DAR's Final Report to NOAA's Coral Reef Conservation Program

The State of Hawai'i's Division of Aquatic Resources has released a report on the outcomes of its monitoring program, "Long-Term Monitoring of Coral Reefs of the Main Hawaiian Islands" prepared by William Walsh, Russell Sparks, Camille Barnett, Courtney Couch, Stephen Cotton, Darla White, Kristy Stone, and Eric Conklin. 

Click here to view the report in Google documents.

Below is the Summary of Findings for MAUI from the report:

Benthic
• Nine of the 20 currently monitored coral reefs have experienced significant changes (paired t-tests of first survey year vs. most recent survey year, p<0.05), with coral cover declining at 7 sites and increasing at 2 sites.
• Coral cover declines at three sites (Honolua Bay, Mā’alaea Bay, and Papaula Point) were so severe that these individual reefs may have already experienced a total coral reef ecosystem collapse.
• Sites experiencing significant coral reef declines appear to be affected by anthropogenic impacts such as land based pollution, sedimentation and overfishing.
• Monitoring sites with stable high coral cover (Kanahena Bay, Olowalu, and Molokini) appear to be away from urban areas, are fairly remote or are located offshore.

Fish
• Comparisons between fully protected reserves versus areas open to fishing show that marine reserves have consistently higher resource fish biomass levels, larger sized fish, greater numbers of apex predators, and the greater abundances of schooling grazers.

Shallow Water Habitat and Fish Surveys (lay-net regulation assessment surveys)
• Fish biomass levels were higher in areas where past lay-net fishing effort was lower.
• Qualitative habitat assessments show the areas that experienced the highest past lay-net fishing effort had the most degraded reef habitats with algal cover at 20% or higher at most of these survey locations.

Kahekili Herbivore Baseline
• 242 Sites have been surveyed to establish a firm baseline of fish, benthic cover, and urchin populations.
• Benthic community structure and fish biomass varied significantly by habitat, and therefore may have markedly different responses to the management implementation.

Volunteer Herbivore Grazing Assessments
• Over 100 trained volunteer community members have participated in 532 surveys, totaling over 2400 contributed hours
• General grazing trends for both acanthurids and scarids were similar. A significant negative correlation for grazing rate versus fish size was observed, which is intuitive because smaller fishes require continuous energy for growth. Conversely, bite sizes increased with fish size.
• The area of algae scraped by scarids over a year has a significant positive linear relationship to size (i.e. larger fish have a greater impact on algal removal).
• Both scarids and acanthurids are critical grazers for controlling algae on the reefs. Not enough data was gathered on kyphosids due to infrequent presence of this family in the study sites.

Roi Control Assessments
• Data has been collected on community efforts to reduce roi populations on Maui. Most of this effort has been at one location, Olowalu.
• When data on both CPUE and the number of roi escaped are combined, a significant decline in roi abundance can be seen.
• While roi have been substantially reduced, they are still present in moderate densities despite months of removal effort.
• Ciguatera analysis of fish weighing over one pound indicates that 69% of the population contains ciguatoxin.

Coral Disease Assessments
• HIMB researchers’ data showed a 47% decrease in coral cover over a period of one year at a site known as Montipora Pond, wherein a nearly monotypic stand of Montipora capitata has a chronic outbreak of Montipora white syndrome. DAR Maui took over monthly monitoring efforts to learn more about this outbreak. The outbreak shows patterns of waxing and waning, with an increase in coral mortality.
• NOAA and DAR Maui have partnered to gather data on coral disease at four sites on Maui in order to test a satellite predictive tool model for Hawai′i. The first of two years of data collection has been completed.