true

ISRA FACTSHEETS

WESTERN INDIAN OCEAN REGION

ISRA FACTSHEETS

WESTERN INDIAN OCEAN REGION

Maavaru Falhu & Moofushi Kandu ISRA

42/125

Maavaru Falhu & Moofushi Kandu ISRA

Maavaru Falhu & Moofushi Kandu

Summary

Maavaru Falhu & Moofushi Kandu is located along the southwestern side of Ari Atoll in the Maldives. The area comprises a large lagoon situated along the inner-atoll margin that is connected to the open ocean via a channel. The bathymetry of the area in combination with tidal currents and Langmuir Circulation leads to a concentration of zooplankton in the lagoon. Within the area there are: threatened species, reproductive areas, and feeding areas (Reef Manta Ray Mobula alfredi).

Maavaru Falhu & Moofushi Kandu

Maavaru Falhu & Moofushi Kandu

DESCRIPTION OF HABITAT

Maavaru Falhu & Moofushi Kandu is located along the southwestern side of Ari Atoll in the Maldives. Maavaru Falhu is a large lagoon situated along the inner-atoll margin of Maavaru Reef located north of Innafushi Island and south of Moofushi Island, whilst Moofushi Kandu is the channel that borders the northern inlet of this lagoon and opens to the ocean on the west. The lagoon is ~4 km in length and ~2.5 km wide, and the channel is ~0.9 km wide inside the atoll with the channel opening ~1.2 km. The lagoon reaches a maximum depth of ~15 m with a benthic cover of fine sand and scattered coral blocks. It is enclosed by a shallow barrier reef of depths between 2–10 m with a primary northern access point along the channel inlet which has a maximum depth of ~20 m inside the atoll, dropping beyond 1,000 m outside the atoll.

The Maldives has two monsoon seasons: the southwest monsoon (May–November), and the northeast monsoon (December–May) (Anderson et al. 2011). Sea surface temperatures fluctuate little between 28–30°C. The location and geomorphology of the shallow lagoon, coupled with the tidal movements and Langmuir Circulation, acts as a zooplankton trap, especially during the northeast monsoon season (Hedley et al. 2018; Moloney et al. 2019; Harris et al. 2020; Harris & Stevens 2021).

This Important Shark and Ray Area is benthopelagic and is delineated from the inshore and surface waters (0 m) to 80 m based on the bathymetry of the area.

CRITERION A

VULNERABILITY

The one Qualifying Species within the area is considered threatened with extinction according to the IUCN Red List of Threatened SpeciesTM. The Reef Manta Ray is assessed as Vulnerable (Marshall et al. 2022).

CRITERION C

SUB-CRITERION C1 – REPRODUCTIVE AREAS

Maavaru Falhu & Moofushi Kandu is an important reproductive area for one ray species.

Between 2007–2022, 458 in-water surveys were conducted in this area with neonates, young-of-the-year (YOY), pregnant females, and courtship recorded (IDtheManta unpubl. data 2022). During these surveys, 232 individual Reef Manta Rays were identified, representing 16% of the total identified throughout Ari Atoll (n = 1,418).

Of all neonate and YOY individuals identified in Ari Atoll (n = 74), 20% were first recorded in the area, making it the primary YOY site in South Ari Atoll (Hedley et al. 2018; Moloney et al. 2019). Maturity estimates were based on individual size between 150–190 cm disc width (DW); length of tail; light ventral/spot pattern pigmentation; creases along pectorals; and often a light pink skin pigmentation on first sighting (Kashiwagi 2014; Stevens 2016). Reef Manta Ray size-at-birth is 130–150 cm DW (Last et al. 2016). In addition, 15 of the YOY sighted in Maavaru Falhu & Moofushi Kandu were observed over consecutive years returning to the area. It is theorised that sheltered, shallow reef lagoons (like Maavaru Falhu) are typically used as nursery sites by devil rays, as they provide calm conditions, safety from large predators, reliable food source, and opportunities for interaction with conspecifics (McCauley et al. 2014; Heupel et al. 2019; Setyawan et al. 2022).

Seventeen individual Reef Manta Rays have been recorded as pregnant at this location since 2014, with all recorded individuals exhibiting cleaning behaviour. Females were determined as pregnant by trained research staff based on the presence of extended abdomens (Stevens 2016). Pregnant Reef Manta Rays typically use cleaning stations during outgoing tides (Hedley et al. 2018; Moloney et al. 2019), and these consistent observations suggest that this site is important to maintaining the health of pregnant rays.

Reef Manta Ray courtship behaviour was observed on 14 separate occasions during the study period and involved 44 individual rays. Observations included shadowing behaviour and mating chains.

CRITERION C

SUB-CRITERION C2 – FEEDING AREAS

Maavaru Falhu is an important feeding area for one ray species.

Reef Manta Rays aggregate in the area in a regular and predictable way when tidal movements and Langmuir Circulation concentrate zooplankton in the shallow lagoon, providing an ideal environment for planktivorous megafauna in the area (Harris et al. 2020; Harris & Stevens 2021). There were 302 in-water surveys conducted in the area between 2012–2022. During 50 of these surveys, photo identification revealed feeding aggregations with an average of eight individuals (standard deviation = 3.77; minimum = 5; maximum = 27 individuals) (IDtheManta unpubl. data 2022). During the northeast monsoon, aggregations are more abundant due to an accumulation of zooplankton in the area resulting from the combination of wind and tidal forcings (Harris et al. 2020). Of the 1,418 Reef Manta Rays recorded throughout Ari Atoll, 18% have been observed feeding in Maavaru Falhu (IDtheManta unpubl. data 2022), making this area one of the most important and regular feeding locations for Reef Manta Rays in Ari Atoll.

Maavaru Falhu & Moofushi Kandu

SUBMIT A REQUEST

ISRA SPATIAL LAYER REQUEST

To make a request to download the ISRA Layer in either a GIS compatible Shapefile (.shp) or Google Earth compatible Keyhole Markup Language Zipped file (.kmz) please complete the following form. We will review your request and send the download details to you. We will endeavor to send you the requested files as soon as we can. However, please note that this is not an automated process, and before requests are responded to, they undergo internal review and authorization. As such, requests normally take 5–10 working days to process.

Should you have questions about the data or process, please do not hesitate to contact us.

    * indicates required

    Industry or sector (*)

    Under the terms and conditions of our User License Agreement , full and appropriate acknowledgement is required in any materials and publications derived from the data (and copies should be sent to the IUCN SSC Shark Specialist Group through the contact form). For any publications making substantial use of the data, the ISRA welcomes the opportunity for co-authorship, collaboration, and to comment prior to publication.


    Furthermore, we need to know whether you are a commercial or non-commercial user. Non-commercial includes scientific research, education or conservation. Commercial is defined as follows: any use by, on behalf of, or to inform or assist the activities of a commercial entity (that operates ‘for profit’) or use by a non-profit for the purposes of revenue generation

    Type of use(*):

    Please specify which layer (ex. all layers, layers within a specific Region, layers within a Jurisdiction or a single ISRA): Purpose (*):

    Please provide a description of how you intend to use the ISRA GIS Dataset. The more details you provide, the faster we can respond to your request. We may require further clarification prior to providing access. (min. 100 characters – max 1,000 characters)



    File format request (*)

    By providing your personal data, you consent to its processing as described below. The IUCN SSC Shark Specialist Group will use the information you provide on this form to send the documents you requested. You can change your mind at any time by writing to the ISRA Data Coordinator www.sharkrayareas.org/contact. All personal details provided will be treated with respect. For any information you can visit our Privacy Policy.
    Please read the User License Agreement and ISRA Layer Metadata Description

    This form uses Google reCaptcha to reduce spam. Privacy - Terms