Passive acoustic determination of herring size

Over the last decade, acoustic signatures of a variety of fishes have been recorded and analyzed. More recently, these vocalizations have been used to passively detect aggregations of fish, demonstrating the potential to supplement and enhance traditional active acoustic surveys. Based on previously published work on acoustic emissions of herring, this paper discusses the possibility of not merely passively detecting absence or presence of aggregations of herring but, additionally, assessing abundance and size. Theoretical considerations as well as data collected in Prince William Sound, Alaska, on Pacific herring (Clupea Pallasii) are presented.