Anders Fernö

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Basic knowledge about learning capacities and awareness in fish is lacking. In this study we investigated which temporal gaps Atlantic cod could tolerate between two associated events, using an appetitive trace-conditioning paradigm with blinking light as conditioned stimulus (CS) and dry fish food as unconditioned stimulus (US). CS–US presentations were(More)
We document one of the most spectacular predator-prey interactions observed in a marine ecosystem, in which groups of killer whales force tens of tons of herrring out of their safe deep-water habitat to the surface where the whales are superior. Killer whales performing this hunting tactic congregate in large groups, dive to the limit of their capacity,(More)
The basic (natural) movement pattern and gear-induced behaviour of female edible crab Cancer pagurus L. were studied by means of a stationary positioning system. Nine crabs were tagged with ultrasonic transmitters and their positions were monitored approximately every third minute for 9–24 days. Because the crabs sometimes hid, the signals were often(More)
When animals associate a stimulus with food, they may either direct their response towards the stimulus (sign-tracking) or towards the food (goal-tracking). The direction of the conditioned response of cod was investigated to elucidate how cod read cue signals. Groups of cod were conditioned to associate a blinking light (conditioned stimulus, CS) with a(More)
Avoiding predation is generally seen as the most common explanation for why animals aggregate. However, it remains questionable whether the existing theory provides a complete explanation of the functions of large shoals formation in marine fishes. Here, we consider how well the mechanisms commonly proposed to explain enhanced safety of group living prey(More)
This study describes how three individual fish, Atlantic cod (Gadus morhua L.), developed a novel behaviour and learnt to use a dorsally attached external tag to activate a self-feeder. This behaviour was repeated up to several hundred times, and over time these fish fine-tuned the behaviour and made a series of goal-directed coordinated movements needed to(More)
The red king crab (Paralithodes camtschaticus) was introduced in the Barents Sea in the 1960s and soon established a viable population. Proper management and exploitation of the Barents Sea king crab stock require better understanding of the spatial dynamics at different scales. This study examines the small-scale movement patterns of seven adult male crabs(More)
*Correspondence: Leif Nøttestad, Institute of Marine Research, Research Group on Pelagic Fish, Nordnesgaten 33, NO-5817 Bergen, Norway e-mail: leif.nottestad@imr.no This study aimed to assess possible shifts in distributional patterns of cetaceans residing in the Norwegian Sea, and to relate the distribution to their feeding ecology during the summer(More)
Food search behaviour in cod, Gadus morhua, was studied by means of a stationary positioning system. Six fish in a fjord in northern Norway were tagged in situ by allowing them to shallow bait-wrapped acoustic tags, and their swimming behaviour was continuously recorded. The fish exhibited a diel activity rhythm, with higher swimming speeds and a larger(More)
We studied the learning capacities and anticipatory behaviour in a "sit-and-wait" predatory fish, the Atlantic halibut, Hippoglossus hippoglossus. In Experiment 1 two groups of halibut received series of light flashes (conditioned stimulus, CS) that started before delivery of food (unconditioned stimulus, US) and persisted until after food delivery, i.e.(More)