dc.contributor.author | Foote, Kenneth G. | |
dc.date.accessioned | 2008-12-03T13:01:16Z | |
dc.date.issued | 1981 | |
dc.identifier.uri | http://hdl.handle.net/11250/114810 | |
dc.description.abstract | A potential source of error in acoustic measurements of fish density is the absorption
part of time-varied-gain functions. This should be determined from the 1977 Fisher and
Simmons equation. Use of its predecessor, the 1962 Schulkin and Marsh equation, is
shown by comparison to introduce large errors in fish density estimates. Adjustment
of the absorption term with changing hydrography is also necessary. This is supported
by an analysis of errors due to deviations from an assumed reference temperature. The
various computations are performed for six echo sounder frequencies used in fisheries
surveying; namely, 30, 38, 49.5, 70, 105, and 120 kHz. A broad hydrographical range
is considered. | en |
dc.format.extent | 743797 bytes | |
dc.format.mimetype | application/pdf | |
dc.language.iso | eng | en |
dc.publisher | [Fiskeridirektoratets havforskningsinstitutt] | en |
dc.relation.ispartofseries | Fiskeridirektoratets skrifter, Serie Havundersøkelser | en |
dc.relation.ispartofseries | vol 17 no 5 | en |
dc.title | Absorption term in time-varied-gain functions | en |
dc.type | Research report | en |
dc.source.pagenumber | s. 191-213 | en |