The largest expanse of intact and actively growing coral reef around Hawaiian Islands is being poorly managed with an expected fall in populations of important fish such as jacks, parrotfishes, snappers, unicorn fishes and chubs, according to the latest research.

Scientists from NOAA’s Pacific Islands Fisheries Science Center – Hawaii Division of Aquatic Resources – and The Nature Conservancy evaluated different management scenarios for one specific area: Puakō, in west Hawaii.

The current management scenario was the poorest performer—with nearly all key ecosystem indicators decreasing or with no meaningful change. Only a reduction in land based pollution would actually increase coral cover, according to the findings. 

Ecosystem stability 

Maintaining the status quo is projected to result in less highly prized fish – such as jacks, parrotfishes, snappers, unicorn fishes and chubs. There will then be an increase in undesirable fish species increase – including moray eels, hawkfishes, tobies, and porcupine fishes. Additionaly, coral reefs will likely become dominated by algae.

West Hawaii has the largest expanse of intact and actively growing coral reef in all of the main Hawaiian Islands. The wide array of ocean life makes it incredibly important for marine biodiversity and human society. 

The coastal ocean and coral reefs provide seafood, resources for tourism and recreation, protection from wave and storm impacts, and the preservation of cultural practices.

But it is also particularly vulnerable to the pressures of an increasing population, coastal development, fishing, pollution, and climate change.

A recent study published in the Journal of Applied Ecology provides a range of options to protect and restore this valuable marine ecosystem for the future.

Reducing pollution

The scientists evaluated how different management strategies would benefit the coastal marine ecosystem and coral reef health.

The evaluation was based on key ecosystem services and indicators. Six different management scenarios were then assessed based on: no change in current management; reduced fishing; reduced land-based pollution; no fishing of herbivores; line-fishing only; marine protected areas.

All of the other management options show improvements in ecosystem structure and resilience. However, reducing land-based sources of pollution was the only scenario where coral cover increased.

Dive tourism would derive the greatest benefit from only line-fishing and no-take areas. The reduced fishing scenario – 90 percent Maximum Sustainable Yield [MSY] – shows positive gains in all three ecosystem services, including the largest to fisheries, however gains were minimal in comparison to other management options.

The scenario with only line-fishing represents the most balanced trade-off for all indicators with positive gains for both ecosystem structure and resilience and dive tourism and only moderate losses for fisheries.

Ultimately, the report concluded that no management solution simultaneously promotes recovery of ecosystem stability while also maximizing the delivery of ecosystem services.

Selecting the ‘best’ management strategy for the region depends on the desired balance between enhancing ecological benefits – improved ecosystem structure and resilience – and improving socio-economic benefits to fishermen and dive tourists.

This Author

Brendan Montague is editor of The Ecologist, founder of Request Initiative and co-author of Impact of Market Forces on Addictive Substances and Behaviours: The web of influence of addictive industries (Oxford University Press). He tweets at @EcoMontague. This story is based on a news release from the British Ecological Society.