The uncertainty in the SBT catch at age matrix has been identified as one of the main sources of unaccounted uncertainty in the SBT stock assessments. The robustness of of the assessment to this uncertainty is unknown. Moreover, a critical issue in the SBT stock assessment is the internal inconsistency that exists among the inputs data and the need to develop improved models that can provide consistent interpretations for all of the available data. These inconstancies are making it increasing difficult to provide robust and scientifically objective conclusions about short term changes in the status of the SBT population. The model used for estimating SBT growth rates has been identified as a likely factor contributing to the apparent inconsistencies in the data. The current model of SBT growth was developed in 1993/94 and make simple assumptions about how growth may have changed since 1951. It assumes that growth rates since 1980 have remained equal to those measured by the 1983/84 tagging program. The current model fails to address the question of whether growth may have increased with the continued declined in the SBT stock since 1980 or the question of whether growth may decrease in the future if the population recovers. Given that incorporation of change in growth between the 1960s and 1980s had significant effects on the stock assessments and substantially reduced estimates of the probability of recovery, it is critical for the provision of reliable assessments and management advice that changes in SBT growth are appropriately and accurately accounted for in the analyses.

Since the currently used growth models were developed, substantial amounts of new information has been collected on SBT growth based on direct aging, otolith increment measurements and tagging experiments conducted in the 1990’s. Initial analyses of some of these data suggest that the assumptions about changes in SBT growth embedded in the current models are likely to be inadequate. There is a need to incorporate these new data within a comprehensive analysis and to develop an integrated model for all the various sources of information on SBT growth. Such an integrated model should provide the basis for addressing uncertainties associated with the catch at age matrix within the SBT stock assessment. Such an integrated growth model would allow for the development of improved assessment models. Such models are needed in order to be able to provide consistent interpretations of the available input data and thus improve the reliability and robustness of the management advice based on these models.