Blar i Faculty of Mathematics and Natural Sciences på forfatter "Handegard, Nils Olav"

Viser treff 1-11 av 11

    • Addressing class imbalance in deep learning for acoustic target classification 

      Pala, Ahmet; Oleynik, Anna; Utseth, Ingrid; Handegard, Nils Olav (Journal article; Peer reviewed, 2023)
      Acoustic surveys provide important data for fisheries management. During the surveys, ship-mounted echo sounders send acoustic signals into the water and measure the strength of the reflection, so-called backscatter. ...

    • Automatic interpretation of otoliths using deep learning 

      Moen, Endre; Handegard, Nils Olav; Allken, Vaneeda; Albert, Ole Thomas; Harbitz, Alf; Malde, Ketil (Peer reviewed; Journal article, 2018-12-17)
      The age structure of a fish population has important implications for recruitment processes and population fluctuations, and is a key input to fisheries-assessment models. The current method of determining age structure ...

    • Automatic interpretation of salmon scales using deep learning 

      Vabø, Rune; Moen, Endre; Smolinski, Szymon; Husebø, Åse; Handegard, Nils Olav; Malde, Ketil (Journal article; Peer reviewed, 2021)
      For several fish species, age and other important biological information is manually inferred from visual scrutinization of scales, and reliable automatic methods are not widely available. Here, we apply Convolutional ...

    • Behavioral responses of herring (Clupea harengus) to 1–2 and 6–7 kHz sonar signals and killer whale feeding sounds 

      Doksæter, Lise; Godø, Olav Rune; Handegard, Nils Olav; Kvadsheim, Petter H.; Lam, Frans-Peter A.; Donovan, Carl; Miller, Patrick J. O. (Peer reviewed; Journal article, 2009)
      Military antisubmarine sonars produce intense sounds within the hearing range of most clupeid fish. The behavioral reactions of overwintering herring Clupea harengus to sonar signals of two different frequency ranges 1–2 ...

    • A deep learning-based method to identify and count pelagic and mesopelagic fishes from trawl camera images 

      Allken, Vaneeda; Rosen, Shale Pettit; Handegard, Nils Olav; Malde, Ketil (Journal article; Peer reviewed, 2021)
      Fish counts and species information can be obtained from images taken within trawls, which enables trawl surveys to operate without extracting fish from their habitat, yields distribution data at fine scale for better ...

    • Effects on individual level behaviour in mackerel (Scomber scombrus) of sub-lethal capture related stressors: Crowding and hypoxia 

      Anders, Neil; Howarth, Kirsten; Totland, Bjørn; Handegard, Nils Olav; Tenningen, Maria; Breen, Michael (Peer reviewed; Journal article, 2019-03-13)
      Stress to fish during harvest in wild capture fisheries is known to negatively influence subsequent survival in catches that are released. Therefore, if fisheries are to be conducted sustainably, there is a need to promote ...

    • Effects on schooling function in mackerel of sub-lethal capture related stressors: Crowding and hypoxia 

      Handegard, Nils Olav; Tenningen, Maria; Howarth, Kirsten; Anders, Neil; Rieucau, Guillaume; Breen, Michael (Peer reviewed; Journal article, 2017-12-28)
      The selectivity of fishing gears with respect to fish species and size is important, both for fisheries management and fishing operations. Purse seining is an efficient, environmentally friendly fish capture methodology ...

    • How to obtain clear images from in-trawl cameras near the seabed? A case study from the Barents Sea demersal fishing grounds 

      Tenningen, Maria; Rosen, Shale; Westergerling, Eugenie Heliana Taraneh; Handegard, Nils Olav (Journal article; Peer reviewed, 2023)
      Underwater camera systems are commonly used for monitoring fish and fishing gear behaviours. More recently, camera systems have been applied to scientific trawl surveys for improved spatial resolution and less invasive ...

    • Machine learning in marine ecology: an overview of techniques and applications 

      Rubbens, Peter; Brodie, Stephanie; Cordier, Tristan; Desto Barcellos, Diogo; DeVos, Paul; Fernandes-Salvador, Jose A; Fincham, Jennifer; Gomes, Alessandra; Handegard, Nils Olav; Howell, Kerry L.; Jamet, Cédric; Kartveit, Kyrre Heldal; Moustahfid, Hassan; Parcerisas, Clea; Politikos, Dimitris V.; Sauzède, Raphaëlle; Sokolova, Maria; Uusitalo, Laura; Van den Bulcke, Laure; van Helmond, Aloysius; Watson, Jordan T.; Welch, Heather; Beltran-Perez, Oscar; Chaffron, Samuel; Greenberg, David S.; Kühn, Bernhard; Kiko, Rainer; Lo, Madiop; Lopes, Rubens M.; Möller, Klas Ove; Michaels, William; Pala, Ahmet; Romagnan, Jean-Baptiste; Schuchert, Pia; Seydi, Vahid; Villasante, Sebastian; Malde, Ketil; Irisson, Jean-Olivier (Journal article; Peer reviewed, 2023)
      Machine learning covers a large set of algorithms that can be trained to identify patterns in data. Thanks to the increase in the amount of data and computing power available, it has become pervasive across scientific ...

    • Simulations of multi-beam sonar echos from schooling individual fish in a quiet environment 

      Holmin, Arne Johannes; Handegard, Nils Olav; Korneliussen, Rolf J.; Tjøstheim, Dag (Peer reviewed; Journal article, 2012-12)
      A model is developed and demonstrated for simulating echosounder and sonar observations of fish schools with specified shapes and composed of individuals having specified target strengths and behaviors. The model emulates ...

    • Simulering av torsk (Gadus Morhua) sin reaksjon på fartøystøy 

      Handegard, Nils Olav (Master thesis, 2000)