Estimates of variability of goldband snapper target strength and biomass in three fishing regions within the Northern Demersal Scalefish Fishery (Western Australia)

摘要: Goldband snapper (Pristipomoides multidens) is an ecologically and economically important species in the Northern Demersal Scalefish Fishery (NDSF). The Carolina M, a trap fishing vessel operating NDSF, was equipped with Simrad ES70 echosounders, operated at 38 120 kHz. In 2014 acoustic data, combination optical recordings of catch, were opportunistically collected during routine operations. December pure, low density goldband schools observed on echograms. situ target strength (TS) estimates derived linked to length distributions catch information curve fitting method. Estimated TS-Length (L) kHz 20.1 log10(L)-70.5 16.4 log10(L)-77 Three grounds, where near simultaneously recorded available selected. Fish school densities within data disaggregated according proportions using kriging. ranged between 9518 individuals per nmi2 high-density region 2512 945 two regions. Sampling variance estimated geostatistics (coefficient variance, CV = 10–20.9%). Other errors considered signal-to-noise ratio (CV < 1%), variation signal due fluctuations temperature salinity 0.5–1.15%), effects diurnal vertical migration variability 1.2–2%). A total 28.2–50.6% for all sources, three