Xanthichthys ringens (PISCES: BALISTIDAE) IN ISLAS DEL ROSARIO (COLOMBIA): A NEW RECORD FOR THE CARIBBEAN CONTINENTAL SHELF SCIENTIFIC NOTE

Trabajo recibido el 23 de enero de 1991 y aceptado para su publicación el 9 de octubre de 1991.

RESUMEN

INTRODUCCIÓN

In August 1990, an artisanal fisherman using hook and line north of Isla Tesoro (10º 14" N, 75º 44" W), the most isolated and sea-ward of the small coraline islands of the archipelago known as Nuestra Señora del Rosario or Islas del Rosario, located on the Colombian coast over the southern Caribbean Sea, caught an adult Xanthichthys ringens. Since this is the first time that a full-grown specimen of the species is collected on the continental shelf of the Caribbean, the report of such finding is the objective of this note. The individual is deposited at the fish collection of the Instituto de Investigaciones Marinas de Punta de Betín (INVEMAR-P) in Santa Marta, Colombia.

Xanthichthys ringens (Linnaeus), Balistes ringens Linnaeus (1758):329 (Ascension Island, apparently an error).

X. rigens, Moore (1967): 695; Böhlke and Chaplin (1968): 666; Wells (1975): 405-406; Hoese and Moore (1977): 265; Guitart (1978): 744-745; Randall et al., (1978): 691-695; Randall (1983): 262; Robins et al., (1986): 303.

INVEMAR-P 2126, Bajo El Guante, Isla Tesoro, Islas del Rosario, 90 m, 20/VIII/1990.

Figura 1.

The measurements taken followed the Randall et al., procedure (1978); if no units appear, they are given as porcentages of standard length. Dorsal fin III, 29; anal fin, 26; pectoral fin, 13; lateral scales, 40; total length, 199 mm; standard length, 165.3 mm; head length, 51.5%; snout length, 20.0% eye diameter, 6.4%; interorbital width, 11.6%; least distance from eye to first dorsal fin, 8.7% body depth, 35.1 %; pectoral fin length, 13.2%; distance from snout to first dorsal fin 32.8%; distance from snout to second dorsal fin, 58.9%; distance from snout to anal fin, 64.5%; dorsal fin height, 20.3%; anal fin height, 18.8%; caudal peduncle depth, 6.9%.

TABLE 1. Localites of the Colombian Caribbean Sea where complete lists of reef fishes have been made,indicating abundant and/or common (++) and rare and/or uncommon(+) balistid species. SM, Santa Marta region (Acero and Garzón1987a); RB, Islas del Rosario and Islas de San Bernardo (Köster,1979; Acero and Garzón, 1985; Moreno and Torres,1990); GU, Golfo de Urabá (Acero and Garzón,1987 b)

The species is mainly known from insular localities in the Caribbean Sea and adjacent tropical waters; the only places in the continental shelf where it had been collected are Florida, Honduras and Brazil. The Honduras record is apparently based on a larval individual, since it is 63 mm SL, and the largest prejuvenile one known is 69 mm SL. Therefore, the Colombian specimen seems to be the first adult caught in the continental shelf of the Caribbean Sea; the only other one record from the southern Caribbean comes from. Curaçao, an island located outside the Venezuelan continental shelf. D.F. Torres (pers. comm., 1990) informed us that he has seen the fish in two places in the southern Caribbean coast: off Puerto Obaldía (Panamá) at about 30 m, and in Bajo Nokomis (off Cartagena, Colombia) at about 37 m; both localites are characterized by a bottom of coral rubble and 1 m tall barrel sponges [Xestospongia muta (Schmidt)], and very clear waters (visibilities about 30 m). The common name for the species is sargassum triggerfish, but since Dooley (1972) found only one individual between 8,400 specimens of 54 fish species, it must be wondered how accurate the name might be. Five species of balistids (excluding leather-jackets) are known from the Colombian Caribbean (Table 1), mainly from the Santa Marta region (11º 15’ N, 74º 12.5’ W) and from Islas del Rosario, which are in that sense as diverse as any other reef area of the tropical western. Atlantic, and rejecting the widely accepted idea that the southern Caribbean has a poorly developed, if any, reef fauna (i.e., Wells, 1988).

Carlos Torres fished the specimen and very kindly gave it to us. Diego F. Torres R. let us know his field notes.

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