<I>Prionurus Laticlavius</I>

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BULLETIN OF MARINE SCIENCE, 78(2): 393–395, 2006

NOTE First reported records of Prionurus laticlavius (Perciformes: Acanthuridae) from the Gulf of California

Oscar Trujillo-Millán, José De la Cruz-Agüero, and Juan F. Elorduy-Garay

Seven species of surgeon fish inhabit the tropical easternP acific (TEP). From these, only five species have been reported from Mexico (other than the offshore islands): Acanthurus achilles Shaw 1803; Acanthurus nigricans (Linnaeus, 1758); Acanthur- us triostegus (Linnaeus, 1758); Acanthurus xanthopterus Valenciennes, 1835; and Prionurus punctatus Gill, 1862 (Allen and Robertson, 1994). The razor surgeonfish, Prionurus laticlavius (Valenciennes, 1846), the only other member of the genus in the TEP, has a confirmed range from Costa Rica to as far south as Ecuador, including offshore islands (Galápagos, Malpelo, Cocos, and Revillagigedo; Grove and Laven- berg, 1997; Robertson and Allen, 2002). Similar in appearance to P. punctatus, P. laticlavius can be distinguished by the lack of the numerous black spots. The razor surgeonfish is a reef-associated species that inhabits shallow waters, forming large schools at a depth range of 3–30 m. Here we report the first observations of the establishment of a razor surgeonfish population in the southern Gulf of California.

Material and Methods

From January 2003 to at least March 2005, several schools of numerous razor surgeonfish were sighted at four localities in the southern Baja California peninsula: Los Frailes (23º24′N, 109°24′W), Ensenada de Muertos (23°58′N, 109°49′W), San Juan de la Costa (24°22′N, 110°40′W), and around the Espíritu Santo Island (24º29′N, 110º21′W). We caught nine specimens of P. laticlavius from these localities and deposited them in Colección Ictiológica of the Centro Interdisciplinario de Ciencias Marinas, at La Paz, Baja California Sur, Mexico (CICIMAR-CI 5852 and CI 5853; Table 1). These specimens represent the first documented records of this species in Mexican mainland waters (i.e., Gulf of California) other than the offshore islands. All specimens were caught at about 5 m depth using a Hawaiian sling while freediving over rocky bottoms. Identification followed Krupp (1995) and Allen and Robertson (1994), and relied on number of fin rays and body coloration H( umann, 1993). Morphomet- ric and meristic data and other curatorial information are presented in Table 1. Prior to the present records, the Marine Vertebrates Collection of the Scripps Institution of Oceanogra- phy, UCSD (www-sioadm.ucsd.edu/siofish), has a record (SIO 61-239) of a razor surgeonfish collected in June 1961, at Punta Los Frailes (23°24′N, 109°24′W) (Froese and Pauly, 2005), although this record has never been included in any peer-reviewed reference.

Results and Discussion

The new records of P. laticlavius and other rocky-reef species (Tavera et al., 2005) in the southern coast of the Baja California peninsula and other areas in the TEP may be linked to recent ENSO (El Niño–Southern Oscillation) events (Victor et al.,

Table 1. Morphometrics and meristics of the nine individuals of Prionurus laticlavius collected off the southwestern coast of the Baja California Peninsula. TL = total length; SL = standard length; Wt = total weight; Wg = gonad weight; PP = Punta Perico; EM = Ensenada de Muertos; SJC = San Juan de la Costa; LF = Los Frailes; - = no data available.

Date TL SL Height Wt Wg Dorsal fin Anal fin Gender Site Catalog (mm) (mm) (mm) (g) (g) number 28 Apr 04 297 240 112 514 - VIII-26 III-23 Male PP 5,853 28 Apr 04 256 205 109 366 - VIII-27 III-24 Male PP 5,853 18 June 04 147 117 65 73 - VIII-27 III-23 Juvenile EM 18 June 04 155 122 68 - - VIII-27 III-24 Juvenile EM 18 June 04 160 127 70 101 - VIII-27 III-24 Juvenile EM 29 July 04 373 304 150 1,111 29 VIII-26 III-24 Female EM 21 Aug 04 197 155 88 - - VIII-27 III-23 Male SJC 5,852 24 Jan 05 335 265 126 452 10 VIII-25 III-23 Female LF 15 Mar 05 320 253 120 382 - VIII-26 III-23 Male LF

2001). ENSO events cause oceanographic conditions that can promote range exten- sions and colonization of new sites by reef-associated fishes. Data on larval duration and long-distance transport are unknown for the razor surgeonfish, but it is possible that this species “extended” its distribution from populations in the Revillagigedo Islands. Although P. laticlavius was recorded in the area in June 1961 (one specimen 91 mm long, probably a juvenile), the species apparently has not been seen for four decades despite intensive ichthyological collecting in the area. The conspicuous pres- ence of the species in the area for more than 2 yrs, the observed population structure (schools of juveniles and adults), and the gonadal maturity of selected specimens verified in the field indicate the establishment of the species in the southern Gulf of California. Comparison among specimens of P. laticlavius and P. punctatus from the same area revealed morphometric and meristic overlapping and some specimens with subtle blended coloration patterns. Considering the observations of probable

Figure 1. External appearance of Prionurus laticlavius (297 mm TL). NOTES 395 hybridizing in other reef-associated species in the Gulf of California (Sala et al., 1999), additional material of Prionurus spp. must be examined to determine if hy- brids are also present.

Acknowledgements

This study was partially funded by Coordinacion General de Posgrado e Investigacion – Instituto Politécnico Nacional to the research project “Biología de algunas especies de arrecife rocoso del Golfo de California.” OTM is a fellow of the Programa Institucional de Formación de Investigadores del Instituto Politécnico Nacional. JDA and JFEG received grants from Sistema de Becas por Exclusividad, Comisión de Operación y Fomento de Ac- tividades Académicas - Instituto Politécnico Nacional, and from Estímulo al Desempeño de Investigación - Instituto Politécnico Nacional. We are grateful to X. Moreno-Sánchez for lending us the specimens from Los Frailes, B.C.S., and to L. Burnes-Romo for the pho- tograph of the razor surgeonfish. We are grateful to two anonymous reviewers who greatly improved the manuscript.

Literature Cited

Allen, G. R. and D. R. Robertson. 1994. Fishes of the tropical eastern Pacific. University of Ha- waii Press, Honolulu. 332 p. Froese, R. and D. Pauly (eds.) 2005. FishBase. Available: www.fishbase.org. Version (09/2005). Created 7/10/2003 [updated: 10/29/05]. Grove, J. S. and R. J. Lavenberg. 1997. The fishes of the Galapagos Islands. Stanford University Press, Palo Alto. 863 p. Humann, P. 1993. Reef fish identification: Galápagos. New World Publications, Inc., Jackson- ville. 192 p. Krupp, F. 1995. Acanthuridae. Sangradores, cirujanos, navajones. Pages 839–844 in W. Fisher, F. Krupp, W. Schneider, C. Sommer, K. E. Carpenter, and V. H. Niem, eds. Guía FAO para la identificación de especies para los fines de la pesca. Vol. II. Pacífico Centro-Oriental, FAO. Rome. Robertson, D. R. and G. R. Allen. 2002. Peces costeros del Pacífico Oriental tropical: un sistema de información. Instituto Smithsoniano de investigaciones tropicales, Balboa. CD-Rom. Sala, E., O. Aburto-Oropeza, and J. L. Arreola-Robles. 1999. Observations of a probable hybrid angelfish of the genusHolacanthus from the Sea of Cortez, Mexico. Pac. Sci. 53: 181–184. Tavera, J. J., A. F. González-Acosta, and J. De La Cruz-Agüero. 2005. First record of Seriola peruana (Actinopterygii: Carangidae) in the Gulf of California. J. Mar. Biol. Assoc., U.K. Biol. Rec. 85(6): 1555. Victor, B. C., G. M. Wellington, D. R. Robertson, and B. I. Ruttenberg. 2001. The effect of the El Niño–Southern Oscillation event on the distribution of reef-associated labrid fishes in the eastern Pacific Ocean. Bull. Mar. Sci. 69: 279–288.

Date Submitted: 28 February, 2005. Date Accepted: 11 October, 2005.

Addresses: Centro Interdisciplinario de Ciencias Marinas, Instituto Politecnico Nacional, Departamento de Pesquerias y Biologia Marina, Apartado Postal 592, 23000 La Paz, Baja California Sur, Mexico. E-mail: .