Publication Abstract

A computer simulation model forpredicting rates and scales of movement of demersal fish on the European continental shelf

G.P. Arnold and B. H. Holford

A quantitative modelhas been developed which predicts geographical movements of demersal fish on the Europeancontinental shelf by combining tidal stream vectors calculated from Admiralty tidal datawith known patterns of fish behaviour. The model interpolates the speed and direction ofthe tidal current at any specified position and allows for the cyclical change of currentspeed between neap and spring tides. Fish behaviour is specified in terms of swimmingspeed and direction, as well as times of vertical migration and the duration of theintervening period in midwater. Times of vertical migration to and from the bottom can bespecified theoretically in relation to regular tidal events (slackwater, high or low tide,etc.), or practically using actual observations made by sonar or data storage (archival)tags. Simulated tracks can be used singly to predict the behaviour of individual fish inrelation to biological problems, or collectively to predict the distribution of wholepopulations in relation to management problems. These predictions can be formulated sothat they can be tested experimentally. The model is being used to reconstruct the groundtracks of fish fitted with data storage (archival) tags and also to predict thetheoretical movements of individuals and populations. It has been validated byreconstructing the ground tracks of fish tracked in the open sea using sector scanningsonar and transponding acoustic tags. Potential applications include estimating transfercoefficients for use in spatial assessment models, assessing the exchange of fish betweenfishable areas and areas closed to fishing for conservation reasons, and providing atheoretical framework for analysing returns from conventional fish tagging experiments.

Reference:

G.P. Arnold and B. H. Holford, 1995. A computer simulation model for predicting rates andscales of movement of demersal fish on the European continental shelf. ICES Journal ofMarine Science, 52: 981-990.