Analysis of vessel movements and strategies using commercial catch and effort data from the New Zealand hoki fishery

Standardized catch rates from a multiplicative model of commercial catch per unit effort data have been examined to investigate vessel movements and strategies. A linear model was fitted to log-transformed commercial catch per unit effort data in the spawning hoki trawl fishery off the west coast of the South Island of New Zealand. The residuals from this model were examined; catch rates from tows done by different vessels at different times of day are standardized and, therefore, comparable. There is evidence that vessels make decisions about where to fish based on both their own recent catch history and on observations about the location and aggregation of other vessels. There is no evidence that there is enough information transfer for vessels to make decisions on the basis of catch rates of the other vessels in the fleet.