Research Document - 2014/061
Summary of Calibration Integration Factor (CIF) Corrections for the 1999 – 2002 Herring Acoustic Surveys in Northwest Atlantic Fisheries Organization (NAFO) Divisions 4VWX
By G.D. Melvin, C.D. Melvin, M.J. Power, S. Osborne, and A. Clay
Abstract
In 2003, the Fisheries and Oceans Canada’s Science Regional Advisory Process reviewed and approved the application of the Calibration Integration Factor (CIF) to acoustic biomass estimates for Northwest Atlantic Fisheries Organization divisions 4VWX herring. Unfortunately, inclusion of this approach required a significant amount of re-analysis of the original calibration and data files to apply the corrections. Survey biomass estimates with and without CIF were provided in the annual review, the former to move forward with the new approach, and the latter to make the current data comparable with historical estimates (1999-2002). This double reporting (with and without CIF) caused some confusion as to which series was being used to evaluate trends in biomass. In essence, the “without CIF” was considered valid for the period 1999 to 2009, while the “with CIF” was only available from 2003. This research document represents an overview of the process and procedures undertaken to update the acoustic survey biomass time series to include the CIF correction for the years 1999 to 2002. The re-analysis is now considered complete and the estimates of spawning stock biomass with CIF representative for the entire time series (1999 to present).
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