Andrea Denise Marshall

Marine Megafauna Foundation · Manta Ray Research Program

Mobulid rays are among the most vulnerable of chondrichthyans to overexploitation by fisheries due to their low population growth rates. In locations where catch data are lacking, long-term sightings data can provide valuable insight to infer population trends and status. We recorded underwater sighting data of reef manta rays (Mobula alfredi), oce...

Many shark populations are in decline around the world, with severe ecological and economic consequences. Fisheries management and marine protected areas (MPAs) have both been heralded as solutions. However, the effectiveness of MPAs alone is questionable, particularly for globally threatened sharks and rays (‘elasmobranchs’), with little known abo...

Two separate sightings, two years apart, of the mimic octopus Thaumoctopus mimicus Norman & Hochberg, 2005 are reported from the Inhambane Province of southern Mozambique within the protected waters of the Vilanculos Coastal Wildlife Sanctuary. Individuals were encountered in May 2020 and 2022 in shallow waters, at a depth of less than 30 cm. Both...

A global survey of coral reefs reveals that overfishing is driving resident shark species toward extinction, causing diversity deficits in reef elasmobranch (shark and ray) assemblages. Our species level analysis revealed global declines of 60 to 73% for five common resident reef shark species and that individual shark species were not detected at...

Opportunistic in‐water and aerial surveys in South Africa and the analysis of contributed citizen science data have extended the known range of reef manta rays Mobula alfredi along the eastern coast of Africa by 140 km (to Mdumbi Beach) and verified the first transboundary movements for the species. Additionally, six new long‐range dispersal record...

Information on the life history and demographics of oceanic manta rays Mobula birostris remains scarce. Using photo-ID data, we describe the demographic structure, population size, and possible environmental drivers of the seasonal occurrence of M. birostris at Isla de la Plata and Bajo Copé, Ecuador. We identified a total of 2803 individuals from...

The largest known reef manta ray (Mobula alfredi) population in Africa has been monitored for more than 20 years at several locations on the coast of the Inhambane Province in southern Mozambique. Nonetheless, before this study, little had been reported on the population dynamics of M. alfredi from Závora, a remote bay in the region. Photographic m...

Background The reef manta ray ( Mobula alfredi ) is a globally threatened species and an iconic tourist attraction for visitors to Indonesia’s Komodo National Park (NP). In 2013, manta ray fishing was banned in Komodo NP and its surroundings, preceding the nationwide manta ray protection in 2014. Over a decade ago, a previous acoustic telemetry stu...

We report two separate sightings of the ornate eagle ray Aetomylaeus vespertilio (Bleeker, 1852) in the Bazaruto Seascape of southern Mozambique. In May 2021, a single individual was encountered at a depth of 30 m during an in-water survey in the Bazaruto Archipelago National Park. Another solitary individual was documented ~55 km away during an ae...

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 suppo...

Reef manta rays (Mobula alfredi) are social elasmobranchs that have structured societies and actively interact with preferred social partners. Being able to detect cues and signals produced by conspecifics is vital in enabling social behavior. Many elasmobranch species communicate via body and fin postures, but it is not yet known if or how mobulid...

Overfishing is the primary cause of marine defaunation, yet declines in and increasing extinction risks of individual species are difficult to measure, particularly for the largest predators found in the high seas. Here we calculate two well-established indicators to track progress towards Aichi Biodiversity Targets and Sustainable Development Goal...

Little is known about the extent of genetic connectivity along continuous coastlines in manta rays, or whether site visitation is influenced by relatedness. Such information is pertinent to defining population boundaries and understanding localized dispersal patterns and behaviour. Here, we use 3057 genome-wide single-nucleotide polymorphisms (SNPs...

An Amendment to this paper has been published and can be accessed via a link at the top of the paper.

The giant oceanic manta ray Mobula birostris was listed in the US Endangered Spe- cies Act as a threatened species in 2018, yet insufficient data exist on manta populations through- out US waters to designate critical habitat. Taxonomic and genetic evidence suggests that manta rays in the Western Atlantic are a separate species (M. cf. birostris) a...

Decades of overexploitation have devastated shark populations, leaving considerable doubt as to their ecological status1,2. Yet much of what is known about sharks has been inferred from catch records in industrial fisheries, whereas far less information is available about sharks that live in coastal habitats³. Here we address this knowledge gap usi...

Site-specific knowledge of spatial ecology is essential for the implementation of effective conservation measures for wide-ranging marine species. We used passive acoustic telemetry to examine the movements and site usage of reef manta rays Mobula alfredi in the Inhambane Province of Mozambique. Acoustic receivers were installed at 14 sites spannin...

The implications of plastic pollution, including microplastics, on marine ecosystems and species are increasingly seen as an environmental disaster. Yet few reports focus on filter-feeding megafauna in regions heavily impacted by plastic pollution, such as Indonesia in the Coral Triangle, a global marine biodiversity hotspot. Here, we evaluate plas...

Intraspecific colour polymorphisms have been the focus of numerous studies, yet processes affecting melanism in the marine environment remain poorly understood. Arguably, the most prominent example of melanism in marine species occurs in manta rays (Mobula birostris and Mobula alfredi). Here, we use long-term photo identification catalogues to docu...

Understanding how individual behavior shapes the structure and ecology of populations is key to species conservation and management. Like many elasmobranchs, manta rays are highly mobile and wide-ranging species threatened by anthropogenic impacts. In shallow water environments, these pelagic rays often form groups and perform several apparently so...

Background: The smalleye stingray (Megatrygon microps) is a large and rare dasyatid ray, patchily distributed across the Indo-West Pacific. Free-swimming individuals have regularly been recorded in Southern Mozambican coastal waters utilizing different inshore environments. Distinctive features of the species include latitudinal rows of white spot...

Manta rays (Mobula spp.) are highly valued in nature-based tourism globally. In Indonesia, although manta rays are protected, critical information is lacking on their habitat use, population dynamics and movements. We investigate the population structure and residency patterns of reef manta rays (Mobula alfredi) in the Nusa Penida Marine Protected...

An opportunistic sighting of a reef manta ray (Mobula alfredi) along the northeastern corner of Cocos Island, Costa Rica, represents the first sighting of this species nearly 6000 km from the nearest confirmed sighting location in the Marquesas Islands and the first record of this species on either side of the American continent. Cocos Island is si...

Manta and devil rays are filter-feeding elasmobranchs that are found circumglobally in tropical and subtropical waters. Although relatively understudied for most of the Twentieth century, public awareness and scientific research on these species has increased dramatically in recent years. Much of this attention has been in response to targeted fish...

Despite their iconic megafauna status and importance to the global tourism economy, both species of manta ray (Mobula birostris, Mobula alfredi) are considered internationally threatened (Lewis et al., 2015, Anderson et al., 2011, Cisneros-Montemayor et al., 2013), primarily due to the high demand for their gill rakers in traditional medicine marke...

Microplastic pollution can impact filter-feeding marine megafauna, namely mobulid rays, filter-feeding sharks, and baleen whales. Emerging research on these flagship species highlights potential exposure to microplastic contamination and plastic-associated toxins. Research and its wide communication are needed to understand the magnitude of the iss...

Traditionally, large planktivorous elasmobranchs have been thought to predominantly feed on surface zooplankton during daytime hours. However, the recent application of molecular methods to examine long-term assimilated diets, has revealed that these species likely gain the majority from deeper or demersal sources. Signature fatty acid analysis (FA...

Comparison of surface zooplankton signature fatty acid (FA) profiles among sampling months with 95% ellipses. Non-metric multi-dimensional scaling ordination of surface zooplankton FA profiles sampled at Isla de la Plata, Ecuador, from August 2013 to October 2013, and August 2014 to September 2014. There was a significant difference among samples (...

Signature fatty acid (FA) profiles (% of total FA ± s.d.) of surface zooplankton collected from Isla de la Plata, Ecuador among sampling months and temperature groupings. Here, the FA profiles of surface zooplankton were significantly different among sampling months and temperature groupings (SIMPER, p <0.05). (DOCX)

Individual Mobula birostris and surface zooplankton fatty acid profiles, along with sampling date and location. (XLSX)

Comparison of surface zooplankton signature fatty acid (FA) profiles between different in situ temperature groupings at time of collection. Non-metric multi-dimensional scaling ordination of surface zooplankton FA profiles sampled at Isla de la Plata, Ecuador, from August—October 2013, and August—September 2014. There was a significant difference i...

Signature fatty acid (FA) profiles (% of total FA ± s.d.) of Mobula birostris among sample collection years. The FA profiles of M. birostris were not significantly different among years (ANOSIM, R = 0.04753, p = 0.27). (PDF)

Similarity percentage analysis (SIMPER) of surface zooplankton fatty acid profiles among cluster groups 1 and 2 (80% similarity). Fatty acids with an average contribution >5% are included and data was not transformed prior to analysis. (PDF)

Similarity percentage analysis (SIMPER) results of Mobula birostris fatty acid profiles for cluster groups A and B (70% similarity). Fatty acids with an average contribution >5% are included and data was not transformed prior to analysis. (PDF)

Detailed methodology for lipid extraction and signature fatty acid analysis. (DOCX)

Mobulid rays are one of the most vulnerable chondrichthyan groups due to their low population growth rates and high susceptibility to fisheries. While estimates of human-induced mortality are lacking, sighting trend data can provide an index of their status. We recorded underwater sightings data of Mobula alfredi , M. birostris and M. kuhlii over a...

Mobulid rays are one of the most vulnerable chondrichthyan groups due to their low population growth rates and high susceptibility to fisheries. While estimates of human-induced mortality are lacking, sighting trend data can provide an index of their status. We recorded underwater sightings data of Mobula alfredi , M. birostris and M. kuhlii over a...

Stable isotope analysis of tissues with different turnover rates allows for a broader temporal view of a species' feeding habits. Epidermal mucus is a rapid to medium turnover 'tissue' in teleost fish, but its use in elasmobranch dietary studies is unknown. In the present study, we conducted stable isotope analysis on mucus and muscle from the gian...

Manta rays are internationally threatened species and population declines have been reported in various locations worldwide. As iconic megafauna species, they are also major drawcards for wildlife tourism industries. Economic valuation of these industries can provide an incentive for the protection of species and natural habitats through the creati...

Supplementary information for sample collection, isotope values for individual Manta birostris and surface zooplankton tows, and mixing model summary statistics.Included here is a detailed sample collection protocol for obtaining M. birostris muscle tissue samples from free swimming animals. Additionally, the CN isotope values for individual Manta...

The characterization of diet for the giant manta ray Manta birostris has been problematic given their large-scale movement patterns and the difficulty in obtaining stomach contents from this species. The large majority of existing information is based on observational data limited to feeding events at the sea surface during daylight. Recently disco...

Manta and devil rays of the subfamily Mobulinae (mobulids) are rarely studied, large, pelagic elasmobranchs, with all eight of well‐evaluated species listed on the IUCN Red List as threatened or near threatened. Mobulids have life history characteristics (matrotrophic reproduction, extremely low fecundity, and delayed age of first reproduction) tha...

Cleaning interactions between the short fin devil ray, Mobula kuhlii, and the blue streaked cleaner wrasse, Labroides dimidiatus, were observed at two sites on a single reef in southern Mozambique. Cleaning interactions were filmed and described, with the number and location of interactions recorded and subsequently binned into six distinct body pa...

Cleaning interactions between the short fin devil ray, Mobula kuhlii, and the blue streaked cleaner wrasse, Labroides dimidiatus, were observed at two sites on a single reef in southern Mozambique. Cleaning interactions were filmed and described, with the number and location of interactions recorded and subsequently binned into six distinct body pa...

Included here is a detailed sample collection protocol for obtaining M. birostris muscle tissue samples from free swimming animals. Additionally, the CN isotope values for individual Manta birostris and surface zooplankton tows are presented, along with mixing model summary statistics for the mean credible interval source contributions of surface z...

Included here is a detailed sample collection protocol for obtaining M. birostris muscle tissue samples from free swimming animals. Additionally, the CN isotope values for individual Manta birostris and surface zooplankton tows are presented, along with mixing model summary statistics for the mean credible interval source contributions of surface z...

Technical justification for the protection of Manta Rays in Mozambique