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ACOUSMED Task 3:Harmonization and optimisation of the acoustic methodology Subtask 3.1: Target strength equations for anchovy and sardine . 2º AcousMed meeting 20-24 November 2010 Palma de Mallorca, Baleares, Spain. TS in situ estimations. J. Miquel, N. Díaz, M. Iglesias,
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ACOUSMEDTask 3:Harmonization and optimisation of theacousticmethodologySubtask 3.1: Target strengthequationsforanchovy and sardine. 2º AcousMedmeeting 20-24 November 2010 Palma de Mallorca, Baleares, Spain
TS insituestimations J. Miquel, N. Díaz, M. Iglesias, Centro Oceanográfico de Baleares Instituto Español de Oceanografía (IEO), Spain
Ecomed 2009 acousticsurvey; november-december. • Anchovy (Engraulisencrasicolus) recruitment. • Nightpelagictrawls. • Selected 7 haulswith a highpercentage of anchovy.
Night hauls monospecific (80%) or with discrete modes on TS and TL Anchovyhauls
Use TS from the haul sampled depth area • We have used the Netsonder (Simrad FS20/25) echogram to define the area to work. • Scarcity of data
Export TS data • EK60 SIMRAD; raw data; no threshold. • Echoview software • Single target detection, Split beam, method 2 • Fishtrack (3 o more detections) • Extract TS mean, max and min • Tsmax –Ts min: > 3 dB • Tortuosity 3D< 3 • TS maxbetween -65 to -40 dB
Export TS data • EK60 SIMRAD; raw data; no threshold. • Echoview software • Single target detection, Split beam, method 2 • Fishtrack (3 o more detections) • Extract TS mean, max and min • Tsmax –Ts min: > 3 dB • Tortuosity 3D< 3 • TS maxbetween -65 to -40 dB
Export TS data • EK60 SIMRAD; raw data; no threshold. • Echoview software • Single target detection, Split beam, method 2 • Fishtrack (3 o more detections) • Extract TS mean, max and min • Tsmax –Ts min: > 3 dB • Tortuosity 3D< 3 • TS maxbetween -65 to -40 dB
Export TS data • EK60 SIMRAD; raw data; no threshold. • Echoview software • Single target detection, Split beam, method 2 • Fishtrack (3 o more detections) • Extract TS mean, max and min • Tsmax –Ts min: > 3 dB • Tortuosity 3D< 3 • TS maxbetween -65 to -40 dB
MEDIAS 0710 acousticsurvey • Wecarriedout 3 pelagicfishingtrawlsduringtheday: almost 100% anchovy. • Weprospecttheareaduringthenight (2-3 hours) colecting data.
Results • -62 dB • Kmedia TL = -84.17 • -56dB • K media TL = -78.53
Results • Modal TL: 13.5 cm • Media TL: 13.36 cm • Maturefemales: • Maturitystage (3) (day) • Hydrated at night (4) ??
Recommended settings (Doray & Massé, WGCEGG 2008): • Pulse length: 0.5 ms • Min. thr: -60 dB • Min.-Max echolength: [0.8 – 1.8] • Max phase deviation: to beadjusted, between 4 to 8 usually.