Journal Article

The specific gravity of mesopelagic fish from the northeastern Pacific Ocean and its implications for acoustic backscatter

Peter Davison

in ICES Journal of Marine Science

Published on behalf of ICES/CIEM

Volume 68, issue 10, pages 2064-2074
Published in print November 2011 | ISSN: 1054-3139
Published online September 2011 | e-ISSN: 1095-9289 | DOI: http://dx.doi.org/10.1093/icesjms/fsr140
The specific gravity of mesopelagic fish from the northeastern Pacific Ocean and its implications for acoustic backscatter

More Like This

Show all results sharing these subjects:

  • Environmental Science
  • Marine and Estuarine Biology

GO

Show Summary Details

Preview

Davison, P. 2011. The specific gravity of mesopelagic fish from the northeastern Pacific Ocean and its implications for acoustic backscatter. – ICES Journal of Marine Science, 68: .

Knowledge of the species present, their morphology, and their size distribution is required to infer biomass from acoustic surveys of fish. The gas content and specific gravity of the body (with gas removed), ρf, was measured for 71 species of mesopelagic fish in the NE Pacific Ocean. Those species that have functional swimbladders when large maintain constant ρf with increasing body size. Species without functional swimbladders as adults show decreased ρf with increasing body size. The acoustic-backscattering cross-section, σbs, was modelled for all individuals collected from three fish species that differed in the presence of a gas-filled swimbladder. The change in σbs with increasing body size was markedly different between the three. The low body density of those mesopelagic fish without gas-filled swimbladders greatly reduces their σbs. In species of fish that possess a functional swimbladder as juveniles and in which the swimbladder regresses with growth, the σbs first decreases, then increases with increased body size. Knowledge of the ontogenetic changes in swimbladder inflation and body density in mesopelagic fish is critical for the construction of the backscattering models used to interpret acoustic surveys.

Keywords: acoustic backscatter; buoyancy; density; mesopelagic fish; swimbladder

Journal Article.  8790 words.  Illustrated.

Subjects: Environmental Science ; Marine and Estuarine Biology

Full text: subscription required

How to subscribe Recommend to my Librarian

Users without a subscription are not able to see the full content. Please, subscribe or login to access all content.