Visiting Scientists

Dr. Francis will be working with CAPAM collaborators from the Inter-American Tropical tuna Commission and the National Marine Fisheries Service. Chris was a visiting scientist from February 3 to March 14, 2014. He recently retired after 37 years employment as a quantitative fisheries scientist in New Zealand.  Trained as a mathematician, his long-term research interest has been in finding the best statistical and analytical tools to allow sound inferences from fisheries data.  He has published on a variety of topics including growth and ageing, survey design, and climate prediction, but in recent years his main focus has been on the statistics of stock assessment models.  He has authored more than 70 stock assessment reports and participated in assessment reviews in the USA (for the Center for Independent Experts), Chile, Europe, and Australia.

In retirement Chris has continued to pursue some of his research interests, particularly in the area of data weighting in stock assessment models.  Following on from his 2011 paper on this topic (CJFAS 68: 1124-1138) he has recently written a paper suggesting that the logistic-normal likelihood might be better than the multinomial for age and length composition data (Francis, R.I.C.C. in press.  Replacing the multinomial in stock assessment models: a first step.  Fisheries Research).  While at CAPAM he hopes to continue work on this topic.  One project will involve looking at the effect on tuna assessments of changing from the multinomial to the logistic-normal.  Another will be to see how the use of time-varying selectivities helps in the treatment of composition data in stock assessment models.  He would be pleased to hear from anyone with an interesting quantitative problem (chris.francis@clear.net.nz).