Manta Alfredi Research Articles

Preliminary insights into the population characteristics and distribution of reef (Mobula alfredi) and oceanic (M. birostris) manta rays in French Polynesia

In French Polynesia, both currently recognized manta ray species, Mobula alfredi and M. birostris, are observed. Despite being an important cultural asset and generating significant economic benefits through manta ray watching tourism, published data on the ecology and threats to these species in the region are scarce. Based on an 18-year dataset of sighting records collected by citizen scientists and during two scientific expeditions, this study provides the first insights into the population characteristics and regional distribution of the two manta ray species in French Polynesia. A total of 1347 manta ray photographs (1337 for M. alfredi and 10 for M. birostris) were examined for the period January 2001–December 2017, with photo-identification techniques leading to the successful identification of 317 individual M. alfredi and 10 individual M. birostris throughout the Society, Tuamotu and Marquesas Islands. We provide the first confirmation of sympatric distribution of both species in the Society Islands. Our results highlight strong and long-term site fidelity of M. alfredi individuals to certain aggregation sites (> 9 years for 16 individuals) and reveal some degree of connectivity between populations, with 10 individuals recorded moving between islands located up to 50 km apart. Analysis of photographs of individuals bearing sub-lethal injuries (n = 68) suggests that M. alfredi are more likely to be injured at inhabited islands (Maupiti or Bora Bora; 75% of all injured individuals) than at uninhabited islands, with 75% of injuries related to boat propeller strikes and fishing gear entanglements. Our findings emphasize the need for further research to allow for a comprehensive evaluation of population structure, size and threats to manta rays in this region.

Social preferences and network structure in a population of reef manta rays

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 socially mediated behaviors. Group structures may result from active choices of individual rays to interact or passive processes. Social behavior is known to affect spatial ecology in other elasmobranchs, but this is the first study providing quantitative evidence for structured social relationships in manta rays. To construct social networks, we collected data from more than 500 groups of reef manta rays (Mobula alfredi) over 5 years in the Raja Ampat Regency of West Papua. We used generalized affiliation indices to isolate social preferences from non-social associations, the first study on elasmobranchs to use this method. Longer lasting social preferences were detected mostly between female rays. We detected assortment of social relations by phenotype and variation in social strategies, with the overall social network divided into two main communities. Overall network structure was characteristic of a dynamic fission-fusion society, with differentiated relationships linked to strong fidelity to cleaning station sites. Our results suggest that fine-scale conservation measures will be useful in protecting social groups of M. alfredi in their natural habitats and that a more complete understanding of the social nature of manta rays will help predict population responses to anthropogenic pressures, such as increasing disturbance from dive tourism. In social animals, relationships between individuals have important implications for species conservation. Like many other sharks and rays, manta rays are threatened species, and little is known about their natural behavior or how their populations are structured. This study provides evidence of social structure in a wild, free-ranging population of reef manta rays. We show for the first time that individual manta rays have preferred relationships with others that are maintained over time, and structured societies. This study extends our knowledge of elasmobranch ecology and population structuring. Results suggest that understanding social relationships in manta rays will be important in protecting populations from human impacts and developing sustainable, localized conservation and management initiatives.

A functional trait approach to identifying life history patterns in stochastic environments.

Temporal variation in demographic processes can greatly impact population dynamics. Perturbations of statistical coefficients that describe demographic rates within matrix models have, for example, revealed that stochastic population growth rates (log(λ s)) of fast life histories are more sensitive to temporal autocorrelation of environmental conditions than those of slow life histories. Yet, we know little about the mechanisms that drive such patterns. Here, we used a mechanistic, functional trait approach to examine the functional pathways by which a typical fast life history species, the macrodetrivore Orchestia gammarellus, and a typical slow life history species, the reef manta ray Manta alfredi, differ in their sensitivity to environmental autocorrelation if (a) growth and reproduction are described mechanistically by functional traits that adhere to the principle of energy conservation, and if (b) demographic variation is determined by temporal autocorrelation in food conditions. Opposite to previous findings, we found that O. gammarellus log(λ s) was most sensitive to the frequency of good food conditions, likely because reproduction traits, which directly impact population growth, were most influential to log(λ s). Manta alfredi log(λs) was instead most sensitive to temporal autocorrelation, likely because growth parameters, which impact population growth indirectly, were most influential to log(λ s). This differential sensitivity to functional traits likely also explains why we found that O. gammarellus mean body size decreased (due to increased reproduction) but M. alfredi mean body size increased (due to increased individual growth) as food conditions became more favorable. Increasing demographic stochasticity under constant food conditions decreased O. gammarellus mean body size and increased log(λ s) due to increased reproduction, whereas M. alfredi mean body and log(λ s) decreased, likely due to decreased individual growth. Our findings signify the importance of integrating functional traits into demographic models as this provides mechanistic understanding of how environmental and demographic stochasticity affects population dynamics in stochastic environments.

Photographic identification and citizen science combine to reveal long distance movements of individual reef manta rays Mobula alfredi along Australia\u2019s east coast

Research into the movement ecology of terrestrial and marine animals is growing globally, especially for threatened species. Understanding how far an animal can move and the extent of its range can inform conservation planning and management. On the east coast of Australia, reef manta rays Mobula alfredi are the subject of a photographic identification study, Project Manta. In June 2018, videos of reef manta rays from the SS Yongala (19.31° S, 147.62° E), were submitted to the Project Manta east coast sightings database. The videos were of two individuals previously identified from North Stradbroke Island (27.42° S, 153.55° E), about 1150 km to the south of the SS Yongala. This represents the greatest point-to-point distance travelled by individual M. afredi and extends the latitudinal range for this sub-population on the east coast. This study highlights that citizen science input can provide valuable data to address knowledge gaps in the distribution and population range of marine species. Knowledge of the 1000+ km range movement potential of individual M. alfredi, highlights the possibility that regional sub-populations may span jurisdictional zones of more countries than previously considered likely, complicating conservation management of this species.

Movement and residency patterns of reef manta rays Mobula alfredi in the Amirante Islands, Seychelles

Movement and residency patterns of reef manta rays Mobula alfredi in the Amirante Islands, Seychelles

Contrasting Habitat Use and Population Dynamics of Reef Manta Rays Within the Nusa Penida Marine Protected Area, Indonesia

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 Area (MPA). From photo-identification data logged by citizen scientists and trained observers (mantamatcher.org), we identified 624 reef manta rays from 5,913 sightings (January 2012–April 2018) based on their unique ventral coloration patterns. Year-round records were collected from two shallow (<20 m) reefs – Manta Bay (MB; n = 3,029 sightings) and Manta Point (MP; n = 3,058) – that are used frequently by tourism operators. Maximum likelihood techniques and a Markov movement analysis were used to model residency patterns and movement between these sites within the MPA. Manta rays at MB were predominantly male (64%, n = 261 individuals), with immature males (14%, n = 59) being sighted most frequently (39%, n = 1,170). In contrast, few immature individuals were sighted at MP (6%, n = 28), and they were sighted on few occasions (2%, n = 45), while mature female manta rays comprised 26% (n = 127) of the MP community and were the most frequently sighted (48%, n = 1,413). Lagged identification rates indicated high site fidelity at each location. However, 44% (n = 278) of individuals moved between the two sites and cumulative discovery curves showed a continued recruitment of individuals over the 6 years of the study. In addition, the behaviors displayed by the manta rays differed markedly between the two sites: MB appears to be a foraging ground, especially for juveniles, and potentially a nursery, while MP is used mainly for cleaning and courtship, indicating a social and reproductive site. Reproductive behavior coincided with the peak annual sightings in May. To prevent disturbance to this threatened species by tourism, regulations for the number of boats and interactions, especially during key reproductive times should be considered. Further, strict fishing regulation in the area is recommended as fishing gear entanglement was identified as a threat to this population.

Quantifying vulnerability of sharks and rays species in Indonesia: Is biological knowledge sufficient enough for the assessment?

Sharks and rays are vulnerable species, which are highly exploited in Indonesian waters but lacked of detailed information on their ecology and fisheries status. This research aims to assess the level of vulnerability of sharks and rays to overfishing using the maximum intrinsic rate of population increase (rmax), derived from the Euler-Lotka equation, as a proxy of extinction risk. It is calculated based on several biological parameters including fecundity, maximum age, age at maturity, and the number of offspring. Using rmax calculation adapted to shark and ray life history traits by accounting for survival to maturity, we were able to calculate rmax values for 26 out of 208 sharks and rays species present in Indonesia. This includes vulnerable species such as Mobula alfredi, Prionace glauca, and Pristis zijsron. This result showed that rmax is a valuable tool which can be used to quantify extinction risk with some level of precision, but it also highlights the necessity to collect important biological information of the most vulnerable species to further estimate their status. This approach requires complementary information related to external threats such as habitat degradation, species economic value and threat level from local fishing effort and related fishing gears.

ID THE MANTA : MANTA SIGHTINGS IN MANTA SANDY - RAJA AMPAT, WEST PAPUA-INDONESIA

Manta ray (Mobula alfredi and Mobula birostris) is an endangered species that protected by international and national law. This species is vulnerable because of commercial fisheries and anthropogenic threats. These threats have impacted the species population worldwide. Raja Ampat is home for both species of the manta ray, and the area is protected with conservation status. Manta Sandy is located in Dampier Strait, is a popular dive site in Raja Ampat visited by thousands of tourist per year. It is vital to ensure the manta sightings in this area to maintain the tourist volume for local economic benefits. Utilization of photo ID and mark-recapture technique conducted to document the spots on the belly of manta ray that identify a unique pattern of each fish. This study conducted in low season from July to August 2018 for 15 days from 08.00-16.00 used two cameras of go pro hero 4 with extra battery power. The result documented time of manta sightings and species characteristic (size, sex, species, behavior, and color morphology). The camera trap recorded four manta rays where the two of them were new identified individuals.

First record of the reef manta ray, Mobula alfredi, from the eastern Pacific

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 situated approximately 500 km away from mainland Costa Rica as well as any other suitable habitat for this species, suggesting the sighted individual may have migrated to this location. The individual was fitted with an acoustic transmitter (V16 Vemco Ltd., Nova Scotia, Canada) which will enable monitoring of its habitat use around the island and potential long-term residency patterns.

Feeding – Cleaning Trade-Off: Manta Ray “Decision-Making” as a Conservation Tool

Identifying critical aggregation sites and behavioral patterns of imperiled species contributes to filling knowledge gaps essential for their conservation. Manta rays present a prominent example of such species, the populations of which are declining globally due to directed fishery, by-catch, and other anthropogenic stressors. Our goal was to explore manta ray aggregation sites in the Philippines in order to determine the factors governing the mantas’ visits – a knowledge gap essential to understand manta ecology, facilitate ecosystem-based fishery management, and promote sustainable manta-based ecotourism. Diving surveys, environmental conditions assessment, and autonomous cameras were employed to study manta behavior and visit patterns to a cleaning station cluster on a commonly fished seamount, visited by both Mobula birostris and Mobula alfredi. Our findings reveal several environmental conditions (e.g. sea state, moon illumination, and flow) that serve as predictors of manta presence/absence at the site. We suggest that these conditions affect both the behavior of the manta’s food (i.e. the spatial distribution of plankton) and the cleaner wrasses’ cleaning effectiveness, which consequently influence manta activity. The findings suggest a trade-off between cleaning and foraging: i.e. mantas tend to visit the cleaning stations when environmental conditions are less favorable for foraging but suitable for effective cleaning; while being absent from the cleaning stations when environmental conditions form plankton aggregates, ideal for efficient feeding. This study sheds light on manta behavior and habitat use on dynamic small spatio-temporal scales (i.e. hundreds of meters to a few kilometers, hours to days), and may be applied in the planning of marine protected areas and in fishery management, as well as contribute to enhancing sustainable exploitation of manta rays by local stakeholders, such as ecotourism operators.

Examination of tourists’ willingness to pay under different conservation scenarios; Evidence from reef manta ray snorkeling in Fiji

Wildlife-focused tourism is often considered as having the potential to play an integral part of threatened species conservation efforts, particularly through financial support. We focused on the direct financing of conservation by investigating tourists’ willingness to pay to snorkel with reef manta rays (Mobula alfredi) at Barefoot Manta, an ecotourism resort in the Yasawa group of islands in Fiji. Our results indicate that 82.4% of people surveyed would be willing to pay a mean value of ~ USD $9.2 (SE 0.9) more than the current cost, a 28% increase. Also, 89% of people surveyed would be willing to pay a mean value of ~ USD $10.2 (SE 0.9) more for a hypothetical scenario where they would snorkel with 50% fewer people, a 31% increase. We also investigated tourists’ willingness to make voluntary donations to the local community above an existing payment of ~ USD $10 that is built into the current snorkel payment of ~ USD $32.5. On average, 91.3% of the tourists interviewed were willing to donate additional funds with an average additional donation of ~ USD $8.6 (SE 0.5) to the community to pay for educational and environmental support, an 86% increase. There were few significant relationships between willingness to pay and demographic factors (including age, income, nationality, education, and others), suggesting that willingness to pay was widely held by the tourist population staying at Barefoot Manta Resort. Together, these results indicate that wildlife-based nature tourism could represent a potential, but not unlimited, income source to fund conservation in the Yasawa group, Fiji islands, and that conservation can arise from partnerships between local communities and the tourism sector.

Variation in occupancy and habitat use of Mobula alfredi at a major aggregation site

Understanding variations in habitat use through time contributes to identification of habitats critical for species survival. Here we used passive acoustic telemetry to examine the residency and site fidelity patterns of the reef manta ray Mobula alfredi at Lady Elliot Island (LEI), a key aggregation site in eastern Australia. Six acoustic receivers were moored around LEI between 2009 and 2012, and 34 acoustic transmitters were deployed on manta rays. All tagged animals returned to this site within their recording period, with some indi viduals visiting the area for up to 23 consecutive days. Using a set of mixed effect models, we analysed the hourly visitation patterns of manta rays in relation to temporal and en vironmental variables. Diel phase and sea temperature showed the strongest effects on the presence of manta rays, with weaker effects detected for wind direction, wind speed and moon illumination. Individuals occupied LEI habitat mostly during daylight hours and in calm weather conditions, which may be linked with behavioural thermoregulation, social inter actions and cleaning activities. Their absence at night may be related to foraging strategies in deeper offshore waters. The effect of sea temperature reflects the greater seasonal occurrence of manta rays at LEI in winter, when temperatures are coolest, potentially in response to regional food availability. The high degree of manta ray site fidelity at aggregation sites underscores the importance of these areas as key daytime habitats for the species. We suggest that conservation measures should prioritise the protection of coastal aggregation habitats from overexploitation and degradation.

The road less traveled.

I peered sidelong into my laptop's keyboard. If I was careless with the mangosteen and papaya in my little tropical island bungalow, the ants were sure to invade—and end up squashed among the keys as I pushed out the morning's emails. I would often end up singing “the ants go marching one by one” while trying to reroute them out the door with sticky trails of decoy papaya juice. (“Hurrah! Hurrah!”) This was not a problem I expected to encounter as part of running my scientific editing business. But it was the price—a small one—of my life as a digital nomad. ![Figure][1] ILLUSTRATION: ROBERT NEUBECKER > “All I would need was a computer and an internet connection.” I've always been a travel junkie. Vacations never cut it, so during my Ph.D. and postdoc in biogeography, I traveled for work anytime I could. But eventually, even the rare desk days became too much. After a visit to the Paris herbarium, where I was sorting through 150-year-old dried tree ferns for my postdoc research, I decided it was time. I needed to be somewhere lush and green, among living ferns. Just a week later, a professor in my department insisted on paying me for my work editing his manuscripts. I had helped many colleagues and friends with this type of work over the years. I enjoyed writing and helping out. But the professor's offer triggered a realization: I could make a living with this work. Even better, all I would need was a computer and an internet connection fast enough to email Word documents and support the occasional Skype call. The adventurer in me saw an opportunity. My postdoc ended 6 months later, and many of my colleagues said they would consider hiring me to edit their manuscripts or books. I was ready to take the leap. Work was slow at first. When I emailed my network to let people know I was officially in business, many expressed interest but didn't have projects ready for me. I had expected this, so—despite fleeting doubts about the course I had chosen—I remained patient. Every day the work emails failed to show up was another chance to explore and find my nomadic rhythm. I trained to be a divemaster in the fast-moving waters between the islands of Bali and Lombok, the famous division that separates Asian and Australian faunas. I loved diving at Bali's Manta Point, where reef manta rays twice my size glided around me. I watched the sun rise over pagodas in Myanmar, saw ash spewing from Volcan de Fuego in Guatemala, ate schnitzel in the Austrian Alps, and felt the earth shake in New Zealand. When people asked how long I was traveling, I responded, “As long as I want,” feeling impossibly lucky. Yet in the beginning, while I was only getting work sporadically, I sometimes wondered what I was doing. Was I really an editor, or was I just a vagabond with a computer? I began reflecting on what defines a profession. Was it working 40 (or more) hours a week? Making ends meet? Was it enough to have a business plan and a passion? For a while, I tried to figure out the “right” way to do it. But as I met other digital nomads, I found that each had a unique story and there was no single right way. So I just kept doing it my way. Eventually, as the stamps in my passport piled up, my business grew. The impostor syndrome melted away. In its place I felt a contentment I never found during my years of research. After two and a half years working and exploring in 18 different countries, I had just finished a major book project and felt that I could call my business a success. However, the now long hours meant I could no longer explore as much as I once had. When I found out that a colleague back in Sweden was creating a biodiversity center, I couldn't help but get excited about working to start it up. The job would involve some travel, which I embraced. I would get work-free vacations, too—a luxury I had come to miss. The time felt right to have a hint of stability again. But I haven't forgotten my time of adventure. Every now and then, I come across early-career researchers thinking of trying a nontraditional path. I'm happy to give them a push away from routine and into the deep end. After all, there might be mantas down there. [1]: pending:yes

Site fidelity and movement patterns of reef manta rays (Mobula alfredi: Mobulidae) using passive acoustic telemetry in northern Raja Ampat, Indonesia

Though extremely valuable to the local marine tourism industry, there is a dearth of published information on the ecology and population dynamics of reef manta rays (Mobula alfredi) in Raja Ampat, West Papua, Indonesia. Knowledge of the movement ecology in particular of this large and scattered population is urgently needed to better manage the rapidly expanding manta-focused tourism. Here we report the results of an initial passive acoustic telemetry study designed to provide local managers with the first detailed knowledge of the site use and movement patterns of reef mantas in northern Raja Ampat. A total of 39 reef mantas were tagged with Vemco V16 acoustic transmitters over a 15-month period between 27 November 2013 and 22 February 2015. To monitor their movements, VR2W acoustic receivers were deployed at eight sites corresponding to known manta cleaning and feeding aggregation sites, with receivers downloaded every six months over a two-year initial monitoring period. The duration between tag deployments and last date of detections at sites ranged from 1 to 682 days (mean ± SE = 237 ± 27). The cumulative number of days of manta detections at receiver sites by individual mantas ranged from 1 to 188 days (mean ± SE = 42 ± 7). Manta Ridge was the most popular site with 565 days of detections. The tagged mantas demonstrated strong site fidelity to the observed aggregation sites, but also exhibited seasonal movements within an approximately 150 km long corridor between sites in the Dampier Strait and the northwest of Waigeo Island. Data analysed from a nearby array of six VR2W receivers in southern Raja Ampat (approximately 180 km to the south of the study area) confirmed that none of the tagged mantas were detected in this array, providing further evidence of strong site fidelity and limited movements within the Raja Ampat Archipelago. More than 96% of detections occurred during the daytime. The number of detections reached a peak around noon at Yefnabi Kecil and Eagle Rock and slightly earlier at Manta Ridge. These findings have been shared with the Raja Ampat Marine Protected Area Management Authority and are now being used in the formulation of a management plan for this vulnerable and economically important species to ensure the long-term health of Raja Ampat’s reef mantas and the sustainability of manta tourism in the region.

Southernmost record of the Giant Manta Ray Mobula birostris (Walbaum, 1792) in the Eastern Pacific

BackgroundManta rays (Mobulidae), Mobula birostris and Mobula alfredi, are widely distributed in tropical and temperate waters. Still, little is known about their movements and their ecological interactions (e.g. behavior and diet). In Peru, M. birostris has only been reported along the northern shore within the Tropical East Pacific Marine Province. No official reports exist from central or south Peru within the Warm Temperate Southeastern Pacific Marine Province.MethodsOn December 22nd 2015, a rare sighting of a ~4 m disc width mobulid ray was recorded as video footage near the Palomino Islets, Lima, Peru.ResultsIn situ observations and subsequent analysis of the footage confirmed that this single mobulid was a M. birostris with a melanistic color morph.ConclusionsThis sighting could be explained by the warm El Niño, primary (chl-a), and secondary (zooplankton) productivity events during that same period. This represents the southernmost record of M. birostris in the southeastern Pacific (12°S) and the first report of this species in the Warm Temperate Southeastern Pacific Marine Province and in the Humboldt Current Large Marine Ecosystem.

Conservation of reef manta rays (Manta alfredi) in a UNESCO World Heritage Site: Large-scale island development or sustainable tourism?

A large reef manta ray (Manta alfredi) aggregation has been observed off the north Sudanese Red Sea coast since the 1950s. Sightings have been predominantly within the boundaries of a marine protected area (MPA), which was designated a UNESCO World Heritage Site in July 2016. Contrasting economic development trajectories have been proposed for the area (small-scale ecotourism and large-scale island development). To examine space-use, Wildlife Computers® SPOT 5 tags were secured to three manta rays. A two-state switching Bayesian state space model (BSSM), that allowed movement parameters to switch between resident and travelling, was fit to the recorded locations, and 50% and 95% kernel utilization distributions (KUD) home ranges calculated. A total of 682 BSSM locations were recorded between 30 October 2012 and 6 November 2013. Of these, 98.5% fell within the MPA boundaries; 99.5% for manta 1, 91.5% for manta 2, and 100% for manta 3. The BSSM identified that all three mantas were resident during 99% of transmissions, with 50% and 95% KUD home ranges falling mainly within the MPA boundaries. For all three mantas combined (88.4%), and all individuals (manta 1–92.4%, manta 2–64.9%, manta 3–91.9%), the majority of locations occurred within 15 km of the proposed large-scale island development. Results indicated that the MPA boundaries are spatially appropriate for manta rays in the region, however, a close association to the proposed large-scale development highlights the potential threat of disruption. Conversely, the focused nature of spatial use highlights the potential for reliable ecotourism opportunities.

High-resolution monitoring from birth to sexual maturity of a male reef manta ray, Mobula alfredi, held in captivity for 7\xa0years: changes in external morphology, behavior, and steroid hormones levels

BackgroundIn this study, we report the first case of a male reef manta ray, Mobula alfredi, becoming sexually mature in captivity and present its reproductive characteristics.MethodsWe investigated changes in external morphology, behavior, and levels of steroid hormones in a male M. alfredi during its sexual maturation process.ResultsAt 2 years and 6 months of age, the male exceeded 300 cm in disc width. Then, at around 3 years of age, the male started to chase a female in the tank and exhibited androgen levels similar to that of another matured male, indicating that the study specimen had begun sexual maturation endocrinologically. Its first copulation event was observed at 5 years and 4 months and appeared behaviorally similar to field observations. Seven months after copulation, we performed a biopsy to collect its semen, including any motile sperm.ConclusionTaken together, these results indicate that the captive male M. alfredi individual shows signs of sexual maturation (size of disc width, testosterone levels, reproductive behavior) already with the age of 2.5 to 3 years. As a first copulation was observed with 5 years 4 months of age and the presence of sperm were confirmed at the age of 5 years 11 months of age, the studied animal reached its full sexual maturity at the latest at the age of around 5 years.

Characteristics of a previously undescribed fishery and habitat for Manta alfredi in the Philippines

Seven species of mobulid rays occur in the Philippines, six of which, including the Giant Manta Ray (Manta birostris) are caught directly or indirectly. In the Bohol Sea, mobulids have been fished since at least the nineteenth century yet the extent is not well-understood. A second species of manta, Manta alfredi was taxonomically resurrected in 2009 and also only recently been confirmed to occur in the Philippines. This study aimed to identify and describe the presence of and fishery for M. alfredi in a previously unknown area of occurrence in the Philippines. Key informant interviews, observation of catch landings, and tissue sample collection were conducted in a fishing village off Dinagat Island. Based on morphological examination and through DNA barcoding using the mitochondrial DNA CO1 gene of tissue samples it was verified that the species targeted in this area is the reef manta ray, Manta alfredi. Local ecological knowledge of the fishers provided important information on the extent and characteristics of the fishery. This relatively recent ray fishery in the Surigao Strait is the source of mobulids during the off-fishing season in Bohol with fishers from this area transporting and selling their processed catches to Bohol. The description of this fishery and habitat for the reef manta ray in the Surigao Strait is important in the understanding of the status of the species in the Philippines and in designing a management framework.

Mechanistic description of population dynamics using dynamic energy budget theory incorporated into integral projection models

Summary Integral projection models (IPMs) provide a powerful approach to investigate ecological and rapid evolutionary change in quantitative life‐history characteristics and population dynamics. IPMs are constructed from functions that describe the demographic rates – survival, growth and reproduction – in relation to the characteristics of individuals and their environment. Currently, however, demographic rates are estimated using phenomenological regression models that lack a mechanistic representation of the biological processes that give rise to observed demographic variation. This lack of mechanistic underpinning limits the ability of the model to predict future dynamics under novel environmental conditions because the model ingredients pertain to current environmental conditions only. Here, we use dynamic energy budget (DEB) theory to construct DEB‐IPMs based on a mechanistic representation of individual life‐history trajectories. We derive the demographic functions describing growth and reproduction from a simple DEB growth model. The functions describing mortality and the association between parent and offspring characteristics do not follow DEB theory and hence are estimated from individual‐level observations. We apply the DEB‐IPM to two contrasting systems: the small, fast‐reproducing bulb mite Rhizoglyphus robini and the large, slow‐reproducing reef manta ray Manta alfredi. In both cases, predictions of population growth rate, lifetime reproductive success and generation time agree with empirical observations. In case of the bulb mite, predictions and observations even agree across different feeding conditions. If the DEB energetics model is accepted as describing growth and reproduction, DEB‐IPMs can be parameterised using easy‐to‐collect life cycle information (growth rate, length at birth, maturation and old age) making them suitable for data‐deficient species. Because species differ only in these DEB parameters, comparative studies of character and population dynamics between species are straightforward, particularly since DEB‐IPMs can be extended to include population feedback on resources, of which we give an example. Most crucially, because DEB theory specifies growth and reproduction rates as explicitly dependent on environmental conditions such as food availability or temperature, DEB‐IPMs provide a mechanistic platform to investigate the biological processes that determine joint change in phenotypic characters, life‐history traits, population size and community structure.

MEDICAL MANAGEMENT OF COELOMIC DISTENTION, ABNORMAL SWIMMING, SUBSTRATE RETENTION, AND HEMATOLOGIC CHANGES IN A REEF MANTA RAY (MANTA ALFREDI)

An adult, female, reef manta ray (Manta alfredi) was evaluated for abnormal swimming and coelomic distention after colliding with a floating dock in an exhibit. Initial clinical signs included abnormal posture and swimming. Clinical signs progressed to include muscle wasting, poor body condition, and coelomic distention. Further diagnostics revealed excessive exhibit substrate within the gastrointestinal tract, gastric ulcers, free coelomic fluid, possible spinal lesion, possible uterine abnormality, and hematologic changes. The ray was treated with repeated gastroscopic examinations to remove substrate from the stomach. Psyllium and mineral oil were administered in gel food to assist with passage of substrate through the gastrointestinal tract. Gastric ulcers were treated with sucralfate. Vitamin B complex, iron dextran, and Yunnan Paiyao were used to treat the anemia. Amikacin and sulfadimethoxine-ormetoprim were administered for suspected bacterial and coccidial infections, respectively. Over the course of 11 mo the ray returned to normal health.