Sonars and echosounders are widely used for remote sensing of life in the marine environment. There is an ongoing need to make acoustic identification species more correct objective thereby reduce uncertainty abundance estimates. In our work, data from multi-frequency working simultaneously with nearly identical overlapping beams processed stepwise a modular sequence improve data, detect schools categorize targets by means Large Scale Survey System software (LSSS). Categorization based on...

Abstract Calibrated, digitized data from multi-frequency echo sounders have been used to generate new, synthetic echograms. The relative frequency response measured at four acoustic frequencies (18, 38, 120, and 200 kHz) is the main feature characterize targets. Synthetic echograms are enhance colour-code sample volumes with similar properties. method invaluable during scrutinizing, particularly in areas many types of target. Several broad categories can be clearly distinguished, detailed...

Calibrated and digitized data from two or more discrete echosounder frequencies can be combined for the purpose of separating extracting acoustic scattering zooplankton fish in mixed recordings. This method is also useful quantifying relative contribution each frequency to total acoustic-backscattering when scrutinizing records large-scale, surveys. Echosounder hardware requirements are defined which would permit ideal extraction such information. These include calibration, transducer...

Echo sounding is a powerful and widely used technique for remote sensing of the marine environment. In order to enhance power echo sounder, postprocessing system has been designed realized in standard software that essentially machine independent. This done by adhering following international standards: UNIX operating system, C programming language, X Window Systems, Structured-Query Language (SQL) communication with relational database, Transport Control Protocol/Internet Protocol (TCP/IP)....

Abstract Korneliussen, R. J., Diner, N., Ona, E., Berger, L., and Fernandes, P. G. 2008. Proposals for the collection of multifrequency acoustic data. – ICES Journal Marine Science, 65: 982–994. Acoustic surveys are used to estimate abundance distribution many fish species, have been based traditionally on data collected at a single frequency. Although it has known some time that use additional frequencies can provide information nature target, knowledge technology required combine so-called...

Abstract Korneliussen, R. J., Heggelund, Y., Eliassen, I. K., and Johansen, G. O. 2009. Acoustic species identification of schooling fish. – ICES Journal Marine Science, 66: 1111–1118. The development methods for the acoustic fish is a long-term objective aimed at reducing uncertainty in acoustic-survey estimates. relative frequency response r(f) measured simultaneously several frequencies one main features that characterize targets, but relationship between nearest neighbours, school...

Pushing scientific echo sounders to the limit involves consideration of "noise", which is inherently frequency dependent and also depends on bottom depth. Here, noise quantified by measurement with a standard sounder, SIMRAD EK500, at 18, 38, 120 200 kHz. The use empirical relationships as function range reduce integration described in general, illustrated particular, for data collected stock Norwegian spring spawning herring (Clupea harengus) when wintering Vestfjord system.

Abstract Korneliussen, R. J., Heggelund, Y., Eliassen, I. K., Øye, O. Knutsen, T., and Dalen, J. 2009. Combining multibeam-sonar multifrequency-echosounder data: examples of the analysis imaging large euphausiid schools. – ICES Journal Marine Science, 66: 991–997. The first high-resolution, quantitative, multibeam sonar (Simrad MS70) ever developed was mounted in a keel RV “G. Sars” with port-orientated beams. Each ping samples volume 60° horizontally × 45° vertically 500 beams, which is...

Abstract Korneliussen, R. J. 2010. The acoustic identification of Atlantic mackerel. – ICES Journal Marine Science, 67: 1749–1758. Calibrated, digitized data from multifrequency echosounders working simultaneously with nearly identical and overlapping beams were used to generate new, synthetic echograms which allow mackerel (Scomber scombrus) be identified acoustically. raw echosounder processed stepwise in a modular sequence analyses improve categorization the targets. relative frequency...

The 3.3 million km2 marine ecosystem around the North Pole, defined as Central Arctic Ocean (CAO), is a blind spot on map of world's fish stocks. CAO essentially comprises permanently ice-covered deep basins and ridges outside continental shelves, only accessible by ice-breakers. Traditional trawling for assessing stocks impossible under thick pack ice, coherent hydroacoustic surveys are unachievable due to ice-breaking noise. Consequently, nothing known about existence any pelagic in CAO,...

As the sea ice reduces in both extent and thickness Arctic Ocean opens, there is substantial interest mapping marine ecosystem this remote until now largely inaccessible ocean. We have used R/V “Kronprins Haakon” during surveys central 2022 2023, to record using modern fisheries acoustics net sampling. The survey reached all way North Pole. In a first, rather manually based post-processing of these acoustic recordings Large-Scale Post Processing System (LSSS), much effort...

As the sea ice reduces in both extent and thickness Arctic Ocean opens, there is substantial interest mapping marine ecosystem this remote until now largely inaccessible ocean. We used R/V Kronprins Haakon during surveys Central (CAO) 2022 2023 to record using modern fisheries acoustics net sampling. The survey reached all way North Pole. In a first, principally manually based post-processing of these acoustic recordings Large-Scale Survey Post-processing System (LSSS), much effort was...

A model is developed and demonstrated for simulating echosounder sonar observations of fish schools with specified shapes composed individuals having target strengths behaviors. The emulates the performances actual multi-frequency echosounders multi-beam sonars generates synthetic echograms that can be compared real echograms. enables acoustic large in situ to evaluated terms individual aggregated It also facilitates analyses sensitivity biomass estimates different strength models their...

Abstract The use of quantitative broadband echosounders for biological studies and surveys can offer considerable advantages over narrowband echosounders. These include improved spectral‐based target identification significantly increased ability to resolve individual targets. An understanding current processing steps is required fully utilise further develop acoustic methods in marine ecology. We describe the involved data from raw frequency dependent strength () volume backscattering using...

Abstract Developing acoustic methods for the identification of fish remains a long-term objective fisheries acoustics. The accuracy abundance estimation may be increased when acoustic-scattering characteristics are known, including their expected variability and uncertainty. modelling approach is valuable during process interpreting multi-frequency echograms. This paper attempts to improve understanding sound backscattering without swimbladder, here represented by Atlantic mackerel (Scomber...

Abstract Gorska, N., Korneliussen, R. J., and Ona, E. 2007. Acoustic backscatter by schools of adult Atlantic mackerel. – ICES Journal Marine Science, 64: 1145–1151. The extent acoustic mackerel (Scomber scombrus) is investigated to improve biomass estimates. Previous studies involving modelled scattering from individual showed that backscattering at high frequencies dominated the contribution backbone. Accurate predictions spectra require consideration entire skeleton, including details...

Abstract Nesse, T. L., Hobæk, H., and Korneliussen, R. J. 2009. Measurements of acoustic-scattering spectra from the whole parts Atlantic mackerel. – ICES Journal Marine Science, 66: 1169–1175. mackerel (Scomber scombrus) are weak sound scatterers compared with fish that have swimbladders. Accurate acoustic estimates abundance require target strength. Different may dominate backscattering spectra. Mackerel schools acoustically recognized mainly by backscatter four times stronger at 200 kHz...

Abstract A diel vertical migration (DVM) pattern of Norwegian spring spawning herring (Clupea harengus) larvae was investigated during 19 and 20 April 2009. Factors influencing DVM included physical biological properties the water column. Data on larvae, prey predators were collected with a depth-stratified multisampling device, inshore Sklinna bank, close to coast, while light conditions calculated using Matlab® algorithm. type I (i.e. deep daytime, shallow at night) observed for mainly...

Distribution of micronekton was investigated during early summer 2013, using data from a cruise covering the central parts four north Atlantic basins, Norwegian Sea (NS), Iceland (ICS), Irminger (IRS), and Labrador (LS). Continuous underway acoustics mapped vertical horizontal distributions, trawl sampling provided on biomass taxonomic composition. The hull mounted catches suggested that, among epipelagic, larger nektonic species (>20 cm length) highest in NS ICS while mesopelagic...

To ensure efficient and sustainable purse-seine fisheries, the catch process must be monitored to better understand reactions of fish gear. In this study, we behaviours herring (Clupea harengus) mackerel (Scomber scombrus) schools during capture using a multibeam imaging sonar (Simrad MS70, 75–112 kHz) mounted on research vessel. The differed between species sets. For both species, acoustic volume backscattering coefficient increased as 0–80% seine was hauled aboard, indicating corresponding...

Fish stock assessment and management requires accurate estimates of fish abundance, which are typically derived from echosounder observations using acoustic target classification (ATC). Skilled operators regularly assisted in classifying targets by software there has been an increasing interest toward machine learning to create improved tools. Recent studies have applied deep approaches data, however, algorithm data-preparation strategies (influencing model output) presently poorly...

Abstract Pedersen, G., and Korneliussen, R. J. 2009. The relative frequency response derived from individually separated targets of northeast Arctic cod (Gadus morhua), saithe (Pollachius virens), Norway pout (Trisopterus esmarkii). – ICES Journal Marine Science, 66: 1149–1154. concept r(f) fish is an important feature used to characterize acoustic targets. It defined as the volume-backscattering coefficient at a specific f that reference frequency. When based on volume backscattering,...

Distortion of acoustic wave caused by nonlinear propagation transfers energy into higher harmonics the transmitted signal. When operating several broadband echosounders with non-overlapping frequency bands to cover a wide range, generated one band may interfere fundamental others. This interference (i.e., crosstalk) can adversely affect measured backscattered amplitude response and in some circumstances, appears as spurious targets above and/or below main target pulse-compressed echograms....