Chris Francis
Chris is acknowledged by many of the world fisheries stock assessment and management elite as one of the world’s leading fisheries stock assessment scientists. Over the last 35 years Chris has contributed hugely to fisheries management in New Zealand, Australia and Internationally through the provision of robust stock assessment advice and through the development of innovative stock monitoring and assessment modelling methods. He is credited with some of the most technically challenging and innovative stock assessments of the last three decades; the majority being on major New Zealand fish stocks in support of the New Zealand Quota Management system and also has led the development of population modelling approaches for protected marine species such as seabirds. Chris is also responsible for some of the important seminal work on the use of Bayesian inference and risk assessment in fisheries and for developing many of the now “accepted-as-standard” stock assessment model parameterisation methods for example the “Francis” methods for calculating mean-recruitment (R-zero), and growth parameters from tagging data.
In addition to over 100 reports for the New Zealand Government, Chris has also produced over sixty papers and articles in the primary literature. This is an outstanding achievement for a scientist who was primarily required to produce government reports. The fact that some of Chris’s innovative work is buried in ‘grey literature’ reports has meant that Chris has often not been duly credited as the author of the idea.
Below are some examples that highlight Chris’s contribution to fisheries management both in New Zealand and Internationally:
• Instrumental in progressing stock assessment in New Zealand during the 1980s from the use of simple yield equations to developing deterministic age structured models (PMOD) that other scientists could use. This was the start of the evolution of modelling approaches and software development that both advanced the assessment of many fish stocks at the time, and lead to the highly sophisticated methods now routinely used in fisheries stock assessment.
• Pioneered the use of Bayesian methods for stock assessment as exemplified in his highly regarded 1992 paper: Use of risk analysis to assess fishery management strategies: a case study using orange roughy (Hoplostethus atlanticus) on the Chatham Rise, New Zealand
• Author of the 2011 paper: Data weighting in statistical fisheries stock assessment models on fitting data in fisheries models is gaining acceptance as “international best practice”.
• Main creative developer of the generalised age or length-structured fish stock assessment software package CASAL. CASAL is increasingly being used world-wide by fisheries research institutions, and is the main research tool for stock assessments in New Zealand. Chris is responsible for designing the basic underlying concepts of CASAL including specifying much of its mathematical detail and structure.
• Main creative developer of “Seabird”, a population dynamics model to model for protected marine species, such as seabirds
• Chris was the first to recognise the fundamental difference between age- and length-based growth estimation, leading to the development of a novel Von Bertalanffy growth curve parameterisation method (the Francis parameters), and a new method and software (GROTAG) for estimating length-based growth from tagging data, and parameters for measurement uncertainty and bias.
• Chris also reviewed and clarified the many equations for growth back-calculation, leading to a greatly improved understanding of the procedure and the pros and cons of the many equations previously used by scientists.
• Development of statistically robust methods to design monitoring surveys and analyse results, including the two-phase random stratified design (1984).
• Independent reviewer of many major stock assessments in North America, Europe, Chile, and Australia.
Chris, above all else, is an excellent teacher and communicator, possessing the rare gift of being able to make the complicated seem simple. Chris’s writing and presentation style demonstrate that strong adherence to statistical and mathematical rigor does not need to come at the expense of straight forward explanation and ease of understanding. These qualities, in conjunction with his highly insightful and systematic approach to solving complicated stock assessment problems, are key reasons why Chris is highly sought after as an independent reviewer, fisheries technical working group adviser, or as invited speaker.
Although now retired Chris is still very active in fisheries stock assessment and management as an independent stock assessment reviewer for North American and European research agencies, and as an international conference speaker. Chris also devotes much of his retirement time to researching and advancing stock assessment methods, including working as a collaborator on innovative research projects that spark his interest. His recent, and highly acclaimed, paper “Replacing the multinomial in stock assessment models: a first step” was published in retirement.
Selected Publications
Francis, R.I.C.C. (1988) Are growth parameters estimated from tagging and age-length data comparable?
Canadian Journal of Fisheries and Aquatic Sciences 45, 936 – 942
Francis, R.I.C.C., D.J. Gilbert and J.H. Annala (1993) Fishery management by individual quotas: theory and practice. Mar. Policy 17(1): 64-65
Francis, R. I. C. C., and Smith, D. C. (1995). Mean length, age, and otolith weight as potential indicators of biomass depletion for orange roughy (Hoplostethus atlanticus) New Zealand Journal of Marine and Freshwater Research 29, 581-7
Francis, R.I.C.C., and Shotton, R. (1997) "Risk" in fisheries management: a review. Canadian Journal of Fisheries and Aquatic Sciences 54: 1699–1715
Francis, R.I.C.C. (2003) The precision of otolith radiometric ageing of fish and the effect of within-sample heterogeneity. Canadian Journal of Fisheries and Aquatic Sciences 60: 441–447
Francis, R.I.C.C.; Campana, S.E. (2004) Inferring age from otolith measurements: a review and a new approach. Canadian Journal of Fisheries and Aquatic Sciences61(7): 1269–1284.
Francis, R.I.C.C.; Clark, M.R. (2005) Sustainability issues for orange roughy fisheries. Bulletin of Marine Science76(2): 337-351.
Francis, R.I.C.C.; Harley, S.J.; Campana, S.E.; Doering-Arjes, P. (2005) Use of otolith weight in length-mediated estimation of proportions at age. Marine and Freshwater Research 56: 735-743.
Francis, R.I.C.C., Campana, S. E. & Neil, H. L. (2010) Validation of fish ageing methods should involve bias estimation rather than hypothesis testing: a proposed approach for bomb radiocarbon validations. Canadian Journal of Fisheries and Aquatic Sciences 67, 1398–1408.
Francis, R.I.C.C. (2011) Data weighting in statistical fisheries stock assessment models. Canadian Journal of Fisheries and Aquatic Sciences 68: 1124-1138.
Francis, R.I.C.C. (2012) The reliability of estimates of natural mortality from stock assessment models Fisheries Research 119 133-134
Francis, R.I.C.C. (2014). Replacing the multinomial in stock assessment models: a first step. Fisheries Research 151: 70– 84