Ichthyological note First record of Pseudocaranx chilensis (Carangidae) from the continental coast of north-central Chile SFI © by Received: 25 Dec. 2017 Accepted: 13 May 2018 * Editor: R. Causse Philippe BÉAREZ (1) & César VILLAROEL (2) Résumé. – Nouveau signalement de Pseudocaranx chilensis The Juan Fernández trevally, Pseudocaranx chilensis (Carangidae) sur les côtes continentales du nord du Chili. (Guichenot, 1848), is considered endemic to the Desventuradas and Juan Fernández Islands, from where it was described (Fig. 1). It is La carangue chilienne Pseudocaranx chilensis est une espèce a coastal pelagic species commonly caught off the islands, where côtière des îles océaniques situées au large du Chili. Elle est consi- dérée comme étant endémique des îles Juan Fernández et Desven- it constitutes a prize catch due to its large size of up to 65 cm total turadas. Cette note présente le premier signalement de cette espèce length (Dyer and Westneat, 2010). autour de l’île Chañaral, située à proximité du continent sur la côte Here we report the sighting of a group of 6 to 8 individuals centre-nord du Chili, ce qui constitue une extension de sa distribu- Pseudocaranx chilensis off Chañaral Island (29°02’S-71°35’W); a tion géographique d’environ 850 km vers l’est. L’observation sous- small island located about 6 km off the mainland coast of north- marine de plusieurs individus errants pourrait résulter d’une migra- central Chile. tion de larves de ce poisson depuis les îles Juan Fernández. Key words. – Southeastern Pacific – New record – Chile – Chañar- RESULTS AND DISCUSSION al Island – Pseudocaranx chilensis – Vagrant. The Pseudocaranx chilensis individuals (Fig. 2) were observed off the northeastern part of the island on the 19th April 2015. A group of 6 to 8 fish were swimming in shallow water 2 to 6 m deep. The family Carangidae is poorly represented along the Pacif- They were probably still juveniles or subadults since their approxi- ic coast of continental Chile. Under “normal” conditions, i.e. non mate size were around 20 cm total length. Little biological informa- El Niño / La Niña years, only three species of carangids occur in tion is available for P. chilensis, but size at first maturity (L50) for the mainland Chilean waters: Trachinotus paitensis Cuvier, 1832; Pseudocaranx dentex (Bloch & Schneider, 1801) in the Azores is Trachurus murphyi Nichols, 1920; and Seriola lalandi Valenci- ennes, 1833. The first is a tropical eastern Pacific species, some- times caught in northern Chile, south to Antofagasta (Medina et al., 2004). The second is distributed from Ecuador to Chile and consti- tutes a major fishery resource. In Chile, it can be found from Arica (18°20’S) to Chiloé Island (42°S) (Arcos et al., 2001). The third species is mostly caught off northern Chile (between Iquique and Coquimbo, 20°-30°S) during the austral spring and summer sea- sons. The last two species are transpacific and are also found near the oceanic islands belonging to insular Chile and west across to New Zealand (Pequeño and Sáez, 2000). The connectivity of their populations is probably maintained across the southern Pacific (see Vásquez et al., 2013; Martinez-Takeshita et al., 2015). Figure 1. – Original drawing of Pseudocaranx chilensis from the descrip- Figure 2. – Individual Pseudocaranx chilensis swimming over the kelp bed tion of Guichenot (1848). at Chañaral Island (depth ~ 5 m). (1) Archéozoologie, archéobotanique : sociétés, pratiques et environnements (UMR 7209). Sorbonne Université, MNHN, CNRS, Muséum national d’Histoire naturelle, 55 rue Buffon, 75005 Paris, France. (2) Explorasub, Chañaral, Chile. [[email protected]] * Corresponding author [[email protected]] Cybium 2018, 42(3): 303-305. First record of Pseudocaranx chilensis from coastal north-central Chile BÉAREZ & VILLAROEL as follows (Afonso et al., 2008): male L50 = 27.8 cm fork length, cies transportation across the flow of the Humboldt Current. The female L50 = 30.0 cm fork length. ichthyofaunas of these islands are comprised of a mixture of sub- The specimens are characterized by the presence of two sepa- tropical and temperate taxa, more similar to western than eastern rate dorsal fins and by conspicuous scutes on the posterior part of South Pacific fauna (Pequeño and Lamilla, 2000; Pérez-Matus et the lateral line; a lateral line with a weak and extended anterior arch, al., 2014; Friedlander et al., 2016). Also, both island groups have with junction of curved and straight parts of lateral line below the more affinity and overlap between them than with the continent middle (vertical from twelfth to fourteenth soft rays) of the second (Pequeño, 2000; Pequeño and Sáez, 2000), suggesting that these dorsal fin. The colour of the body is pale yellowish to steely blue two island groups should be considered as a single biogeographic dorsally, silvery below; a yellow stripe is present along the sides, unit (Dyer and Westneat, 2010). wider over the straight part of the lateral line; dusky yellow cau- How the recently observed P. chilensis arrived at Chañaral dal fin, soft dorsal and anal fins; a diffuse black spot on the upper Island is not clear. Adults are not long-distance foragers (Afonso et margin of the opercle (see video available at http://sfi-cybium.fr/fr/ al., 2008); therefore, since the observed individuals were still juve- first-record-pseudocaranx-chilensis-carangidae-continental-coast- niles or subadults, it seems likely that they arrived through larval north-central-chile). transport and grew once settled near the island. Unfortunately, no Pseudocaranx chilensis is a subtropical to temperate spe- information is available for the pelagic larval duration for this spe- cies that has been described from the Juan Fernández Islands cies and little is known at the genus level. (Guichenot, 1848), and until now it has been considered as absent Where they came from is also not clear; but, it seems that from continental Chile (Pequeño, 1989, 1997). Hence, the young Pseudocaranx chilensis is much more common in the Juan Fern- specimens observed at Chañaral Island, located only 6 km off the ández Islands where it represents a good part (20%) of the biomass coast, most likely come from the Chilean oceanic islands, either the (Arana, 2000; Ramírez et al., 2013; Friedlander et al., 2016). Also, Desventuradas or Juan Fernández Islands (Fig. 3). the northeastward drift (Dyer and Westneat, 2010: fig. 2; Andradeet The Juan Fernández Islands are situated ca 650 km off the al., 2014) would most likely have transported the fish larvae from coast of Chile, west of Valparaíso. They are composed of three the Juan Fernández Islands to Chañaral Island. It is noteworthy to main volcanic islands: Robinson Crusoe (33°40’S-78°50’W), the mention here that vagrant Juan Fernández fur seals have been found closest to the mainland, Alejandro Selkirk and Santa Clara. The on the west coast of South America, from southern Peru to southern Desventuradas Islands are a group of four small islands located Chile (Osman, 2007). ca 900 km off the coast of Chile, east of Caldera. San Ambrosio The observation of Pseudocaranx chilensis likely represents (26°20’S-79°53’W) is the largest and closest island. Both groups of vagrant individuals. However, these vagrants demonstrate that spe- islands are quite far from the mainland, and are located at more or cies exchanges are possible between the subtropical oceanic islands less equal distance from the Chañaral Island (29°02’S-71°35’W): and the temperate mainland coast, and could be indicators of a ca 850 km. potential future colonisation, by this species, of the mainland coast The main superficial current in the area is the Humboldt Current that drives cold water from the Antarctic region northward, parallel of Chile. Climate-driven changes are often responsible for geo- to the coast, creating a strong biogeographic barrier between these graphic range shifts in fish (Stuart-Smithet al., 2016), which could islands and the continent (Thiel et al., 2007; Friedlander et al., be part of the explanation. Slight changes to marine currents and 2016). No eastward current exists between the Desventuradas, the small sea temperature increases could facilitate the eastward trans- Juan Fernández Islands and the mainland, which would allow spe- port of larval P. chilensis and the recruitment of juveniles along the mainland coast, if suitable habitats and temperature regimes were encountered. Their survival at Chañaral Island, which seems to be a recent event, might, therefore, be linked to climate change. Since Chañaral Island is part of the Humboldt Penguin National Reserve, it would be worth monitoring the presence of P. chilensis around the island to observe if a population is about to settle. Acknowledgements. – The authors thank Laurie Bouffandeau for her help with the drawing of the map, Jill Cucchi for copy-editing, and an anony- mous reviewer for his comments. REFERENCES AFONSO P., FONTES J., MORATO T., HOLLAND K.N. & SAN- TOS R.S., 2008. – Reproduction and spawning habitat of white trevally Pseudocaranx dentex, in the Azores, central north Atlantic. Sci. Mar., 72(2): 373-381. AndRADE I., HORMAZÁBAL S. & COmbES V., 2014. – Intrathermocline eddies at the Juan Fernández Archipelago, southeastern Pacific Ocean.Lat. Am. J. Aquat. Res., 42: 888- 906. ARANA P.M., 2000. – Experiencias de pesca con red de enmalle en las islas Robinson Crusoe y Santa Clara, Chile. Invest. Mar., Valparaíso, 28: 231-237. ARCOS D.F., CUBILLOS L.A., NÚÑEZ S.P., 2001. – The jack Figure 3. – Map of north-central Chile showing the oceanic islands and mackerel fishery and El Niño 1997-98 effects off Chile.Prog. Chañaral Island where Pseudocaranx chilensis was sighted. Oceanogr., 49: 597-617. 304 Cybium 2018, 42(3) BÉAREZ & VILLAROEL First record of Pseudocaranx chilensis from coastal north-central Chile DYER B.S. & WEstnEAT M.W., 2010.