The Hawaiian Koʻa Wheel: Coral health and bleaching assessment color reference card for Hawaiian corals.
Phase I- To monitor the extent of bleaching, managers, educators, community groups and researchers have widely used the “CoralWatch coral health card” developed for Australian coral genus’ by the University of Queensland. However, the colors developed for this card are not transferrable to many of the key coral species in Hawai‘i and the wider Pacific. In addition, the numbering system does not allow quantification of the severity of bleaching. The tool we are developing through quantified field and laboratory research, validation testing, and surveys is unique in its circular design allowing quantification by degrees that follow the degradation of color in four major quadrants to represent the colors of all major coral species in Hawai‘i.
To accurately quantify the change in color during bleaching, we have conducted controlled temperature induce bleaching assays using six common Hawaiian species with over 500 fragments. All corals were photographed and sub-sampled daily for photosynthetic efficiency and fluorescence. Photographs are being analysed using an automatic function in Adobe Photoshop™ to generate RGB values to determine hue, saturation, and brightness.These images provide reliable correlations between the photographs and changes in the color of the coral at various stages of bleaching and recovery. Samples taken for chlorophyll a and symbiont density will be correlated with color hues. Professional underwater photographers were used to assure natural colors and for uniform consistency (Yuko and Keoki Stender). This phase is scheduled for completion by the end of 2017.
Phase II- We will first validate the gradient of colors determined in Phase I in diverse field situations. Since this tool is intended to be used by multiple untrained observers, we will also evaluate the degree of variability between observers and their ability to distinguish gradients of color. We have a variety of observers (e.g., highschool, undergraduate students, scientists, state and local resource management staff, and community members) to assess corAL in the lab and in the field on O‘ahu, Kaua‘i, and Hawai‘i.
- The health of numerous coral reefs throughout the state can be evaluated using this tool. Initially, the state of the reefs must be determined before declines can be reversed. This will aid in identification of areas where management efforts should focus.
- Widespread use of the coral assessment wheel will help detect areas of refuge that are more resilient to climate change by identifying regions with low occurrence of bleaching.
- The Hawaiian Ko‘a card will give individuals and communities a sense of kuleana (responsibility) and mālama (stewardship) for the reefs in their ‘ahupua‘a (land division).
- The education provided about bleaching and the ability to directly experience the visual transformation in the corals can be a force for change that can be passed on.
- Assessment data can be of service in evaluating the efficacy of management efforts to slow climate impacts.
- Once bleaching is quantified it can be linked to temperature to eliminate other extraneous factors that can also cause bleaching (sediment, pollutants, high nutrients). We have been working closely with DAR’s Alien Species team and researchers to standardize and evaluate temperature gauge methodology (Bahr et al. 2016), and have over 50 temperature loggers deployed statewide.
- This collective project can provide kokua for the state’s objective to effectively managing 30% of Hawai‘i’s reefs by the year 2030 by defining the health of our reefs. This can only be achieved in collaboration with the community, researchers, and educators.
- Observation is critical in determining the condition of reefs. The color gradients on the assessment card will train ocean users to detect slight color differences and relate this to coral health.
- Statewide assessment data derived from this project will be incorporated into the ridge to reef database to increase spatial and temporal recognition of changes in the mauka/makai
- Measurable baselines and subsequent declines can be established for reefs statewide.
- Assessment of bleaching severity can assist in locating areas to concentrate management efforts.
- We can provide habitat protection by community driven management through provision of education and resources.
Determining Sediment Tolerance Thresholds for Hawaiian Corals
Hawaiian coral metabolic tolerance levels to sedimentation have not been previously determined. By resuspending fine clay particles in recirculating respirometry chambers we are defining the tolerance limits for dominant species of corals. Each chamber is equipped with an oxygen probe allowing for continuous monitoring of oxygen production and consumption in coral colonies exposed to sediment stress over time. These controlled experiments are assisting in the understanding of coral community metabolism through measurements of calcification and photosynthesis. Results from this project will help define management strategies for conservation and mitigation.
Coral Acclimatization/Adaptation to Increasing Temperatures
There is sparse research to support or refute whether corals will be able to acclimate to rising ocean temperatures. In 1970, our founder Paul Jokiel and his colleague Steve Coles conducted the first thermal tolerance experiments on Hawaiian corals. They determined that corals will bleach between 1-2o C of their summer maximum temperatures. These findings formed the basis of subsequent bleaching research and continues to be used in calculations to model predictions for bleaching (eg. NOAA’s CoralWatch). Thermal tolerances have not been reassessed since that time. The first bleaching event did not even occur until 1983 and was not observed in the Hawaiian Islands until 1996. Now almost half a century later we replicated the initial experiments to quantify whether or not acclimatization/adaptation has occurred. This exciting research uses the same seawater system, mesocosms, coral species collected from the same reef flat, and replicates other conditions of the original experiment. Although Dr. Jokiel is only with us in spirit, we have brought in his colleague, Dr. Coles, to conduct the assessments and classifications of the original experiments. The manipulative experimental phase and the initial recovery phase is complete.
Hawaiʻi Coral Health Surveys
The Coral Reef Ecology Team is dedicated to ongoing work focusing on anthropogenic impacts on coral reefs. We are currently conducted coral health surveys in Kāneʻohe Bay and Hanauma Bay Nature Preserve to better understand how humans shape coral reefs.
Hā‘ena CBSFA (2016-2020)
The Community-Based Subsistence Fishing Area (CBSFA) in waters off Hā‘ena, Kaua‘i is an area of special interest to the State of Hawai‘i. The purpose of this five-year project is to assist the Division of Aquatic Resources (DAR) in evaluating this Hā‘ena CBSFA special management area. Monitoring inside and outside this region will be critical in determining the efficacy of any marine remedial management actions. We are partnering with DOBOR, DAR Maui Monitoring, DAR O‘ahu Monitoring, DAR Invasive Species and the Kaua‘i Education and Outreach teams to survey 100 random locations annually using the Kaua‘i Assessment Habitat Utilization (KAHU) methodology for fishes, benthic components, and urchins. Sediment grain-sizes and composition will be also determined. Temperature loggers have been deployed at 25 stations throughout the area.
Pila‘a, Kaua‘i (2016-2020)
In 2001, our lab surveyed the extensive damage to a reef downstream from a large site where illegal grading took place at Pila‘a, Kaua‘i. Our survey results and court testimony assisted in securing the largest unprecedented settlement to the State of Hawai‘i for reef damage. The initial baseline survey will be repeated using the same methods in order to document recovery. We have begun assessments using the Kaua’i Assessment Habitat Utilization (KAHU) methodology for comparability with other sites. We are determining coral recruitment rates using standard recruitment arrays and establishing a long-term monitoring site to document any changes in fish and benthic populations. In collaboration with USGS we will be analyzing the record of coral growth and sedimentation over past centuries through coring large corals. This method identifies annual bands and the sedimentation signature within each band over the length of long cores.
Effectiveness of Coral Relocation as a Mitigation Strategy 2005-Ongoing
Coral reef restoration and management techniques are in ever increasing demand due to the global decline of coral reefs in the last several decades. Coral relocation has been established as an appropriate restoration technique in select cases, particularly where corals are scheduled for destruction. We removed coral from the HIMB navigation channel and relocated it to a similar nearby dredged reef in 2005 for safe vessel navigation. This was a joint project that included Army divers of the 7th Engineering Detachment’s 29th Engineering Battalion, Marine Options Program students, UH undergrads, graduate students, and the Division of Aquatic Resources. This multi-agency project received the UH Team of the Year Award and was advanced to the State Team of the Year competition in 2009. Coral recovery at the donor site and changes in fish populations at the receiving site were tracked periodically over the following decade in 2008, 2012, and 2016. Coral regrowth at the donor site in the navigation channel was rapid until a recent bleaching event in 2014-15 reduced coral cover by more than half. The transplant of mature colonies increased spatial complexity at the nearby receiving site, immediately increasing fish biomass, abundance, and species diversity that was maintained throughout subsequent surveys. Our research indicates that unlike the majority of historical accounts of coral relocation in the Pacific and relocation projects our lab has undertaken (eg. Kawaihae), corals transplanted into wave-protected areas with similar conditions as the original site can suffer low mortality. Data on long-term monitoring of coral transplants in diverse environments is central in developing management and mitigation strategies. We will continue to reassess the long-term changes every five years or whenever events that precipitate change occur.
Statewide Monitoring CRAMP (1998-ongoing)
In 1998 when we developed the Coral Reef Assessment and Monitoring Program (CRAMP) in response to management needs, there was no long-term widespread monitoring program in this state. It was vital to get a baseline of what our reefs looked like, to recognize any changes that may occur, and to identify any impacts that are affecting these reefs. Over 60 sites span the full spectrum of habitats, encompassing the full latitudinal range and include the entire range of protection status from open access sites with no other legal protection except what applies to the entire state to fully protected sites, and a gradient of natural and anthropogenic impacts. This extensive dataset is being used to find trends and patterns on a statewide, island, and site scale and identify forcing functions that drive them. Researchers, managers, and educators are utilizing the data for a wide variety of purposes. We currently partner with the DLNR’s Division of Aquatic Resources to monitor sites and to set up new sites such as the one planned for Pila‘a, on Kaua‘i.
Hanauma Bay Biological Carrying Capacity (2017-ongoing)
The Hanauma Bay Nature Preserve (HBNP) project will assess anthropogenic use and global impacts in relation to biological carrying capacity. The Hanauma Bay biological carrying capacity study is designed to determine the acceptable limits of disturbance to the marine resources of Hanauma Bay. It will do so by (1) reviewing recent and historical data and compiling this data into one annotated bibliography, (2) performing several new observational experiments, and (3) continuing to monitor the long-term sites established in 1999. By monitoring human activity in each area of the bay in harmony with coral skeleton trampling (using dead coral skeletons), coral recruitment, and sediment suspension experiments, we will be able to determine if the current level of human use allows Hanauma Bay to sustain its marine resources. In addition to new field surveys, by resurveying long-term monitoring sites and documentation of temperatures and currents from year to year, it allows us to determine changes in the biological populations over time and relate these changes to shifts in activities (ex. fish feeding). By blending historical data with data from past and present observational experiments , we will have a better understanding of the Bay’s current condition and will be able to make informed recommendations toward protecting its marine resources for continued future use.
Ridge to Reef (Mauka/Makai) Connections (2015-2017)
We are developing protocols that prioritize watersheds and coastal waters for protection and restoration in Hawai‘i. Quantitative watershed and coral reef condition indices are being integrated with a GIS-based, predictive model to produce geographically realistic planning and evaluation tools. We are integrating quantitative model output from terrestrial watershed and coral reef condition indices to evaluate the ecological condition of the “ridge to reef” system. This project provides spatial maps to determine which of the 580 watersheds in the state have the strongest connections to adjacent reefs and would most benefit from watershed restoration efforts. This will help address the scientific needs of the agencies responsible for the management and mitigation of Hawaiian coral reef ecosystems. This project was funded by the Environmental Protection Agency.
HAWAI‘I ISLAND MAP KAUA‘I MAP O‘AHU/MAUI NUI MAP
Our lab has conducted multiple coral reef studies in Pelekane Bay and the larger Kawaihae area since 1995 to better understand the response of the reef community to cumulative human impacts, effectiveness of management measures, and recovery potential. The most recent studies between 2010 and the present focus on key biological and ecological processes investigating coral settlement, growth, partial-mortality, and community structures in relation to land-based sedimentation and environmental quality. These studies in Pelekane Bay were carried out collaboratively with federal government agencies, and non-governmental organizations, and the community to address the broader issues of land-derived impacts on coral reefs. Our findings suggest significant impacts of sedimentation on biological and ecological processes of corals and recovery potential.