Corresponding author: Chiu-Min Cheng ( ogcoho@gmail.com ) Academic editor: Ronald Fricke
© 2021 Hsuan-Ching Ho, Chi-Ngai Tang, Chiu-Min Cheng.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Ho H-C, Tang C-N, Cheng C-M (2021) A southward range extension of a wreckfish, Stereolepis doederleini (Actinopterygii: Acropomatiformes: Polyprionidae), to tropical water off eastern Taiwan. Acta Ichthyologica et Piscatoria 51(4): 365-370. https://doi.org/10.3897/aiep.51.e73207
|
A wreckfish, Stereolepis doederleini Lindberg et Krasyukova, 1969, inhabits typical cold or temperate waters and was previously known from Great Bay (Sea of Japan), Korea, south to Kyuhu-Palau Ridge of Japan. In the present report, a specimen of this fish was collected from southeastern Taiwan representing the southernmost distribution of the cold-water genus Stereolepis in the Northern Hemisphere, with a southward extension into the tropical region. It is also the first record of a member of the family Polyprionidae from Taiwan. Here we document the species found in Taiwan, with a detailed description of the specimen.
Actinopterygii, Acropomatiformes, biogeography, cold-water fish, distribution
The wreckfish family Polyprionidae is a group of large marine fishes, growing up to 250 cm in length, and attaining high market values by some of its members (
Of these species, S. doederleini was previously recorded from around Great Bay, Korea to Kyuhu-Palau Ridge of Japan (
Recently, a younger specimen of S. doederleini was collected from deep water by hook and line from off Fugang, Taitung, southeastern Taiwan. The finding reveals a southward extension of its distribution from cold or temperate into tropical water. A detailed description of this specimen is provided.
Methods for counts and proportional measurements followed
Stereolepis doederleini Lindberg et Krasyukova, 1969;
NMMB-P32813, 385 mm SL, off Fugang (ca. 22°43′N 121°20′E), Taitung, southeastern Taiwan, March 2020, by deep-water longline, ca. 400 m, purchased at local auction.
Morphological measurements presented as a percentage of SL. Dorsal-fin elements XI, 10; anal-fin elements III, 7; pectoral-fin rays 19 (right side)/18 (left side), two dorsalmost rays unbranched, others branched; pelvic-fin rays I, 5; principal caudal-fin rays 9 (upper lobe) + 8 (lower lobe), procurrent caudal-fin rays 9 (dorsal)/8 (ventral), total caudal-fin rays 24. Gill rakers on first gill arch 4 + 13 = 16, 3 rudimental plus 1 developed on upper limb and 7 developed plus 6 rudimental on lower limb. Pored lateral-line scales 73, including 3 on caudal-fin base. Rows of cheek scales 11. Circumpeduncular scale rows 39. Scales above lateral line 15, counted slitting posteriorly from dorsal-fin origin. Scales below lateral line 28 (counted from anal-fin origin slitting up anteriorly to lateral line) or 23 (counted from anal-fin origin slitting up posteriorly to lateral line). Vertebrae: 12 precaudal + 14 caudal = 26 in total. Vertebral formula 0/0/0+2/1+1/1/1/1/1/1/1/1 (predorsal and spinous dorsal fin only).
Head length 2.7 times in SL (36.9% SL); body depth at pectoral-fin base depth 2.9 (34.2); body width at pectoral-fin base 5.2 (19.2); predorsal length 2.7 (36.4); prepectoral length 2.8 (36.4); prepelvic length 2.7 (37.1); distance between origins of pelvic and anal fins 2.8 (36.4); dorsal-fin base length 2.1 (48.1); anal-fin base 7.0 (14.2); caudal-peduncle length 5.2 (19.2); caudal-peduncle depth 8.5 (11.8); pectoral-fin length 5.1 (19.6); pelvic-fin length 4.7 (21.1); pelvic-fin spine length 9.6 (10.4); caudal-fin length 4.8 (21.0).
Snout length 2.9 times (34.1% HL) in head length; fleshy eye diameter 5.5 (18.1); fleshy interorbital width 3.2 (30.9); bony interorbital width 3.6 (28.1); upper-jaw length 2.1 (46.9); post-orbital length 1.9 (52.5); distance from margin of eye to angle of subopercle 2.6 (38.1); suborbital height 7.7 (13.0); maxillary height 6.6 (including supramaxilla, maxilla, and premaxilla) (15.1); first dorsal-fin spine 8.4 (11.8); second dorsal-fin spines 3.5 (28.8); third dorsal-fin spine 2.3 (43.1); fourth dorsal-fin spine 2.0 (50.2); 11th dorsal-fin spine 4.9 (20.3); longest dorsal-fin ray 2.6 (39.2); first anal-fin spine 13.2 (7.6); second anal-fin spine 6.2+ (broken distally) (~16.1); third anal-fin spine 5.8 (17.3); longest anal-fin ray 2.7 (37.6).
Body moderately slender, deepest region at about middle of abdomen; less compressed. Dorsal profile smooth, nape slightly raised, dorsal-fin base straight at spinous region, slightly raised at soft-rayed region (Fig.
Mouth moderately large, terminal, its gape slightly oblique, forming ca. 10° angle with horizontal body axis; lower jaw slightly overhanging upper jaw; posterior end of maxilla extending to vertical through middle of eye. First suborbital bone (lacrimal) well developed, slightly overlapped with anterior portion of maxilla, its lower margin smooth. Two nostrils well in front of eye. Anterior nostril rounded, bearing high rim with flap, its broader reaching anterior margin of posterior nostril when reflected. Posterior nostril elliptical, horizontal axis longer and slightly above the anterior nostril, with very low flashy rim along its lower margin (Fig.
Opercle with strong spine, pointed and rather distinct, mostly exposed from skin and extending to slightly overhanging posterior margin of opercle (Fig.
Single dorsal fin with long base, deeply concaved at posterior third, spinous portion strongly arched with its base longer than that of soft-rayed portion, base of spinous portion 2.4 times base of soft-rayed portion (Fig.
Pectoral fin moderately large, long oval (Fig.
Teeth villiform on jaws, vomer, and palatines; no teeth at symphysis of upper jaw. Vomer with wide triangular patch of small villiform teeth; no backward prolongation of vomerine tooth patch. Palatine with a narrow band of numerous rows of small teeth. No teeth on pterygoids or tongue. Pseudobranch present.
Gill rakers on first gill arch 3 (rudimental) + 1 (developed) on upper limb, 7 (developed) + 6 (rudimental) on lower lobe.
Scales weakly ctenoid, including those on cheek, interorbital, operculum, chest, nape, chest, and base of pectoral fin. No scale on snout and chin. Predorsal scales beginning in plane about halfway between posterior margin of orbit and upper end of gill slit.
Lateral line complete, lateral line scales not enlarged, each with simple sensory tubule. Rows of scales above and below lateral line parallel to it. Bases of soft-rayed portions of dorsal and anal fins covered by small scales. Pectoral and caudal fins with scales basally.
When fresh, body yellowish brown dorsally and grayish ventrally with all fin darker, except for membranes of spinous dorsal fin translucent; 5 broad, irregular white stripes on lateral side of body; white bar on head and cheek right behind eye; soft dorsal fin and caudal fin with bright white margin. Body dark brown in general, with 5 broad pale stripes, uppermost one along dorsal-fin base, and other 4 on lateral side of body; fins darker, except for membranes of spinous dorsal fin pale; posterior margins of soft dorsal fin and caudal fin pale.
Distribution. Known from Russia (Sea of Japan) (
The Taiwanese specimen is identified as Stereolepis doederleini based on the distinct coloration with 5 broad pale stripes on lateral sides of body among the family. It differs from the only other congener, S. gigas, co-occurring in the northwestern Pacific, by having the spinous dorsal fin distinctly higher than the soft dorsal fin (vs. the former distinctly lower than the later in S. gigas); the caudal fin truncate (vs. slightly concave or emarginated); 5 pale stripes on lateral sides of body (vs. black patches on lateral sides of body); lateral-line scales less than 73 (vs. about 80), scale rows below lateral 28‒31 (vs. 35‒40), and posterior end of maxilla reaching a vertical through posterior margin of eye (vs. reaching a vertical through anterior margin to middle of eye) (
It is notable that
The presently reported material of Stereolepis doederleini was caught by hook-and-line from deep water off Fugang fishing port, Taitung, eastern Taiwan. A portion of the local fisheries there are targeting high economical value demersal species such as Doederleinia berycoides (Hilgendorf, 1879) and Atrobucca nibe (Jordan et Thompson, 1911) and it is likely that S. doederleini was a bycatch with these species by deep water line fishery, where the habitat is assumed to be deep sandy or muddy sea floor (CNT, personal observation).
The discovery of Stereolepis doederleini in eastern Taiwan may represent a rare dispersal case of a cold-water species to southern and warmer regions. Similar cases were documented by
We thank Mr. Yu-Hong Chuo for providing a photo and a specimen for our study and Dr. Keita Koeda for providing useful information. This study was supported by the National Museum of Marine Biology and Aquarium, Taiwan, and the National Kaohsiung University of Science and Technology, Taiwan.