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Tropical rays are intrinsically more sensitive to overfishing than the temperate skates

Lookup NU author(s): Ellen Barrowclift-Mahon, Professor Per Berggren



This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).


© 2023 The AuthorsOverfishing, habitat loss, and climate change are driving population declines in many species. Understanding a species' capacity to recover from these and other threats is necessary for prioritising management. The maximum intrinsic rate of population increase (rmax) can be used to compare which species or groups are particularly sensitive to ongoing threats. To investigate global patterns of intrinsic sensitivity of rays and skates (superorder Batoidea), we calculated rmax of 85 species using a modified Euler-Lotka model that accounts for survival to maturity. We examined how rmax varies with body mass, temperature, and depth using an information-theoretic approach through model selection, accounting for phylogenetic non-independence. Although we observed an overall positive relationship between rmax and temperature, we found that warm, shallow-water rays were more intrinsically sensitive to exploitation (lower rmax) than cold, deep-water skates (higher rmax). We hypothesise that this pattern is likely driven by their different reproductive strategies as live-bearing rays have fewer offspring compared to egg-laying skates, and caution that future research should focus on understanding differences in the mortality schedule of juveniles and sub-adults to understand if survival to maturity is comparable. Our findings highlight the high vulnerability of warm, shallow-water ray species to overexploitation and other threats due to their intrinsically low maximum population growth rates. These differences in rmax have conservation implications for our understanding of the geographic patterns in extinction risk, suggesting that tropical rays are more intrinsically sensitive.

Publication metadata

Author(s): Barrowclift E, Gravel SM, Pardo SA, Bigman JS, Berggren P, Dulvy NK

Publication type: Article

Publication status: Published

Journal: Biological Conservation

Year: 2023

Volume: 281

Print publication date: 01/05/2023

Online publication date: 29/03/2023

Acceptance date: 04/03/2023

Date deposited: 20/04/2023

ISSN (print): 0006-3207

ISSN (electronic): 1873-2917

Publisher: Elsevier Ltd


DOI: 10.1016/j.biocon.2023.110003


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Canada Research Chairs program
Natural Science and Engineering Research Council
UK Research and Innovation (UKRI)-Mitacs UK-Canada Globalink Research Placement
the IAPETUS2 Doctoral Training Partnership