Global reconstruction of life-history strategies: a case study using tunas

Horswill, C. , Kindsvater, H.K., Juan-Jordá, M.J., Dulvy, N.K., Mangel, M. and Matthiopoulos, J. (2019) Global reconstruction of life-history strategies: a case study using tunas. Journal of Applied Ecology, 56(4), pp. 855-865. (doi: 10.1111/1365-2664.13327) (PMID:31217633) (PMCID:PMC6559282)

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1. Measuring the demographic parameters of exploited populations is central to predicting their vulnerability and extinction risk. However, current rates of population decline and species loss greatly outpace our ability to empirically monitor all populations that are potentially threatened. 2. The scale of this problem cannot be addressed through additional data collection alone, and therefore it is common practice to conduct population assessments based on surrogate data collected from similar species. However, this approach introduces biases and imprecisions that are difficult to quantify. Recent developments in hierarchical modelling have enabled missing values to be reconstructed based on the correlations between available life-history data, linking similar species based on phylogeny and environmental conditions. 3. However, these methods cannot resolve life-history variability among populations or species that are closely placed spatially or taxonomically. Here, theoretically motivated constraints that align with life-history theory offer a new avenue for addressing this problem. We describe a Bayesian hierarchical approach that combines fragmented, multi-species and multi-population data with established life-history theory, in order to objectively determine similarity between populations based on trait correlations (life-history trade-offs) obtained from model fitting. 4. We reconstruct 59 unobserved life-history parameters for 23 populations of tuna that sustain some of the world’s most valuable fisheries. Testing by cross-validation across different scenarios indicated that life-histories were accurately reconstructed when information was available for other populations of the same species. The reconstruction of several traits was also accurate for species represented by a single population, although credible intervals increased dramatically. 5. Synthesis and applications The described Bayesian hierarchical method provides access to life-history traits that are difficult to measure directly, and reconstructs missing life-history information useful for assessing populations and species that are directly or indirectly affected by human exploitation of natural resources. The method is particularly useful for examining populations that are spatially or taxonomically similar. The reconstructed life-history strategies described for the principal market tunas have immediate application to the world-wide management of tuna fisheries that use the steepness of the stock recruitment relationship to determine population productivity.

Item Type:Articles
Glasgow Author(s) Enlighten ID:Horswill, Dr Catharine and Matthiopoulos, Professor Jason
Authors: Horswill, C., Kindsvater, H.K., Juan-Jordá, M.J., Dulvy, N.K., Mangel, M., and Matthiopoulos, J.
Subjects:Q Science > QL Zoology
College/School:College of Medical Veterinary and Life Sciences > Institute of Biodiversity Animal Health and Comparative Medicine
Journal Name:Journal of Applied Ecology
ISSN (Online):1365-2664
Published Online:17 December 2018
Copyright Holders:Copyright © 2018 The Authors
First Published:First published in Journal of Applied Ecology 56(4): 855-865
Publisher Policy:Reproduced under a Creative Commons License

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
709611The interplay between life history evolution and population dynamics can help us conserve data-poor species and reveal how they evolvedJason MatthiopoulosNatural Environment Research Council (NERC)NE/P004180/1RI BIODIVERSITY ANIMAL HEALTH & COMPMED