Ximing Xu

Department of Mathematics and Statistics, Dalhousie University

“Robust State-Space Models For Fish Stock Maturities”

Date: Thursday, October 23, 2014

We formulate robust state space models and develop inference

tools in the context of fisheries science and management. Our

prototype model concerns the maturity of fish by age over time,

knowledge of which is fundamental to understanding the dynamics and

productivity of fish stocks, a key component in fish stock

assessment. Our state space model incorporates dynamics over time and

yields robust estimates of the proportion of fish mature at various

ages for a collection of cohorts of interest. The estimates are

obtained using an iterative weighted likelihood where the

high-dimensional unobserved dynamics of the state space model and the

optimization over the fixed parameters are handled with the Automatic

Differentiation Model Builder. The data used to both demonstrate and

validate our new approach comes from the annual sampling program of

Fisheries and Oceans Canada, the primary scientific and regulatory

body responsible for stock assessments.

Important Dates

July 1: Canada Day (University Closed)

July 2: Canada Day observed (University Closed)

Where are they now?

Hsing-Ming Chang, Ph.D. (2012)

Robert Platt, M.Sc. (1993)