Developments in innovative electronic tagging technologies, otolith chemistry analyses, and genetic methods have all allowed ecologists to address long-standing questions on migration ecology, population structure, and connectivity of marine and diadromous fish populations. In many cases these findings have contradicted unit stock assumptions underlying fisheries stock assessments and management frameworks. The effective integration of this information has been slow, however, largely due to challenges in characterizing dynamic processes (e.g. spatio-temporal stock structuring, migration ecology). In many cases, the novel information on migration and population structure is not directly suitable for incorporation into stock assessment models, due to the spatial and temporal resolution of sampling. When considering the effects of climate change, the incorporation of changing patterns of movement, connectivity, and subsequent mixed-stock composition can also present serious challenges.
There are multiple approaches to integrating these dynamic processes into stock assessment modelling and management; however, it is still rare that assessments address the wealth of emerging information on migration, connectivity and stock structure. Mixed-stock composition information derived from otoliths, genetics, and tagging can be used to revise data inputs to stock assessment (e.g. assign catch to its natal origin), potentially resulting in more accurate estimates of abundance, fishing mortality, and vulnerability to fishing. Information from data storage and satellite tags can provide information on fish movements between regions, which can be directly integrated into assessment models to account for stock mixing and connectivity. Synthesis of interdisciplinary stock structure information can also be used to inform spatial and temporal management strategies aimed at conserving unique populations, or can be used to redefine harvest stock units.
Despite the benefits of proactively restructuring assessment and management strategies to incorporate the best available science, further work is needed to ensure that biological, economic, and social trade-offs are fully considered in the context of adaptive assessment and management. The objective of this theme session, therefore, is to review recent work which applies novel information on migration ecology, connectivity, and population structure – information coming from an array of stock identification methods to inform fisheries stock assessment and management strategies.
Theme session E will address the following topics: