Haikun XuPosition: Senior Quantitative Fisheries Scientist - La Jolla Headquarters
Stock Assessment Program
- Responsible for conducting the bigeye tuna stock assessment.
- Participation in the SPC-IATTC collaboration for conducting the Pacific wide bigeye tuna stock assessment.
- Participation in the SPC-IATTC collaboration for conducting the South Pacific albacore stock assessment.
- Ph.D., Stony Brook University, USA, 2016
- B.Sc., Peking University, China, 2012
Dr. Haikun Xu joined the Stock Assessment Program in 2018. He is the stock assessment scientist responsible for conducting the stock assessment of bigeye tuna in the eastern Pacific Ocean. Haikun’s research focuses on a variety of topics including improving stock assessment methods, standardizing fishery-dependent catch-per-unit-effort observations, and understanding the impacts of climate on fish and fisheries. As part of his Ph.D. research at Stony Brook University, Haikun incorporated environmental effects on recruitment of yellowtail flounder into a state-space age-structured stock assessment. For his postdoctoral research, Haikun worked at the University of Washington where he developed a new semi-parametric method for autocorrelated age- and time-varying selectivity which has been implemented in Stock Synthesis, the stock assessment model used at IATTC. He also investigated the best practices for weighting composition data in stock assessments when the new age- and time-varying selectivity options are used. Since Haikun joined the staff, he has adapted a spatiotemporal delta-generalized linear mixed model to analyze the spatiotemporal dynamics of the dolphin-associated purse-seine fishery for yellowfin tuna and, more importantly, to provide an improved index of relative abundance and associated length compositions to the stock assessment model.
- Stock, Brian C., Haikun Xu, Timothy J. Miller, James T. Thorson, and Janet A. Nye. 2021. Implementing two-dimensional autocorrelation in either survival or natural mortality improves a state-space assessment model for Southern New England-Mid Atlantic yellowtail flounder. Fisheries Research
- Keisuke Satoh, Haikun Xu, Carolina V.Minte-Vera, Mark N.Maunder, Toshihide Kitakado 2021. Size-specific spatiotemporal dynamics of bigeye tuna (Thunnus obesus) caught by the longline fishery in the eastern Paciﬁc Ocean. Fisheries Research
- Mark N.Maunder, James T.Thorson, Haikun Xu, Ricardo Oliveros-Ramos, Simon D.Hoyle, Laura Tremblay-Boyer, Hui Hua Lee , Mikihiko Kai, Shui-KaiChang, Toshihide Kitakado, Christoffer M.Albertsen, Carolina V.Minte-Vera, Cleridy E.Lennert-Cody, Alexandre M.Aires-da-Silva, Kevin R.Piner 2020. The need for spatio-temporal modeling to determine catch-per-unit effort based indices of abundance and associated composition data for inclusion in stock assessment models. Fisheries Research
- Thorson, James T., Meaghan D. Bryan, Peter-John F. Hulson, Haikun Xu, and André E. Punt. 2020. Simulation testing a new multi-stage process to measure the effect of increased sampling effort on effective sample size for age and length data. ICES Journal of Marine Science
- Lennert-Cody, C.E., Maunder, M.N., Román, M.H., Xu, H., Minami, M., Lopez, J. 2020. Cluster analysis methods applied to daily vessel location data to identify cooperative fishing among tuna purse-seiners. Environmental and Ecological Statistics
- Xu, Haikun, James T. Thorson, and Richard D. Methot. 2019. Comparing the performance of three data-weighting methods when allowing for time-varying selectivity. Canadian Journal of Fisheries and Aquatic Sciences
- Xu, H., Lennert-Cody, C. E., Maunder, M. N., Minte-Vera. C. V. 2019. Spatiotemporal dynamics of the dolphin-associated purse-seine fishery for yellowfin tuna (Thunnus albacares) in the eastern Pacific Ocean. Fisheries Research
- Xu, H., Thorson, J.T., Methot, R.D., Taylor, I.G. 2018. A new semi-parametric method for autocorrelated age-and time-varying selectivity in age-structured assessment models. Canadian Journal of Fisheries and Aquatic Sciences
- Xu, Haikun, Timothy J. Miller, Sultan Hameed, Larry A. Alade, and Janet A. Nye 2017. Evaluating the utility of the Gulf Stream Index for predicting recruitment of Southern New England-Mid Atlantic yellowtail flounder. Fisheries Oceanography
- Xu, Haikun, Hye-Mi Kim, Janet A. Nye, and Sultan Hameed. 2015. Impacts of the North Atlantic Oscillation on sea surface temperature on the Northeast US Continental Shelf. Continental Shelf Research