Aquacult. Sci. 63（2），199－201（2015）

Short Paper

Collection record of spotted halibut. Verasper variegatus juveniles from In the Seto Inland Sea, cultured juveniles have been the central Seto Inland Sea, Japan released since 1996 in Osaka Bay (Tsujimura 2006) and since 2004 in Iyo-nada Sea (Kato et al. 2001) in order to enhance the decreased stock biomass. However, to 1 2 1 Masaki HATA , Noriko OTSUKI , Hiroki TANAKA , date, a significant increase in the natural population has Takeshi TOMIYAMA2 and Jun SHOJI1,＊ not been observed. There has been much less informa- tion on the early life history of spotted halibut in the

Abstract: Spotted halibut Verasper variegatus juveniles Seto Inland Sea while occurrence, distribution, feeding were first collected from tidal flats around river mouths habit and growth of the juveniles have been reported in Hiroshima Prefecture, the central Seto Inland Sea. in other areas in Japan (Nagasaki and Fukushima A juvenile of 24.0 mm total length (TL) was collected Prefectures: Noichi et al. 2006; Wada et al. 2011, 2012b). from the Kurose River, Kure City, on 18 March 2014 and In the present study, the first records of wild spotted another of 63.0 mm TL from the Kamo River, Takeha- halibut juveniles from the Seto Inland Sea are given. ra City, on 30 May 2014. Salinity at the sampling sites This information will help us conduct more efficient ranged 3.7-14.7. The juveniles fed mainly on crusta- enhancement of the decreased stock biomass through ceans such as amphipods and mysids. Tidal flats with increasing post-release growth and survival of cultured low salinity are suggested as one of the juvenile habitats juveniles and conservation of the natural populations. in the Seto Inland Sea. Fish sampling was conducted at an interval of about two weeks (every spring tide period) from February to Key words: Spotted halibut; Juvenile; Occurrence; Seto May 2014 at two sites (Fig. 1), around the river mouths Inland Sea of the southwestern Japan. Bottoms of these sampling sites are composed of muddy sand. Maximum tidal amplitude approximates 4 m during spring tides. Fish were collected with scoop nets (0.4×0.3 m mouth size, Spotted halibut Verasper variegatus is a spe- 3 mm mesh) within wading depth (<1.0 m) for 1-2 h cies of the family Pleuronectidae with a high commer- around low tide by three to six people. Temperature cial value distributed in coastal waters of the western and salinity of bottom water were measured with a North Pacific (Chen et al. 1992; Nakabo and Doiuchi multiple environmental measurement system (ACTD- 2013). Cultured spotted halibut juveniles have been CMP, JFE Advantech Co., Ltd.) and a data logger (U24- released in several prefectures in Japan to enhance the 002-C, Onset Computer Corporation). Spotted halibut decreased stock biomass (Tsuzaki 1995; Nakamura juveniles were photographed after the collection and et al. 1997; Nemoto et al. 1999; Japan Sea Farming were preserved in 99% ethanol. Standard (SL) and total Association 2002; Wada et al. 2010, 2012a). lengths (TL) of the juveniles were measured in the lab- Compared to other flatfish species, spotted halibut oratory. have been shown to inhabit shallow waters during the A spotted halibut juvenile (20.0 mm SL, 24.0 mm TL) juvenile stage (Minami and Tanaka 1992; Wada et al. was collected near the river mouth of Kurose River on 2007, 2012b). Microsatellite and mitochondrial DNA 18 March 2014 (Fig. 2). Water temperature was 12.9℃ analyses have shown that there is genetic differentia- and salinity was 3.7 at the collection site (Table 1). tion among several local populations in Japan (Ortega- Another spotted halibut juvenile (53.6 mm SL, 63.0 mm Villaizán et al. 2006; Sekino et al. 2011). Clarification of TL) was collected near the river mouth of the Kamo the life history and planning stock management inde- River on 30 May 2014 (Fig. 2). Water temperature was pendently for each population are indispensable for effi- 21.6℃ and salinity was 14.7 at collection (Table 1). cient enhancement of decreased stock biomass of the Black spots are distributed on the dorsal and anal fins

Received 22 December 2014; Accepted 4 March 2015. 1 Takehara Marine Science Station, Graduate School of Biosphere Science, Hiroshima University, 5-8-1 Minato-machi, Takehara, Hiroshima 725-0024, Japan. 2 Laboratory of Biology of Aquatic Resources, Graduate School of Biosphere Science, Hiroshima University, 1-4-4 Kagamiyama, Hiroshima 739-8528, Japan. ＊ Corresponding author: Tel, (+81) 82-424-7122; Fax, (+81) 82-424-7122; E-mail, [email protected] (J. Shoji). 200 M. Hata, N. Otsuki, H. Tanaka, T. Tomiyama and J. Shoji

Table 1. Information on the sampling date, location, environmen- Japan 35º00’ tal conditions, and standard and total lengths of spotted halibut Verasper variegatus juveniles collected near the river mouths of Sea the Kurose River and the Kamo River in 2014 Date of collection Mar 18 2014 May 30 2014 Pacific Hiroshima Location Kurose Riv. Kamo Riv. Ocean Prefecture 36’ Latitude (N) 34°13´49˝ 34°19´33˝ Longitude (E) 132°36´15˝ 132°53´51˝ Depth (m) 0.3 0.5 Water temperature (℃) 12.9 21.6 20 km 34º12’N Salinity 3.7 14.7 Standard length (mm) 20.0 53.6 132º 00’ E 30’ 133º00’ Total length (mm) 24.0 63.0 Takehara Kure Kurose River X Kamo larger juvenile were mysids (Neomysis intermedia: River n = 11) and decapods (Pagurus sp.: n = 1). 1 km Collections of larger numbers of spotted halibut juve- X 1 km niles have been reported at only enclosed sandy beaches (Noichi et al. 2006) and tidal flats (Wada et al. 2006, Fig. 1. Map showing the locations (crosses) near the river mouths of the Kurose River and the Kamo River where spotted 2011, 2012b). Contrastingly, stone flounder Kareius halibut Verasper variegatus juveniles were collected. bicoloratus and marbled flounder Pseudopleuronectes yokohamae juveniles which cohabit with spotted hali- but juveniles in shallow waters on the northern Pacific coast have been reported to inhabit sandy beaches exposed to the ocean (Wada et al. 2011). In the pres- ent study, spotted halibut juveniles were collected on tidal flats near river mouths. These results and the lack of any records from other areas in the Seto Inland Sea (sandy beaches, tidal flats and seagrass beds: Tsujino et al. 1995; Shoji and Tanaka 2002; Iwamoto et al. 2009) strongly suggest that the major habitats of spotted hali- but juveniles are very restricted within shallow waters. Salinities of the sampling site where spotted halibut juveniles were collected in the present study (3.7-14.7) were lower than those in the previous studies (16.6- 33.7: Noichi et al. 2006; Wada et al. 2006, 2011, 2012b). A previous laboratory experiment showed a high toler- ance to low salinity conditions in spotted halibut at late metamorphosed juvenile (I) stage (Aritaki et al. 2001): survival rate > 80% for 7 days at salinity > 2 (Wada et al. 2007). Although the number of fish samples was small

Fig. 2. Color photographs of live spotted halibut Verasper varieg- in the present study, stomach contents analysis showed atus juveniles collected near the river mouths of the Kurose River spotted halibut juveniles fed mainly on crustaceans as (top, 24.0 mm TL) and the Kamo River (bottom, 63.0 mm TL). reported in other areas (Noichi et al. 2006; Wada et al. Scale bars=10 mm. 2010, 2011). We suggest that tidal flats around river mouths with low salinity, in addition to enclosed sandy beaches and tidal flats (Noichi et al. 2006; Wada et al. and a white band around the pectral fin on the right 2011, 2012b), form one of the important habitats for side of the juveniles. Stomach contents of the smaller spotted halibut juveniles, and conservation of such hab- juvenile were composed of amphipods (Corophium itats is important for enhancement of wild spotted hali- spp.: n = 6; Grandidierella spp.: n = 4) and those of the but populations in the Seto Inland Sea. Spotted halibut juveniles from the Seto Inland Sea 201

Acknowledgments Asahida and N. Taniguchi (2006) Genetic population eval- uation of two closely related flatfish species, the rare barfin We thank Yuya Shigematsu, Yuhei Ogino, Takuya flounder and spotted halibut, along the Japanese coast. Fish. Kuwahara, Tatsuya Utsunomiya, Kyohei Shioyama Sci., 72, 556-567. and Sadaharu Iwasaki, Graduate School of Biosphere Sekino, M., K. Saitoh, D. Shimizu, T. Wada, K. Kamiyama, S. Gambe, S. Chen and M. Aritaki (2011) Genetic structure in Science, Hiroshima University, for their assistance in species with shallow evolutionary lineages: a case study of the field sampling. the rare flatfish Verasper variegatus. Conserv. Genet., 12, 139- 159. Shoji, J. and M. Tanaka (2002) Larval and juvenile fishes collected References in the surf zones of Hiuchi-nada, the central Seto Inland Sea, Aritaki, M., K. Ohta, Y. Hotta and M. Tanaka (2001) Morphological Japan. Aquacult. Sci., 50, 123-128 (in Japanese with English development and growth of laboratory-reared spotted halibut abstract). Verasper variegatus. Nippon Suisan Gakkaishi, 67, 58-66 (in Tsujimura, H. (2006) Mitochondrial DNA variability of the spot- Japanese with English abstract). ted halibut Verasper variegatus released in Osaka Bay. Bull. Chen, D., C. Liu and S. Dou (1992) The biology of flatfish Osaka Pref. Fish. Exp. Stn., 16, 7-10 (in Japanese). () in the coastal waters of China. Neth. J. Sea Tsujino, K., T. Abe and T. Kusakabe (1995) Larval and juvenile Res., 29, 25-33. fishes occurring on surf zones of southern coast in Osaka Iwamoto, Y., K. Mishiro, T. Morita, Y. Kamimura, K. Mizuno, T. Bay. Bull. Osaka Pref. Fish. Exp. Stn., 9, 11-32 (in Japanese). Umino and J. Shoji (2009) Larval and juvenile fishes col- Tsuzaki, T. (1995) Present status and problems of seedling produc- lected at sandy beaches of upper Hiroshima Bay, Seto Inland tion of spotted halibut, Verasper variegatus. Suisanzoshoku, 43, Sea. Aquacult. Sci., 57, 639-643 (in Japanese with English 273-276 (in Japanese with English abstract). abstract). Wada, T., N. Mitsunaga, H. Suzuki, Y. Yamashita and M. Tanaka Japan Sea Farming Association (2002) Spotted Halibut Sea (2006) Growth and habitat of spotted halibut Verasper var- Farming Technology Development and Promotion Report. iegatus in the shallow coastal nursery area, Shimabara Japan Sea Farming Association Report 81, Japan Sea Farming Peninsula in Ariake Bay, Japan. Fish. Sci., 72, 603-611. Association, Tokyo, 86 pp (in Japanese). Wada, T., M. Aritaki, Y. Yamashita and M. Tanaka (2007) Kato, T., S. Hirata and Y. Kohno (2001) Migration and dispersion Comparison of low-salinity adaptability and morphological of released seeds of spotted halibut Verasper variegatus in development during the early life history of five pleuronectid Iyo-nada, Seto Inland Sea. Bull. Ehime Pref. Fish. Exp. Stn., 9, , and implications for migration and recruitment to 33-38 (in Japanese). their nurseries. J. Sea Res., 58, 241-254. Minami, T. and M. Tanaka (1992) Life history cycles in flatfish Wada, T., T. Yamada, D. Shimizu, M. Aritaki, H. Sudo, Y. from the Northwestern Pacific, with particular reference to Yamashita and M. Tanaka (2010) Successful stocking of their early life histories. Neth. J. Sea Res., 29, 35-48. a depleted species, spotted halibut Verasper variegatus, in Nakabo, T. and R. Doiuchi (2013) Family . In Miyako Bay, Japan: evaluation from post-release surveys and “Fishes of Japan with Pictorial Keys to the Species, Third landings. Mar. Ecol. Prog. Ser., 407, 243-255. Edition” (ed. by T. Nakabo), Tokai University Press, Hadano, Wada, T., K. Kamiyama, S. Shimamura, I. Matsumoto, T. Mizuno pp. 1675-1683 (in Japanese). and Y. Nemoto (2011) Habitat utilization, feeding, and growth Nakamura, R., A. Yamada and M. Terui (1997) Seeding of artificial of wild spotted halibut Verasper variegatus in a shallow brack- juveniles of spotted halibut [Verasper variegatus (Temminck ish lagoon: Matsukawa-ura, northeastern Japan. Fish. Sci., et Schlegel)] in Tokyo Bay. Bull. Kanagawa Pref. Fish. Res. 77, 785-793. Inst., 2, 55-63 (in Japanese). Wada, T., K. Kamiyama, S. Shimamura, T. Mizuno and Y. Nemoto Nemoto, Y., T. Fujita and M. Watanabe (1999) Studies on spotted (2012a) Effectiveness of stock enhancement of a rare species, halibut (Verasper variegatus Temminck and Schlegel): I. Bull. spotted halibut Verasper variegatus, in Fukushima, Japan. Fukushima Pref. Fish. Exp. Stat., 8, 5-16 (in Japanese). Aquaculture, 364-365, 230-239. Noichi, T., Subiyanto and I. Hirata (2006) Occurrence and feed- Wada, T., N. Mitsunaga, K. W. Suzuki, Y. Yamashita and M. ing habit of the settled larval and juvenile spotted halibut Tanaka (2012b) Occurrence and distribution of spotted hal- Verasper variegatus at sandy beaches on the western coast ibut Verasper variegatus and Japanese flounder Paralichthys of Kyushu, Japan. Nippon Suisan Gakkaishi, 72, 366-373 (in olivaceus in shallow nursery grounds around Shimabara Japanese with English abstract). Peninsula, western Japan. Fish. Sci., 78, 819-831. Ortega-Villaizán, R. M., M. Aritaki, S. Suzuki, M. Ikeda, T.