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      Large-Scale Trade in Legally Protected Marine Mollusc Shells from Java and Bali, Indonesia

      1 , * , 1 , 2 , 1

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          Tropical marine molluscs are traded globally. Larger species with slow life histories are under threat from over-exploitation. We report on the trade in protected marine mollusc shells in and from Java and Bali, Indonesia. Since 1987 twelve species of marine molluscs are protected under Indonesian law to shield them from overexploitation. Despite this protection they are traded openly in large volumes.

          Methodology/Principal Findings

          We collected data on species composition, origins, volumes and prices at two large open markets (2013), collected data from wholesale traders (2013), and compiled seizure data by the Indonesian authorities (2008–2013). All twelve protected species were observed in trade. Smaller species were traded for <USD1.00 whereas prices of larger species were USD15.00–40.00 with clear price-size relationships. Some shells were collected locally in Java and Bali, but the trade involves networks stretching hundreds of kilometres throughout Indonesia. Wholesale traders offer protected marine mollusc shells for the export market by the container or by the metric ton. Data from 20 confiscated shipments show an on-going trade in these molluscs. Over 42,000 shells were seized over a 5-year period, with a retail value of USD700,000 within Indonesia; horned helmet ( Cassis cornuta) (>32,000 shells valued at USD500,000), chambered nautilus ( Nautilus pompilius) (>3,000 shells, USD60,000) and giant clams ( Tridacna spp.) (>2,000 shells, USD45,000) were traded in largest volumes. Two-thirds of this trade was destined for international markets, including in the USA and Asia-Pacific region.


          We demonstrated that the trade in protected marine mollusc shells in Indonesia is not controlled nor monitored, that it involves large volumes, and that networks of shell collectors, traders, middlemen and exporters span the globe. This impedes protection of these species on the ground and calls into question the effectiveness of protected species management in Indonesia; solutions are unlikely to be found only in Indonesia and must involve the cooperation of importing countries.

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          Most cited references 2

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          Nautilus pompilius Life History and Demographics at the Osprey Reef Seamount, Coral Sea, Australia

          Nautiloids are the subject of speculation as to their threatened status arising from the impacts of targeted fishing for the ornamental shell market. Life history knowledge is essential to understand the susceptibility of this group to overfishing and to the instigation of management frameworks. This study provides a comprehensive insight into the life of Nautilus in the wild. At Osprey Reef from 1998–2008, trapping for Nautilus was conducted on 354 occasions, with 2460 individuals of one species, Nautilus pompilius, captured and 247 individuals recaptured. Baited remote underwater video systems (BRUVS) were deployed on 15 occasions and six remotely operated vehicle (ROV) dives from 100–800 m were conducted to record Nautilus presence and behavior. Maturity, sex and size data were recorded, while measurements of recaptured individuals allowed estimation of growth rates to maturity, and longevity beyond maturity. We found sexual dimorphism in size at maturity (males: 131.9±SD = 2.6 mm; females: 118.9±7.5 mm shell diameter) in a population dominated by mature individuals (58%). Mean growth rates of 15 immature recaptured animals were 0.061±0.023 mm day−1 resulting in an estimate of around 15.5 years to maturation. Recaptures of mature animals after five years provide evidence of a lifespan exceeding 20 years. Juvenile Nautilus pompilius feeding behavior was recorded for the first time within the same depth range (200–610 m) as adults. Our results provide strong evidence of a K-selected life history for Nautilus from a detailed study of a ‘closed’ wild population. In conjunction with population size and density estimates established for the Osprey Reef Nautilus, this work allows calculations for sustainable catch and provides mechanisms to extrapolate these findings to other extant nautiloid populations (Nautilus and Allonautilus spp.) throughout the Indo-Pacific.
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            Nautilus at Risk – Estimating Population Size and Demography of Nautilus pompilius

            The low fecundity, late maturity, long gestation and long life span of Nautilus suggest that this species is vulnerable to over-exploitation. Demand from the ornamental shell trade has contributed to their rapid decline in localized populations. More data from wild populations are needed to design management plans which ensure Nautilus persistence. We used a variety of techniques including capture-mark-recapture, baited remote underwater video systems, ultrasonic telemetry and remotely operated vehicles to estimate population size, growth rates, distribution and demographic characteristics of an unexploited Nautilus pompilius population at Osprey Reef (Coral Sea, Australia). We estimated a small and dispersed population of between 844 and 4467 individuals (14.6–77.4 km−2) dominated by males (83∶17 male∶female) and comprised of few juveniles (<10%).These results provide the first Nautilid population and density estimates which are essential elements for long-term management of populations via sustainable catch models. Results from baited remote underwater video systems provide confidence for their more widespread use to assess efficiently the size and density of exploited and unexploited Nautilus populations worldwide.

              Author and article information

              Role: Editor
              PLoS One
              PLoS ONE
              PLoS ONE
              Public Library of Science (San Francisco, CA USA )
              30 December 2015
              : 10
              : 12
              [1 ]Oxford Wildlife Trade Research Group, Oxford Brookes University, OX3 0BP, Oxford, United Kingdom
              [2 ]Institute of Neuroethology, University of Veracruz, Xalapa, Mexico
              Leibniz Center for Tropical Marine Ecology, GERMANY
              Author notes

              Competing Interests: The study was funded in part by two commercial funders, Dierenpark Amsterfoort and Cleveland Zoo. This does not alter the authors' adherence to all PLOS ONE policies on sharing data and materials.

              Conceived and designed the experiments: VN DS KAIN. Analyzed the data: VN KAIN. Contributed reagents/materials/analysis tools: VN DS KAIN. Wrote the paper: VN DS KAIN.

              © 2015 Nijman et al

              This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

              Page count
              Figures: 4, Tables: 4, Pages: 18
              Funding provided by Leverhulme Trust (RPG-084,, the Cleveland Zoo Asian Seed Fund (, Dierenpark Amersfoort (, and Mohamed bin Zayed Species Conservation Fund ( The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
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