Dear colleagues, My co-authors and I are pleased to announce the following publication: Martien*,* Karen K., Aimée R. Lang, Barbara L. Taylor, Patricia E. Rosel, Samantha E. Simmons, Erin M. Oleson, Peter L. Boveng, and M. Bradley Hanson. 2019. The DIP delineation handbook: a guide to using multiple lines of evidence to delineate demographically independent populations of marine mammals. NOAA Technical Memorandum NMFS-SWFSC-622. 135pp. In the handbook, we review 11 types of data, which we term 'lines of evidence,' that can be used to evaluate population structure: 1) morphology, 2) genetics, 3) movements, 4) distributional hiatuses, 5) contaminants, 6) stable isotopes and fatty acids, 7) life history, 8) trends in abundance, 9) habitat, 10) association data, and 11) acoustics. For each of these lines of evidence, we discuss their strengths and weaknesses for evaluating structure and give examples of how they have been used. The handbook focuses on the delineation of Demographically Independent Populations (DIPs), which is the level of population structure that is relevant to many management paradigms, including the U.S. Marine Mammal Protection Act (MMPA). Because the availability and utility of different lines of evidence varies among species, we summarize the data that are available for the currently designated MMPA stocks so as document some of the factors that limit our ability to collect robust data sets for certain groups of species. Finally, we discuss Structured Expert Decision Making as a means of integrating multiple different data types and handling uncertainty when delineating DIPs for management purposes. The handbook is intended to serve as a reference at all stages of DIP delineation, from prioritizing and planning research, to reviewing research results, to evaluating proposed DIPs. Though the handbook began as part of an effort to increase consistency and transparency in stock delineation under the MMPA, we believe that it will have wide applicability to both academic and applied studies of population structure at scales relevant to management. The handbook can be downloaded here: https://swfsc.noaa.gov/publications/TM/SWFSC/NOAA-TM-NMFS-SWFSC-622.pdf Cheers, Karen -- Karen K. Martien, Ph.D. Southwest Fisheries Science Center 8901 La Jolla Shores Dr. La Jolla, CA 92037, USA Phone: 858-546-7058 Fax: 858-546-7003 Karen.Martien@noaa.gov http://swfsc.noaa.gov/mmtd-mmgenetics