Corals: ‘canaries’ in coastal communities?

Misaki Takabayashi, John Burns, Narrissa Spies, Makani Gregg, Patrick Yasukawa

Marine Science Department /Tropical Conservation Biology and Environmental Science

University of Hawaiʻi at Hilo

Corals in context of ahupua‘a

• Most reefs in MHI are fringing = direct contact

• Corals are foundation species of reef ecosystem

• Intimate relationships with humans

• Sessile (stuck on seafloor)• Holobiont in delicate

balance• Host with immune system

So, what does it mean when corals are not healthy?

Coral DiseasesWhat coral diseases might indicate:

“However, these studies should include comprehensive efforts to better understand the relationship between coral diseases and environmental changes, largely anthropogenic in nature, occurring on coral reefs around the world. These environmental insults are the cause of the physiological stress that subsequently leads to coral mortality and morbidity by many mechanisms including overwhelming infections by opportunistic pathogens.”

(Lesser et al. 2007)When studying coral diseases:“A rigorous assessment of disease needs epizootiological data in order to have diagnostic utility. Analyzing disease morphology (gross and cellular), pathogenesis, etiology, and associated epizootiology allows for determination of the impacts a disease may have on an afflicted coral population. Considering the lack of characterization of many coral diseases to date there is a severe need to address these factors for any outbreak of lesions in coral populations.”

(Burns, Rozet, Takabayashi, in review)

Coral(individual)

How does disease affect• Symbiodinium photosynthesis?• coral reproduction?• skeletal density?• calcification gene expression?• vulnerability to bleaching?

Disease prevalence correlated with?• terrigenous effluence?• water flow?• temperature?

WaterQuality

Wiegner lab, UHH

How do coral disease affect corallivores?• abundance• food preference

CorallivoresTurner lab, UHH

Disease prevalence & severity affected by • species?• colony size/orientation?• population structure?• community structure?

Corals(population,community)

Disease Characterization

• Morphological signs

• Impacts at the cellular level

• Temporal changes

Type A Type B

Assess Disease Threat

• How does the disease affect organismal function?

• What is the severity of the disease?

• Quantify impacts to the affected population

0 1 2 3 4 50

1

2

3

4

Water Motion

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GA

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rIdentify Drivers of Resilience

Linear Regression R2=74.8p<0.01

Characterizing coral health on Hawaii Island

Project Aims

To characterize and compare………..

1. Population structure2. Disease prevalence3. Severity

…………….between sites on Hawaii Island.

6 Sites

WaiuliWaiopaeKeauhou

Pohue Kailua

Kaloko Honokohau NHPKahuwai

Methodology

• 12 randomly selected 25m transects

• Colonies that touch transect get surveyed

• Things recorded:– Species, size, depth(m), disease sign, % or # of disease sign

• Pre-measured 1m rope

• Photo documentation

• ERDAS Imagine 1.0