An integrated model of seasonal changes in stock composition and abundance with an application to Chinook salmon

Population-specific spatial and temporal distribution data are necessary to identify mechanisms regulating abundance and to manage anthropogenic impacts. However the distributions of highly migratory species are often difficult to resolve, particularly when multiple populations’ movements overlap. Here we present an integrated model to estimate spatially-stratified, seasonal trends in abundance and population composition, using data from extensive genetic sampling of commercial and recreational Chinook salmon (Oncorhynchus tshawytscha) fisheries in southern British Columbia. We use the model to estimate seasonal changes in population-specific standardized catch per unit effort (a proxy for abundance) across six marine regions, while accounting for annual variability in sampling effort and uncertain genetic stock assignment. We also share this model as an R package stockseasonr for application to other regions and species. Even at the relatively small spatial scales considered here, we found that patterns in seasonal abundance differed among regions and stocks. While certain locations were clearly migratory corridors, regions within the Salish Sea exhibited diverse, and often weak, seasonal patterns in abundance, emphasizing that they are important, year-round foraging habitats. Furthermore, we found evidence that stocks with similar freshwater life histories and adult run timing, as well as relatively proximate spawning locations, exhibited divergent distributions. Our findings highlight subtle, but important differences in how adult Chinook salmon use marine habitats. Down-scaled model outputs could be used to inform ecosystem-based management efforts by resolving the degree to which salmon overlap with other species of concern, as well as specific fisheries. More broadly, variation in stock-specific abundance among regions indicates efforts to identify mechanisms driving changes in size-at-maturity and natural mortality should account for distinct marine distributions

Science Applications Forum Enhancing fisheries education through the Canadian Fisheries Research Network: a student perspective on interdisciplinarity, collaboration and 4 inclusivity 5 6

Abstract 31 Fisheries sciences and management involve complex problems not easily addressed by a single 32 set of stakeholders or methodologies from one discipline; accordingly, the Canadian Fisheries 33 Research Network (CFRN) was initiated to increase fisheries research capacity in Canada 34 through interdisciplinary and inclusive research collaborations. We compared the value of the 35 CFRN students' learning experience to that offered in traditional fisheries programs at Canadian 36 universities in training post-graduate students to tackle complex fisheries problems. This paper 37 presents 1) a review of the current state of fisheries education across Canada and 2) reflections 38 on our training within the CFRN, and challenges to implementing its innovative approach to 39 fisheries education. We found few dedicated fisheries programs in Canada and concluded that 40 fisheries research typically relies on securing a supervisor with an interest in fisheries. In 41 contrast, the CFRN enhanced our university training through interdisciplinary and inclusive 42 research collaborations, and by exposure to the realities of industry, government and academics 43 collaborating for sustainable fisheries. We propose a new approach to post-graduate level 44 fisheries education, one that combines interdisciplinarity, collaboration, and inclusivity to 45 produce more capable fisheries scientists and managers. Furthermore, we made 46 recommendations on how universities, researchers, and funding agencies can successfully 47 incorporate these themes into fisheries education. 4

Spatial and length-based models for management of migratory transboundary species : application to Pacific hake (Merluccius productus)

This dissertation develops new modeling tools to provide new scientific perspectives on migratory transboundary fish populations. I particularly focus on two main issues: (1) the interaction between age/size based migratory movement, spatial availability, and fisheries exploitation rates, and (2) time-varying fisheries selectivity caused by size based migration and cohort targeting. I use Pacific hake (Merluccius productus) as a case study. Pacific hake occurs off the Pacific coast of the U.S.A. and Canada and is characterized by ontogenetic migratory movement (older fish migrate further north), strong recruitment events, and time-varying selectivity due to targeting of strong cohorts. In this dissertation, I present two new modeling approaches, and explore the effects of spatial structure on management outcomes using a closed-loop evaluation. First, I use a Lagrangian approach to develop a migration model that describes the Pacific hake dynamics including seasonal migrations, fisheries dynamics, and cohort targeting. Second, I introduce a new stock assessment method that bypasses the requirement of estimating selectivity by using catch at length and growth parameters to produce estimates of exploitation rate at age. This method produces mixed results because of low precision in selectivity estimates. Third, I evaluate the impacts of harvest control rules on the outcomes experienced by Canada and the U.S.A while sharing the Pacific hake resource. I use the migration model described above in a closed-loop simulation to evaluate the long-term impact of 61 harvest control rules. The results indicate that there are differences in performance of harvest control rules between the two nations when maximizing potential long-term yield and log yields. This is a result of the reduced availability of the resource in Canadian waters as the overall harvest rate increases. Caps on allowable catch may help to avoid reduced availability issues. I believe that the results and conclusions presented in this dissertation can inform the future management and modeling of Pacific hake. In addition, the methods presented here could be used for management of other resources subject to time-varying selectivity and other transboundary stocks managed under agreements that do not consider spatial management explicitly.Science, Faculty ofZoology, Department ofGraduat

A Lagrangian approach to model movement of migratory species

We introduce introduce a Lagrangian movement model that can be used to characterize cyclic migrations of iteroparous fish populations. We demonstrate how movement parameters can be estimated using conventionally available catch at age data and provide a description of the potential bias that may arise from model misspecification, data aggregation and non standardized sampling effort. The model can be extended to incorporate covariates representing biological and environmental forces that alter the distribution and migration range of exploited populations. We expect that this movement model will be a useful tool to model fish migration, to illustrate how fisheries dynamics are affected by fish migration and to be used as an operating model in closed loop simulations. We expect that this movement model will be a useful tool to model fish migration. The model can be used to illustrate how fisheries dynamics are affected by fish migration and could also be used as an operating model in closed loop simulations to test the robustness of management frameworks to spatial structure and connectivity.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Enhancing fisheries education and research through the Canadian Fisheries Research Network: A student perspective on interdisciplinarity, collaboration and inclusivity

Fisheries involve complex problems not easily addressed by a single discipline, methodology, or set of stakeholders. In 2010, the Canadian Fisheries Research Network (CFRN) was initiated to increase fisheries research capacity in Canada through interdisciplinary and inclusive research collaborations. As post-graduate students in the network, we reflected on the type of training necessary to tackle fisheries problems and reviewed opportunities available at Canadian universities to receive such training. This paper presents an overview of fisheries education currently available in Canada, reflects on our training within the CFRN, and proposes improvements to fisheries education and research. Our review of the subject revealed few dedicated fisheries programs, limited interdisciplinary programs, few specialized fisheries training programs, and a heavy reliance on academic supervisors to secure research opportunities in fisheries. In contrast, the CFRN enhanced our training by deliberately focusing on tools and techniques to address fisheries issues, providing venues to foster interdisciplinary and inclusive research collaborations, and exposing the realities of stakeholder collaborations. We call for post-graduate-level fisheries education and research that is interdisciplinary, collaborative, and inclusive to produce well-rounded scientists and managers, and we suggest ways that universities, researchers, and funding agencies can incorporate these themes into fisheries education and research