Global status and research priorities for rhino rays

Abstract

Global biodiversity continues to decline in the terrestrial and aquatic realms. Across animal groups, threatened species are at risk of extinction if not managed effectively and permitted to recover. The cartilaginous fish order Rhinopristiformes (rhino rays) comprises 5 families: sawfishes, wedgefishes, guitarfishes, giant guitarfishes, and banjo rays. While the global plight of sawfishes, which are heavily depleted and have undergone range contraction unprecedented in cartilaginous fishes, has drawn attention to their status, the other families have received less focus to date. To highlight research on the non-sawfish rhino rays, the American Elasmobranch Society held the inaugural Global Wedgefish & Guitarfish Symposium in 2021. This Special Issue of Endangered Species Research presents a series of papers from that symposium. Rhino rays (68 species globally) face an extremely elevated risk of extinction, with nearly three-quarters of species threatened (72.7 %; Critically Endangered, Endangered, or Vulnerable on the IUCN Red List of Threatened Species) and nearly half (48.5 %) of all species classified as Critically Endangered. This level of critical endangerment is amongst the highest of all 136 vertebrate orders, with rhino rays ranking only below sturgeons and paddlefishes (order Acipenseriformes) and coelacanths (Coelacanthiformes). Recommendations for research priorities were developed through an expert-elicitation approach in the fields of status, taxonomy, life history, habitat, molecular ecology, fisheries, trade, and ex situ breeding. Only significant investment in research priorities will strengthen the information base upon which to make conservation and management decisions and secure a future without extinctions for rhino rays.