The materials and methods paper found below may be of interest to those who study toothed whale echolocation or use passive acoustic monitoring at sea. Best, Magnus Wahlberg and Peter T. Madsen Requests for reprints can be directed to Peter.madsen@biology.au.dk Or Magnus.Wahlberg@biology.au.dk Recording and quantification of ultrasonic echolocation clicks from free-ranging toothed whales Deep Sea Research Part I: Oceanographic Research Papers P.T. Madsen <http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VGB-4NS2GC9-2&_u ser=642076&_coverDate=05%2F18%2F2007&_alid=603396580&_rdoc=1&_fmt=summary&_o rig=search&_cdi=6034&_sort=d&_docanchor=&view=c&_ct=3&_acct=C000034578&_vers ion=1&_urlVersion=0&_userid=642076&md5=3ccfab8080ecfdae1d443f22660ac27c#hit2 #hit2> next term <http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VGB-4NS2GC9-2&_u ser=642076&_coverDate=05%2F18%2F2007&_alid=603396580&_rdoc=1&_fmt=summary&_o rig=search&_cdi=6034&_sort=d&_docanchor=&view=c&_ct=3&_acct=C000034578&_vers ion=1&_urlVersion=0&_userid=642076&md5=3ccfab8080ecfdae1d443f22660ac27c#aff1 #aff1> a, <http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VGB-4NS2GC9-2&_u ser=642076&_coverDate=05%2F18%2F2007&_alid=603396580&_rdoc=1&_fmt=summary&_o rig=search&_cdi=6034&_sort=d&_docanchor=&view=c&_ct=3&_acct=C000034578&_vers ion=1&_urlVersion=0&_userid=642076&md5=3ccfab8080ecfdae1d443f22660ac27c#aff2 #aff2> b, <http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VGB-4NS2GC9-2&_u ser=642076&_coverDate=05%2F18%2F2007&_alid=603396580&_rdoc=1&_fmt=summary&_o rig=search&_cdi=6034&_sort=d&_docanchor=&view=c&_ct=3&_acct=C000034578&_vers ion=1&_urlVersion=0&_userid=642076&md5=3ccfab8080ecfdae1d443f22660ac27c#cor1 #cor1> Corresponding Author Contact Information, <mailto:peter.madsen@biology.au.dk> E-mail The Corresponding Authorand M. Wahlberg <http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VGB-4NS2GC9-2&_u ser=642076&_coverDate=05%2F18%2F2007&_alid=603396580&_rdoc=1&_fmt=summary&_o rig=search&_cdi=6034&_sort=d&_docanchor=&view=c&_ct=3&_acct=C000034578&_vers ion=1&_urlVersion=0&_userid=642076&md5=3ccfab8080ecfdae1d443f22660ac27c#aff1 #aff1> a, <http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VGB-4NS2GC9-2&_u ser=642076&_coverDate=05%2F18%2F2007&_alid=603396580&_rdoc=1&_fmt=summary&_o rig=search&_cdi=6034&_sort=d&_docanchor=&view=c&_ct=3&_acct=C000034578&_vers ion=1&_urlVersion=0&_userid=642076&md5=3ccfab8080ecfdae1d443f22660ac27c#aff3 #aff3> c aZoophysiology, Department of Biological Sciences, Build. 1131, University of Aarhus, Denmark bWoods Hole Oceanographic Institution, Woods Hole, MA 02543, USA cFjord & Bælt, Margrethes Plads 1, 5300 Kerteminde, Denmark Received 8 October 2006; revised 15 March 2007; accepted 2 April 2007. Available online 18 May 2007. Toothed whales produce short, ultrasonic clicks of high directionality and source level to probe their environment acoustically. This process, termed echolocation, is to a large part governed by the properties of the emitted clicks. Therefore derivation of click source parameters from free-ranging animals is of increasing importance to understand both how toothed whales use echolocation in the wild and how they may be monitored acoustically. This paper addresses how source parameters can be derived from free-ranging toothed whales in the wild using calibrated multi-hydrophone arrays and digital recorders. We outline the properties required of hydrophones, amplifiers and analog to digital converters, and discuss the problems of recording echolocation clicks on the axis of a directional sound beam. For accurate localization the hydrophone array apertures must be adapted and scaled to the behavior of, and the range to, the clicking animal, and precise information on hydrophone locations is critical. We provide examples of localization routines and outline sources of error that lead to uncertainties in localizing clicking animals in time and space. Furthermore we explore approaches to time series analysis of discrete versions of toothed whale clicks that are meaningful in a biosonar context. Keywords: Toothed whale; Ultrasound; Recording; Click; Hydrophone; Array; Echolocation Peter T. Madsen Zoophysiology, Dept. of Biological Sciences University of Aarhus Build. 1131, C.F. Moellers Alle 8000 Aarhus C, DENMARK
