South Ari Atoll Research Articles

The impact of injury on apparent survival of whale sharks (Rhincodon typus) in South Ari Atoll Marine Protected Area, Maldives

The whale shark (Rhincodon typus) is an endangered species with a declining global population. The South Ari Atoll Marine Protected Area (SAMPA), Maldives, is one of few locations globally where year-long residency of individuals occurs. This SAMPA aggregation appears to consist almost exclusively of immature males. Due to its year-round residency, this local aggregation is subjected to a high degree of tourism pressure. This ecotourism contributes to the high level of interest and protection offered to whale sharks by the local community. Unfortunately, if regulations are not followed or enforced, tourism can bring with it major stressors, such as accidental injuries. We used POPAN capture-mark-recapture models and lagged identification rate analysis to assess the effect of major injuries on whale shark residency within SAMPA. Injuries may be obtained outside SAMPA. We found individuals with major injuries had a higher apparent survival in the area than those without. Lagged identification rates also demonstrated that sharks with major injuries are more likely to return to the area. We suggest that major injuries result in sharks prolonging their time in the developmental habitat. These findings have implications for individual fitness and the population viability of this endangered species. We propose targeted conservation strategies be considered to protect sharks from further injury. Based on the presented spatio-temporal distributions of sharks, and current local knowledge of sighting patterns, speed limit zones and propeller-exclusion zones should be implemented and enforced. If carried out alongside tourist education, these measures will contribute to the protection of whale sharks within SAMPA and beyond. Furthermore, our results can aid research direction, alongside regulation and enforcement development, at similar sites worldwide.

Anthropogenic injury and site fidelity in Maldivian whale sharks (Rhincodon typus)

AbstractWhale sharks collect in predictable seasonal aggregations across the tropics. South Ari Atoll in the Maldives is one of a few aggregation sites where whale sharks can be encountered year‐round. Here, areas with high levels of tourism‐related boating traffic overlap with the whale shark hotspot, increasing the probability of anthropogenic injury. Whale sharks have been reported to remain faithful to this aggregation site following injury, despite the costs of injury and the risk of re‐injury. However, the impacts of injury on site fidelity and residency behaviour are not fully understood.Encounter data on individual sharks from the Maldives Whale Shark Research Programme database (2006–2018) were analysed to assess the relationship between injury and site fidelity in whale sharks. There was no difference in geographic site use, with injured and non‐injured individuals being encountered in the same areas. However, there were differences in residency timings: injured resident whale sharks (individuals repeatedly encountered over 6 months or longer) spent significantly more time at the atoll and less time absent, and were seen more consistently than non‐injured residents. Increased residency duration, return rate and number of residency periods correlated with increasing injury number.These differences in behaviour imply a cost to injury, with whale sharks potentially remaining at this site to recover. With boat traffic being concentrated at the aggregation site, injured sharks may be more vulnerable to further injury. Alternatively, these individuals may remain at the atoll despite injury because the benefits gained from this area outweigh the potential costs, with more resident individuals facing greater exposure to anthropogenic threats. These findings highlight the importance of this location and emphasize the need for improved management of anthropogenic activities, particularly boating traffic, at aggregation hotspots to reduce injury rates and any subsequent impacts on behaviour and fitness.

<p><strong>Discovery of <em>Wilsonosiphonia fujiae</em> (Rhodomelaceae, Rhodophyta) from the Maldives Islands and transfer of <em>Polysiphonia rhizoidea</em> from Hawaiʻi to <em>Wilsonosiphonia</em></strong></p><br /><em></em>

Wilsonosiphonia is a newly described marine algal genus with three species. The genus was previously confused with the widely distributed taxon Polysiphonia, and because of this, the taxonomy and distribution of Wilsonosiphonia is likely underestimated. We report the discovery of a minute filamentous red alga, Wilsonosiphonia fujiae (Rhodophyta) in the Maldives Islands, a taxon which was considered endemic to Brazil. Specimens were collected at Fulhadoo, Goidhoo Atoll and Dhidhdhoo Islands, South Ari Atoll, which are ca. 160 km apart, during January and July, 2019, respectively. Thalli formed dense patches on the upper intertidal in regions of shaded rock. Both mitochondrial cox1 and plastid rbcL sequencing confirmed the occurrence of W. fujiae in the Maldives, which is also in agreement with morphological observations. Based on the low pairwise divergences of COI-5P and rbcL sequences between the Maldives and Brazil specimens, we suggest that W. fujiae is a recently introduced yet cryptogenic species in the Maldives. Additionally, as a result of our phylogenetic analyses, it became evident that sequences from the Hawaiian Islands, which were listed as members of the genus Polysiphonia, represent species-level diversity within the genus Wilsonosiphonia. Based on both morphological characteristics and the COI-5P phylogeny, we here reinstate Polysiphonia rhizoidea from Hawaiʻi and transfer it to Wilsonosiphonia, as W. rhizoidea comb. nov.

Evaluating stakeholder participatory processes in policy development for Marine Protected Areas

This paper evaluates two stakeholder participatory workshops (local communities and tourism stakeholder) to support the development of a management plan for South Ari Atoll Marine Protected Area (SAMPA), Maldives. SAMPA is the largest MPA in the country declared by Maldives to preserve one of the largest whale shark aggregations in the world. However, to date it exists with no management plan to date. The objective of the workshops was to consult with stakeholders on a range of potential regulatory and governance mechanisms proposed for the MPA that can be included in a potential management plan. The paper finds that the two stakeholder workshops had, both functional and dysfunctional aspects that influenced the potential design of a management plan for SAMPA. Overall, the workshops represented a clear opportunity for collective learning and collaboration that fostered dialogue and deliberation. However, important and influential stakeholders were under-represented at the workshops. Furthermore, a reluctance of government to demonstrate how the outcomes of the workshop would be integrated in its decision-making left many participants feeling sceptical about the fairness, equity and effectiveness of the processes that would follow. With no management plan to date, this paper proposes that any future stakeholder process in SAMPA should be underpinned by well informed governance and regulatory options that have the support and commitment of the government which can ensure SAMPA's ecosystem services are sustained to benefit long-term human well-being.

Comparing length-measurement methods and estimating growth parameters of free-swimming whale sharks (Rhincodon typus) near the South Ari Atoll, Maldives

Whale sharks (Rhincodon typus) are an endangered species whose growth and reproductive biology are poorly understood. Given their conservation concern, estimating growth parameters, as traditionally derived from vertebral samples of dead animals, is challenging. We used a non-invasive approach to investigate growth parameters of whale sharks frequenting the South Ari Atoll, Maldives, by analysing repeat measurements of free-swimming sharks over a 10-year period. Total lengths of the sharks were estimated by three measurement methods. Visual estimates underestimated the sizes of large sharks, whereas laser and tape measurements yielded results that were similar to one another. The Maldives aggregation consisted of primarily male (91%) juvenile (total length=3.16–8.00m) sharks and sharks new to the area were significantly smaller than were returning sharks, which suggests that this site may constitute a secondary nursery ground. Estimates of von Bertalanffy (VBG) growth parameters for combined sexes (L∞=19.6m, k=0.021year–1) were calculated from 186 encounters with 44 sharks. For males, VBG parameters (L∞=18.1m, k=0.023year–1) were calculated from 177 encounters with 40 sharks and correspond to a male age at maturity of ~25 years and longevity of ~130 years. Differences between these estimates and those from other studies underscore the need for regional studies.

Fully General Chao and Zelterman Estimators with Application to a Whale Shark Population

Summary We introduce generalized Chao and generalized Zelterman estimators which include individual, time varying and behavioural effects. Under mild assumptions in the presence of unobserved heterogeneity, the generalized Chao estimator asymptotically provides a lower bound for the population size and is unbiased otherwise. Corrected versions guarantee bounded estimates. To include the best set of predictors we propose the biased empirical focused information criterion bFIC. Simulations indicate that bFIC might give considerable improvements over other selection criteria in our context. We illustrate with an original application to size estimation of a whale shark (Rhincodon typus) population in South Ari Atoll, in the Maldives.

Vulnerability of different types of fishers to potential implementation of a management plan in a Marine Protected Area (MPA) in the Maldives

Understanding vulnerability of different types of fishers to the implications of a Marine Protected Area (MPA) is crucial to its long-term sustainability. It helps direct management decisions of the MPA in a way that negative impacts on specific fishers can be mitigated. This study explored the vulnerability within specific groups of fishers, namely, commercial, subsistence and recreational fishers in the context of the largest MPA in the Maldives – the South Ari Atoll Marine Protected Area (SAMPA). SAMPA is subject to a future management plan that is likely to bring changes in how resources can be accessed in the area. In order to explore the vulnerability of the fisher groups, their sensitivity to this change was measured through an exploratory factor analysis and a sensitivity index. It was found that commercial fishers were likely to be the most vulnerable group as the management plan could potentially threaten their livelihood. Subsistence fishers were found to be next, as changes in access to SAMPA will potentially influence how they obtain their dietary protein. Recreational fishers were also found to vulnerable due to the nature of their fishing operation. However, relative to other groups, their vulnerability was likely to be much lower. To ensure strategic measures are designed to alleviate these potential vulnerabilities, this study proposed collaborative stakeholder participation throughout the development process of SAMPA's management plan, and also as a platform to build much needed confidence in MPAs among fishers in the Maldives.

Whale shark economics: a valuation of wildlife tourism in South Ari Atoll, Maldives.

Whale sharks attract large numbers of tourists, divers and snorkelers each year to South Ari Atoll in the Republic of Maldives. Yet without information regarding the use and economic extent of the attraction, it is difficult to prioritize conservation or implement effective management plans. We used empirical recreational data and generalized mixed statistical models to conduct the first economic valuation (with direct spend as the primary proxy) of whale shark tourism in Maldives. We estimated that direct expenditures for whale shark focused tourism in the South Ari Marine Protected Area for 2012 and 2013 accounted for US$7.6 and $9.4 million respectively. These expenditures are based on an estimate of 72,000–78,000 tourists who are involved in whale shark excursions annually. That substantial amount of income to resort owners and operators, and tourism businesses in a relatively small area highlights the need to implement regulations and management that safeguard the sustainability of the industry through ensuring guest satisfaction and whale shark conservation.

Analysis of whale shark Rhincodon typus aggregations near South Ari Atoll, Maldives Archipelago

AB Aquatic Biology Contact the journal Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections AB 8:145-150 (2010) - DOI: https://doi.org/10.3354/ab00215 Analysis of whale shark Rhincodon typus aggregations near South Ari Atoll, Maldives Archipelago Morgan J. Riley*, Michelle S. Hale, Adam Harman, Richard G. Rees School of Earth & Environmental Sciences, University of Portsmouth, Burnaby Road, Portsmouth, PO1 3QL, UK *Email: morgan@whalesharkresearch.co.uk ABSTRACT: We made surveys for whale sharks Rhincodon typus on a total of 99 d from April through June each year from 2006 to 2008 along the southern fringe of the South Ari Atoll, Maldives Archipelago. We recorded the length and sex of each shark observed and made photographs to facilitate repeated identification from their spot patterns using pattern-recognition software. We identified 64 whale sharks from digital photographs taken during 220 sightings over 3 yr. Approx. 87% of those sharks were immature males. The average length of recognisable sharks was 5.98 m (range 2.5 to 10.5 m), significantly shorter than that reported for whale sharks in other aggregations in the Indian Ocean. Our findings suggest that these sharks are either a small proportion of a local population or perhaps an even smaller component of a regional population in the western Indian Ocean. We applied a Lincoln-Petersen closed-population mark-recapture model and a Jolly-Seber open-population model to estimate population size, but found that neither model provided reliable results because key assumptions of each were not met. KEY WORDS: Whale shark · Rhincodon typus · Maldives Archipelago · Mark-recapture · Photo-identification Full text in pdf format PreviousNextCite this article as: Riley MJ, Hale MS, Harman A, Rees RG (2010) Analysis of whale shark Rhincodon typus aggregations near South Ari Atoll, Maldives Archipelago. Aquat Biol 8:145-150. https://doi.org/10.3354/ab00215 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in AB Vol. 8, No. 2. Online publication date: January 20, 2010 Print ISSN: 1864-7782; Online ISSN: 1864-7790 Copyright © 2010 Inter-Research.