First record of abnormal body coloration in a rockfish Sebastes trivittatus (Scorpaenoidei: Sebastidae)

Abstract

Abnormal body coloration (malpigmentation) in teleost fishes usually occurs as either a deficiency (albinism or hypomelanosis) or an excess (melanism or hypermelanosis) of pigmentation (e.g., Simon et al. 2009; Jawad et al. 2013). A particular form of the former, phenotypically expressed as bright yellow or orange body coloration, has been referred to as xanthism or xanthochroism (e.g., Amaoka 1995; Carson 2011; Lewand et al. 2013). Although malpigmentation in teleosts has been extensively studied in the context of aquaculture, especially in Pleuronectiform fishes in relation to developing asymmetry (e.g., Matsumoto and Seikai 1992; Venizelos and Benetti 1999; Burton 2010), it has been largely overlooked in natural populations. Abnormal coloration in rockfishes of the genus Sebastes has occasionally been reported, mostly from the eastern North Pacific (e.g., Phillips 1957, 1964; reviewed in Love et al. 2002). However, most of these were considered to have been caused by skin tumors, resulting in black patches on the body, with other color abnormalities having been relatively rarely documented [Love et al. 2002; but see Muto et al. (2013) for partial albinism; Lewand et al. (2013) for xanthochroism]. On 7 July 2014, a single individual of Sebastes trivittatus, exhibiting a rare example of abnormal body coloration, was captured by gill net at a depth of 17 m, near Daikokujima Island, off Muroran, Hokkaido, Japan (Fig. 1a). A brief description of the specimen is given below. Morphological characters were examined following Muto et al. (2011). The terminology of the head spines followed Randall and Eschmeyer (2001). The specimen was deposited in the Kyoto University Fish Collection (FAKU). Description (based on FAKU 137112, male, 189.5 mm in standard length). The following measurements are expressed as percentage of standard length: head length 38.2; snout length 9.3; orbit diameter 9.4; interorbital width 4.9; postorbital length 19.9; upper-jaw length 19.5; body width 17.1; body depth 1 35.0; body depth 2 26.9; caudal-peduncle depth 9.6; upper-peduncle length 10.8; lower-peduncle length 18.6; dorsal-fin base length 60.9; spinous dorsal-fin base length 37.2; soft dorsal-fin base length 24.2; anal-fin base length 15.3; preanal length 65.4; predorsal length 34.7; prepelvic length 41.7; first dorsal-fin spine length 7.1; second dorsal-fin spine length 11.6; third dorsal-fin spine length 17.0; fourth dorsal-fin spine length 19.5; fifth dorsal-fin spine length 19.9; antepenultimate dorsal-fin spine length 11.8; penultimate dorsal-fin spine length 9.9; last dorsal-fin spine length 12.2; first anal-fin spine length 8.2; second anal-fin spine length 16.5; third anal-fin spine length 15.3; longest (second) anal-fin soft ray length 19.9; pectoral-fin length 30.1; pelvic-fin length 25.2; pelvic-fin spine length 14.7. Dorsal-fin rays XIII, 13; anal-fin rays III, 6; pectoral-fin rays 18, uppermost ray unbranched, second to ninth Electronic supplementary material The online version of this article (doi:10.1007/s10228-015-0471-x) contains supplementary material, which is available to authorized users.