Characterizing the spatial distribution of a semi-demersal gadoid ...
No abstracts are to be cited without prior reference to the author.High-resolution, two-dimensional measurements of density are collected routinely during echo- integration trawl surveys. Echo-trace classification (ETC), the detection of aggregations within echograms, is used to describe and analyze...
| Main Authors: | , |
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| Format: | Article in Journal/Newspaper |
| Language: | unknown |
| Published: |
ASC 2005 - U - Theme session
2024
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| Online Access: | https://dx.doi.org/10.17895/ices.pub.25350586 https://ices-library.figshare.com/articles/conference_contribution/Characterizing_the_spatial_distribution_of_a_semi-demersal_gadoid/25350586 |
| Summary: | No abstracts are to be cited without prior reference to the author.High-resolution, two-dimensional measurements of density are collected routinely during echo- integration trawl surveys. Echo-trace classification (ETC), the detection of aggregations within echograms, is used to describe and analyze spatial distributions of pelagic organisms. This approach is appropriate for species that form well-defined schools, but is limited when used for species that form demersal layers or diffuse pelagic shoals. As an alternative to ETC metrics, we used landscape indices to quantify and characterize spatial heterogeneity walleye pollock (Theragra chalcogramma) density distributions. Survey transects were divided into segments of equal length and a series of landscape metrics were calculated to measure occupancy, fragmentation, acoustic density structure, and vertical distribution. Ordination and classification techniques were used to examine relationships among metrics and to develop a classification typology for ... |
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