Developing best handling practice guidelines to safely release mantas and mobulids captured in commercial fisheries

The Family Mobulidae is represented by two genera and 11 recognized species, comprising the manta rays (Manta spp., n=2) and devil rays (Mobula spp., n=9). It is a diverse family of planktivorous elasmobranchs occurring worldwide in tropical, subtropical and temperate waters (Compagno and Last 1999). Mobulidae also contains the largest rays, reaching over 7 m disc width (Tremblay-Boyer and Brouwer 2016). Most mobulid species have been reported as bycatch by several fishing methods, including purse seine, longline, trawl and gillnets, and are also taken as target species (White et al. 2006, Couturier et al. 2012, Hall and Roman 2013, Mas et al. 2015, Tremblay-Boyer and Brouwer 2016, Francis and Jones 2017). Mobulids have life history characteristics (e.g. slow growth, extremely low fecundity, and delayed age of first reproduction) that make them exceptionally susceptible to overexploitation (Couturier et al. 2012, Croll et al. 2016). Most mobulid species that have been classified by the IUCN Redlist (IUCN, 2014) are listed as Near Threatened or Vulnerable. However, one mobulid species, (M. mobular), is listed as Endangered and three could not be assessed because of insufficient data (Couturier et al. 2012). The purpose of this document is to provide a comprehensive overview of available information on post release survivorship for mantas and mobulids captured in non-target fisheries to establish guidelines of best handling practices for release methods, to enhance survivorship of incidental rays.