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Doctoral theses

Current Record: 1991 of 2443

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Identifier

uch.biology.phd//1994machias

Title

Το ηχοανακλαστικό δυναμικό της σαρδέλας (sardina pilchardus), και οι παράγοντες που το επηρεάζουν

Alternative Title

Factors affecting target strength of sardine (sardina pilchardus)

Author

Μαχιάς, Αθανάσιος Κ

Thesis advisor

Τσιμενίδης, Νικόλαος

Abstract

The present work examines the variations in the swimbladder volume, wsimbladder cross-sections and the target strenght(TS) of sardine(Sardina Pilchardus), in relation to the size and the intrinsic physiological factors of the fish(lipids, gonads, stomach).Totally 50 sardines were reconstructed in computer by digitizing. The volume of fish, swimbladder, gonads and stomach, as well as the maximum cross-section of swimbladder were calculated using the software "slicer". It was also calculated the lipid contents. It was found that the swimbladder volume and maximum cross-section can be estimated from two distinct modelsQone for the reproductive period and one for the reproductive dormant period. The theoretical expected T.S values of fish sampled with trawls-nets were compared with field measurements, taken with dual beam echo-sounder.Two different models were proposed for the simulation of the expected values. Comparison results were successful and confirmed tha estimated models can be used for the forecast of TS.

Language

Greek

Subject

ΑΛΙΕΥΤΙΚΑ ΥΔΡΟΑΚΟΥΣΤΙΚΑ; ΕΣΩΤΕΡΙΚΗΔΟΜΗ ΚΑΙ ΦΥΣΙΟΛΟΓΙΑ; ΗΧΟΑΝΑΚΛΑΣΤΙΚΟ ΔΥΝΑΜΙΚΟ; ΝΗΚΤΙΚΗ ΚΥΣΤΗ; Σαρδέλες

Issue date

1994-06-29

Collection

School/Department--School of Sciences and Engineering--Department of Biology--Doctoral theses

Type of Work--Doctoral theses

Permanent Link

https://elocus.lib.uoc.gr//dlib/a/f/0/metadata-dlib-1994machias.tkl