Collective behaviour is an intriguing pattern-forming process in nature, and how individual rules scale to collective phenomena are still being learned. An area of particular interest is to understand how information is transferred in animals groups, and how stimuli is amplified or dampened through social interactions.
The project will perform lab experiments on schooling fish in response to external stimuli, and investigate the role of the social interactions. The fish will be observed using video cameras, and techniques to extract the behavioural information will be further developed.
An important aspect of the proposal is to establish a link between the highly controlled laboratory observations to in situ experiments. The results from the laboratory will be used to form rigorous hypotheses on the collective behavioural rules in herring, a key species both economically and ecologically. These will be tested on herring in a net pen setup. We will use both video cameras and acoustic cameras to observe the behaviour, and the methods developed from the laboratory experiments will be refined to fit the herring net-pen system.
We are particularly interested in sound stimulated collective behaviour, since anthropogenic noise pollution is an increasing concern worldwide. To achieve this a range of different sound sources will be used, and the different noise fields will be modelled and verified before being exposed to the fish. The role of near field effects and range effects will be investigated, and the results will be related to in situ sound exposure experiments, in particular where sound pressure levels has failed to explain the behaviour.
Finally, the expected acoustic image on a 4D scientific multi-beam sonar will be predicted from simulated schools. These predictions will be based on the experimentally derived rules, and the result will be used to evaluate the feasibility to use sonars to observe internal school dynamics in the open ocean.
- Improve techniques to derive collective behavioural information from schooling fish in the laboratory and from herring in a net pen.
- Model, test and verify sound fields in the laboratory and in a net pen using various sound sources, and use it to stimulate reactions in the fish.
- Test hypotheses of the relation between collective information transfer and direct stimuli in the laboratory, including sound exposures from the sound fields derived in b).
- Test laboratory results on herring in a net pen.
- Use the results from the net pen to link the laboratory results to large scale aggregations of herring, and investigate how sonar systems can be used to observe these phenomena in the field.