| Publication date | January 20, 2021 |
|---|---|
| Sector | Natural Ecosystems |
| Region name | Overseas (Hawaii, USA) |
The tropical coral reefs that extend off the west coast of Maui, Hawai’i, USA, are habitats for a variety of fish and other organisms, and play a very important role in tourism and the local fishing industry. However, climate change has had a negative impact on coral reefs, with coral coverage (see Note) off Kaanapali Beach falling by 40% between 1994 and 2006.
The decline in coral reef habitat and concurrent increase in algal blooms is assumed to caused by an imbalance between factors that promote algal growth (wastewater and fertilizer contamination) and those that inhibit it (herbivorous fish and sea urchin populations). In order to recover a balance more favorable to coral, it is necessary to suppress algal growth.
The Department of Land and Natural Resources in Hawai’i has proposed, as one measure, a change in fishery regulations to protect herbivorous organisms that feed on algae, such as fish and sea urchins. The intent is that an increase in herbivores may help to suppress algal blooms. The current state and trends of coral reefs on Maui Island, as well as the details of the herbivorous organism protection program are first summarized. Using 16 presentations and other events, information on the issue was disseminated to over 800 state residents. In addition, efforts were made to gain the support of indigenous peoples and stakeholders most affected by the regulations. As a result, the conservation plan was well received by the local population.
In 2009, the Kahekili Herbivore Fisheries Management Area (KHFMA) was established in order to prevent the decline of coral reefs off the coast of North Kaanapali Beach and Kahekili Beach Park where specific regulations or conservation measures to protect herbivorous organisms did not exist. It was subsequently made illegal to catch, kill, harm or dispose of living organisms such as surgeonfishes, parrotfishes, and rudderfishes in the KHFMA . In addition, catching sea urchins and feeding of fish were also prohibited.
As of 2015, biomass for parrotfishes and surgeonfishes in the KHFMA increased by 139% and 28%, respectively (Fig.). In addition, the crustose coralline algae cover suitable for the colonization and growth of coral larvae increased from 2% in 2009 to 15% in 2015. By contrast, the coverage of macroalgae remained low in this period.
Although the local reception of the herbivorous organism conservation plan was not uniformly positive, fishermen, including spear fishermen who were able to observe the decline of the coral reefs first-hand, recognized and strongly supported the conservation plan, which contributed to the maintenance of local coral reefs and ecosystem services. Indigenous fishermen also viewed the initiative as serving the purpose of maintaining resources for future generations.
KHFMA is an excellent example of the collaboration between state agencies and local communities and is expected to enhance the resilience of coral reefs in the future.
Fig. Changes in biomass of (A) Parrotfishes and (B) Surgeonfishes
(Source: Ivor D. Williams, Darla J. White, Russell T. Sparks, Kevin C. Lino, Jill P. Zamzow, Emily L. A. Kelly, Hailey L. Ramey. "Responses of Herbivorous Fishes and Benthos to 6 Years of Protection at the Kahekili Herbivore Fisheries Management Area, Maui”)
