Manta Birostris Research Articles

Occurrence of Microbial Loads in Smoked Fishes Marketed in the Lakeside Village of Guezin (Southern Benin) and Associated Microbiological Hazards

Fish is highly nutritious with high protein content. However, it is a suitable medium for growth of microorganisms, if poorly processed. This study reports the occurrence of microbial loads in smoked fishes marketed in the lakeside village of Guezin (Southern Benin) and associated microbiological hazards. The results obtained indicated that the fish smoking activity in the lakeside village, is exclusively done by women (100%), in households and an informal situation, using traditional equipment. A total of thirteen species of fish, such as Manta birostris, Marcusenius Senegalensis, Liza falcipinis, Hydrocynus brebis, Elops lacerta valvercienne, Silurus linnaeus, Silurus glanis, Arius africanus, Heterotis niloticus, Strongylura senegalensis valenciennes, Ethmalosa finbriata, Gymnocranius griseus and Ameiurus melas are mostly smoked in this area. Microbial loads determined by using standard microbiological procedures, underlined the contamination of smoked fishes by microorganisms, with a high occurrence of Aspergillus strains (83.31%). This occurrence of fungi species could be due to absorption of moisture during storage, which could supported the growth of the microorganisms, in addition to the contamination during processing, handling and display on the market stall. It is then recommended that fish processors should ensure that fish products are properly hot smoked and dried so as to prevent fungal growth and mycological hazards.

Life History, Growth, and Reproductive Biology of Four Mobulid Species in the Bohol Sea, Philippines

In light of the global decline of mobulid populations and the necessity for sustainable fisheries management, baseline data for population dynamics were collected from a targeted fishery in the Bohol Sea, Philippines. This study focused on life-history parameters and reproductive cycles of four mobulid rays (Mobula thurstoni, M. japanica, M. tarapacana, and Manta birostris), and re-estimated their intrinsic population growth rates. Size and reproductive data were collected from 1,509 specimens (30% of catch) landed in two fishing seasons in 2015 and 2016. Size-at-birth was reviewed, and analysis of the embryos and follicles did not show any clear seasonality in the reproductive cycle, but supported an interbreeding interval. Females of all species matured at a larger size than males, and exhibited a larger size-at-pregnancy than -at-maturity. This delay in reproduction resulted in population growth rates lower than the actual rmax when based on size-at-pregnancy (rmat=rmax=0.016-0.055 year-1 and rpreg=0.008-0.044 year-1), and a population doubling time of 15.8-86.6 years. This study suggests that population growth rates previously reported were overestimated. In light of the Convention on International Trades of Endangered Species (CITES) and Convention on Migratory Species (CMS) assessments, while fisheries management should reflect the delayed maturation of these species and the slower population growth potential, at the current status of these population, the sustainability of any exploitation level seems unrealistic and strongly discouraged.

Important juvenile manta ray habitat at Flower Garden Banks National Marine Sanctuary in the northwestern Gulf of Mexico

Oceanic manta rays (Mobula birostris) are large pelagic planktivores that are threatened globally by targeted fisheries and bycatch. While studies of oceanic mantas have increased substantially in the past decade, major knowledge gaps remain in their basic biology, ecology and life history. The juvenile stage in particular is virtually unstudied, as juvenile oceanic mantas are rarely observed in the wild and are known primarily from fisheries and captive individuals. Here, we present evidence suggesting that Flower Garden Banks National Marine Sanctuary (FGBNMS) is an important habitat for juvenile manta rays. Recent genetic evidence indicates that both oceanic mantas and a proposed third manta species (Mobula cf. birostris) are present at FGBNMS. Size estimates of mantas sighted at FGBNMS over 25 years of monitoring efforts indicate that 95% of individuals are smaller than the size at maturity for male M. birostris, and 80% are smaller than the size at maturity for M. alfredi. Photographic records of juvenile males with undeveloped claspers further corroborate these findings. Temporal patterns of use and the prevalence of juveniles suggest that this region may serve as nursery habitat for M. birostris and M. cf. birostris. Further research is necessary to determine the importance of the region to juveniles of each species, as well as long-term patterns of habitat use and residency.

Novel signature fatty acid profile of the giant manta ray suggests reliance on an uncharacterised mesopelagic food source low in polyunsaturated fatty acids.

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) of muscle tissue was used to examine the assimilated diet of the giant manta ray Mobula birostris, and then compared with surface zooplankton that was collected during feeding and non-feeding events at two aggregation sites off mainland Ecuador. The FA profiles of M. birostris and surface zooplankton were markedly different apart from similar proportions of arachidonic acid, which suggests daytime surface zooplankton may comprise a small amount of dietary intake for M. birostris. The FA profile of M. birostris muscle was found to be depleted in polyunsaturated fatty acids, and instead comprised high proportions of 18:1ω9 isomers. While 18:1ω9 isomers are not explicitly considered dietary FAs, they are commonly found in high proportions in deep-sea organisms, including elasmobranch species. Overall, the FA profile of M. birostris suggests a diet that is mesopelagic in origin, but many mesopelagic zooplankton species also vertically migrate, staying deep during the day and moving to shallower waters at night. Here, signature FA analysis is unable to resolve the depth at which these putative dietary items were consumed and how availability of this prey may drive distribution and movements of this large filter-feeder.

Kinematics of swimming of the manta ray: three-dimensional analysis of open-water maneuverability.

For aquatic animals, turning maneuvers represent a locomotor activity that may not be confined to a single coordinate plane, making analysis difficult, particularly in the field. To measure turning performance in a three-dimensional space for the manta ray (Mobula birostris), a large open-water swimmer, scaled stereo video recordings were collected. Movements of the cephalic lobes, eye and tail base were tracked to obtain three-dimensional coordinates. A mathematical analysis was performed on the coordinate data to calculate the turning rate and curvature (1/turning radius) as a function of time by numerically estimating the derivative of manta trajectories through three-dimensional space. Principal component analysis was used to project the three-dimensional trajectory onto the two-dimensional turn. Smoothing splines were applied to these turns. These are flexible models that minimize a cost function with a parameter controlling the balance between data fidelity and regularity of the derivative. Data for 30 sequences of rays performing slow, steady turns showed the highest 20% of values for the turning rate and smallest 20% of turn radii were 42.65±16.66degs-1 and 2.05±1.26 m, respectively. Such turning maneuvers fall within the range of performance exhibited by swimmers with rigid bodies.

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.

Use of epidermal mucus in elasmobranch stable isotope studies: a pilot study using the giant manta ray (Manta birostris)

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 giant manta ray Manta birostris. Mucus δ13C values were depleted and closer to surface zooplankton δ13C values compared with muscle, whereas there was no significant difference in δ15N values between these two tissue types. Using diet tissue discrimination factors from the literature, there was no significant difference in the expected prey profile between muscle and epidermal mucus. However, a broader range in δ13C values of expected prey was shown for mucus compared with muscle. The results suggest that if M. birostris mucus is indicative of recent dietary intake, resource use during aggregative behaviour off Ecuador is broader, but with no obvious resource switching. The present study is the first example of using bulk stable isotope analysis to evaluate mucus to investigate feeding ecology in elasmobranchs. However, the time course for the change in mucus isotope signature still needs to be determined through controlled feeding studies in an aquarium setting.

Interactions between Manta birostris and Sotalia guianensis in a World Heritage listed Brazilian estuary.

During 1442 h of visual observations over 7 years throughout the World Heritage listed Paranaguá estuarine complex, Brazil, seven occurrences of interactions were observed at a single location involving breaching Manta birostris displacing schools of teleosts, which were subsequently preyed upon by Sotalia guianensis. Although the interactions were not definitively categorized as being amensal, commensal or mutual, their restriction to isolated space (adjacent to a protected area) and time (summer) supports previous assertions the area is important to regional productivity and the continuation of protected-area status.

Captures of manta and devil rays by small-scale gillnet fisheries in northern Peru

There is a growing global concern for the conservation of manta and devil rays (Mobulidae). Populations of mobulids are falling worldwide and fisheries are one of the main activities contributing to this decline. Mobulid landings have been reported in Peru for decades. However, detailed information regarding the description of mobulid captures is not available. This study provides an assessment of mobulid captures and fish-market landings by small-scale gillnet fisheries from three landing sites in northern Peru. Onboard and shore-based observations were used to monitor captures and landings respectively between January 2015 and February 2016. All mobulid species known to occur in Peru were recorded from landings, with immature Mobula japanica as the most frequent catch. No manta rays (Manta birostris) were reported as caught although one specimen was observed as landed. The mean nominal CPUE was 1.6±2.8 mobulids[km.day]−1 while the average capture per set (fishing operation) was 2.0±8.09 mobulids[set]−1. Smooth hammerhead shark (S. zygaena) and yellowfin tuna (T. albacares) were target species highly associated with mobulid captures. The majority of mobulid captures occurred in nearshore waters and over the continental shelf off Zorritos and San Jose. Mobulid capture showed a temporal trend, increasing between September 2015 and February 2016, with a peak in October 2015 (10.17±0.23 mobulids[km.day]−1), reflected by landings that showed an additional peak in May. A generalized linear zero-inflated negative binomial two-part model (GLM ZINB) indicated that longitude and latitude explained both the zero-inflated binomial model, as well as the count negative binomial model, which also included season as a explanatory variable for differences in mobulid captures. The mean CPUE (mobulids[km.day]−1) and mean Variance values obtained from the fitted final model were 1.73 and 25.51, respectively. Results also suggest that high mobulid captures could reflect an opportunistic behaviour of fishermen who catch mobulids when target species are not as abundant. Considering the global conservation status of mobulids, (Manta and Mobula), and acknowledging that M. birostris was the only species not recorded captured in the study but is the only species legally protected in Peru, further studies are necessary to support the possible inclusion of Mobula species in national management plans.

Environmental factors influencing aggregation of manta rays (Manta birostris) off the northeastern coast of the Yucatan Peninsula

AbstractManta rays inhabit tropical, subtropical and temperate waters. Aggregation sites of manta rays have been recognized worldwide, but the reasons for this behavior are still poorly understood. This study describes environmental factors influencing aggregation sites of the giant manta ray (Manta birostris) off the northeastern coast of the Yucatan Peninsula. Observations of manta rays were obtained from scientific surveys conducted during 2006–2011. Environmental data were obtained from satellite imagery. The maximum entropy (Maxent) method for habitat modeling was used to determine the effects of environmental conditions on the species and predict suitable habitat for manta rays in this region. Primary productivity and distance to the coast were the most influential variables, suggesting that aggregation occurs in highly productive coastal waters. The distribution of manta rays predicted by the Maxent model showed that the most suitable habitat within the study area is located off the northeastern coast of the Yucatán Peninsula, more precisely, northeast of Isla Holbox and northwest of Isla Contoy. Seasonal patterns of distribution suggest that the most suitable conditions are present from July through September.

Mobulid rays feed on euphausiids in the Bohol Sea.

Mobulid rays have a conservative life history and are caught in direct fisheries and as by-catch. Their subsequent vulnerability to overexploitation has recently been recognized, but fisheries management can be ineffective if it ignores habitat and prey preferences and other trophic interactions of the target species. Here, we assessed the feeding ecology of four mobulids (Manta birostris, Mobula tarapacana, M. japanica, M. thurstoni) in the Bohol Sea, Philippines, using stomach contents analysis of fisheries specimens landed between November and May in 2013–2015. We show that the mobulids feed heavily on euphausiid krill while they are in the area for approximately six months of the year. We found almost no trophic separation among the mobulid species, with Euphausia diomedeae as the major prey item for all species, recorded in 81 of 89 total stomachs (91%). Mobula japanica and M. thurstoni almost exclusively had this krill in their stomach, while M. tarapacana had a squid and fish, and Ma. birostris had myctophid fishes and copepods in their stomachs in addition to E. diomedeae. This krill was larger than prey for other planktivorous elasmobranchs elsewhere and contributed a mean of 61 364 kcal per stomach (±105 032 kcal s.e., range = 0–631 167 kcal). Our results show that vertically migrating mesopelagic species can be an important food resource for large filter feeders living in tropical seas with oligotrophic surface waters. Given the conservative life history of mobulid rays, the identification of common foraging grounds that overlap with fishing activity could be used to inform future fishing effort.

Elasmobranchs observed in deepwaters (45-330m) at Isla del Coco National Park, Costa Rica (Eastern Tropical Pacific)

Isla del Coco is an oceanic island 500km off the Pacific coast of Costa Rica. It is a National Park and its marine fauna has been relatively well protected. The island is famous for its elasmobranch (sharks, rays and skates) sightings in shallow waters. Here we present a catalogue of the deepwater elasmobranchs observed with the DeepSee submersible. Five species of sharks, six species of skates and one ray have been observed between 45 and 330m depth. Triaenodon obesus, the white tip reef shark, was commonly observed between 80 and 301m, but only in the afternoons. Sphyrna lewini, the scalloped hammerhead shark, was observed as deep a 303m, but commonly between 45 and 90m, and close to the island. Odontaspis ferox, the smalltooth sand tiger shark, was observed between 82 and 316m. Echinorhinus cookei, the prickly shark, was observed between 91 and 320m. Rhincodon typus, the whale shark, was observed only close to the island, between 77 and 80m. Taeniura meyeni, the marbled ray, was observed only close to the island, between 45 and 90m. A Dasyatis sp., similar to the the diamond stingray, was observed only once close to the island at 60m; this is the first report of this genus at Isla del Coco National Park. Manta birostris, the giant manta, was only observed close to the island at 90m. Mobula tarapacana, the sicklefin devil ray, was observed between 60 and 326m, extending its maximum depth almost 10 times what has been reported. Aetobatus narinari, the spotted eagle ray, was observed only close to the island between 60 and 82m. Torpedo peruana, the Peruvian torpedo ray, was observed only once at 313m, and is the first record of this species from Isla del Coco National Park. Citation: Cortés, J., A. Sánchez-Jiménez, J.A. Rodríguez-Arrieta, G. Quirós-Barrantes, P.C. González & S. Blum. 2012. Elasmobranchs observed in deepwaters (45-330m) at Isla del Coco National Park, Costa Rica (Eastern Tropical Pacific). Rev. Biol. Trop. 60 (Suppl. 3): 257-273. Epub 2012 Dec 01.

DNA barcoding of Mobulid Ray Gill Rakers for Implementing CITES on Elasmobranch in China.

The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) has been counted on for conserving threatened marine fish since it regulates the commercial international trade of these species. Implementation of the international treaty for Mantas included on CITES Appendix II is challenging due to insufficient information on species identification and markets management. To fill the gap in such aspects, we identified five species of Mobulid rays (Mobula spps. and Manta spp) by using COI and NADH2 mtDNA markers in dried ray gill rakers from Chinese markets, namely, Mobula japonica (representing 54.8% of the sample set), M. tarapacana (14.4%), M. kuhlii (13.3%), M. thurstoni (6.4%), along with Manta birostris (11.2%; CITES Appendix II). The utilization and conservation statuses of these species were discussed. Based on combination of DNA barcodes and key morphological characters, we developed a three-step process for identifying the gill rakers of Mobulid rays which has been adopted by frontline enforcement in China. We hope that our work can serve as a foundation and basis to reinforce objectives of international treaties, regulation of consumer-driven markets, regional cooperation, and national fishery management on endangered elasmobranchs in China as well as related countries.

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.

Manta birostris, predator of the deep? Insight into the diet of the giant manta ray through stable isotope analysis

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 discovered aggregation sites for the giant manta ray off mainland Ecuador are some of the most accessible to date and provide a unique opportunity for researchers to gather much needed information on this elusive species. To assess how important surface zooplankton is to giant manta ray diet, we conducted stable isotope analysis (15N and 13C) on M. birostris muscle and surface zooplankton. Trophic position estimates placed M. birostris overall at a secondary consumer level of approximately 3.4 but there was large variation in δ15N and δ13C values among individuals. Manta birostris muscle tissue δ13C values were also not consistent with this species feeding predominantly on surface zooplankton and suggest that the majority of dietary intake is of mesopelagic origin. Given the conservative life history and fisheries pressure on large planktivores, knowledge of their trophic role and foraging strategies is essential to better understand their ecology and develop effective conservation measures.

The History and Characteristics of the Mobulid Ray Fishery in the Bohol Sea, Philippines.

The fishery for mobulid rays, also known as devil rays, has been practiced in the Bohol Sea for over a century yet very little is known about its history and characteristics. This study provides the first detailed description of the mobulid ray fishery in the Bohol Sea, Philippines. It describes the history and evolution of the fishery from the 19th century to 2013. It characterizes the fishery based on the species targeted, gears used, the organization, catch distribution, processing, monetary value, and the market of its by-products. This paper also analyses the changes that occurred through time, the management of the fishery and the drivers of the fishery. A multi-disciplinary approach was employed by combining ethno-historical research methods and catch landing monitoring in four primary sites within the Bohol Sea. This fishery began as an artisanal fishery using sail and row boats equipped with harpoons and gaff hooks practiced in at least four coastal villages in Bohol, Camiguin and Limasawa. The fishing fleet has decreased since the beginning of the 20th century however, with the motorization of the fishery and shift to the use of gillnets, the extent of the fishing grounds and market of the products have expanded. Four species of mobulid rays are caught in the Bohol Sea: Manta birostris, Mobula japanica, Mobula thurstoni and Mobula tarapacana. A fifth species, targeted by a fishing community off Dinagat as an off-shoot of the Bohol fishery is most likely the Manta alfredi. Currently, the fishery for mobulids is centered in Bohol Province where it has been practiced longest. The monetary value of mobulids in this region has increased and the dependence of fishing communities for their livelihood is significant. The unique characteristics of this fishery and the socio-cultural context within which it operates merits a thorough investigation in order to design the appropriate management strategy.

Spatial ecology and conservation of Manta birostris in the Indo-Pacific

Information on the movements and population connectivity of the oceanic manta ray (Manta birostris) is scarce. The species has been anecdotally classified as a highly migratory species based on the pelagic habitats it often occupies, and migratory behavior exhibited by similar species. As a result, in the absence of ecological data, population declines in oceanic manta have been addressed primarily with international-scale management and conservation efforts. Using a combination of satellite telemetry, stable isotope and genetic analyses we demonstrate that, contrary to previous assumptions, the species appears to exhibit restricted movements and fine-scale population structure. M. birostris tagged at four sites in the Indo-Pacific exhibited no long-range migratory movements and had non-overlapping geographic ranges. Using genetic and isotopic analysis, we demonstrate that the observed movements and population structure persist on multi-year and generational time scales. These data provide the first insights into the long-term movements and population structure of oceanic manta rays, and suggest that bottom-up, local or regional approaches to managing oceanic mantas could prove more effective than existing, international-scale management strategies. This case study highlights the importance of matching the scales at which management and relevant ecological processes occur to facilitate the effective conservation of threatened species.

Deep-water feeding and behavioral plasticity in Manta birostris revealed by archival tags and submersible observations

Foraging drives many fundamental aspects of ecology, and an understanding of foraging behavior aids in the conservation of threatened species by identifying critical habitats and spatial patterns relevant to management. The world’s largest ray, the oceanic manta (Manta birostris) is poorly studied and threatened globally by targeted fisheries and incidental capture. Very little information is available on the natural history, ecology and behavior of the species, complicating management efforts. This study provides the first data on the diving behavior of the species based on data returned from six tagged individuals, and an opportunistic observation from a submersible of a manta foraging at depth. Pop-off archival satellite tags deployed on mantas at the Revillagigedo Archipelago, Mexico recorded seasonal shifts in diving behavior, likely related to changes in the location and availability of zooplankton prey. Across seasons, mantas spent a large proportion of their time centered around the upper limit of the thermocline, where zooplankton often aggregate. Tag data reveal a gradual activity shift from surface waters to 100–150m across the tagging period, possibly indicating a change in foraging behavior from targeting surface-associated zooplankton to vertical migrators. The depth ranges accessed by mantas in this study carry variable bycatch risks from different fishing gear types. Consequently, region-specific data on diving behavior can help inform local management strategies that reduce or mitigate bycatch of this vulnerable species.

Contingency checking and self-directed behaviors in giant manta rays: Do elasmobranchs have self-awareness?

Elaborate cognitive skills arose independently in different taxonomic groups. Self-recognition is conventionally identified by the understanding that one’s own mirror reflection does not represent another individual but oneself, which has never been proven in any elasmobranch species to date. Manta rays have a high encephalization quotient, similar to those species that have passed the mirror self-recognition test, and possess the largest brain of all fish species. In this study, mirror exposure experiments were conducted on two captive giant manta rays to document their response to their mirror image. The manta rays did not show signs of social interaction with their mirror image. However, frequent unusual and repetitive movements in front of the mirror suggested contingency checking; in addition, unusual self-directed behaviors could be identified when the manta rays were exposed to the mirror. The present study shows evidence for behavioral responses to a mirror that are prerequisite of self-awareness and which has been used to confirm self-recognition in apes.

Notes on the presence of Manta alfredi in the Tubbataha Reefs Natural Park, Cagayancillo, Palawan, Philippines

In 2011, a review of 33 photographs of mantas taken at the Tubbataha Reefs Natural Park (TRNP), Cagayancillo, Palawan, Philippines revealed that most of the mantas photographed were clearly reef manta rays (Manta alfredi) with only one photograph of Manta birostris. Previously identified in surveys within the park as oceanic manta ray M. birostris, the presence of M. alfredi has never been established until now. Using various parameters, the pictures in the Tubbataha Management Office (TMO) database were reviewed and noted. The identification of M. alfredi was more consistently based on the presence of black marks located posterolateral to the last gill slits and between the rows of gill slits. The identification of the species was further validated by experts after viewing three photographs from the said database. This represents a new elasmobranch species record for the TRNP and, technically, for the Philippines as well. Furthermore, the confirmed presence of both globally significant species of manta rays should have a strong bearing on the conservation policies of the park as well as that of the country. Further research on population dynamics, structure and abundance is recommended. Contributing to global efforts to generate better understanding of the species through partnership with international organizations is also recommended.