold increases). It has been argued by Bohnsack (2003) that protecting at least 20% of a species’ habitat in reserves will provide insurance that at least that much of the spawning potential remains.
[sigh] Armchair ecology on the computer screen. Refer to the economies of exploitation in Resource Management for a better explanation.
|TACC||Commercial Landings||Recreational Catch||TAC||Total Landings|
Conclusion: Reserves as tools for science and management
Fisheries management is broader than fisheries yield enhancement, or even maintenance. This is a distinction that those debating marine reserves frequently fail to make. Increasingly, modern fisheries legislation, including the New Zealand Fisheries Act (1996) requires that not only fish stocks, but also essential fish habitat, be managed sustainably. In order to achieve this, complex interactions must be accounted for e.g. habitat protection, by-catch species and changes in population structure. Given the difficulty of modeling even one stock accurately, marine reserves are probably the best way to achieve the goals of conservation, ecosystem management and verifiably sustainable fisheries. Given the less-than-perfect track record of even our best fisheries management systems, marine reserves are an option that must [?]be implemented.
The author has just explained why marine reserves do not help fisheries management, backed by scientific evidence. Now he bases the need for marine reserves on the less than perfect track record of fisheries management, losing out of sight the very disappointing track record of coastal marine reserves. Due to coastal pollution, such reserves can no longer protect the environment. We wonder how marine reserves can reduce by-catch, since these arise from fishing. We also wonder how they protect against seabird by-catches.Evidence from New Zealand suggests that their impacts on fishers and fishery economics are at worst neutral [oops], but that they also bring many benefits in terms of protecting habitat and populations of exploited species [oops]. Reserves must be used in combination with other management systems to achieve overall protection of marine resources. For example, reserves may displace fishing effort, which may have undesired effects on fished areas especially where fishing overcapacity exists. Even though the level of impact is likely to be minor if less than 20% of habitat is protected, population growth and increasing access to marine environments mean that, even with reserves, pressure on fish stocks and the marine environment will increase. Without a range of other management tools (e.g. QMS) reserves may introduce a false sense of security and exacerbate problems elsewhere. As with anything new, there is a certain level of fear and ignorance surrounding marine reserves. With time, it is likely to become more and more apparent that we have nothing to lose and everything to gain from including marine reserves as one of a range of essential management tools for the marine environment. [sigh]
As far as population structure is concerned, marine reserves may offer protection and restoration of old wise fish, but this is not borne out in practice. For instance, spotted black grouper and other serranids have not appeared in protected areas. Something else is amiss.
This whole article has failed to substantiate why marine reserves are necessary. It has also failed to look at alternatives, and it has failed to identify all matters wrong with the present situation and it has failed to identify the main threats to our seas. Ignorance, amazingly, reigns particularly with those who call themselves scientists but who fail to observe the real threats to our seas while being too arrogant to listen to what seamen have to say. Read FAQs to avoid making the same mistakes. These scientists have succumbed to an ideological course for political gains, rather than following the scientific trail of discovery of how things work. In doing so they have been blind to the obvious. Not willing to bite the hand that feeds them, they have played the hand of a rogue government department which deems its advocacy role more important than telling the truth. As a result, a whole generation of people may lose their trust in Governance and science.
In an article like this, which is obviously aimed at the general public, one would expect references to be freely available. However, this is not so. Scientists have created themselves an exclusive ivory tower to which layman's access is forbidden. None of the articles below are freely available. To make matters worse, the Department of Conservation refuses access to scientific reports paid for by the NZ public purse. Under threat of legal action and invocation of the Official Information Act, we are gradually gaining access to these reports. So much for the Department's legal obligation to engage in widespread consultation!
Department of Conservation scientific reports: consult the Seafriends Library and recent additions.
Ministry of Fisheries: many reports on their web site free of charge
University of Auckland: dissertations can be read in the library but not copied.
Ecological Applications: with some difficulty old editions can be accessed free of charge on the Web.
Marine & Freshwater Research: the RSNZ does not provide these free of charge to non-members.
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