A Global Synthesis of Population Demographic Models in Sharks and Rays

Abstract

Demographic models are vital tools in fisheries management, particularly for data‐limited species such as sharks and rays. However, a significant gap exists in the statistical quantification of productivity metrics related to elasmobranchs. This study addresses this gap by conducting a meta‐analysis of population models for sharks and rays, framed within a scientometric context. We reviewed 91 publications, which revealed a modest positive trend in research over time. Our findings suggest that the geographical distribution of life history traits may be more important than ecological variables in determining elasmobranch vulnerability to fishing. Furthermore, Rays and oviparous elasmobranchs generally exhibit higher finite rates of population growth (λ) compared to sharks and viviparous elasmobranchs, respectively. However, when correcting for phylogenetic relationships, these differences become statistically non‐significant, highlighting the importance of accounting for phylogenetic non‐independence when interpreting interspecific trends in demographic traits. A significant negative correlation between mean lambda values and IUCN status was found, indicating that species at greater risk of extinction have lower lambda values. Odontaspididae and Mobulidae are identified as the most vulnerable shark and ray families to fishing pressure, respectively. Our results suggest that elasmobranchs inhabiting lower latitudes and warmer temperatures are more vulnerable to fishing pressure. Methodological approaches have evolved, with a notable increase in the use of matrix models over time. Most elasmobranchs studied demographically are classified as least concern, particularly rays. This highlights the need for intensified research efforts focused on threatened species, as well as addressing geographic biases prevalent in developing countries.