Benefits of marine protected areas

Marine protected areas can have a range of ecological, social, cultural and economic benefits, which are summarised below. The extent to which these benefits can be achieved in practice, is largely dependent on the characteristics, location, design and on-going management of the areas.

Protection of biodiversity and increased productivity

There have as yet been no studies in New Zealand to establish the direct impact of marine reserves on biodiversity. However, international research has conclusively shown that, where extractive activities are prohibited, abundance of previously exploited marine species in marine reserves can increase dramatically, and that this can occur within relatively short periods of time. ²⁶⁹³

An increase in the abundance of previously fished species can have a positive flow-on effect, through rebalancing predator-prey relationships, and overall the food web. For example, the increase in snapper and rock lobster within the Cape Rodney-Okakari Point marine reserve was associated with a marked decrease in the abundance of sea urchins (on which snapper and rock lobster prey), and a regeneration of kelp beds (on which the sea urchins prey). This, in turn, is thought to have increased productivity and diversity within the marine reserve. This is because kelp forests are major primary producers, support a richer and more diverse faunal community, and are “central to ecosystem function and diversity.” Scientists have estimated that macroalgae primary productivity in the reserve has increased by 58 per cent over a 20 year period. ²⁶⁹⁴

Increased resilience and maintenance of ecosystem services

Well-designed marine protected areas can help to promote healthy ecosystems which are resilient, and able to adapt to stresses, because they are complex systems with inbuilt buffers. Resilience enables marine communities to better withstand pressures whilst still retaining their basic function, including the delivery of the ecosystem services upon which we all rely. ²⁶⁹⁵  Critical services include climate regulation, oxygen production, nutrient recycling and production of protein for human consumption.

Benchmarking of environmental health

The complexity of marine ecological dynamics makes it hard for scientists to assess the impact of human-derived pressures on the marine environment. ²⁶⁹⁶  Modelling can assist, but cannot provide all the answers. The establishment of areas in which specific activities are excluded, can play an important role in providing ‘benchmarks’ or ‘controls’, against which human impacts and management of the rest of the marine area can be evaluated. ²⁶⁹⁷

In particular, because marine reserves exclude fishing, they can provide useful information on the characteristics of an unfished population, which can then be compared with those of the fished stock. This can provide an indication of the extent of change caused by fishing, and therefore help inform fisheries sustainability decisions. ²⁶⁹⁸

Fisheries spill-over

Marine protected areas can potentially benefit commercial and recreational fishers by contributing to fish stocks outside the protected area. This can occur if harvestable-size stock moves from the closed area to open areas where they can be caught, or if eggs and larvae cross the boundary and establish outside the closed area.

The spillover of harvestable species from reserves is evident from the presence of fishers around the edges of the protected areas. For example, cray pots often line the reserve boundaries around the marine reserve at Leigh. ²⁶⁹⁹  The likelihood of such ‘spill-over’ depends on the mobility and habits of the species concerned, conditions inside and outside the marine protected area, and the area’s design (for example, longer edges enhance the likelihood of spill-over). ²⁷⁰⁰

Marine reserves can support denser populations of larger fish for resident species that are heavily fished. ²⁷⁰¹  A recent study of three marine reserves in the Greater Hauraki Gulf (at Leigh, Tāwharanui and Hahei) found that there were on average 13 times more large snapper, above the legal size limit, within the reserves than outside them. ²⁷⁰²  This has important implications for reproduction. Larger fish can produce far more eggs, per unit of body weight, than smaller fish. In addition, there is evidence that the larvae produced by larger fish have better survival rates. ²⁷⁰³

Protection of geological features or processes

Marine protected areas can be used to protect geological features and processes identified as particularly unique or typical. This may be closely interlinked with the protection of the biodiversity they support. For example, deepsea vents are valued both as rare geological features and for the unique ecological communities which are dependent on them. 

Protection of cultural values

The protection of marine space can be of considerable cultural value. For example, the establishment of the Whanganui A Hei – Cathedral Cove marine reserve was supported by Ngāti Hei, because the area included tapu sites associated with tribal massacre. Ngāti Hei believed that the establishment of the reserve enhanced their mana. Likewise, the Sugar Loaf Islands marine protected area includes tapu sites for at-sea burials.

Increased recreational and tourism opportunities

Studies of the impacts of marine reserves in New Zealand have shown a range of tourism and recreation benefits. For example, the establishment of the Tonga Island marine reserve adjacent to the Abel Tasman National Park, increased the recreational value of the area and, in turn, attracted greater numbers of visitors. In response, new accommodation enterprises have established, and there are growing numbers of water taxi operators. There has also been a significant growth in the number of kayak companies, from the two operating prior to the establishment of the marine reserve, to at least 13 currently. ²⁷¹⁰

Education and science

Marine reserves provide the opportunity for scientists to study marine communities which are largely intact, and which are not directly disturbed by fishing activity. For example, science undertaken in the Cape Rodney - Okakari Point marine reserve has made a major contribution to our understanding of rocky reef systems in New Zealand. ²⁷¹³

Scientsts are able to observe unharvested populations of fish in marine reserves. This is important to enable the development of understanding about the natural behaviours and population dynamics of fish species. In addition, reserves enable scientists to carry out longitudinal studies on individuals, which are not possible where fishing takes place, as the individual studied will likely be lost to harvesting during the experiment. ²⁷¹⁴

Educational facilities often co-locate with marine reserves, as the reserves provide an excellent place for students and members of the public to observe marine life. For example, the Goat Island Marine Discovery Centre has been located near the marine reserve at Leigh and the Sir Peter Blake Marine Education and Recreation Centre is located adjacent to the Long Bay-Ōkura Marine Reserve.

Last updated at 7:17PM on February 8, 2018