caa a22 4500 397550669 CHVBK 20180308164749.0 cr unu---uuuuu 161202e199604 xx s 000 0 eng 10.1006/jmsc.1996.0015 doi (NATIONALLICENCE)oxford-10.1006/jmsc.1996.0015 Spatial organization of pelagic fish: echogram structure, spatio-temporal condition, and biomass in Senegalese waters [Elektronische Daten] [Pierre Petitgas, Jean Jacques Levenez] Understanding the spatial distribution of fish schools is expected to enable future improvement in the reliability of acoustic abundance estimates as well as catch data. The analysis of echograms will provide detailed morphological descriptions of fish aggregations together with characteristics of their habitat. The data set studied here is a series of comparable echograms taken during monitoring surveys and showing important fluctuations in biomass. Echoes are coded into different consistent morphological types. First, we study how the occurrence of these types varies with diel cycle, sea-bottom depth, and fish density by computing a chi-square table. Second, characteristics of inter-school spatial structure are analysed by computing indicator variograms. Third, location of high-density values within the areas where schools are present is studied by computing indicator cross-variograms. A descriptive model of habitat occupation is proposed where some parameters are related to biomass level and others are not. © 1996 International Council for the Exploration of the Sea Regular Articles nationallicence geostatistics nationallicence schools nationallicence spatial structure nationallicence survey design nationallicence Petitgas Pierre aut Levenez Jean Jacques aut ICES Journal of Marine Science Oxford University Press 53/2(1996-04), 147-153 1054-3139 53:2<147 1996 53 icesjms https://doi.org/10.1006/jmsc.1996.0015 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1006/jmsc.1996.0015 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Petitgas Pierre aut NATIONALLICENCE 700 1- Levenez Jean Jacques aut NATIONALLICENCE 773 0- ICES Journal of Marine Science Oxford University Press 53/2(1996-04), 147-153 1054-3139 53:2<147 1996 53 icesjms Metadata rights reserved CC BY-NC-4.0 http://creativecommons.org/licenses/by-nc/4.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-oxford