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Contents

Clownfish in the ...... 3 Anemones in the Maldives ...... 4 Clownfish and Anemone Symbiosis ...... 4 Climate Induced Bleaching events ...... 6 Monitoring Ecosystem Change ...... 6 Anemone Database ...... 7 Current Insights ...... 7 Contribute to our database! ...... 8 Data Needed ...... 8 What’s Provided ...... 9 Anemone ID ...... 9 Methodology for Monitoring Bleaching in Anemones ...... 10 Overview of Citizen Science Methods ...... 10 Monitoring your Anemone ...... 10 Anemone Bleaching/Recovery Protocol ...... 11 IC-anemone app – Saving Nemo ...... 12 Maldives National Coral Monitoring Framework ...... 12

Send database contributions to: [email protected]

By Cassie Hoepner and Zoe Tapps – Aquarium Biologists Atoll Marine Centre

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Clownfish in the Maldives

The Maldives has a vast range of unique and abundant marine life, from whale sharks and manta rays to arrays of coral and many colorful species. One of the most iconic reef species whose popularity has increased in recent years, through the film Finding Nemo, is the clownfish. There are 28 species of clownfish who form a symbiosis with only 10 host anemone species, despite there being around 1000 different anemone species. The Maldives is home to 2 main species out of the 28 of clownfish:

Amphiprion nigripes (Maldivian Clownfish) This clownfish solely associates with the Magnificent () and can only be found in the central Indian ocean around the Maldives and Sri Lanka.

Amphiprion clarkii (Clarks Clownfish)

This clownfish is a generalist and associates with 9 of the 10 host anemone species. This species also has a wide

distribution and can be found from to the Maldives.

These fish are abundant on many reefs across all atolls in the Maldives, but their populations are threatened by their growing popularity through the aquarium trade and the threat of climate change on their symbiotic home. The Sebae Clownfish also occurs in the Maldives, however, it is not very common and rare to spot.

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Anemones in the Maldives

Anemones, like clownfish occur over a variety of reefs all throughout the Maldives and at various depths. Of the 10 species of host anemones for clownfish, 4 main anemone species occur in the Maldives.

• Heteractis sp. – most commonly Heteractis Magnifica

• Stichodactyla sp.

• Ecantamea quadricolor

• Cryptodendrum adhaesivum

Heteractis sp. and Stichodactyla sp. are the most commonly found species of anemones though some reefs can have high numbers of Encantamea quadricolor; Cryptodendrum adhaesivum is the most difficult to find and the most toxic of all the host species found in the Maldives.

Clownfish and Anemone Symbiosis

Anemones and clownfish form an important symbiosis that is integral to both their survival.

Anemones act as a toxic home for the clownfish excluding predators and offering shelter to the clownfish. In return the clownfish give extra nutrients and aeration to the anemone and will even defend their anemone from predators.

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Climate induced bleaching events

Climate change is a major threat to the future of this symbiosis, bleaching events impact anemones through the same mechanisms as coral. Anemones have a 3-way symbiosis with clownfish and the symbiotic algae – zooxanthellae – that lives inside their cells. During extended stress events such as increased sea surface temperature and high solar irradiance, zooxanthellae are no longer able to effectively. Anemones, like corals, can detect this change and subsequently expel the algae from their cells in search of a new strain better adapted to these compromised conditions. If a better adapted alga is not available, the coral and anemones have lost an essential provider of nutrients and appear white – known as bleached - due to the absence of zooxanthellae which provides them with colour.

Monitoring ecosystem change

In order to detect changes within the reef ecosystem, it needs to be consistently monitored for change. In order to detect this change there needs to be a baseline from which to measure any changes.

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Anemone Database

This database aims to identify the location of anemones and clownfish throughout the Maldives in order to provide the baseline from which change in both abundance and distribution as well as health can be directly monitored. This database will also be able to inform future research on both anemones and clownfish and aid in experimental design by providing easily accessible information on distribution and abundance on local reefs

Current Insights

Currently, the database monitors more than 60 anemones throughout Lhaviyani Atoll and is looking to expand to other atolls throughout the Maldives. All 4 main anemones species in the

Maldives have been identified, with the majority Heteractis Magnifica.

Through observing these anemones and clownfish the database has offered a range of unique insights: Stressed anemones at Maldivian and Clark’s Komandoo Sandbank. clownfish co-inhabiting an anemone. Large colonial anemone moved to a slightly deeper Seen on 3 different location these individuals occasions. unable to move.

This feisty Clark’s Carpet anemone feeding clownfish was seen at night with its stomach defending its anemone exposed. from a Hawksbill Turtle by

Naifaru Jetty swimming into its head on Kuredu House Reef.

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Contribute to our database!

In order to monitor anemones and clownfish throughout the Maldives the Atoll Marine Centre needs contributors to our database. We currently monitor our local island and neighboring reefs but are unable to reach all of Lhaviyani in particular dive sites, nor other atolls through the country.

Please submit your anemone and clownfish contributions to:

[email protected]

Data Needed

Please include the following in your submission:

• Location (gps if possible) • Anemone species • Anemone health (H – Healthy, B- Bleached, S- Stressed, D- Dead) • Colonial/solitary • Depth (Deep/Shallow or m if possible) • Clownfish species • Number of adults/juveniles/babies • Photograph (multiple photos are welcome) When photographing the anemone please consider:

• Lighting • Identifying markers (to help you find the anemone again)

Same anemone pictured, image 2 gives a lot more information and will be able to be recognized easier.

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What’s Provided

When you contribute to our database we will provide you with a range of informational posters on anemones and clownfish, access to the findings of the database as well as methods to quantify and monitor bleaching/recovery in anemones during extended stress events. We will also send you a reminder email every 3-6 months in order to remind you to monitor your anemone.

Anemone ID

We will also provide an anemone ID for every individual you submit to the database. This unique

ID number will enable you to regularly update us on the health of this anemone and allows for continuous monitoring overtime. This ID can be displayed in your office or marine/dive centre to remind you to monitor this individual while also showing guests that you are participating in a citizen science initiative to monitor the reef!

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Methodology for monitoring bleaching in anemones

Overview of citizen science methods

Monitoring ecosystem change, while important, is subject to a range of variables that can affect its accuracy. One of the most effective ways to monitor change globally is through citizen scientists, however this data is often influenced by observer bias and can change dramatically person to person. Methodology involving citizen science and avoids this bias can ensure reliable data is consistently collected. Applying a photographic method to monitor change through image analysis removes the opinion of the observer from the data collection process and can yield more accurate results.

Monitoring your anemone

When monitoring your anemone if

you detect a change in its health

please contact us a soon as possible so

we can begin monitoring the

bleaching/recovery process of this

anemone. In order to assess bleaching

you can photograph the anemone with a colour reference chart – can be provided to you – once a month and send the pictures through to the database for image analysis. Please ensure the lighting of the anemone in these pictures are consistent as possible between each photo to ensure accuracy.

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Anemone Bleaching & Recovery Protocol

In order to quantify bleaching and then recovery in anemones via photography, a colour reference chart, circle or stick with white & black tape is needed. This enables the photo to be standardized using image analysis and then assigned a bleaching value according to colour (percentage whiteness).

When assessing these anemones overtime it is very important that the lighting in the photographs are kept as consistent as possible. While this is more difficult in a field environment taking photographs at a regular time of day and avoiding overcast days (when possible) can help.

Take the photograph directly over the anemones making sure its entire circumference is captured and your colour reference is clearly visible. If using a colour reference that can also quantify size (eg colour reference circle pictured above- known diameter of 10.5cm), make sure it is level with the anemone as perception can effect accurate measurement if the reference is above or below.

Keep the anemone in focus rather that the colour reference and make sure the photos a consistent distance from the anemone (eg 30cm).

This method can also e used to monitor the anemone regaining colour post-bleaching (recovery).

0 - Black

255 - White 11

IC-anemone app – Saving Nemo

Saving Nemo is an Australian NGO working to protect clownfish and other ornamental species from the aquarium trade. They are creating an app to monitor anemone and clownfish populations globally through citizen science. In the future this database will be able to be contributed to directly from your phone, allowing instant input of data and accessibility to all citizen scientists.

Maldives National Coral Monitoring Framework

The data contributed to this database will be submitted to the National Coral Monitoring Framework in order to make this data available throughout the Maldives.

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