Research, Outreach, & Reports

Click to read our open-access paper published in December 2023, Evidence for managing herbivores for reef resilience

Infographic describing HIMARC’s methods for creating maps of indicator condition around the Main Hawaiian Islands.

Overview of HIMARC Research Methods

Working with our data providing partners, we combine information from over 18,000 fish surveys and 11,000 benthic surveys measuring seven indicators. Surveys are taken via SCUBA.

These seven indicators were chosen after a thorough review of scientific literature. They represent specific measurements that are applicable to management and tell us about coral reef health and resilience.

After receiving data, HIMARC data specialists conduct back-and-forth quality analyses on the data alongside each data provider. After quality analysis, the datasets are combined and calibrated to correct for differences between methodologies and other factors.

This video clip from HIMARC’s Calibrate-a-thon workshop in Fall 2022 shows a scientific diving team from the Hawai‘i Division of Aquatic Resources swimming along a transect and collecting data on fish abundance.

How does HIMARC conduct our research?

Understanding the relationships between drivers and indicators of reef condition allows us to inform decisions regarding marine resource management using the best available science.

Using a statistical analysis called Bayesian Hierarchical Modeling allows us to understand the relationships between the drivers and the fish and benthic indicators. These models allow us to create continuous maps that predict the condition of all nearshore reefs around the Main Hawaiian Islands, providing flexible data products that are used for a variety of management applications, and serve as information on nearshore ecological condition equitable and accessible for stakeholders around Hawaiʻi.

The combined datasets are then layered with 27 drivers (variables that we hypothesize to influence the reef condition).

Published Research and Reports

Publications listed below are either authored by HIMARC ʻOhana members or utilize the HIMARC database. Click on the image of each publication to download the full PDF, or click the summary below each paper to read a short description of the research. 

2023

Evidence for managing herbivores for reef resilience

  • Mary K. Donovan, Chelsie W. W. Counsell, Megan J. Donahue, Joey Lecky, Laura Gajdzik, Stacia D. Marcoux, Russell Sparks & Christopher Teague

    2023 (December), Proceedings B

  • This paper includes an analysis of patterns and drivers of herbivore biomass and benthic condition of nearshore reefs around the Main Hawaiian Islands.

    Here are some main findings:

    1) We document a large variation in herbivore biomass statewide, and identify multiple drivers that explain that variation, including both fishing and land-based pollution

    2) When herbivore biomass is below 80% of the potential biomass, assuming no fishing while accounting for all other drivers, the condition of the reef is predicted to decline

    These findings have important implications for how we can increase the resilience of our reefs to global climate change.

Linking land and sea through an ecological-economic model of coral reef recreation

  • Kirsten L.L. Oleson, Kenneth J. Bagstad, Carlo Fezzi, Megan D. Barnes, Mary K. Donovan, Kim A. Falinski, Kelvin D. Gorospe, Hla Htun, Joey Lecky, Ferdinando Villa, Tamara M. Wong

    2020 (July), Ecological Economics

  • This paper developed a model that links ecological and economic benefits to coral reef management. The study found that people who enjoy coral reefs recreationally tended to prefer sites with better water quality and ecological conditions, which were both best improved with integrated land-sea management. This kind of model can help managers choose where to take action based on the outcome’s value to society and net benefits to both people and reefs.

  • Alan M. Friedlander, Mary K. Donovan, Edward E. DeMartini, Brian W. Bowen

    2020 (August), Journal of Biogeography

  • A quarter of all Hawaiian shore fish species are endemic, meaning they are found nowhere else in the world. This paper surveyed reef fish assemblages in the Hawaiian Archipelago to inform regional management and conserve these unique biological communities. They found that endemic fishes made up 50% of the total numerical abundance of fishes in the Northwest Hawaiian Islands (NWHI) and 20% of the total numerical abundance of fishes in the Main Hawaiian Islands (MHI). It is critical to conserve places with high endemism because range-restricted species are generally considered to be at a higher risk of extinction due to localized disturbances.

2020

Dominance of endemics in the reef fish assemblages of the Hawaiian Archipelago

2019

Parsing human and biophysical drivers of coral reef regimes

  • Jean-Baptiste Jouffray, Lisa M. Wedding, Albert V. Norström, Mary K. Donovan, Gareth J. Williams, Larry B. Crowder, Ashley L. Erickson, Alan M. Friedlander, Nicholas A.J. Graham, Jamison M. Gove, Carrie V. Kappel, John N. Kittinger, Joey Lecky, Kirsten L.L. Oleson, Kimberly A. Selkoe, Crow White, Ivor D. Williams, Magnus Nyström

    2019 (January), The Royal Society Publishing

  • Understanding how multiple drivers can combine to influence coral reef conditions can improve local management. That’s why this paper modeled the influence of both human and biophysical factors on reef regimes. The paper outlined four specific regimes that coral reefs can fall into (with varying levels of coral cover, fish biomass, and algae cover) and examined the occurrence of each regime in relation to human and biophysical predictors. Reef regimes with little coral cover or fishes were most influenced by anthropogenic effects like effluent and boat fishing, while reef regimes with higher fish biomass and lower percentages of algae cover were most influenced by the biophysical predictors of habitat complexity, wave action, and depth. Local management can use this information to identify priority areas of the reef and inform better strategies.

2018

  • Lisa M. Wedding, Joey Lecky, Jamison M. Gove, Hilary R. Walecka, Mary K. Donovan, Gareth J. Williams, Jean-Baptiste Jouffray, Larry B. Crowder, Ashley Erickson, Kim Falinski, Alan M. Friedlander, Carrie V. Kappel, John N. Kittinger, Kaylyn McCoy, Albert Norström, Kirsten L. L. Oleson, Kostantinos A. Stamoulis, Crow White, Kimberly A. Selkoe

    2018 (March)

    PLOS One

  • The condition of coral reefs is influenced by multiple natural and human factors. Understanding how these complex layers of drivers affect reef ecosystems is critical to effective management. However, large spatio-temporal datasets are difficult to analyze and use for management due to their complexity. This paper fills this gap in knowledge by creating a methodology to synthesize and map data on environmental and anthropogenic drivers that can be applied to large spatio-temporal datasets. This methodology can be used to inform localized and regional management to promote reef resiliency.

Advancing the integration of spatial data to map human and natural drivers on coral reefs

Combining fish and benthic communities into multiple regimes reveals complex reef dynamics

  • Mary K. Donovan, Alan M. Friedlander, Joey Lecky, Jean-Baptiste Jouffray, Gareth J. Williams, Lisa M. Wedding, Larry B. Crowder, Ashley L. Erikson, Nick A.J. Graham, Jamison M. Gove, Carrie V. Kappel, Kendra Karr, John N. Kittinger, Albert V. Norström, Magnus Nyström, Kirsten L. L. Oleson, Kostantinos A. Stamoulis, Crow White, Ivor D. Williams, Kimberly A. Selkoe

    2018 (November)

    Scientific Reports

  • Many reefs worldwide are being reported as transitioning from coral-dominated to algae-dominated ecosystems. This research investigated how reef regimes vary spatially and temporally around the Main Hawaiian Islands. They found that there are five dominant reef regimes with varying levels of coral, calcified coralline algae, macroalgae, turf algae, and fish biomass. The trajectory of reef decline, or transition to another regime, is often not a linear one. They also found that changes in benthos often followed regulations placed on fish harvest, and that the most direct factor in reducing coral cover is thermal stress, which possibly has a lagging effect on fish assemblages. In order to address this, management efforts might be most effective when focusing on areas of reef where there is still high fish biomass and coral cover with a mixture of macroalgae and turf algae, since this regime was observed as having the greatest frequency of transitions to other regimes.

  • Mariska Weijerman, Lindsay Veazey, Susan Yee, Kellie Vaché, Jade M. S. Delevaux, Mary K. Donovan, Kim Falinski, Joey Lecky, Kirsten L. L. Oleson

    2018 (November)

    Frontiers in Marine Science

  • To inform effective marine management, managers need to know the potential outcomes of different management actions under future climate scenarios. This paper uses a spatially-explicit biophysical ecosystem model to evaluate the socio-economic tradeoffs of land- and marine-based management taken under different climate scenarios with the impacts of both local and global stressors. This paper found that land-based management reduces coral decline, fisheries management increases fish biomass, and marine-based management decreases macroalgal cover, consequently reducing the decline in reef condition and trophic integrity. However, these benefits from local management are unable to prevent reef decline unless global actions to reduce climate change are also taken. This shows the importance of local management in bolstering reef resilience in the face of climate change.

  • Alan M. Friedlander, Mary K. Donovan, Haruko Koike, Paul Murakawa, Whitney Goodell

    2018 (December)

    Aquatic Conservation: Marine and Freshwater Ecosystems

  • This paper characterizes existing marine protected areas (MPAs) in Hawai‘i and examines the efficacy of the areas in promoting conservation and fisheries management goals. They found that areas with full or high levels of protection harbored higher biomass of fishes, but that the percentage of areas with these levels of protection in the Main Hawaiian Islands (MHI) is very low. This paper also found that large MPAs that cover a variety of habitats have the greatest benefits for increasing resource fish species, but that creating large MPAs can have socio-economic costs to the local community. In this regard, it might be best to benefit both fish biomass and the local economy to create a network of smaller, well-managed MPAs to reach conservation goals. They noted that the current small size of Hawai‘i’s MPAs are not meeting their conservation and fisheries management goals, but that they can be designed as effective components of a larger network to gain the same benefits.

  • Kostantinos A. Stamoulis, Jade M. S. Delevaux, Ivor D. Williams, Matthew Poti, Joey Lecky, Bryan Costa, Matthew S. Kendall, Simon J. Pittman, Mary K. Donovan, Lisa M. Wedding, Alan M. Friedlander

    2018

    Ecological Applications

  • We need more information on fishing patterns and impacts on targeted fishes in order to design effective marine managed areas. To fill this need, this study mapped fishing efforts around the Main Hawaiian Islands, characterized habitat variables that support high levels of fish biomass, and modeled the recovery potential of targeted fish species based on these maps. This paper found habitats that best supported high fish biomass are typically eastern-facing with high levels of topographic complexity, wave power, and depth. It also found that areas on the eastern sides of O‘ahu and Kaua‘i have the highest recovery potential if fishing pressure is reduced, identifying these areas as potential places to prioritize for management. Protecting areas like these that already harbor high fish biomass benefits adjacent fisheries by supplementing larval distribution and spillover, as well as not having negative impacts on the fishery economy because these areas already have low fishing effort.

  • Editors: Bryan M. Costa and Matthew S. Kendall

    2016 (July)

    BOEM Report OCS Study BOEM 2016-035 and NOAA Technical Memorandum NOS NCCOS 214

  • This assessment describes the physical and biological marine environment of Hawai‘i as well as spatial distributions of marine life. This report was designed to help the Bureau of Ocean Energy Management evaluate potential future offshore energy proposals.

  • Alan M. Friedlander, Mary K. Donovan, Kostantinos A. Stamoulis, Ivor D. Williams, Eric K. Brown, Eric J. Conklin, Edward E. DeMartini, Kuulei S. Rogers, Russell T. Sparks, William J. Walsh

    2017 (July)

    Aquatic Conservation: Marine and Freshwater Ecosystems

  • This research compared fish assemblages on reefs in the remote, uninhabited Northwestern Hawaiian Islands to the inhabited Main Hawaiian Islands. They found that the biomass of resource species is negatively correlated with human population density. Out of 35 resource species studied, half of the species had 2-3 times as many fish in the NWHI than the densely populated MHI. However, the paper also found that smaller-than-regional scale factors importantly influence the demographics and abundance of reef fishes. This shows the need for local, moku-scale management of marine resources.

Managing local stressors for coral reef condition and ecosystem services delivery under climate scenarios

Characteristics of effective marine protected areas in Hawai‘i

Seascape models reveal places to focus coastal fisheries management

2017

2016

Human-induced gradients of reef fish declines in the Hawaiian Archipelago viewed through the lens of traditional management boundaries

Marine Biogeographic Assessment of the Main Hawaiian Islands

Coral reefs benefit from reduced land-sea impacts under ocean warming

  • Jamison M. Gove, Gareth J. Williams, Joey Lecky, Eric Brown, Eric Conklin, Chelsie Counsell, Gerald Davis, Mary K. Donovan, Kim Falinski, Lindsey Kramer, Kelly Kozar, Ning Li, Jeffrey A. Maynard, Amanda McCutcheon, Sheila A. McKenna, Brian J. Neilson, Aryan Safe, Christopher Teague, Robert Whittier & Gregory P. Asner

    2023 (August), Nature

  • This paper uses HIMARC data to investigate which environmental and human factors might influence reef condition after marine heatwaves and coral bleaching. Authors found that reefs with more herbivorous fish and less wastewater input had a greater probability of higher coral cover following bleaching. Reefs with low wastewater input and urban runoff also had the highest coral survivorship during the bleaching event.