Blar i Articles på forfatter "Macaulay, Gavin"
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Accuracy of the Kirchhoff-approximation and Kirchhoff-ray-mode fish swimbladder acoustic scattering models
Macaulay, Gavin; Pena, Hector; Fässler, Sacha M.M.; Pedersen, Geir; Ona, Egil (Journal article; Peer reviewed, 2013)The acoustic backscatter from pressure release prolate spheroids and a three-dimensional representation of a fish swimbladder (Chilean jack mackerel, Trachurus symmetricus murphyi) was calculated using four target strength ... -
Acoustic micronektonic distribution and density is structured by macroscale oceanographic processes across 17–48° N latitudes in the North Atlantic Ocean
García-Seoane, Eva; Klevjer, Thor A.; Mork, Kjell Arne; Agersted, Mette Dalgaard; Macaulay, Gavin; Melle, Webjørn Raunsgård (Peer reviewed; Journal article, 2023)This study investigates the large-scale distribution patterns of the acoustic scattering layers and micronekton density across the Northeast Atlantic Ocean during daylight hours. A research cruise on board R/V “Kronprins ... -
An acoustic method to observe the distribution and behaviour of mesopelagic organisms in front of a trawl
Underwood, Melanie; García-Seoane, Eva; Klevjer, Thor A.; Macaulay, Gavin; Melle, Webjørn Raunsgård (Peer reviewed; Journal article, 2020) -
Antarctic krill (Euphausia superba) catch weight estimated with a trawl-mounted echosounder during fishing
Krafft, Bjørn Arne; Krag, Ludvig A.; Pedersen, Ronald; Ona, Egil; Macaulay, Gavin (Peer reviewed; Journal article, 2023)Reporting reliable catch weight estimates is important for all fisheries management. This study explores the potential for precise and direct estimation of catch weight (green weight) for the Antarctic krill (Euphausia ... -
Comparisons of echo-integration performance from two different multiplexed echosounders
Macaulay, Gavin; Schoulding, Ben; Ona, Egil; Fässler, Sascha M. M. (Journal article; Peer reviewed, 2018)A time-series of acoustically derived aquatic biomass estimates relies on the acoustic equipment maintaining the same performance throughout the time-series. This is normally achieved through a regular calibration process. ... -
Diel vertical movements determine spatial interactions between cod, pelagic fish and krill on an Arctic shelf bank
Skaret, Georg; Johansen, Geir Odd; Johnsen, Espen; Fall, Johanna Jennifer Elisabeth; Fiksen, Øyvind; Englund, Gøran; Fauchald, Per; Gjøsæter, Harald; Macaulay, Gavin; Johannesen, Edda (Peer reviewed; Journal article, 2020)Predator-prey spatial interactions are essential to understand ecosystem processes like predation rates and trophic interaction strength. In marine systems, such spatial interactions are highly dynamic and difficult to ... -
Distribution and biomass estimation of Antarctic krill (Euphausia superba) off the South Orkney Islands during 2011-2020
Skaret, Georg; Macaulay, Gavin; Pedersen, Ronald; Wang, X.; Klevjer, Thor A.; Krag, L.A.; Krafft, Bjørn Arne (Peer reviewed; Journal article, 2023)Antarctic krill is a key species in the Southern Ocean and subject to the most extensive fishery in the Antarctic. The Norwegian Institute of Marine Research has conducted acoustic-trawl monitoring of krill off the South ... -
Experimental evidence of threat-sensitive collective avoidance responses in a large wild-caught herring school
Rieucau, Guillaume; Boswell, Kevin M.; De Robertis, Alex; Macaulay, Gavin; Handegard, Nils Olav (Peer reviewed; Journal article, 2014)Aggregation is commonly thought to improve animals’ security. Within aquatic ecosystems, group-living prey can learn about immediate threats using cues perceived directly from predators, or from collective behaviours, for ... -
Instantaneous areal population density of entire Atlantic cod and herring spawning groups and group size distribution relative to total spawning population
Makris, Nicholas C.; Godø, Olav Rune; Yi, Dong Hoon; Macaulay, Gavin; Jain, Ankita Deepak; Cho, Byunggu; Gong, Zheng; Jech, J. Michael; Ratilal, Purnima (Journal article; Peer reviewed, 2018)The wide‐area group behaviour of spawning Atlantic cod and herring is investigated. By a combination of Ocean Acoustic Waveguide Remote Sensing (OAWRS) and conventional sensing methods, first‐look images of the instantaneous ... -
Nonlinear crosstalk in broadband multi-channel echosounders
Khodabandeloo, Babak; Ona, Egil; Macaulay, Gavin; Korneliussen, Rolf (Peer reviewed; Journal article, 2021)Distortion of acoustic wave caused by nonlinear propagation transfers acoustic energy into higher harmonics of the transmitted signal. When operating several broadband echosounders with non-overlapping frequency bands to ... -
Quantitative processing of broadband data as implemented in a scientific split-beam echosounder
Andersen, Lars Nonboe; Chu, Dezhang; Handegard, Nils Olav; Heimvoll, Harald; Korneliussen, Rolf; Macaulay, Gavin; Ona, Egil; Patel, Ruben; Pedersen, Geir (Peer reviewed; Journal article, 2023)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 and significantly ... -
Remote sizing of fish-like targets using broadband acoustics
Kubilius, Rokas; Macaulay, Gavin; Ona, Egil (Peer reviewed; Journal article, 2020) -
Standing stock of Antarctic krill (Euphausia superba Dana, 1850) (Euphausiacea) in the Southwest Atlantic sector of the Southern Ocean, 2018-19
Krafft, Bjørn Arne; Macaulay, Gavin; Skaret, Georg; Knutsen, Tor; Bergstad, Odd A; Lowther, Andrew; Huse, Geir; Fielding, Sophie; Trathan, Philip; Murphy, Eugene; Choi, Seok-Gwan; Chung, Sangdeok; Han, Inwoo; Lee, Kyounghoon; Zhao, Xianyong; Wang, Xinliang; Ying, Yiping; Yu, Xiaotao; Demianenko, Kostiantyn; Podhornyi, Viktor; Vishnyakova, Karina; Pshenichnov, Leonid; Chuklin, Andrii; Shyshman, Hanna; Cox, Martin J; Reid, Keith; Watters, George M; Reiss, Christian S; Hinke, Jefferson T; Arata, Javier; Godø, Olav R; Hoem, Nils (Peer reviewed; Journal article, 2021)Estimates of the distribution and density of Antarctic krill (Euphausia superba Dana, 1850) were derived from a large-scale survey conducted during the austral summer in the Southwest Atlantic sector of the Southern Ocean ...