Observation of group courtship/copulating behavior for free-living Indo-Pacific Leopard sharks, Stegostoma tigrinum

Abstract

Reproductive behaviors in wild sharks remain largely undocumented, yet they are critical for understanding population dynamics and informing conservation strategies. The Indo-Pacific Leopard shark (Stegostoma tigrinum), listed as endangered by the IUCN, has primarily been studied in captivity, with little information on its natural mating behaviors. Here, we present the first documented observations of group copulation in free-living S. tigrinum, recorded at Abore Reef, New Caledonia. Our observations detail a sequential mating event involving two males and a single female over a 90-min period. The mating behavior followed a structured sequence, including prolonged pre-copulation positioning, male grasping of the female’s fins and tail, conspicuous siphon sac, copulatory thrusting, and clasper use consistent with previous reports from captive settings. These findings provide novel insights into the species’ reproductive strategies and highlight the importance of identifying and protecting key mating habitats. Given the conservation concerns surrounding S. tigrinum, understanding these mating mechanisms and recognizing reproductive sites are crucial for effective species management. Our study underscores the need for further field observations to better understand the reproductive ecology of S. tigrinum and support targeted conservation efforts. Digital video images related to the article are available at: http://www.momo-p.com/showdetail-e.php?movieid=momo250903st01a.