Marine Protected Areas: finding a Balance


It is a depressing thought that the oceans are facing such a devastating future. The race is on to find ways of reducing our effect on the planet and its oceans, improve the rapidly collapsing fish stocks and to avoid further destruction of habitat. Scientists are keen to find all the ways possible to understand the problems we face from this situation and to research the possible solutions.

Protected coral within a New Zealand marine reserve

One of the promising areas driving this goal is the current trend for Marine protected areas or MPAs and in particular reserve networks. MPAs provide on one hand havens for vulnerable species and habitats, and on the other a strong larval based recruitment in surrounding areas. Where this combination can be successfully be achieved, then both goals of protecting biodiversity and providing the means to create a manageable commercial fish stock are plausible results. If this situation can be created the both sides of the argument can be happy. (Roberts 2001a)

It should be remembered that there are several grades of MPAs, and not all of them provide the same protection. Within British legislation we have, Special Areas of Conservation (SACs); Special Protected Areas (SPAs); Voluntary Marine Conservation Areas (VMCAs); Voluntary Marine Nature Reserves (VMNRs); No Take Zones (NTZs) and the newest of the areas, Marine Conservation zones (MCZs) which were brought into legislation with the new Marine and Coastal Access act – Nov 2009. (UKMPAcentre)

It should also be noted that whilst these areas exist and are covered by legislation, very few of them prohibit damaging activities including fishing. Concern has been shown by some towards the inadequacies of current law regarding some of these sites. Pressure from conservation charities have added weight to arguments for developing more MPAs and for increasing the protection given to these sites.

In addition to our own national laws, Natura 2000 can provide European legislation, The UK currently has around 45 sites(SACs and SPAs) recognised by Natura 2000, which are now considered  as European marine sites(EMSs) we also have a number of additional sites which have been submitted to the European Commission.(JNCC, Natural England)

It now remains to be seen if the new legislations and the increased national and international efforts to improve on the present MPA situation. It can be hoped that the interest being shown in the marine environment by both government bodies and the general population can be expanded and will result in a greater improvement of laws as well as a greater understanding of marine networks.  

 Marine reserves are protected by law, and whilst some activities are permitted, fishing and some other potentially damaging activities are forbidden. Over the past few years major progress has been made in the implementation of these areas resulting in around 5000 current MPA sites which are accepted by the International union for conservation of nature and natural resources which is known as the IUCN, whist this sounds hopeful it is still accounts for less than 1% of the earth’s oceans (IUCN).

 Substantial research has been organised to gain valuable insight into just how important the development of these areas are and the potential to solve many problems concerning the marine crisis we currently face. (Roberts 2001, Sala 2002, Gaines 2010)

Recent investigations show that much of our knowledge of marine biodiversity is still shrouded in mystery. We have an incomplete picture of the natural marine habitats and their inhabitants. Without attempting to provide some areas of coastal seas and oceans which are protected from exploitation, free from the pressures of fishing and other damaging activities we would struggle to know the full extent of marine life and ecosystems worldwide.

Studies have investigated the theory behind Reserves including the relationships of fisheries coupled with the effort to conserve areas and their inhabitants. Models have been drawn up on these situations and have led to much advancement on the subject. Many scientists now accept that networks of reserves seem to be the way forward. (Roberts 2001a, Roberts 2001b, Gaines 2010)

 Many studies have been made on reserves abilities to repopulate greater areas than the reserve itself and essentially create a balance in line with fishing areas rendering benefits to both conservation and also commercial fishing. As Theories and evidence mounts to show that in the best cases recoveries can be made and areas can indeed increase biomass, it becomes clearer that an extreme amount of variables are at work for the success or failure of each reserve.   Ultimately what works in one set of circumstances will not neccaceraly work in the next. (Roberts 2001a, Roberts 2001b, Sala 2002)

Most experts seem to agree that networks of reserves have many benefits over single isolated reserves particularly where the reserve is concerned in keeping stocks of fish at a sufficient quantity to allow the larger surrounding area to support fishing. (Botsford 2003, Sala 2002) 

It is believed that networks need to cover an extensive area and protect the full range of marine habitats in the surrounding area. One network of reserves which has become a working example for the design is the network of reserves in the Gulf of California. The design involved a group of reserves covering all types of habitat with an intention to protect 20% of all the given environments, which included mangroves, seamounts, rocky shores and algal beds.  (Sala 2002)

Marine reserves are used for many situations including as a protective measure for endangered species, fragile habitats, as a maintenance tool for marine ecosystems and commercial fishing, and as a scientific tool marking biodiversity and reference. They are in themselves considered an essential  conservation system. However in order for them to adequately provide a realistic chance of being a strong player in the recovery of the oceans a considerable amount of design and control needs to be applied to them.  (Botsford 2003, Roberts 2001b, Gains 2010)

One major possible feature of networks of marine reserves is their effect on overall fish stocks. A number of studies suggest that there may be significant improvements to the stability of fish populations where reserve networks are put into place. (Roberts 2001a)

There Have been some success stories in recent years providing evidence that marine reserves have had a positive effect on neighbouring fisheries surrounding the reserves(Roberts et al. 2001)and that by designing networks of marine reserves specifically to an area and its inhabitants can gain even greater levels of success.(Roberts  2001a)

Much research has been made with regard to networks, but as so few have been given full protection and most having only been in operation for a short time scale most information on real working situations is in its infancy. One area that has reported success is the New Zealand reserve network which was initially founded in 1975 and showed promise quite rapidly resulting in expansion of the reserves into a fully protected network, in attempts to create a scientifically productive area. It has aided scientists to ascertain the productivity of protected areas in relationship to the fisheries which can operate up to the reserves boundaries.  (New Zealand Government) 

Goat Island, Part of the New zealand marine reserve network

Estimates vary for what the optimum percentage of habitat to be included within a reserve is in order to preserve biodiversity, however the current accepted amount of protected habitat in any one area which is thought to help create a balance of fishing and biodiversity seems to be a minimum of 20%. Whilst this is a basic guide the best solution seems to be to place a variation of sized reserves at differing distances to each other to create a mixture of viable areas available for protected larval distribution. (Botsford 2003, Sala 2002)

Due to the Dispersal of marine life during reproduction and then through planktonic larval stages of development, marine reserves will not fully protect any one population of a species. However by placing multiple protected areas at varying distances and sizes around a coast line or habitat then the effects are likely to provide settlement both inside the reserves and outside the reserves providing populations of species on either side of the protection. This process is the basis for larval dispersal, and the recruitment to new areas. (Botsford 2003, Sala 2002)

The term Larval Recruitment refers to the larvae distribution by water circulation and current movement this allows the larvae to settle in a new area not necessarily within the space around the parent, but on occasion many kilometres away. The planktonic larvae of different species manage to move across a range of distances, therefore the effects of protecting a population are able to benefit a far greater area than just the reserve itself. (Botsford 2003, Sala 2002, Gaines 2010) By using what we know about larval dispersal we can create a patchwork of reserves which create a feasible compromise between the fisheries and the conservationists.

With the full weight of the conservation argument it would be easy to assume fishing is bad, and the only way to protect our oceans is to stop the practice altogether but we should not loose site of the importance of the fishing industry.  We are warned time and time again of the future collapse of commercial fish stocks, yet fishing goes on and very little sign of serious conservation reform is shown. It is worth remembering that fisheries work to provide a service, and as much of the world particularly the poorest, developing nations rely heavily on fish as their main source of protein so without the fishing industry much of the developing world would suffer (UNEP). A fine balance needs to be found between the marine environment and also the requirements of people who depend upon it. Without this compromise very little can be achieved to improve the outlook on either side of the argument.

So far very few answers have been delivered which address the needs of both parties within marine conservation and the fisheries, MPAs and marine reserve networks may be one of the key principles available for exploitation.   Whilst traditionally the thought of the fisheries and conservationists benefiting equally from an action would seem unlikely, it may be more of a reality than many would assume.

We are a long way from a harmonious resolution to the balance of human need and destruction of the natural world. Huge steps have been taken to develop answers to individual issues. Some situations seem hopeless but nothing is likely to succeed without the collaboration of the industries concerned. 


Botsford LW, Micheli F and Hastings A (2003) Principles for the design of marine reserves. Ecol Appl 13:S25-S31

Gaines S.D, White C, Carr H and  Palumbi R (2010) Designing Marine reserve networks for both conservation and fisheries management. PNAS, 107, 18286-18293.

Roberts CM, Bohnsack JA, Gell F, Hawkins JP and Goodridge R (2001) Effects of marine reserves on adjacent fisheries. Science 294: 1920-1923

Roberts CM, Halpern B S, Palumbi SR and Warner RR (2001) Designing marine reserve networks: why small isolated protected areas are not enough. Conservation Biology in Practice 2: 11-17

Sala E, Aburto-Oropeza O, Paredes G, Parra I, Barra JC and Dayton PK (2002) A general model for designing networks of marine reserves. Science 298: 1991-1993



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