Amplifier linearity accounts for discrepancies in echo-integration measurements from two widely used echosounders

Author:

De Robertis Alex1ORCID,Bassett Christopher1ORCID,Andersen Lars Nonboe2,Wangen Ivar2,Furnish Scott1,Levine Michael1

Affiliation:

1. National Oceanic and Atmospheric Administration, Alaska Fisheries Science Center, National Marine Fisheries Service, 7600 Sand Point Way NE Seattle, WA 98115, USA

2. Kongsberg Maritime AS, Strandpromenaden 50, P.O. Box 111, Horten 3191, Norway

Abstract

Abstract The Simrad EK60 echosounder is widely used in acoustic-trawl surveys. It has recently been replaced by the EK80, which can be configured to operate in a manner similar to the EK60. To examine whether EK80s can be substituted for EK60s, the echosounders were configured to alternate transmissions from common transducers at four frequencies during three acoustic-trawl surveys. Significant differences between echo-integration measurements of fish were observed at 18, 38, and 70 kHz. EK80 measurements were 3–12% lower than those from EK60. At 120 kHz EK80/EK60 ratios were less than, but not statistically different from one. The EK80/EK60 discrepancy increased with range. The observed discrepancies were identified to be related to slight over-amplification of low-power signals (<−90 dB re 1 W) by EK60. EK80 amplified signals linearly over a wider range of measured powers. After accounting for over-amplification of weak signals by the EK60, the range dependence was removed and both echosounders produced equivalent results. The impact of over-amplification by the EK60 will be relatively small for surveys of strong scatters (fishes with swimbladders) at short ranges, but has the potential to be greater for surveys of weak scatterers and/or long observation ranges.

Funder

NOAA’s Alaska Fisheries Science Center and NOAA’s Office of Science

Technology, Advanced Sampling Technology Working Group

National Marine Fisheries Service

Publisher

Oxford University Press (OUP)

Subject

Ecology,Aquatic Science,Ecology, Evolution, Behavior and Systematics,Oceanography

Reference32 articles.

1. Broadband echosounder observations of frequency response during from fisheries surveys in the Gulf of Alaska;Bassett;ICES Journal of Marine Science,2017

2. Acoustic surveys for juvenile anchovy in the Bay of Biscay: abundance estimate as an indicator of the next years recruitment and spatial distribution patterns;Boyra;ICES Journal of Marine Science,2013

3. 2016 USA–Norway EK80 Workshop Report: evaluation of a wideband echosounder for fisheries and marine ecosystem science;Demer;ICES Cooperative Research Report,2017

4. Calibration of acoustic instruments;Demer;ICES Cooperative Research Report,2015

5. Silent ships do not always encounter more fish (revisited): comparison of acoustic backscatter from walleye pollock recorded by a noise-reduced and a conventional research vessel in the eastern Bering Sea;De Robertis;ICES Journal of Marine Science,2011

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