Study Finds Best Locations to Restore Hawaiian Reef Fisheries

Healthy reef in Hawai‘i. PC: K. Stamoulis.

A new study published by researchers at the University of Hawai‘i at Mānoa highlights opportunities to restore and sustain Hawaiian reef fisheries.

Excess fishing has depleted coastal fisheries across the globe, threatening the food security and cultural identities of many coastal and island communities, including Hawai‘i. The recent study identifies areas in the Hawaiian Islands that could provide the greatest increase in reef fish stocks, if managed properly.

Hawai‘i’s fisheries provide more than two million pounds of fish each year throughout the state, and fishing is intimately linked to recreation, traditional cultural practices and knowledge, as well as social gatherings.

The study determined the best sites to focus on for conservation efforts by developing regional “seascape models” that combine fishing patterns and reef fish survey data to map key habitats that support abundant coastal fishery stocks. Using a computer model, the research team simulated the effects of removing fishing pressures from specific areas. The resulting maps revealed the areas with the highest potential for recovering reef fisheries on each island, providing a crucial store of data for resource managers.

Highest recovery potential (top, red); currently healthy stocks (bottom, green). PC: K Stamoulis.

“The results provide hope in terms of the scale of potential recovery in the areas we identified,” said lead authors of the study Kostantinos Stamoulis, a UH Mānoa researcher at the time of the work, and Jade Delevaux, geospatial analyst at the UH Mānoa School of Ocean and Earth Science and Technology (SOEST).

Fish stocks were predicted to increase by more than 500 percent on average for the identified areas on O‘ahu, the most heavily fished island. Areas with the highest recovery potential for coastal fisheries across the island chain were located on: east Kaua‘i, southeast and southwest O‘ahu, south and northwest Moloka‘i, Ma‘alaea bay and the west shore of west Maui, west Hawai‘i Island north of Makole‘a point, and east Hawai‘i Island around Cape Kumukahi and north of Kaloli point.

While full recovery of this fisheries could take decades, protecting areas with the highest recovery potential could serve as hatching grounds to replenish overfished areas.

In general, the study found that areas near the rural north shores of all islands are not heavily fished, have high quality habitats, and support the most abundant stocks of reef fish.

The State of Hawai‘i has committed to effectively manage 30 percent of Hawai’i’s nearshore waters by 2030. To accomplish this, the Division of Aquatic Resources is leading a statewide analysis of existing science in partnership with The Nature Conservancy to identify areas for effective marine management.

“This new study will help us identify those areas with the greatest potential for increasing reef fish populations on all islands,” said Bruce Anderson, administrator for the Department of Land and Natural Resources Division of Aquatic Resources. “This scientific information will be compared with an ongoing spatial analysis as part of the Marine 30×30 Initiative. Ultimately our intention is to combine this information with local knowledge and collaboratively identify what to do in management focus areas.”

“To ensure food security and overall ecosystem sustainability into the future, we must significantly increase the amount of area protected from overfishing and other human impacts,” said Alan Friedlander, chief scientist for National Geographic’s Pristine Seas program and a co-author of the paper. “Our study provides an ecosystem-based approach that helps to identify areas that will benefit the most from increased management in Hawai‘i and elsewhere.”