Identification of patterns in cod behavior

G.K. Jonsson1, V. Thorsteinsson2 and M.S. Magnusson3

1Human Behaviour Laboratory, University of Iceland, University of Aberdeen and PatternVision
2The Marine Research Institute, Reykjavik
3Human Behaviour Laboratory, University of Iceland and PatternVision

The potential of using Theme™ (Noldus Information Technology bv, The Netherlands) in behavior studies of commercial fish stocks was tested using data from tagging experiments with adult cod (Gadus morhua L.) in Icelandic waters. The cod was tagged with Data Storage Tags (DSTs) sampling temperature and depth with 10 minutes intervals and memory capacity up to 260,000 records. The development of using such technology in behavior research advanced greatly during the last decades of the 20th century into the 21st. Increasing memory capacity in Data Storage Tags (DSTs) makes it possible to collect more data which is useful to resolve many questions in fish behavior.

The quantity on other hand can make the analysis difficult or impossible without some sophisticated computer programs. The time series were prepared for T-pattern analysis with Theme. This included the detection and delimitation of tidal influence in the data and event basing raw data according to prede.ned events. Preliminary results indicate that a Theme analysis can make a significant contribution to the analysis of cod behavior, offering an increased advantage to view and understand hidden patterns within large number of data points. A high number of temporal patterns were detected, patterns of repeated vertical movements and speed and acceleration changes. A number of specific temporal patterns were also identified within and across individual cod vertical movements. Special attention is given to a) behavioural patterns that are tidal-wave related and the comparison of tidal-wave related patterns to other patterns and b) behavioral patterns related to temperature and depth data. Future objective is to search for patterns of vertical movement in relation to environmental parameters.

Paper presented at Measuring Behavior 2005 , 5th International Conference on Methods and Techniques in Behavioral Research, 30 August - 2 September 2005, Wageningen, The Netherlands.

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