title: Growth, productivity, and relative extinction risk of a data-sparse devil ray.
abstract: Devil rays (Mobula spp.) face intensifying fishing pressure to meet the ongoing international demand for gill plates. The paucity of information on growth, mortality, and fishing effort for devil rays make quantifying population growth rates and extinction risk challenging. Furthermore, unlike manta rays (Manta spp.), devil rays have not been listed on CITES. Here, we use a published size-at-age dataset for the Spinetail Devil Ray (Mobula japanica), to estimate somatic growth rates, age at maturity, maximum age, and natural and fishing mortality. We then estimate a plausible distribution of the maximum intrinsic population growth rate (rmax) and compare it to 95 other chondrichthyans. We find evidence that larger devil ray species have low somatic growth rate, low annual reproductive output, and low maximum population growth rates, suggesting they have low productivity. Fishing rates of a small-scale artisanal Mexican fishery were comparable to our estimate of rmax, and therefore probably unsustainable. Devil ray rmaxis very similar to that of manta rays, indicating devil rays can potentially be driven to local extinction at low levels of fishing mortality and that a similar degree of protection for both groups is warranted.
authors.affiliation: Earth to Ocean Research Group, Department of Biological Sciences, Simon Fraser University, Burnaby, BC, Canada.
authors.forename: Sebastián A
authors.initials: SA
authors.lastname: Pardo
authors.affiliation: Earth to Ocean Research Group, Department of Biological Sciences, Simon Fraser University, Burnaby, BC, Canada.|Department of Ecology, Evolution, and Natural Resources, Rutgers University, New Brunswick, NJ, USA.
authors.forename: Holly K
authors.initials: HK
authors.lastname: Kindsvater
authors.affiliation: Fisheries Biology Consultant, Boulevard Chahue #66 Mz 6, Sector R, La Crucecita, Bahías de Huatulco, Oaxaca, Mexico.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Cuevas-Zimbrón
authors.affiliation: Laboratorio de Ecología Pesquera, Departamento de Oceanografía Biológica, CICESE, Ensenada, Baja California, Mexico.
authors.forename: Oscar
authors.initials: O
authors.lastname: Sosa-Nishizaki
authors.affiliation: Ciencias de la Sustentabilidad, El Colegio de la Frontera Sur, Lerma, Campeche, Mexico.
authors.forename: Juan Carlos
authors.initials: JC
authors.lastname: Pérez-Jiménez
authors.affiliation: Earth to Ocean Research Group, Department of Biological Sciences, Simon Fraser University, Burnaby, BC, Canada.
authors.forename: Nicholas K
authors.initials: NK
authors.lastname: Dulvy