First Observation on the Mating Behaviour of the Marbled Ray, Taeniurops Meyeni, in the Tropical Eastern Pacific
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Environ Biol Fish https://doi.org/10.1007/s10641-018-0818-z First observation on the mating behaviour of the marbled ray, Taeniurops meyeni, in the tropical Eastern Pacific C. Arnés-Urgellés & E. M. Hoyos-Padilla & F. Pochet & P. Salinas-de-León Received: 11 May 2018 /Accepted: 28 September 2018 # Springer Nature B.V. 2018 Abstract Elasmobranch reproductive behaviour re- males swim in a close formation chasing an individual mains understudied, particularly for batoids (rays). Most female; (2) pre-copulatory biting: oral grasping of the of the information available originates from opportunistic female’s posterior pectoral fin by the males, with anterior observations of mating scars in the wild and/or from bending of one clasper and rotation of the pelvic region individuals held in captivity. Here we describe the first towards the female’s cloaca; (3) copulation/ insertion of complete mating sequence of the marbled ray the male’s clasper followed by ‘ventral to ventral’ position (Taeniurops meyeni) in the wild. The event was filmed and energetic thrusting of the male’s pelvic region; (4) at Isla del Coco National Park in Costa Rica, in the post-copulatory behaviour: the male removes its clasper Tropical Eastern Pacific. The complete sequence lasted from the female’s cloaca while releasing her posterior approximately 3 hrs and is defined by the following pectoral fin and (5) separation: the male sets the female behaviours: (1) close following or chasing: a group of free and separates himself from the group. The mating behaviour described here shares some similarities with the few other studies of batoids in the wild and highlights Electronic supplementary material The online version of this the need to further understand their mating system to article (https://doi.org/10.1007/s10641-018-0818-z)contains guide conservation plans for this vulnerable species. supplementary material, which is available to authorized users. C. Arnés-Urgellés (*) : P. Salinas-de-León Keywords Elasmobranch Batoids Reproduction Charles Darwin Research Station, Charles Darwin Foundation, Life-history. Isla del coco Galapagos, Ecuador e-mail: [email protected] E. M. Hoyos-Padilla Introduction Pelagios Kakunjá, Sinaloa 1540, 23070 La Paz, B.C.S., C.P, Mexico Mating sequences in elasmobranchs (sharks and rays) have been rarely documented in the wild. Most available E. M. Hoyos-Padilla Fins Attached: Marine Research and Conservation, 19675 Still information on the reproductive behaviour of this group Glen Drive, Colorado Springs, CO 80908, USA of species has been obtained from opportunistic observations of mating scars in females in the wild F. Pochet or from individuals held in captivity (Henningsen 2000; Undersea Hunter Group, San Jose, Costa Rica Kajiura et al. 2000; Chapman et al. 2003; Henningsen P. Salinas-de-León et al. 2004; Whitney et al. 2004) with limited direct Pristine Seas, National Geographic Society, Washington, DC, observations of courtship and mating recorded for wild USA populations (but see Tricas 1980;Nordell1994; Environ Biol Fish Chapman et al. 2003;Yanoetal.1999;Pierceetal. BVulnerable^. However, despite its significant popula- 2009; Salinas-de-León et al. 2017b). tion reduction and evident vulnerability (White et al. Most of the research describing elasmobranch repro- 2015), little is known about its biology and no specific duction has been conducted on sharks, and very little on information on its reproduction has been produced in the rays (batoids). Only eight species of batoids, out of the TEP. In this study, we provide the first detailed descrip- approximately 600 recorded, have been observed copu- tion of a complete mating event sequence for the mar- lating in the wild (Chapman et al. 2003;Mulletal. bled ray in the wild. 2010). Despite this lack of data on their reproductive behaviour, large numbers of batoid species are highly Observations exploited by target and non-target fisheries around the world (Worm et al. 2013;Oliveretal.2015). In the The mating event was recorded at Manuelita Coral Tropical Eastern Pacific (TEP) marine ecoregion Garden, Isla del Coco, Costa Rica, in June 2016 (Spalding et al. 2007) batoids are frequently caught as (Fig. 1). A group of approximately 26 marbled rays by-catch in commercial fisheries, mainly shrimp were initially seen swimming in a compact formation trawling, making up for a significant proportion (> close to the sandy bottom at 30 m depth (Fig. 2a). The 40%) of fishing landings (Gómez and Mejía-Falla group was significantly male-biased, with just one fe- 2008; Smith et al. 2009; Mejía-Falla et al. 2012). male being chased by all the males. This group chase Additionally, these species commonly occur in marine concluded with three males closing in on the single coastal habitats where they are permanently ex- female high up in the water column at a depth of 12 m posed to anthropogenic stressors like artisanal and (Fig. 2b). At midwater, two males successfully bit and recreational fishing, habitat destruction, and pollu- grasped the female on the posterior margins of its pec- tion (Gómez and Mejía-Falla 2008;Mulletal.2010). toral disc, with one male on each pectoral fin (Fig. 2c). Thus, understanding their reproductive strategies and Soon after, a third male also grasped the female by the life-history becomes critical for population management rear edge of its left pectoral fin (Fig. 2c). Male 1 and conservation. positioned itself at the right side of the female and The marbled ray or blotched fantail ray, Taeniurops flexed one of its claspers forward (Fig. 2d), man- meyeni (Müller & Henle 1841), is a large batoid species aging to insert the right clasper into the female’scloaca reaching up to 1.8 m in disc width and 3.3 m in total (Fig. 2e). Clasper insertion occurred at a shallower depth length (Last et al. 2016). Marbled rays are widely dis- range from 5 to 10 m. tributed across the Indo-Pacific Ocean. However, in the After successfully achieving clasper insertion, male 1 TEP they are only known at two oceanic islands: Isla del flipped over and adopted a ‘ventral to ventral’ position Coco in Costa Rica and the Galapagos Islands in (Yano et al. 1999; Chapman et al. 2003) with the female, Ecuador, both considered elasmobranch hotspots while maintaining a grip of its pectoral fin (Fig. 2f). (McCosker and Rosenblatt 2010; Friedlander et al. Male 1 actively thrusted its pelvic region for approxi- 2012; Salinas-de-León et al. 2016). The mating se- mately one minute while maintaining ‘ventral to ventral’ quence described here was documented at Isla del position. During this rapid motion, sperm is being trans- Coco located approximately 550 km off the Pacific ferred from the urogenital papilla to the clasper groove Coast of Costa Rica. Isla del Coco was designated a of the male into the female’s genital tract (Luer and National Park in 1978 and recognized as a UNESCO Gilbert 1985; Pratt and Tanaka 1994). Subsequently, World Heritage Site in 1997 (Cortés-Núñez 2008). Even male 1 removed its right clasper from the female’s though batoid populations are protected from fisheries cloaca and stopped biting its pectoral fin. After separat- in this marine protected area (MPA), the marbled ray is ing from the female, a cloud of sperm was clearly visible still targeted by unregulated fisheries in many parts of in the water column (Fig. 2g). the world for the consumption of its meat (Stobutzki After separating from the female, male 1 shook its et al. 2002; Smith et al. 2009; Kyne and White 2015). claspers and these appeared to return to their natural Considering that this species is highly affected by relaxed position (Fig. 2h). Throughout the entire copu- overfishing (White et al. 2015; Kyne and White 2015) lation event that lasted approximately 2 min, from the the International Union for Conservation of Nature time male 1 inserted its clasper, both male 2 and male 3 (IUCN) Red List has the marbled ray listed as continued to hold on to the female by oral grip. After Environ Biol Fish Fig. 1 Isla del Coco Island, Costa Rica, detailing the location of Manuelita Coral Garden (blue dot) around Manuelita Islet, where the copulation event was recorded male 1 swam away, the rest of the group started to sink anterior bending of one of the claspers and rotation of to the bottom (at approximately 30 m) and observations the pelvic region towards the female’s cloaca; (3) of other males successfully achieving clasper insertion Copulation: the insertion of the male’s clasper followed with the same female were not witnessed. The female by ventral to ventral position and energetic thrusting of remained passive and did not engage in any avoidance the male’s pelvic region; 4) Post-copulatory behaviour: behaviour during the entire sequence. The complete the male removes its clasper from the female’scloaca mating event described here, from swimming as a while releasing his posterior pectoral fin; (5) group, the chase, matting, and final separation, lasted Separation: the male separates from the group approximately three hours observed over consecutives (Fig. 2a-h). During step 5, a cloud of sperm was clearly SCUBA dives (Supplementary material 1). visible in the water column. The mating sequence de- scribed for T. meyeni follows a similar sequence report- ed for other batoids in the wild, such as, the white Discussion spotted eagle ray, Aetobatus narinari (Tricas 1980), the yellow stingray, Urobatis jamaicensis (Young In this study, we provide the first detailed description of 1993), the round stingray, Urobatis halleri (Nordell the mating behaviour of the marbled ray T. meyeni. 1994), the giant manta ray, Mobula birostris (Yano Behavioural patterns observed here can be summarized et al. 1999) and the southern stingray, Hypanus as follows: (1) Close following or chasing: males chase americanus (Chapman et al.