Title

Consecutive Acoustic Observations of an Atlantic Herring School in the Northwest Atlantic

Abstract

Several successive images of the same school of Atlantic herring (Clupea harengus) were collected over the course of ∼1 h just north of Georges Bank in the Northwest Atlantic. Although the fish may not have been in their natural, undisturbed state, we observed what appeared to be the fish school fragmenting and dispersing, using a split-beam and a multibeam echosounder. Calibrated, 38 kHz, split-beam echosounder (Simrad EK60) and trawl-catch data provided accurate measures of the fish density beneath the vessel. Uncalibrated, 400 kHz, multibeam-echosounder (Reson 7125) data provided synoptic observations of the fish school including estimates of the school volume, morphology, and behaviour. Observations of the angular dependence in the multibeam-echosounder measurements of backscatter from fish allow investigation of the efficacy of extrapolating fish-school densities measured by the split-beam echosounder to the entire school.

Publication Date

4-9-2009

Journal or Conference Title

ICES Journal of Marine Science

Volume

66, Issue 6

Pages

1270-1277

Publisher Place

New York, NY, USA

Publisher

Elsevier

Digital Object Identifier (DOI)

10.1093/icesjms/fsp090

Document Type

Journal Article