In situ acoustic target strength of juvenile capelin

• Published in: ICES Journal of Marine Science
• Main Authors: O'Driscoll, Richard L., Rose, George A.
• Format: Text
• Language: English
• Published: Oxford University Press 2001
• Subjects: Short Communications; Bonavista Bay; Newfoundland
• Online Access: http://icesjms.oxfordjournals.org/cgi/content/short/58/1/342; https://doi.org/10.1006/jmsc.2000.1015

A dispersed, monospecific aggregation of juvenile (0+) capelin was detected acoustically in shallow (20–70 m) water in Bonavista Bay, northeastern Newfoundland in January 2000. This provided a rare opportunity to measure acoustic target strength (TS) of very small (mean length=51 mm) capelin in situ . Mean observed TS at 38 kHz was −61.0 dB. Observed TS was similar to TS predicted by the Norwegian-Icelandic capelin TS-length relationship (TS=19.1 log L (cm)−74), but ∼2 dB lower than predicted by the existing TS-length relationship for capelin in Newfoundland waters at 38 and 49 kHz (TS=20 log L (cm)−73.1). Combining present data with previous 38 kHz data indicates the relationship TS=23.3 log L (cm)−77.1 (r2=0.95, n=6) for capelin of lengths 5–14 cm in Newfoundland waters.