Contribution to acoustic targets identification in Northwest Africa by statistical schools properties

摘要

Acoustic abundance estimation relies, among other things, on reliable species identification. This process normally involves targeted trawling during surveys to identify the acoustic targets. The aim of this paper is to aid researchers to recognize acoustic fish targets off Northwest Africa using acoustic properties of the main small pelagic schools, Sardina pilcbardus, Sardinella aurita, S. maderensis, Tracburus trecae, T. tracburus, Scomber japonicus, Engraulis encrasicolus and Decapterus rhonchus.During the R/V Dr. Fridtjof Nansen acoustic survey from Cap Cantin in Morocco to Southern border of Senegal in October-December 2003 and 2004, echograms illustrating typical monospecific school patterns were collected using the Echoview programme. Acoustic parameters and descriptors of each school were used to describe typical patterns. Statistical analysis was then carried out to define possible characterizations of the targeted species by those parameters.