Protecting the million-dollar mantas; creating an evidence-based code of conduct for manta ray tourism interactions

Murray, Annie; Garrud, Eleanor; Ender, Isabel; Lee-Brooks, Katie; Atkins, Rebecca; Lynam, Rebecca; Arnold, Kathryn E.; Roberts, Callum M.; Hawkins, Julie P.; Stevens, Guy M. W.

doi:10.1080/14724049.2019.1659802

Cited by 40 publications

(42 citation statements)

References 39 publications

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“…The current directive of FNA remains equivalent to date (with regulated diving sites and control of the number of people and boats entering the protected area), although, there are likely more people in the water in recent years. Guidelines and formal codes of conduct (Murray et al, 2019) are highly recommended for manta ray interaction, aiming to minimize disturbance to manta ray population, especially regarding juvenile individuals and sensitive nursery habitats.…”

Section: Discussionmentioning

confidence: 99%

Sightings trends and behaviour of manta rays in Fernando de Noronha Archipelago, Brazil

Bucair¹,

Venables

Balboni³

et al. 2021

Mar Biodivers Rec

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Despite substantial progress in mobulid research over the past decade, knowledge gaps in manta ray ecology and behaviour remain, particularly in the South Atlantic Ocean. Opportunistic photographic and video records of manta rays collected between 2002 and 2019 at Fernando de Noronha Archipelago (FNA) in northeast Brazil provide evidence to support the year-round use of the region by manta rays (believed to be Mobula cf. birostris). From a total of 130 sighting records, manta rays exhibited feeding behaviour in 36.9% (n = 48) of sightings, indicating that the shallow waters surrounding the archipelago are used as feeding grounds. Approximately half of the records (53.8%) corresponded to identified individuals that were re-sighted repeatedly, using the area in different seasons and for several years. Of the compiled records, 69.2% of sightings were of small individuals (≤3 m disc width). All identified males had undeveloped claspers and females had no visible mating scars, suggesting a juvenile population. Despite being limited to a small local sample, here we present the first report of manta rays at FNA and provide preliminary evidence of feeding behaviour by juvenile manta rays in Brazil. This information contributes to our understanding of the regional distribution and habitat use of manta rays in Brazilian waters.

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Section: Discussionmentioning

confidence: 99%

Sightings trends and behaviour of manta rays in Fernando de Noronha Archipelago, Brazil

Bucair¹,

Venables

Balboni³

et al. 2021

Mar Biodivers Rec

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“…The extent of benefits afforded to M. alfredi by these MPAs, however, will depend on the regulations incorporated into their management. Both the prohibition of fishing for manta rays and the adherence to protocols regarding human-manta ray interactions for tourism (Venables et al, 2016;Murray et al, 2019), for example, would benefit M. alfredi at these sites, if enforced. Ultimately, by encompassing important habitat for M. alfredi at D'Arros Island and St. Joseph Atoll, these MPAs provide an opportunity to conserve a key aggregation site for the Seychelles population, until a targeted, national-scale management strategy can be developed and implemented for the species.…”

Section: Vertical Movementmentioning

confidence: 99%

Regional Movements of Reef Manta Rays (Mobula alfredi) in Seychelles Waters

et al. 2020

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The decline in numbers of reef manta rays (Mobula alfredi) throughout their range has highlighted the need for improved information on their spatial ecology in order to design effective conservation strategies for vulnerable populations. To understand their patterns of movement in Seychelles, we used three techniques-archival pop-up satellite tags, acoustic tags, and photo-identification-and focussed on the aggregation at D'Arros Island and St. Joseph Atoll within the Amirantes Group. M. alfredi were photographed within six of the seven Island Groups of Seychelles, with 64% of individuals being resighted at least once between July 2006 and December 2019 over timeframes of 1-3,462 days (9.5 years; median = 1,018 days). Only three individuals from D'Arros Island were resighted at a second aggregation site located more than 200 km away at St. François Atoll during photo-identification surveys. Satellite-tracked M. alfredi (n = 5 tracks; maximum 180 days) remained within the boundary of the Seychelles Exclusive Economic Zone, where they spent the majority of their time (87%) in the upper 50 m of the water column in close proximity to the Amirantes Bank. The inclusion of acoustic tagging data in the models of estimated satellite-track paths significantly reduced the errors associated with the geolocation positions derived from archived light level data. The insights gained into the patterns of horizontal and vertical movements of M. alfredi using this multi-technique approach highlight the significance of D'Arros Island and St. Joseph Atoll, and the wider Amirantes Group, to M. alfredi in Seychelles, and will benefit future conservation efforts for this species within Seychelles and the broader Western Indian Ocean.

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“…As a slow-growing species which is late to mature, producing only a few offspring during their lifetime, population recovery from exploitation is slow [15,25]. Furthermore, other anthropogenic threats, such as habitat degradation, the climate crisis, and unregulated tourism pressure, are all likely to hinder survivorship [25][26][27][28][29]. Aggregation behaviour can be spatially and temporally predictable, potentially increasing their vulnerability to exploitation [7].The M. alfredi population of the Maldives Archipelago is the largest documented to date; engaging in a biannual migration which is influenced by the South Asian Monsoon [7,30].…”

Section: Introductionmentioning

confidence: 99%

“…Mobula alfredi are particularly vulnerable to disturbance at aggregation sites where the species come to feed or engage in cleaning and social and reproductive activities [15,16]. At feeding areas, M. alfredi can abandon feeding when their path is obstructed by visitors [27] and lethal and sublethal injuries can be caused by fishing gear entanglement, boat strikes and propeller injuries [32]. At cleaning stations, anthropogenic activities, such as the destruction of coral reefs for boat access or contact damage by divers and snorkellers, can lead to habitat degradation [32], potentially influencing M. alfredi visitation patterns [33] and compromising individual fitness [34].…”

Section: Introductionmentioning

confidence: 99%

Environmental drivers of reef manta ray (Mobula alfredi) visitation patterns to key aggregation habitats in the Maldives

Harris

Stevens

2021

PLoS ONE

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A detailed understanding of the dynamics of small-scale (10s km) habitat use by the reef manta ray (Mobula alfredi) in the Maldives Archipelago is required to develop an effective national conservation management plan for this wide-ranging species. Here, a combination of photo-ID sightings data and acoustic telemetry were used to investigate both long-term M. alfredi visitation trends and small-scale movement patterns to key habitats on the eastern side of Baa Atoll (Hanifaru Bay feeding area, Dhigu Thila multifunctional site, and Nelivaru Thila cleaning station). All tagged and most of the sighted M. alfredi exhibited high affinity to the eastern side of Baa Atoll, where 99% of detections occurred, and 69% of individuals were re-sighted in multiple years. Sightings data suggests that visitation patterns may be associated with differences in habitat use by sex and maturity status. Boosted regression trees indicated that tag detection probability at Hanifaru Bay increased with increased westerly wind speed (>5ms-1) during the day, close to a new and full moon just after high tide, and when the tidal range was low. Interaction effects between predictors suggest that wind-driven oceanographic processes, such as Langmuir Circulation, maybe working to increase zooplankton concentration at this location. Tag detection probability increased at Dhigu Thila under similar conditions. At Nelivaru Thila, it increased at lower wind speeds (<5ms-1), close to a full moon, three hours after high tide. These results suggest that M. alfredi may utilise cleaning stations during the day when environmental conditions are not suitable for feeding. There was a high level of connectivity between these three locations, which suggests they form part of a network of key habitats that provide essential services to M. alfredi locally. Future conservation efforts should focus on identifying all areas of key habitat use for this species within the Maldives; applying strict protective measures to these sites and any connecting migration corridors which link them.

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Protecting the million-dollar mantas; creating an evidence-based code of conduct for manta ray tourism interactions

Cited by 40 publications

References 39 publications

Sightings trends and behaviour of manta rays in Fernando de Noronha Archipelago, Brazil

Sightings trends and behaviour of manta rays in Fernando de Noronha Archipelago, Brazil

Regional Movements of Reef Manta Rays (Mobula alfredi) in Seychelles Waters

Environmental drivers of reef manta ray (Mobula alfredi) visitation patterns to key aggregation habitats in the Maldives

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