Dear Colleagues, We are excited to announce a new collaborative paper with updated best practice recommendations for the use and application of external telemetry devices on pinnipeds. You may find and download our open-access publication at: https://animalbiotelemetry.biomedcentral.com/articles/10.1186/s40317-019-018... Citation Horning M, Andrews RD, Bishop AM, Boveng PL, Costa DP, Crocker DE, Haulena M, Hindell M, Hindle AG, Holser RR, Hooker SK, Hückstädt LA, Johnson S, Lea MA, McDonald BI, McMahon CR, Robinson PW, Sattler RL, Shuert CR, Steingass SM, Thompson D, Tuomi PA, Williams CL & Womble JN. Best practice recommendations for the use of external telemetry devices on pinnipeds. Animal Biotelemetry. 2019 Dec;7(1):1-7. Abstract Pinnipeds spend large portions of their lives at sea, submerged, or hauled-out on land, often on remote off-shore islands. This fundamentally limits access by researchers to critical parts of pinniped life history and has spurred the development and implementation of a variety of externally attached telemetry devices (ETDs) to collect information about movement patterns, physiology and ecology of marine animals when they cannot be directly observed. ETDs are less invasive and easier to apply than implanted internal devices, making them more widely used. However, ETDs have limited retention times and their use may result in negative short- and long-term consequences including capture myopathy, impacts to energetics, behavior, and entanglement risk. We identify 15 best practice recommendations for the use of ETDs with pinnipeds that address experimental justification, animal capture, tag design, tag attachment, effects assessments, preparation, and reporting. Continued improvement of best practices is critical within the framework of the Three Rs (Reduction, Refinement, Replacement); these best practice recommendations provide current guidance to mitigate known potential negative outcomes for individuals and local populations. These recommendations were developed specifically for pinnipeds; however, they may also be applicable to studies of other marine taxa. We conclude with four desired future directions for the use of ETDs in technology development, validation studies, experimental designs and data sharing. Paper inquiries may be directed towards the primary and corresponding author, Markus Horning at markush@alaskasealife.org<mailto:markush@alaskasealife.org>. Best regards, Sheanna Steingass, PhD | Marine Mammal Program Leader Oregon Department of Fish and Wildlife O: 541.757.5245 sheanna.m.steingass@state.or.us<https://mallard.dfw.state.or.us/owa/redir.aspx?C=WWX4I5WM1of6I5BGqwE3kHLHwXpzY75099PVssX5VDG7kN5WKc_WCA..&URL=mailto%3asheanna.m.steingass%40state.or.us>