Marine Conservation

By Dr J Floor Anthoni (2001)
To save the sea is quite different from saving wildlife on land. The sea is such a unique place, so strange, and  most of it has been left relatively undisturbed. Marine reserves are one of the ways to reduce threats to the sea. To create a marine reserve should be easy, but our ignorance of the sea and how to protect it, has caused some failures from which we should learn. Learn to do the right things for the right reasons. Unfortunately the science of marine conservation is replete with untested myths , fallacies and lies that prevent us from finding the right solutions.
An introduction to this article. The main threats to the sea, and our conservation toolkit to combat these. Levels of protection and kinds of marine reserves.
An exhaustive list of perceived benefits, many of which have not been proved, living in our minds only, or having limited applicability. What marine reserves can't do and what they do extremely well.
Objectives and perspectives of terrestrial and marine conservation. Thinking logically about a new conservation strategy, based on Dr Bill Ballantine's ideas: Representative networks of marine reserves, representing all climate zones and habitats. Rotational closed areas. The thistledown effect.
An historical perspective. Factors in terrestrial and marine conservation. The results of 25 years of active marine conservation in NZ. Heavy rain, the new threat. Degraded and degrading marine reserves.
 saving biodiversity
Gradually a consensus appears about how to save the marine environment. By focusing on biodiversity rather than benefits, the human factor becomes less important. Here are some action points.
ecological aspects
Understanding spillover and larval dispersal, networks of marine reserves and why many reserves fail.
related pages
on this web site
Frequently Asked Questions about marine reserves, with honest and incisive answers. (23 p)
Myths and Fallacies in speeches and newspaper articles, dissected by Floor Anthoni  (large)
From hunter to caretaker: an article about marine conservation, containing the essence of this chapter, and with discussion points at the end (19 p, needs updating)
Threats: a summary of threats to humans, land, soil, water and air. (20 p)
Realms: a summary of the most important ecological realms: land, soil, fresh water and seas. (4 p)
Marine habitats: an introduction to marine habitats and their strange living conditions. (14 p)
Soil: dependence, geology, fertility, sustainability, degradation, erosion and conservation. (120 p)
Marine reserves are not working. Why hurry? A press article written by Floor Anthoni, Jan 2001. (4p)

Marine Reserves Act (1971) updated to 1961. Printer-friendly version. (16p)
Marine Reserves Act (1971) original version updated to 1987, now obsolete. (12p)
Marine Reserves Bill 2002 submission: our submission to the proposed MRA2002. (4p) Visit the DoC web site for a complete version of this Bill, and more (8 p, PDF).  Read a summary of this bill.and read for comparison the submission of the Marine Sciences Society [broken link:] and that of Forest and Bird .
Executive Order 13158: Marine Protected Areas, May 26, 2000, U S A equivalent of NZ's MRA. (3p)

Fishing: a chapter about fishing, whaling, overfishing and fishing regulation (planned)
Global warming: a chapter about the mechanisms of global warming and its consequences. (7 parts, must-read!)
El Niño: a chapter about the mechanism of the El Niño weather phenomenon. (planned)

Internet links
  • Pew Oceans Commission ( is an independent group of American leaders conducting a national dialogue on the policies needed to restore and protect living marine resources in US waters. It will report to Congress in 2002. Several good reports available.
  • WWF Panda Org: for a complete treatment of marine reserves. Callum M Roberts & Julie P Hawkins: Fully-protected marine reserves: a guide is available for download and free of charge. It is an extensive account on the benefits of marine reserves, but weak on their weaknesses and principles . Almost pure propaganda! (127 pages and more).
  • UNEP-WCMC World Conservation Monitoring Centre ( extensive databases, maps and information about heritage parks.
  • Environment Australia ( Australia's marine conservation policies and marine parks.
  • UNEP-GPA Global Programme for Action ( fighting marine pollution from land-based activities (extensive).
  • SPREP - South Pacific Regional Environment Programme ( environmental action in the South Pacific. Promoting co-operation. (incomplete)
  • UN WSSD - World Summit on Sustainable Development ( progress in implementing sustainable development has been extremely disappointing since the 1992 Earth Summit, with poverty deepening and environmental degradation worsening. What the world wanted, the General Assembly said, was not a new philosophical or political debate but rather, a summit of actions and results. Was this achieved?
  • Marine Reserves for NZ ( ): Dr Bill Ballantine's web site with PDF papers.
  • The Science & Environment Policy Project ( Fred S Singer's critical appraisal of conventional wisdom about gobal warming, ozone depletion, natural resources and more.
  • MPA news ( International news and analysis on marine protected areas (MPAs)
  • MPA US Government ( steering the creation of MPAs in the US. They have an extensive library reference list.
  • Reader please not that this chapter on marine conservation builds further on the principles outlined before. Make sure you have read the chapters on resource management, biodiversity and principles of conservation, before proceeding with this one. It is at least important to understand the enormous differences between life on land and in the sea, discussed in biodiversity/marine., and  in introduction to marine habitats and realms.
    The Seafriends web site is dedicated to the preservation of our oceans and the world in general. It does so by looking at all aspects of our problems and how to understand these. Only by the process of understanding, and by being strictly honest, can each of us contribute with what he can do best. We are not greenies who wish to push our beliefs onto others, but we want knowledge, logic and common sense to prevail. We can see how and when marine reserves fail, and unfortunately we have seen many such failures. We understand the limitations of marine reserves. Only by being honest and by understanding our mistakes, can we hope to progress to better solutions that will work and will keep working. Unfortunately, we have often been brushed off as anti-conservationists, or being against marine reserves. Nothing could be further from the truth. This 'controversial' chapter therefore, should be read with care, since (hopefully) it forms the basis for policies towards better marine conservation. There are so many zealous conservationists travelling the globe while lecturing and writing about marine reserves, which they have never visited under water themselves. This chapter was written by someone with over 2000 dives inside and outside many marine reserves.

    The literature on marine reserves is prolific, since anyone can make a contribution. It disappointed me that it took a year longer than planned, to write this chapter. It is an indictment of science that so much pure opinion is being published and so little hard fact. In fact, a new discipline is about to be born, leaving the public out of the field. I have therefore tried to distill all important thoughts and facts, so that nothing important is left out. In this way you can learn what matters in a short while, to play your role in marine conservation, with what you can do best.

    Although marine conservation and marine reserves have international importance, most of this section will be illustrated with the New Zealand situation, partly because that is what I am familiar with, and partly because New Zealand wishes to lead the way in this aspect of human endeavour.

    Floor Anthoni, December 2002.

    Note! for best printed results, set your page up with a left margin of 1.5cm (0.6") and right margin of 1.0cm (0.4"). Read tips.
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    Larsen cartoon Introduction

    The sea is a large body. Not only is it vast, covering nearly three quarters of the globe, but it is also deep. As opposed to the terrestrial habitat, which is smeared over the surface of continents in a layer no more than 40 metres thick (and effectively much less), the sea is 4000m deep on average, with places descending to 10km. The sea is also a very different kind of habitat, almost unimaginably different from the terrestrial world we know so well. It is a hostile place, impossible to travel to by foot or automobile, and even by boat, can be very unpleasant. Please read about this in biodiversity/marine. The sea is not inhabited by people and therefore does not suffer the consequences of extensive habitat change (forests into pastures), habitation (cities and roads), and whatever civilisation has wrought (extraction and pollution of various kinds plus introduced species). One would thus be tempted to ask whether the sea needs conserving at all.

    sick sea cartoon The seas have always been a dependable provider of protein-rich food, to the extent that as recently as fifty years ago, the oceans were thought to be able to provide all the food humanity needs. However, in recent times, the inexhaustible bounties of the sea have shown their limits. Fisheries everywhere in the world have either reached their limits or have collapsed. In all, our report card for managing the oceans, does not look good. But it has not been for lack of trying. Most nations have established controls over their inland and marine fisheries a long time ago, in order to protect them from overexploitation. The recent creation of Exclusive Economic Zones (EEZ) around fishing nations, is yet another tool in the toolkit of marine conservation. So, what are the current threats to our seas and what are our tools to manage these?

    As the world population increases at its fastest rate ever, the sea experiences a very sudden increase in stresses, some old and some new:

    In the summary above, the most pressing threats to the sea are by far: overfishing, soil erosion and nutrient discharge. Whereas overfishing has its natural limits (you stop fishing when there is no more fish), soil erosion and nutrient discharge appear to be limitless, and they are increasing rapidly. Read about soil erosion on this web site.
    causes and effectsCauses and effects
    The diagram shown here sums up the most important threats to the sea, what causes them, and what effects they have on the marine environment. In brown the main products (agents) from civilisation: mud, nutrients, poisons and debris. 
    When cuts are made in the land, either by ploughing, roading, development and dwellings, heavy erosion follows. The mud, and particularly its finest particles, the clay, cannot be stopped by sedimentation ponds or other inventions, and it flows unhindered into the sea, where it releases its nutrients. Nutrients from overfertilised farm soils, and farm animal  dung, are washed into the sea without becoming part of the soil chemistry. Sewage from human settlements, treated or not, cause heavy loads of nutrients to enter the sea near human settlements. 

    Nutrients in the sea cause plankton blooms, and when these exceed what is normal (eutrophication), the plankton ecosystems become impaired, leading to unwanted effects like obscuring the light, thereby killing seaweeds. Diatoms in the plankton can join together in strings, forming suffocating mats. These can kill burrowing clams, and sessile filterfeeders like seasquirts, bryozoans and sponges. Some mats of blue-green algae can kill grazers such as sea urchins and snails.
    Impaired plankton ecosystems can lead to concentrations of highly poisonous plankton organisms (mostly dinoflagellates), causing direct mortality of planktonic organisms like shrimps and larvae of many kind, and those feeding on these in the planktonic food chain. It leads to mass mortality of fish of all kind, but it spares those feeding solely on plants. It can also kill sessile organisms like sponges.

    With the sewage and stormwater, come a large number of chemicals, used in household and industry. Many of these are poisonous, causing slow kill by being accumulated slowly in marine organisms.

    The main effect of fishing is that mature fish are taken from the marine ecosystem, often by targeting specific species. In doing so, the ecosystem can become unbalanced, with the loss of large fish of some species, while small fish of other species are able to increase their numbers. Trawling also 'ploughs' the sea bottom, which could lead to the destruction of sensitive benthic (bottom) communities. However, the sea bottom is extremely flat and not prone to 'erosion', while also its soil organisms are used to large scale disturbance by storms. 

    Debris from fishing and marine transport are often ditched overboard, soiling the marine environment and snagging marine life. However, this threat is very small compared to those mentioned above.

    The effect of loss of light on marine habitatsThis diagram shows how seemingly innocent loss of light will degrade the marine environment profoundly. The image shows three cross-sections of a rocky shore. The leftmost is a healthy environment in clear water. There are four distinct habitat zones: the bladderkelp zone in the wave-washed surface waters, the barren urchin-grazed zone underneath, followed by a closed-canopy kelp forest. Beyond where the kelp can no longer grow through lack of sunlight, extends the deep reef habitat, represented by filter-feeding organisms like sponges.
    As the water clarity decreases, all zones move up, and their total extent decreases. This is accompanied by the loss of many species, particularly those sensitive to poor water quality (like filter-feeders), but also many species of fish and plant. The kelp canopy opens up. Biodiversity and biomass decrease.
    As the water becomes filthier still, the environment contracts further and different plants take the place of the kelp. The deep reef community disappears. Beneath all this extends a barren zone, covered in silt. The marine environment can barely exist.

    Formation of a dead zoneDead-zones can be formed in the sea where large amounts of mud and nutrients flow into the sea, such as at the mouth of a river with a large modified catchment area (like the Mississippi). The water contains mud and nutrients from agriculture and human wastes. As the mud disperses, it releases more nutrients, while clouding the water. Dense plankton blooms follow, clouding the water further. Dead plankton organisms sink down as detritus, and they are recycled by bacteria breaking them down to nutrients again. This requires much oxygen. The darkness of the water prevents the phytoplankton from producing the required oxygen. As the situation worsens, more and more oxygen is used up until all organisms die, and a dead-zone is formed. As human populations increase and the land degrades, requiring more and more fertiliser, dead-zones will become more commonplace. At he mouth of the Mississippi River (west of it) now every year large dead zones form of 22,000 km2. these areas are totally devoid of fish and other life except for anoxic bacteria. Farming using excessive nitrogen fertilisers in the river's catchment area is blamed for this and a plan has been formulated to reduce dead zones by 30% by the year 2015.

    Now that we have established that serious threats exist to our seas, let's look at the conservation tools available. They aim to make the resource last, hopefully forever. Most regulations are enshrined in law so that they apply to everyone, ensuring that all stakeholders are treated (disadvantaged) equally.

    As one can see, our conservation tools are not able to stop mud and nutrients from flowing into the sea, which has become our main problem along our coasts. In the remainder of this chapter, we'll concentrate on marine reserves and their benefits and limitations. Fishery and its implications will be treated in a separate chapter. Perhaps it is the right place here to make an important distinction between conservation and management. Fishermen talk about management, and conservationists about conservation. What do they mean?
    Management = the threats remain, but managed at a magnitude to cause no permanent harm.

    Conservation = taking all (human-caused) threats away, permanently.

    Marine reserves, like terrestrial wildlife reserves, can come in a variety of forms, depending on the amount of extraction allowed. In this respect it pays to review the following possible scenarios, arranged in order of the amount of extraction allowed: Which of the above scenarios will deliver the most benefit is not easy to say. Extraction gives measurable benefits to people, but is usually detrimental to the environment. However, all natural populations benefit from a limited amount of extraction, although some areas are too sensitive to sustain exploitation. Thus complete protection may not deliver the largest net benefit, but it has merits of its own. It must also be remembered that by relieving the pressure on one area, one therefore increases the pressure on other areas.

    The terminology for marine reserves is rather confusing and differs in different countries. The Americans use the following terms:

    Australia has different names for zones of varying intensities of protection and restricted activities

    New Zealand also has a number of protected marine reserve concepts:


    Perceived benefits of protection

    In New Zealand marine conservation started from the need of marine scientists to do undisturbed measurements in the sea. They needed a place where their experiments would not be eaten. But gradually the concept grew, and other benefits were perceived. Eventually a long and exhaustive list of benefits became the conservationist's argument for having more marine reserves. But first the simple list of expectations:
    The simple list of benefits above has expanded over time, with the addition of more and more detail. Just hang in there and read this list carefully, because it contains many fallacies, myths and duplications.
     Marine Reserves Called Best Hope for Ocean Species
    Population densities were on average 91 percent higher than those outside reserves. Biomass was 192 percent higher; average organism size was 31 percent higher; species diversity was 23 percent higher. Myths & Fallacies (5).
    Sanctuaries must get their act together
    In 1991 the Potter Commission (commissioned by NOAA) suggested $30M/year as adequate funding. Actual amount was $4M. In 2000 actual funding became $26M/yr. A sanctuary must have: own boat, manager, outreach + science coordinator, interpretation centre, facilities. Congress decided that no new sanctuaries should be created until the existing ones establish active programs of education, research, monitoring and onshore facilities from the limited budget. But should sanctuaries be held up for lack of funding? The recource may be lost by waiting.

    As one can see, the perceived benefits of marine reserves may not substantiate at all, either because such benefits have been constructed in our minds, lacking a sense of reality, or they may not eventuate due to poor reserve design, such as making the areas too small, or with their boundaries in the wrong place, or by lack of funding. This will be discussed in a further chapter. One should be skeptical about claims like those discussed above, also because some benefits will be achieved only in some situations. Coral reefs, for example, are fished in their entirety: reef fish for food, clams for food, shells and starfish for collectors, corals for aquariums, small reef fish for aquariums, seahorses for doubtful medicines, turtles and much more. It is understandable then that closure of an area then leads to spectacular recovery. However, in temperate seas where such elaborate extraction is unusual, and commercial fish species are mainly migratory, bottom dwelling or pelagic, the closure of an area gives a much less spectacular recovery or benefit.

    It is furthermore helpful to remember that marine reserves do not protect against the following threats:

    From the above, it becomes evident, that the best ways to conserve the marine environment, is for fisheries to get their act together, and for us all to reduce sediment and sewage flows into the sea. To fish in an environmentally friendly way does not cost more or yield less than what we are doing now. Fixing sediment and sewage, however, is a very much more difficult matter.
    If we agree that conservation means taking all threats away permanently, then marine reserves have only little influence on the quality of the environment where other threats remain.

    Having learnt what marine reserves can't do, what is it that marine reserves do particularly well?

    Marine conservation did not happen overnight. It is a reactionary process, in which we react to problems as they occur, finding solutions as they are needed. But perhaps we need to think it through logically, from the ground up. What is expected of a protected area, is the subject of next chapter.


    Objectives of marine conservation

    Rather than imagining what reserves could do, this chapter deals with what the policies are behind marine conservation and how these developed. The objectives as expressed by various countries follows here.

    USA National Wildlife Refuge System (NWRFS): predominantly terrestrially oriented.
    • preserve, restore and enhance in their natural ecosystems (when practicable) all species of animals and plants that are endangered or threatened with becoming endangered.
    • perpetuate migratory bird resources.
    • preserve biological diversity.
    • provide the public with an understanding and appreciation of fish and wildlife ecology and the human role in the environment.
    However: it does not look at biological diversity overall, but only at endangered species and commercially or recreationally important species.

    USA National Marine Sanctuaries Program (NMS, 1972)
    • to identify areas of the marine environment of special national significance due to their resource or human-use value.
    • to provide authority for comprehensive and coordinated conservation and management of these marine areas that will complement existing regulatory authorities.
    • to support, promote and coordinate scientific research on, and monitoring of the resource of these marine areas.
    • to enhance public awareness, understanding, appreciation, and wise use of the marine environment.
    • to facilitate, to the extent compatible with the primary objective of resource protection, all public and private uses of the resources of these marine areas not prohibited pursuant to other authorities.
    Close observers mention that it suffers from the following problems: indadequate funding; no management; no research; no education efforts. It is interested only in values with respect to resource use and human use. It does not mention biodiversity, or a no-take policy. It is poorly defined in terms of conservational values. 

    WASHINGTON, DC, August 27, 2001 (ENS) - America's large system of nature preserves fails to encompass the full range of the nation's biodiversity, a new report shows. The study by U.S. Geological Survey biologists shows that the United States has selectively protected lands that lack commercial, agricultural or other human values, leaving entire ecosystems unrepresented.

    Canada wishes to have a system of marine protected areas in place by the year 2010. It wishes to go along the following lines:
    1. working with people & communities
    2. respecting the treaty process
    3. ecosystem based management
    4. learning by doing, flexibility & adaptability
    5. precautionary approach
    6. managing for sustainability
    It has established a working group to guide the process, with a mandate to:
    1. provide policy, advice, interpretation
    2. oversee public communications
    3. manage a joint central system for tracking and monitoring the MPA.
    4. ensure a consistent approach
    5. co-ordinate efforts
    The working group identifies, assesses and recommends priorities regarding:
    1. key marine areas identified by government agencies, First Nations, marine stakeholders, community groups, academic institution, individuals
    2. assessment according to MPA criteria
    3. recommendation based on consistency with the objective of MPA strategy, & complementary to other marine uses & activities, as already planned regionally
    4. decision making: recommendation reviewed by government. Additional studies may be needed. Management authority legalised.
    5. management plan: the agency supporting the MPA is responsible for making a management plan: purpose, goals, objectives, how to be reached, permissible uses, where, what, when. Management plans are subject to periodic review.

    Resource Management Act New Zealand (1993): Managing the use, development and protection of natural and physical resources in a way, or at a rate, which enables people and communities to provide for their social, economic, and cultural wellbeing and for their health and safety, while:
    • sustaining the potential of natural and physical resources (excluding minerals) to meet the reasonably foreseeable needs for future generations;
    • safeguarding the life-supporting capacity of air, water, soil, and ecosystems
    • avoiding, remedying, or mitigating any adverse effects of activities on the environment;
    • maintaining or enhancing the quality of the environment;
    • maintaining biodiversity;
    • exploiting at ecologically sustainable optimum yields;
    • protecting Maori taonga (treasure/heritage).

    New Zealand Biodiversity Strategy, March 2000.
    • maintain and restore a full range of New Zealand's habitats and ecosystems
    • maintain the genetic resources of our important introduced species, which provide much of the foundation for our economy.
    • enhance community guardianship of our indigenous species and where they live, and promote co-ordinated community action to bring species extinction to a halt
    New Zealand's Marine Reserves Act 1971: the purpose of marine reserves
    • for conducting marine research
    • total protection of all species
    • no disturbance
    Additions and amendments have been proposed to the act, for it to protect biodiversity, to apply to the entire EEZ (370km rather than 23); to be more specific about its application and consultation process; to allow for a wider range of purposes rather than just for scientific research; to include references to the Treaty of Waitangi. Maori are opposed to no-take reserves because they want to exercise their traditional fishing rights.
    New Zealand Department of Conservation's strategic business plan for 1998/2002
    In New Zealand, the Department of Conservation is in charge of no-take marine reserves. Its strategic business plan for 1998/2002 sets the following goals for achieving marine heritage protection, based on recommendations by the Australian and New Zealand Environment and Conservation Council (ANZECC 1998):
    • establishing a representative network of protected marine areas.
    • effectively managing all marine protected areas.
    • providing the greatest practicable protection to migratory cetacean species.
    • reducing fisheries bycatch of seabirds and marine mammals.
    Johannesburg WSSD World Summit for Sustainable Development, 2002 (Oceans and fisheries)
    • Encourage the application by 2010 of the ecosystem approach for the sustainable development of the oceans.
    • On an urgent basis and where possible by 2015, maintain or restore depleted fish stocks to levels that can produce the maximum sustainable yield MSY
    • Put into effect the FAO international plans of action by the agreed dates: for the management of fishing capacity by 2005; and to prevent, deter and eliminate illegal, unreported and unregulated fishing by 2004.
    • Develop and facilitate the use of diverse approaches and tools, including the ecosystem approach, the elimination of  destructive fishing practices, the establishment of marine protected areas consistent with international law and based on scientific information, including representative networks by 2012 .
    • Establish by 2004 a regular process under the United Nations for global reporting and assessment of the state of the marine environment.
    • Eliminate subsidies that contribute to illegal, unreported and unregulated fishing and to over-capacity.

    Representative networks
    From the above, it can be seen that marine conservation is still in its infancy. However, Dr Bill (W J) Ballantine from Leigh, came up with a proposal that enshrines the essence of a marine reserves system: 
    • representation: marine reserves representing all habitats in all climate zones. A bit of everything everywhere (diversity).
    • replication: to have a few duplicates of each type, by way of insurance. A bit extra (overcapacity & replication).
    • networks: marine reserves to be located 'within reach' of each other, so that they may reinforce one another. Not few and far between (connectivity).
    • sustainability: the network and each node to be large enough to be sustainable on its own, regardless of the condition of the area outside. You must be able to see it on a map of the country (overcapacity).
    f212116: Dr Bill Ballantine doing limpet research
    f212116: Dr Bill Ballantine on his study area

    It is not surprising that these principles correspond roughly to nature's way of achieving resilience, as discussed in Resource Management/natural resilience: resilience = diversity + overcapacity + replication + connectivity + adaptability. It suggests that adaptability should be added to Bill Ballantine's list; adaptability to changing circumstances and flexible management.
    The amount of the sea proposed to be set aside, ranges from 10 to 50%, depending on the arguments brought forward. Those clamouring for 10% see it as an insurance policy. Those tending towards 50% see it as an alternative to failed fisheries management. Using New Zealand as an example, we'll have a look at what is involved to implement Bill Ballantine's proposition.
    All climate zones, and replication
    NZ biogeographical regions Countries with a west coast and an east coast, which are also stretched north to south, surrounded by isolated islands, have a large range of marine climate zones or biogeographical regions. The map shows those for New Zealand. Currents on the west coast are cold currents; those on the east coast warm ones. Just south of NZ the water temperature changes suddenly, south of the subtropical convergence, waters becoming subantarctic. The Kermadecs are a specialised case of  subtropics, north of the Tasman Front. In all, there are eight marine climate zones, distinguishable by the organisms found along these coasts. We thus need at least 8 reserves, and when including some duplication, at least 16.

    Oceanic provinces and zonesAll habitats
    The coastal benthic (bottom) habitat zones continue past the littoral (intertidal), down the sublittoral, which includes various habitats, from rock to sand and muddy bottom. Before it descends into the trench, four other habitat zones can be distinguished, all present around New Zealand. The deep pelagic habitat (oceanic), has an equal number of zones, as shown in the diagram. These zones are again represented by seamounts, rising from the ocean bottom to a few hundred metres depth, and within reach of fishing gear. Such sea mounts have been discovered to house a most varied community of fragile and long-lived deep water species, now targeted for protection. Note at this point, that deeper than 200m, the water temperature is about the same everywhere, so that tropical sea mounts have much the same habitats as subantarctic ones.

    Where the coast is protected by outlying barrier islands, the coast is subjected to a varying degree of wave exposure, with its accompanying variety in marine environments. Several marine reserves are then needed to cover this kind of variety, which is not found on land.

    Closer inshore, are found inlets and estuaries, each with their own water flow characteristics. At times, and by careful design, a single marine reserve can cover several habitat zones such as an inlet, a beach, a sandy and a muddy bottom, an exposed and a sheltered reef. Benthic reserves can cover both mud and sand flats and rock flats in a single area.
    In all, our figure of 16 must now be multiplied by 2 or 3 for carefully chosen large reserves and 4-5 for small, randomly placed reserves. Thus the total number for New Zealand must be at least 30-70, according to this reasoning.
    Sustainable networks
    If it is true that fish larvae do not travel further than 100km, then marine reserves should be located no further than 100km apart. New Zealand's coastline is about 15,000km, which demands 150 marine reserves, spread evenly around. In order for a marine reserve to be sustainable, it should be sufficiently large. Experience has shown that 5-10 km2 is insufficient by far, and 50-100km2 is to be preferred, which surmounts to squares of 10km on edge. By this reasoning, a marine reserve should extend for about 10km, spaced by 90km of open access, amounting to 10% of the coastline in 150 reserves, or 150 x 100 = 15,000km2. New Zealand's entire land area is 270,500km2. Our coastal reserves would thus amount to just over 5% of the land area. 

    The folly does not stop here, because more and more scientists are now saying that marine reserves should not be separated by more than 20-30km and that 20% of the coast should be protected. For New Zealand this would add up to 900 coastal marine reserves!

    Larger reserves can be created in the open ocean within the Exclusive Economic Zone (EEZ), which in itself measures 14 times our land area, or around 1.2 million square nautical miles (= 4,100,000 km2). The Kermadec Islands marine reserve consists of 4 circles extending to the territorial limit (12 nautical miles= 22.2km), or almost 7,500km2. To cover our EEZ with 10% in reserves, would amount to 550 additional reserves of this size.

    These figures, and the amount of management and policing it requires, look rather silly. Proponents for 20% in marine reserves, make these figures look worse still. But the main question is, whether the public will lend support for such extravagance, and pay for its maintenance. After establishing the first marine reserve in Leigh in 1975, some 15 followed in the pursuing 25 years. Politicians now want to set aside 10% of the sea by the year 2005! Others will argue that we cannot afford not to. Common sense, however, says that the benefits do not outweigh the costs.

    Rotational reserves
    What about closing areas of the sea temporarily for a few years and then reopening them again while rotating such areas? What benefits and costs would be involved?

    For managing very large areas with few fishermen such as the Grand Banks in the Atlantic, rotational closed areas may provide a solution, but for coastal situations where many small fishermen are found, they are too invasive.

    an historical perspective

    NZ land and sea reservesThis map shows the North and South Islands of New Zealand side by side, and all terrestrial and marine reserves, to scale. It also shows in black the areas which consist solely of bare rock or ice. Click on the map for a larger version. The marine reserves hugging the coastline, have been drawn in red, but arrows are needed to show where they are. In all, there are an impressive number of 19 marine reserves, but when school children (9-11 years old) are shown this map, in order to give a report card for our conservation effort in 25 years, they give it their thumbs-down. When asked whether these marine reserves would have an influence on the environment, they unanimously say no. If we had ten times more, would that make a difference? After some hesitation they again don't believe so.

    The land reserves or national parks as we call them, symbolise our first efforts in conservation, and today we are proud to have them, as witnessed by the many overseas tourists who come here for tramping, camping and canooing. But these parks have a number of things in common:

    So these national parks are in essence useless tracts of land that we could do nothing with. We could not even give parts away to returning servicemen after the war. But they could be 'fenced off' and set aside. Conservation was thus an accident meeting no opposition. It is a fact that most productive land has now been deforested and milled. The very prime of productive land has even been paved over by cities and roads. We have no sizable parks of the woodlands that once stood where productive farms extend today. The extensive forests of kahikatea swamp cypress have been cut up entirely to make butter boxes for exporting butter. A few forests of the giant kauri tree have been preserved by private initiative. Then the Department of Conservation almost allowed this precious heritage to be destroyed by the introduced possum from Australia. In the mountains various species of deer roam around, destroying the native forests and mountain vegetation. Everywhere introduced predators like feral cats, stoats, rats and even dogs, threaten the native birds who have not evolved to cope with predation. So the essence is, that everywhere on land, the threats remain, also inside national parks. Conservation there is thus questionable.
    f022119: snorkeldiver surrounded by fish
    f022119: people visiting a marine reserve with a dive mask on, will see the environment underwater. Expecting to be fed a little, many fish surround them, creating the impression that the reserve is a pristine place full of friendly fishes.
    f022914: for those unable to go under water, a glass-bottom boat may provide first-hand experience. 
    f960810: the rocky shore is used for teaching
    f960810: Seafriends runs educational programmes for school children. Here they are shown the wonders of the intertidal zone. In order to minimise damage, we now ask students to go bare foot.
    f214320: full of expectation and energy
    f214320: in high spirits and full of expectation, school children descend to the beach, dressed in full protective wetsuits.
    f214323: instruction before a guided snorkeldive
    f214323: before going into the water, they get instructed about how to use the gear, what to do and not to do, and what our safety rules are. For most it becomes an unforgettable experience.
    f980424: a guided snorkeldive
    f980424: the adventure begins. For many it is their first time in the sea. In a short time they learn to rely on the flotation of the wet suit, and how to use mask and flippers. All the time, fish are swimming around their legs.

    In contrast to terrestrial conservation, marine conservation was an entirely new idea, meeting fierce opposition, because of:

    But as seen before, the sea is worthy of protecting, because: In the early 1970s, the idea of marine conservation was born, first for the purpose of scientific research, but the idea widened to include the environment as benefactor, and indeed people too. Today, the concept is marketed to the public on the premise of overstated direct benefits to themselves, and immediately. The concept is very attractive, because
    That marine reserves have found general acceptance today, is borne out by the 1300 MPAs established worldwide by1998. The dates for some of the better known ones are: 1935 Florida Keys, 1936 Gt Barrier Reef, 1941 Phillipines, 1958 Bahamas, 1960 Mexico, all in mostly tropical seas.

    Back in the seventies, the failure of fisheries management was overly demonstrated by the collapses of one fishery after another: mussel, crayfish, scallop, oyster, orange roughy, snapper and so on (in  NZ). Marine reserves would take this threat away, and the concept was powerfully simple. But after the mid-eighties, the situation had changed considerably. The Labour Lange Government under new-right policies of laissez-faire, had abolished the subsidy on fertiliser 'to remove price distortions' and 'to level the playing field'. Aerial topdressing stopped almost completely, and a few years later the hill country began bleeding into the sea. At around the same time our climate changed, and rains began to pour down in a tropical way, theirrain drops causing considerably more impact damage than usual on the bare soils, which were starved of fertiliser. At the same time, other subsidies for pest control were phased out and possums took reign. It resulted in accelerated coastal erosion. Encouraged by new markets, farming moved from sheep to dairy (milk cows), and fertilisers were applied generously to meet demand. These leached into waterways and into the sea. The new economic policies required immigration of wealthy asian millionaires with their numerous families, leading to a population increase, and with it a disproportional increase in waste and human sewage. While developing the land for shops and buildings, it became customary to landscape the soil on a grand scale, using an ever increasing number of earth moving machines. To sum it up, the land suddenly, in the course of only ten years, became the sea's number one enemy, and it is still getting worse rapidly. In November 1998, 85% of the crayfish in the Goat Island marine reserve demonstratively walked out due to filthy waters, only to be caught outside in no time at all. "The reserve has proved successful because the fish spilled over" said the local fishermen and the matter was laid to rest. (See also Conservation/Lessons from Leigh).

    f004414: the Goat Island marine reserve
    f004414: view of Goat Island in the marine reserve near Leigh, New Zealand. It is an idyllic spot with exceptional qualities like clear water, shelter, many habitats, rich biodiversity, and safe swimming. Here divers are seen doing their final sea tests before the Christmas holidays. The coastal Pohutukawa trees are in bloom.
    f013205: after a heavy rain storm
    f013205: since about 1990, mud started to enter the marine reserve, which had not been seen before 1980. This mud kills those marine creatures that are unable to swim to safer waters. The environment degraded.

    Filthy seas are not an entirely new phenomenon. In the early 1900s, farming in the South Island has seen its share of dust storms and swollen muddy rivers, rabbit plagues and degrading tussock (a kind of rough desert grass) lands. When all is said about it, one cannot escape the impression of a massive ecological disaster unfolding over New Zealand. A new threat (heavy rain) over degrading soils, becomes a two-fold disaster: we are not only losing our precious soils, belonging to our children and theirs, but we are also losing our coastal seas, belonging to them too. Is this stupidity or fate? For this reason a large chapter on this web site has been devoted to soil and erosion.

    The bottom line is that a new threat, and a bigger one than extraction (as proved by the crayfish walk-out), and less controllable, is wreaking havoc to our coasts, including our marine reserves, which cannot protect against it. A recent survey of our marine reserves by myself, has shown that most are degraded and degrading, and not worth having. See marine reserves index. It has become clear that we must change our focus in order to effectively save the seas, but above all we need to be honest.

    Only by saving the land, can we save our seas.
    Floor Anthoni, 1990

    Cheaper by the dozen
    In New Zealand the marine reserves issue has become a political hot potato, with protagonists clamouring for the moral high ground. We have major political parties talking about 20% of our seas in marine reserves, within a time span of less than ten years. We now have departments with budgets, whose sole task it is to create new marine reserves. In business-speak, the Government 'purchases' marine reserves from them. We now create marine reserves at any cost. It has become a numbers-game. In the meantime, the bureaucracy and some marine scientists have been dishonest to the public. The benefits they promised have not materialised and it is clear that they cannot ever be produced. We have over half our marine reserves located in the bad-lands of the sea, deteriorating year by year, without any hope of ever improving. We have deceived the public, and how long can this go on before they find out and withdraw all their support? We have become obsessed with quantity rather than quality.
    New Zealand is marketed overseas as a 'green and clean' country, with hundreds of millions of dollars spent on promotion, marketing and advertising. In the end, even our own people have started to believe this myth. To say the opposite and to raise a voice of caution is now akin to blasphemy or high treason. It threatens people's jobs and incomes and the economy of the nation.
    "The picture of conservation that I found in New Zealand, Australia and Malaya was distressingly familiar. Small bands of dedicated, underpaid and overworked individuals are fighting a battle against public apathy and political and big business chicanery. By and large people are only apathetic because they do not realise what is going on, but the most dangerous part of the problem is political apathy, because it is only at the top level that you can get things done."
    Gerald Durrell in Two in the bush, Collins 1966.

    The majority of nature reserves is far too small to support viable populations.
    Gilpin and Soule, 1986: Minimum viable populations.

    So many land reserves, but so few in the sea
    A main argument brandished in favour of marine reserves, is that we have so many land reserves (over 1000 in NZ, covering about 10% of the land area, some say 30%), but so few in the sea. Thus it is reasonable to have as many sea reserves. So our 25 years of effort, resulting in no more than 19, is only a poor beginning, and we should have many more. The whole idea of land reserves, is to take them out of private ownership, so that they cannot be logged, burnt or built on, which would alter their environment irreversibly. The State will then look after them in perpetuity. Likewise, a sea reserve is taken out of the commons (no ownership), into public ownership for protection. However, since the sea is not under threat of deforestation, burning, logging or development, which results in a major change (destruction?) of the environment, the argument has little value for sea reserves. Also remember that the sea does not harm land reserves, but the land harms sea reserves. Sewage does not flow up-hill to soil montane parks. Our national parks are essential useless tracts of land that are inaccessible and unproductive, but our seas are valuable, accessible and productive everywhere. So there exists an important difference between the two, and the argument has no foundation.
    Since land reserves have been created for many reasons (lookouts, unused bits of road, scenic, parks, farm parks, beaches, mountains, glaciers and even mining and logging), the reasons for having reserves in the sea should be equally flexible, it is argued. But the number of different uses we make of the sea, is much more limited: taking, farming and looking.


    Saving marine biodiversity

    A consensus appears slowly among scientists, about how to achieve marine conservation, although it is not clear which actions are least costly while most effective.
    For a more complete treatment on environmental action, visit GPA- UNEP's Global Programme for Action. (Words are easier than effective and timely action). Note that only 40 years ago, all the above-mentioned activity would be of minor importance. Expecting the world population to double in the coming 40 years, it is unimaginable how regulated living will become.
    De-facto marine reserves
    In every sea-bordering nation, large tracts of sea have always been off-limits for fishing and anchoring. In New Zealand, these are the de-facto marine reserves, created for international shipping lanes, cable ways (1650km2), ammunition dumps (1344km2) and more. In New Zealand, a total area of over 3000km2 [1] has been prohibited this way for trawling and anchoring. This is a huge area compared to the total area in 16 coastal marine reserves of less than 150km2. One would have expected scientific research to have been conducted in these areas, for the benefit of knowing their importance to fishing and biodiversity, but in the almost a whole century that these areas have been available for such study, this has not eventuated. What's more, the fish stocks in these areas have declined like they have done outside, making the whole concept of marine reserves in our coastal seas, questionable.
    [1] Setting Course for a Sustainable Future. Report of the Parliamentary Commissioner for the Environment, 1999 p37.
    Reserves for fishing?
    The main two stake holders in fishing (and thus conservation) are the commercial and the amateur fishermen. They blame each other for the demise of the fish stocks. Since one of the things a marine reserve does well, is to separate stake holders (takers and lookers e.g.), the idea arises to have reserves for amateur fishermen only. Their task is now to manage these areas such that fishing there delivers the most pleasure and yield. They will make the rules, without interference from others. This will face them with the consequences of their actions, while allowing scientists and fisheries managers to measure the effect amateur fishermen have on the environment. In New Zealand, the Hen and Chicken Island group off Whangarei would be an ideal testing ground, because the Poor Knights (nearby) has been taken from them as a no-take reserve, and fishermen like to anchor their boats in the shelter of islands and the mainland's coast.

    Likewise, an area could be set aside for spearfishermen. It will give them the responsibility to devise rules to keep fish while eating them too. The Aldermen Island group, out from the Coromandel Peninsula, would be ideal since it has already suffered major damage from spearfishing.


    Ecological aspects

    Much of our understanding of marine reserves comes from imagining a kind of Garden of Eden (paradise) under water, a place with clear water, bountiful fish and wise old fish as well. When we visit one of our coasts today as a diver, we often experience something entirely different. Not only does the sea seem deserted, it also looks like an untended, withering garden, with dust covering the few bottom dwelling species that are left.
    Those people who never visit the sea with mask and scuba gear, find it hard to imagine what the seascape looks like. Yet even those who do so frequently, find it hard to believe what the sea looked like long ago, when told by veteran divers, now about to die out. Children snorkelling in the shelter of Goat Island, are enraptured by their experience, being able to meet friendly fishes so close by. But all these people have one thing in common: they want to preserve the sea as they have known it. This raises the question whether we want to roll the clock back 50 years, or freeze the present situation. What would we need to do to achieve the one objective or the other or both? No-take marine reserves have been toted as the one and only tool for this purpose. But the assertion goes further. Marine reserves can also provide fisheries benefits because fish spill over from the area of plenty to the area of poverty outside. It all sounds plausible, but how can we understand it in an objective way? We do so by the theory of the economics of exploitation. (See Resource management/economies of exploitation)

    In order to stay with a familiar picture, we'll use the same diagram as presented in the chapter on Resource Management. The basic assumption is that a marine reserve can be thought of as a single population, although in fact, it consist of a large number of interacting populations, each grazing or predating on the other. When a place is almost entirely denuded, then left to recover, most of the quantities measured, like number of species, number of individuals and sizes, follows a logistics curve as shown in diagram A. This shows the quantity measured from low to maximum (empty to full) against a time scale in years. Recovery seems to proceed slowly in the beginning (years 0,1,2, the exponential phase) but it is in fact an explosive growth since recovery is not limited by restrictions of space and food. In the middle of the curve, growth rate is at maximum (maximal growth phase), after which it evens out because of lack of space or food (). Note that this part of the curve is seldom reached because all populations are kept in check by their natural exploiters. A pristine environment thus never reaches the max level. Notice the last (orange) step between year 4 and 5, which is about 25% of max. This suggests that in order to fish sustainably, we should not fish the stock down past 70-75% of its natural level. Even so, this would make life difficult already for other predators like dolphins who do not possess our technology.

    In diagram A the growth curves are shown for a fast growing population (purple), medium growth (red) and slow growth (green). Think of them as the silver fish, the reef fish and the large predators. Diagram B shows growth horizontally, rather than time. As can be seen, growth is maximal somewhere near the middle. Note that in an ecological sense, growth equals a gain in stored energy. The blue line shows the effort (energy) required to fish from the three populations. Where the line intersects, more energy is gained from exploitation, than lost in the effort of exploitation. This then leads to diagram C, depicting the amount of energy gained or lost. Clearly, all species must gain more energy than they expend, or else they would die. So they are able only to exploit the stock down partially, which proves that natural populations are self stabilising. Note however, that food is not always easily available all year, so many organisms have alternative survival strategies.

    The diagrams now continue with the situation for shark (D) and dolphin (E), not relevant now. But the last diagram (F) shows that human technologies have given us the power to exploit the stock right to its zero level, also because the rewards for our effort go up as the catch comes down and the price goes up. Humans have thus gained the power to destroy the environment, which no natural organism has. Fishermen often do not realise how effective their fishing methods have become. For instance, which natural hunting predator has a mouth hundreds of metres wide and half that tall? Trawling nets and purse nets do. Which natural predator attracts its prey by odours from food, from hundreds of metres away? Line fishers and pot fishers do. Which natural ambushing predator has a mouth tens of thousands of metres long and fifty metres deep? Gill nets do.

    It is this awesome technology that allows us to exceed Maximum Sustainable Yield (MSY), somewhere in the middle of the curve, without us even noticing. Yet exceeding MSY means that the stock is being fished down, unable to restore itself to a healthy state. Note in this respect that nature has some invisible de-facto protection mechanisms like inclement weather, high seas, remoteness and unproductivity which leave many stocks relatively unfished. Having marine reserves in such areas makes little sense. However, close to populated areas, the sea has often been fished to extinction. The effect a closed area has, will thus be highly dependent on where it is located. A closed area on a heavily fished coast with clear water, will show spectacular recovery, whereas one located far away or in dirty water, will not. Obviously, if a marine reserve is small, its recovery will have but a small effect, due to fish leaking out.

    We now come to the question of how much is spilling out to please fishermen? To answer this question, we treat the reserve as a single population, and leakage from the reserve as predation. It can now readily be understood that leakage should not exceed 25-35% of the stock if the reserve is to remain sustainable. This quantity is in fact equal to that of a sustainable fishery. In practice, such spillout is not possible, since natural predation inside a successful reserve is higher than outside, and many resident species do not migrate easily. The spill over from a no-take marine reserve can thus theoretically never equal or exceed the lost fishery! This argument is often lost on protagonists when they clamour for marine reserves as fisheries management tools. Note that actual measurements of spillover are supporting this. But there is another problem.

    In order to protect slow-growing species (green curve), marine reserves must prevent spillout even further by creating disproportionately large marine reserves with wide buffer zones. These will protect old groupers and some itinerant (wandering) species, and provide for a healthier age structure. The problem is, that such reserves spill proportionally less fish out than those of minimal size. A good, sustainable marine reserve thus should not return more than 25% of the lost fishery! Marine reserves are obviously unsuitable as an alternative to fisheries management. But there is another problem.

    Driven by the ideology of fisheries management with marine reserves, protagonists reason that networks of protected areas may be able to achieve this. It is thought that if marine reserves are kept small to maximise spill-out, then perhaps by having many of them within reach of their offspring (spawn, larvae), will make it work like one larger protected area. However, this does not alter the ecological reasoning set out above, and the total leakage from such a network should also not exceed 5% of the lost fishery. Having many small protected areas furthermore complicates their integrity, management and policing. Obviously, even networks of no-take protected areas are not an alternative to fisheries management.

    Reader, please note that the above is not mainstream marine science, but derived from economic laws. It is the first time that clear evidence is presented of the quantity of the spillover effect, based on ecological principles. Please contact the author for comments or improvements.

    Larval dispersal

    Marine reserves are thought to benefit areas outside by their larger contribution to the offspring of fished species. Indeed measurements show that there are more and larger fish inside than outside. Their combined spawn mass has been calculated to be three times larger or more. As larvae are dispersed by ocean currents, tidal currents, eddies and wind-driven currents, they will mostly leave their origin, to settle somewhere outside. If more larvae are produced, then more will settle outside, where fewer predators are found. Thus the benefit of a closed area may reach far out.
    Scientists are working all around the world to get a grip on this, and to prove where larvae originated from. They use sophisticated techniques such as DNA analysis, otolith marking and more. However, results are still elusive, and the theory remains unproven so far. Because there is a problem.

    Planktonic ecosystems are the least understood environments of all, because their communities move fast with ocean currents; their organisms are minute, fast growing and short-lived. Some organisms are simultaneously plant, animal and bacterium. The green soup contains guilds (functional groups) of all kind: plants, grazers, predators, viruses, larvae of nearly all marine species, decomposing bacteria, nitrifying and denitrifying microbes and much more. Furthermore, the plankton ecosystems over the continental shelves live in close interaction with the sea soil and myriad organisms contributing their spawn. In this natural orchestra, timing is important as barnacles deliver their spawn right when larval food has become plentifully available, and so on. The fish larvae of fished species are but a tiny section of this orchestra. But there is another problem.

    On land, animals produce limited offspring because to do otherwise would be wasteful and excessive. Mammals give birth to one or a few babies, insects to hundreds and plants to thousands of seeds. Some of these produce fruits to help dispersal. But in the sea, both animals and plants reproduce profligately (wastefully) to the extent that for most species less than 0.01% of their spawn will ever produce a replacement (recruit). Such waste is needed to convert the sunlight into ever larger food particles, in stages, which we call  the food chain. Whereas on land two or three stages from grass to sheep to wolf are common, in the sea this consists of many, from phytoplankton to zooplankton, to larvae, to small fish, to bigger fish, to predators, to apex (top) predators. Even the zooplankton has many stages as many larvae grow over ten million times before they leave it, to settle out where they belong (recruiting). So, the path from spawn to recruit to adult is one of extreme waste and extreme uncertainty. It can be said therefore, that marine creatures spawn mainly to make food (over 99.99%) rather than offspring (less than 0.01%). Note that small fishes such as triplefins cannot afford this kind of waste, and they have resorted to various means of nest care. Note also that predation (exploitation) is very natural in the sea, reason why many fisheries have survived human onslaught. But where does that leave the additional spawn mass from marine reserves?

    The whole planktonic ecosystem, although oscillating wildly, is on the whole looped back (effects influencing their causes) in many mysterious and unknown ways. For instance, as the predators in a marine reserve increase, and with it their spawning mass, the spawn of the creatures they feed on decreases, and thus the food for the predators' larvae. For instance, snappers eating sea urchins will reduce the urchin's spawn, which causes a major decrease in the total spawn from the reserve. Urchins are closer to the base of the food chain, grazing on fast growing algae. Because they do not spend much energy in moving, they produce disproportionately more spawn. Because predators move around, while wasting energy also in other ways, they must eat many urchins in order to gain the energy to produce the spawn equivalent of one urchin. As a result, the larger fish decrease the total amount of spawn from the reserve, which also reduces the food for their own larvae. In all, the whole issue of larval production and dispersal remains academic and of little value to fisheries.

    The thistledown effect
    Thistle head in evening sun Thistles are invasive weeds, quick growing, fast seeding plants which propagate over vast distances by the shape of their seeds. These bulk up by a network of fine hairs, so that they can be carried by the wind. It is amazing to find them crossing the sea for 40km, to arrive at a remote island. The fluffy seeds are called thistledown.
    Marine organisms have a similar advantage, because their eggs and larvae are carried in the water, while sea currents transport them far away. Fish larvae can travel 50-100km, and 'stragglers' may arrive from warm waters, 1000km away. The thistledown effect is claimed to give marine reserves a disproportionately large advantage as a source of tiny colonisers, acting like an insurance. It is reasoned that even a small reserve can produce a lot of larvae, an acceptable assumption because fish there are about twice as numerous and larger than outside, producing three times or more eggs. Large fish can produce over a million eggs each, by far enough to restock the entire outside, one may think.
    However, this is not how nature works in the sea. A vast overkill in larvae (from all species and phyla) is needed to convert the energy of the sun into parcels of energy (little fish) that are large enough for sizeable fish to eat. This happens in stages, which we call the food chain or food web. Thus a predator fish in the end, lives from food produced by its own eggs. It illustrates nature's intricate system of harmony between its many players, and it explains why so many sea creatures are broadcast spawners, wasting almost all their eggs in reproduction. It is a survival strategy that, although wasteful for each, is beneficial for all. Fisheries scientists, accounting only for some fish species, while believing that a low stock is able to produce enough offspring, apparently are ignorant of the intricacy of such food chains. This is one of the main reasons that fisheries worldwide collapsed. If we wish to save commercial fisheries, we must manage them with larger and more balanced stocks. Marine reserves would simply not help. The thistledown effect is a myth, with neither scientific proof nor foundation.

    How marine reserves can fail

    It is not entirely certain, how failure can be defined. Some people argue that if a reserve saves only one fish, it is worth having. They do not seem concerned that an important freedom of the seas, to be able to go wherever one wants, to take whatever one can get, is taken away from people making a living or enjoying the sport and thrill of it. People on little income often depend on the sea for sustenance. Minimising costs by going out in small boats, these people fish wherever shelter can be found from waves and wind.
    Man has always lived with the sea in close harmony, taking what he needs from its seemingly inexhaustible larder. The whole marine ecosystem is a fish-eat-fish world, where predation is common fare on many levels of the foodweb. Predation by people is just another facet. For time immemorial, people have lived with the sea this way and this has become the natural situation. But now there are just too many people demanding their share. Instead of taking, we have entered the more difficult era of sharing. Now it is no longer reasonable what one can get, but what one can leave for others.

    Marine reserves aim to save some unspoilt areas for present and future generations in a state that will not worsen over time. They are like time capsules, where time stands still. However, many marine reserves have failed. Why? Here are some important causes, arranged by their severity:

    One thing is certain: if a reserve gets worse over time, it is not sustainable.

    With all the discussion and research on marine reserves, there is still no agreed method for assessing the health of an area, and whether it is getting better or worse. Worse still, many researchers are so single-mindedly focused or so inexperienced, that they are unable to see degradation. This is not entirely surprising, since one has to learn to see what is no longer there. Degradation does not readily show in species lists, fish counts and fish catches. Other methods are needed. As a result, conservation managers are often unaware that their marine reserves are or have become unsustainable.

    For more information, read the section on observing degradation (new) and marine reserve design (planned).
    Also in the indepth section, why reserves fail  and more (easy reading).
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