Tropical rays are intrinsically more sensitive to overfishing than the temperate skates. (May 2023)

• Record Type: Journal Article
• Authors: Barrowclift, Ellen; Gravel, Sarah M.; Pardo, Sebastián A.; Bigman, Jennifer S.; Berggren, Per; Dulvy, Nicholas K.
• Is Part Of: Biological conservation. Volume 281(2023)
• Publication Date: 2023-05
• Subjects: Demography -- Life history theory -- Metabolic scaling -- Temperature size rule -- Reproductive mode; Conservation of natural resources -- Periodicals; Nature conservation -- Periodicals; Ecology -- Periodicals; Environment -- Periodicals; Environmental Pollution -- Periodicals; Electronic journals; 333.9516
• DOI: 10.1016/j.biocon.2023.110003
• Languages: English
• ISSNs: 0006-3207

Abstract

Abstract: Overfishing, 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 ( r max ) 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 r max of 85 species using a modified Euler-Lotka model that accounts for survival to maturity. We examined how r max 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 r max and temperature, we found that warm, shallow-water rays were more intrinsically sensitive to exploitation (lower r max ) than cold, deep-water skates (higher r max ). 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 r max have conservation implications for our understanding of the geographic patterns in extinction risk, suggesting that tropical rays are more intrinsically sensitive.