The relative frequency response, as derived from individually separated targets on cod, saithe and Norway pout

The relative frequency response is an important acoustic feature used to characterise acoustic targets. This response has been defined as the sv, volume backscattering coefficient, for a specific frequency relative to that of a reference frequency (38 kHz). The acoustic data commonly used in these calculations are derived from integrated measurements in a region containing multiple targets. In this study the relative frequency responses at 18, 38, 70, 120, and 200 kHz have additionally been measured using filtered target strength data on all frequencies. The spatial comparability of the sv-data is thus avoided, while the single-target detection becomes a new challenge. Target strength was extracted from in situ measurements, using calibrated and digitised data from a Simrad EK60 with split-beam transducers transmitting simultaneously at all five frequencies. Selected series with nearly pure catches of Atlantic cod (Gadus Morhua L.), saithe (Pollachius virens L.) and Norway pout (Trisopterus esmarkii L.) were analysed. The frequency response derived by the new method is compared with standard integration method

Postprocessing system for echo sounder data

Author Posting. © Acoustical Society of America, 1991. This article is posted here by permission of Acoustical Society of America for personal use, not for redistribution. The definitive version was published in Journal of the Acoustical Society of America 90 (1991): 37-47, doi:10.1121/1.401261.Echo sounding is a powerful and widely used technique for remote sensing of the marine environment. In order to enhance the power of the echo sounder, a postprocessing system has been designed and realized in standard software that is essentially machine independent. This has been done by adhering to the following international standards: UNIX operating system, C programming language, X Window Systems, Structured‐Query Language (SQL) for communication with a relational database, and Transport Control Protocol/Internet Protocol (TCP/IP). Preprocessed data are transferred from the echo sounder to the postprocessing system by means of a local‐area network (LAN), namely Ethernet. Development of the postprocessing system, for analysis of such diverse scatterers as plankton, pelagic, and bottom fish, and the bottom itself, is documented in the following way. The history of echo integration is summarized. User requirements for the new system are listed. Reasons are given for the choice of the particular computing environment, including both hardware, software, and external communications. The system design, consisting of data flow and graphical user interfaces, is described. Implementation of the system is defined through integration techniques and a discussion of performance issues. Operating procedures and the first field trials of the system are described. Several features characteristic of and perhaps unique to the postprocessing system are, for example: (1) user definition of arbitrarily shaped integration regions, including non‐constant‐depth intervals, by means of interactive graphics; (2) preprocessor error correction, e.g., adjustment of the noise threshold or redefinition of the detected bottom; (3) use of several color map techniques in order to extract such information as signal strength and shape; and (4) the scheme of interconnections of graphical user interfaces, database, and data files. This work does not introduce a set of computer instructions. It does describe a design philosophy and method of realization that may have broader applications in acoustics than that ostensibly concerned only with the quantitative estimation of fish abundance

Whole genome scan reveals the genetic signature of African Ankole cattle breed and potential for higher quality beef

BACKGROUND: Africa is home to numerous cattle breeds whose diversity has been shaped by subtle combinations of human and natural selection. African Sanga cattle are an intermediate type of cattle resulting from interbreeding between Bos taurus and Bos indicus subspecies. Recently, research has asserted the potential of Sanga breeds for commercial beef production with better meat quality as compared to Bos indicus breeds. Here, we identified meat quality related gene regions that are positively selected in Ankole (Sanga) cattle breeds as compared to indicus (Boran, Ogaden, and Kenana) breeds using cross-population (XP-EHH and XP-CLR) statistical methods. RESULTS: We identified 238 (XP-EHH) and 213 (XP-CLR) positively selected genes, of which 97 were detected from both statistics. Among the genes obtained, we primarily reported those involved in different biological process and pathways associated with meat quality traits. Genes (CAPZB, COL9A2, PDGFRA, MAP3K5, ZNF410, and PKM2) involved in muscle structure and metabolism affect meat tenderness. Genes (PLA2G2A, PARK2, ZNF410, MAP2K3, PLCD3, PLCD1, and ROCK1) related to intramuscular fat (IMF) are involved in adipose metabolism and adipogenesis. MB and SLC48A1 affect meat color. In addition, we identified genes (TIMP2, PKM2, PRKG1, MAP3K5, and ATP8A1) related to feeding efficiency. Among the enriched Gene Ontology Biological Process (GO BP) terms, actin cytoskeleton organization, actin filament-based process, and protein ubiquitination are associated with meat tenderness whereas cellular component organization, negative regulation of actin filament depolymerization and negative regulation of protein complex disassembly are involved in adipocyte regulation. The MAPK pathway is responsible for cell proliferation and plays an important role in hyperplastic growth, which has a positive effect on meat tenderness. CONCLUSION: Results revealed several candidate genes positively selected in Ankole cattle in relation to meat quality characteristics. The genes identified are involved in muscle structure and metabolism, and adipose metabolism and adipogenesis. These genes help in the understanding of the biological mechanisms controlling beef quality characteristics in African Ankole cattle. These results provide a basis for further research on the genomic characteristics of Ankole and other Sanga cattle breeds for quality beef. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12863-016-0467-1) contains supplementary material, which is available to authorized users

Advances in Bergen Echo Integrator

The Bergen Echo Integrator (BEl) is a software system designed for convenient postprocessing of echo sounder data. BEl is realized in international standards and is essentially machine independent. Development of BEl for analysis of such diverse scatterers as plankton, pelagic fish, bottom fish and bottom itself is reviewed. The system design is described and the latest advances are discussed. Among these: a more flexible database, an improved man-machine interface, an easier procedure for accessing data and a system for mapping the data. General operating procedures are described for extraction of information while scrutinizing acoustical data

Some methods for the generation of combined-frequency echograms

Calibrated and digitised data from two or more discrete echo sounder frequencies can be combined for the purpose of separating and extracting the acoustic scattering from zooplankton and fish in mixed recordings. Methods are described for echogram manipulation and for the construction of new synthetic combined-frequency [m] echograms. Examples of extracted scattering information from mixed layers of fish and small scattering organisms, such as copepods and euphausiids, are shown, and the potential of each of the different cm methods is discussed. Key words: Acoustic, interpretation, echo integration, multi-frequency, synthetic echogram. NORSK SAMMENDRAG: Kalibrerte digitaliserte data fra to eller flere akustiske frekvenser på ekkolodd kan kombineres med formål å skille fra hverandre og trekke ut ekko fra zooplankton og fisk i blandede forekomster. Metoder for manipulering av ekkogram og for bmbinering av akustiske data inn i nye syntetiske ekkogram blir beskrevet. Eksempler på hvordan ekko informasjon fra blandede registreringer av fisk og smil organismer som kopepoder og krill vises, og potensialet til hver enkelt av kombinert frekvens metodene diskuteres

Echogram noise quantification with application to herring observations

Abstract only. Journal home page: http://scitation.aip.org/jasa

Detection of spatial distribution of acoustic categories

Abstract only

Verified acoustic identification of Atlantic mackerel

Calibrated, digitised data from simultaneously working multi-frequency echo sounders with nearly identical and overlapping acoustic beams have been used to generate new, synthetic echograms where only targets identified as Atlantic mackerel are retained. Echo sounder raw data are processed stepwise in a modular sequence of analysis to improve the ability to categorise acoustic targets. The relative frequency response measured over up to six acoustic frequencies, 18, 38, 70, 120, 200 and 364 kHz, is the main acoustic feature used to characterise acoustic backscatter. Mackerel seems to have a frequency-independent backscatter below approximately 100 kHz, and above approximately 200kHz, but at 4 times higher level of the backscatter. Results from numeric modelling explaining the measured relative frequency response of mackerel are shown. Synthetic echograms containing targets identified acoustically as mackerel are presented and evaluated against trawl catches. Even though catching of the fast-swimming mackerel is difficult, the trawl catches from two Norwegian research vessels confirm that the targets identified acoustically as mackerel is really mackerel

Combined algorithms for detection of acoustic categories

There is a current desire to harvest marine resources by managing total marine ecosystems rather than single species of the ecosystems. By means of algorithms applied on high-quality multi-frequency acoustic data, species, or rather acoustic categories, of the ecosystem can be identified. This information may significantly increase the accuracy of acoustic survey estimates of fish and to some extent also for zooplankton. Multi-frequency split beam echo sounders with nearly identical and overlapping acoustic beams have been regularly used in acoustic surveys for fish stock abundance estimation at Institute of Marine Research for the last five years. Calibrated raw data from up to six simultaneously working echo sounders at 18, 38, 70, 120, 200 and 364 kHz was used as input to a stepwise, modular sequence of analysis, like bottom detection, noise quantification and removal, target categorisation and school detection in near real-time. Direct generation of new, synthetic echograms, based upon the measured or modelled relative frequency response of the targets is one of the most useful features of the systems. The result of the categorisation process can be used to show the spatial distribution of different acoustic categories in a single synthetic echogram, or to keep some and remove other acoustic categories in echograms at a single frequency