Factors Affecting the Time Series Bias in Stock–Recruitment Relationships and the Interaction Between Time Series and Measurement Error Bias

Abstract

The stock–recruitment relationship (SRR) and the recruitment to spawning stock relationship (RSR) of the tiger prawn (Penaeus esculentus) in Exmouth Gulf, Western Australia, were used to examine the time series bias and measurement error bias by Monte Carlo simulations. The bias of the SRR parameters was decreased by adding environmental variables which reduced the variation about the SRR. However, because of the many variables which may be tested and the short time series of data usually available, one needs to be careful about possible spurious correlations. The variation about the RSR also needs to be taken into account, since it has an inverse relationship with the bias in the SRR. Simulating the effect of measurement error as well as the random variation about the SRR and RSR helps to determine the possible combinations of measurement error and random variation which may result in the observed variation about the SRR and RSR. These simulations also indicate that there is an interaction between measurement error and random variation about the SRR/RSR on the bias of the parameters of the SRR. This suggests that the time series bias and measurement error should be investigated simultaneously.