A new study published in the journal PLOS found that decreasing shark populations are negatively affecting the health of surrounding coral reefs. Top predators like sharks play an important role in marine food webs, and their absence often correlates with a reduction in ecosystem productivity. The picture below shows just how important top predators are in the food web. This decline in shark populations is attributed to overexploitation by Indonesian shark fishermen but is ultimately a result in poor governance of the aquatic ecosystem. Balancing the needs of ecosystems, stakeholders, governments, etc. in predicaments like this is particularly tricky. What gets protected? How are fishermen monitored? How is ecosystem health monitored? How are fish populations accurately measured?
The Great Barrier Reef Marine Park (GBRMPA) is an archetype for successful governance, managing environmental health and the interests of stakeholders by employing ecosystem based management and adaptive management schemes. But I worry the scope of governance of the Great Barrier Reef may not protect it from long term damage. Without proper management of other oceans resources, protection of the Great Barrier Reef may be impossible.
Place based management, an overarching scheme within GBRMPA, relies on a clear definition of boundaries and space. Managers have divided the park into hundreds of unique zones, and while this has led to all sorts of success, it does not take into consideration what happens outside of these zones. What about migratory populations? What about overfishing of these species? Some top predators migrate more than a thousand miles which far extends the capacity of GBRMPA’s place based management scheme. These predators are then unprotected and in places like Indonesia are subject to overexploitation. A reduced presence of predators returning to the GBR (as a result of improper management elsewhere) could bring the same issues faced by coral reefs in Indonesia.
I know that without defining boundaries, the GBRMPA could not effectively function, but this hypothetical stresses the need of global cooperation when dealing with environmental problems. The earth is a closed system. Successfully managing an ecosystem in the long run is not possible without recognizing its interdependence with everything around it.
Sources:
In text photo – http://media-1.web.britannica.com/eb-media/48/6548-004-B83C9736.jpg
News article – http://www.enn.com/wildlife/article/46455
Cover photo – http://www.redorbit.com/media/uploads/2013/09/sharks-coral_SS_31029865_091913-617×416.jpg