Assessing Indonesian manta and devil ray populations through historical landings and fishing community interviews

Manta Trust, Dorchester, Dorset, United Kingdom
Reef Check Foundation Indonesia, Denpasar, Indonesia
Research Center for Oceanography, Indonesian Institute of Sciences, Jakarta, Indonesia
Research Center for Fisheries Management and Conservation, Agency for Marine and Fisheries Research, Ministry of Marine Affairs and Fisheries, Jakarta, Indonesia
WildAid, San Francisco, California, United States
Wildlife Conservation Society, Indonesia Program, Bogor, Indonesia
WWF-Indonesia, Jakarta, Indonesia
Conservation International Indonesia, Jakarta, Indonesia
DOI
10.7287/peerj.preprints.1334v1
Subject Areas
Aquaculture, Fisheries and Fish Science, Conservation Biology, Environmental Sciences, Marine Biology
Keywords
mobula, mobulids, fisheries, Indonesia, socio-economics, declining catch rates, Lamakera, Tanjung Luar, Cilacap, alternative livelihoods
Copyright
© 2018 Lewis et al.
Licence
This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ Preprints) and either DOI or URL of the article must be cited.
Cite this article
Lewis SA, Setiasih N, Fahmi, Dharmadi D, O'Malley MP, Campbell SJ, Yusuf M, Sianipar AB. 2015. Assessing Indonesian manta and devil ray populations through historical landings and fishing community interviews. PeerJ Preprints 6:e1334v1

Abstract

International concern is growing with regard to the sustainability of manta and devil ray (collectively mobulids) fisheries as demand for mobulid products has increased in international markets over the last decade. While Indonesia has been reported to be one of the worlds’ top three catchers of mobulid rays, detailed information on these fisheries and the status of Indonesian mobulid populations are lacking. Through collection of historical and recent mobuild fisheries data from published and unpublished sources, this study aimed to identify trends in abundance of Indonesian manta and devil rays and explore socio-economic factors and incentives associated with mobulid fisheries. Comparison of catches from 2001-5 to the most recent data from 2013-14 revealed dramatic declines in mobulid landings over the study period of 64% at Cilacap, 75% at Lamakera, and 94% at Tanjung Luar. The largest declines were observed for Manta spp. and the two large devil rays, Mobula tarapacana and Mobula japanica. Anecdotal reports indicated that catches had declined substantially at three additional sites and local extirpations are strongly suspected to have occurred at three locations. A lack of data on the population ecology of Indonesia’s mobulids makes it difficult to determine whether natural fluctuations may be playing a part in the declining catch rates. However, mobulid life history traits, including low reproductive rates and late age of sexual maturation, indicate that fishing pressure is likely the primary driver in these declines. Interviews in Lamakera, a community which depends on income from its targeted mobulid fishery, suggest that programs focused on education, training and infrastructure development to enable shifts to sustainable livelihood alternatives are likely to offer the most successful path to long-term conservation and management of manta and devil rays, while simultaneously yielding economic and social benefits to fishing communities.

Author Comment

This is a preprint submission to PeerJ.