1. Centro Peruano de Estudios Cetológicos (CEPEC), Pucusana, Lima, Peru.
2. J.C.M. and J.A.S. are supported by the Darwin Sustainable Artisanal Fisheries Initiative in Peru and Whitley Fund for Nature. University of Exeter, Cornwall Campus, Penryn, Cornwall, TR10 9EZ, United Kingdom, and Pro Delphinus, Enrique Palacios 630–204, Lima 18, Peru.