Estimability of natural mortality and other population parameters in a length-based model: Pandalus borealis in Kachemak Bay, Alaska
Because stock-assessment models have become more complex, the question of estimability of population parameters is important. We conducted simulation-estimation experiments with a length-based model of the pink shrimp (Pandalus borealis Krøyer) population in Kachemak Bay, Alaska, to compare the robu...
| Published in: | Canadian Journal of Fisheries and Aquatic Sciences |
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| Main Authors: | , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Canadian Science Publishing
2000
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| Subjects: | |
| Online Access: | http://dx.doi.org/10.1139/f00-220 http://www.nrcresearchpress.com/doi/pdf/10.1139/f00-220 |
| Summary: | Because stock-assessment models have become more complex, the question of estimability of population parameters is important. We conducted simulation-estimation experiments with a length-based model of the pink shrimp (Pandalus borealis Krøyer) population in Kachemak Bay, Alaska, to compare the robustness of various modeling approaches to specifications of natural mortality (M), catchability (q), a survey gear selectivity parameter (L 50 ), and data imprecision. Our goal was to determine the estimability of various parameters, particularly M, q, and L 50 . Simulation results suggest that interannual variations in M and L 50 could be estimated, if the underlying values have a trend over time. However, parameter q should be fixed at a chosen value, even when it varies over time. Estimated M for the Kachemak Bay P. borealis population increased in the 1980s, perhaps owing to increased predation mortality by groundfish. |
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