Why marine reserves are important
Marine reserves are important for preserving the biological diversity ('biodiversity') of marine areas. They protect rare and threatened species, important natural habitats and provide benefits for fisheries species. Scientific research from around the world supports the concept that marine reserves are one of the best ways of protecting marine biodiversity. This sounds good in theory, but why are marine reserves important in Moreton Bay Marine Park?
What is a marine reserve?
Marine reserves, also known as protection zones, marine national park zones, green zones or 'no take' zones, are areas within a marine park that exclude all extractive activities (nothing can be taken from these areas). Marine reserves have been implemented worldwide 1 in response to international concern for the conservation of marine biodiversity. In Australia, the number of marine reserves has increased to meet international obligations and national policies 2.
International studies show that marine reserves are most effective when they are established in interconnected networks. Networks are effective because the majority of organisms freely move and interact between different areas in the marine environment 3. For example, larvae, eggs and adult marine life tend to move with the currents and coastal waters depending on oceanographic conditions.
Networks of marine reserves protect marine populations throughout their diverse life cycles and protect the habitats that support them.
What are the benefits of marine reserves?
A general summary of the potential benefits of marine reserves follows.
Benefits to marine biodiversity:
- marine biodiversity maintained
- rare, vulnerable and threatened species protected
- habitat protected.
Benefits to exploited species, such as fisheries species:
- abundance, size and biomass increased
- reproductive potential increased
- 'spillover', or movement, into adjacent areas.
Benefits to the local community:
- protects cultural and spiritually significant sites (such as sacred places, middens, fish traps, shipwrecks and historic marine structures)
- increased marine-based tourism potential (marine reserves often contain unique natural features which become popular for tourism and recreational activities)
- provides research and public education opportunities provided.
Marine reserves in Moreton Bay Marine Park
Moreton Bay Marine Park supports a unique combination of habitats and wildlife. The marine park sits at the meeting point of the tropical north and temperate south. This mixing zone gives Moreton Bay Marine Park its diversity of habitats and species. Some of these species are unique to Moreton Bay Marine Park.
In the 1997 zoning plan there were six marine reserves in Moreton Bay Marine Park, representing 0.5% of the total area of the marine park. These zones were found at:
- Tripcony Bight
- Flinders Reef
- Peel Island
- Willes Island
- Swan Bay
- McCoys Creek.
These six reserves protected particular habitat types and communities such as mangroves, seagrass beds and coral reefs. The reserves were relatively small and isolated rather than interconnected through a network system. Habitat types such as deep water habitats, rocky shores and algal beds were not protected in any marine reserves under the 1997 zoning plan.
Did you know?
Moreton Bay Marine Park has recorded:
- over 750 species of fish
- over 120 species of coral
- the highest diversity and abundance of whales and dolphins in Australia
- the world's largest population of dugong next to a capital city
- populations of the endangered grey nurse shark
- six of the world's seven species of marine turtles.
Success of marine reserves in Moreton Bay Marine Park
A four year study of marine reserves in Moreton Bay Marine Park showed that they do work. The study, which commenced in 2002, investigated the impacts on marine reserves at Tripcony Bight and Willes Island that had been protected since 1997. The results indicated that after five years of protection, the two marine reserves studied in Moreton Bay Marine Park provided benefits to marine biodiversity and fisheries species 4. In particular, the study revealed the following benefits of marine reserves.
Benefits to marine biodiversity
Nekton (invertebrates and fish)
- Marine biodiversity was maintained within the marine reserves but not increased (including over 100 species of nekton).
- Marine reserves provided refuge for rare and vulnerable species including turtles, dugong and a range of elasmobranchs (i.e. stingrays and sharks) 5.
Benefits to fisheries species
Mud crabs Scylla serrata
- Mud crab catch rates were three times higher in marine reserves compared to adjacent fished sites.
- There was a 10% increase in average size of mud crabs, indicating increased reproductive potential within marine reserves compared to outside areas (that is, larger female crabs can produce more eggs).
- Tag-recapture data revealed mud crabs moved outside of marine reserves into adjacent fished sites ('spillover' effect) 6.
Finfish—Yellowfin bream Acanthopagrus australis and dusky flathead Platycephalus fuscus
- Yellowfin bream and dusky flathead catch rates were between three to seven times higher in marine reserves compared to adjacent fished sites.
- Mean sizes of yellowfin bream and dusky flathead were between 10 to 20% greater inside the marine reserves compared to adjacent fished sites.
- Biomass of yellowfin bream and dusky flathead were between 15 to 90% greater inside the marine reserves compared to adjacent fished sites. This indicates increased reproductive potential for both species within the marine reserves.
- Tag-recapture data revealed yellowfin bream and dusky flathead moved outside marine reserves into adjacent fished sites ('spillover' effect) 7.
5 Pillans, S., Ortiz, J.C., Pillans, R.D. & Possingham, H.P. (2007) "The impact of marine reserves on nekton diversity and community composition in subtropical eastern Australia", Biological conservation 136:455-469
6 Pillans, S., Pillans, R.D., Johnstone, R.W., Kraft, P.K., Haywood, D.D.E. & Possingham, H.P. (2005) "Effects of marine reserve protection on the mud crab Scylla serrata : in a sex-biased fishery in subtropical Australia", Marine ecology progress series 295:201-213