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Corresponding author: Yusuke Miyazaki ( miyazaki@shiraume.ac.jp ) Academic editor: Nina Bogutskaya
© 2019 Yusuke Miyazaki, Akinori Teramura, Hiroshi Senou.
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:
Miyazaki Y, Teramura A, Senou H (2019) Preliminary report on bycatch fish species collected from the Tokyo Submarine Canyon, Japan. ZooKeys 843: 129-147. https://doi.org/10.3897/zookeys.843.32410
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An ichthyofaunal list of bycatch species was compiled, the fish captured by bottom gill-nets set at approximately 300 m depth in the Uraga Suido Channel central Japan. Fragmentary ichthyofaunal lists are available for this area; these lists have focused on chondrichthyans or commercial actinopterygians, but voucher specimens have not been prepared for museum storage. An initial list of the fish fauna was compiled with vouchers, and seven species not previously recorded from the channel are reported. Most of these species belong to the Class Actinopterygii; Apristurus platyrhynchus (Tanaka, 1909), Beryx decadactylus Cuvier, 1829, Hoplostethus japonicus Hilgendorf, 1879, Sebastes iracundus (Jordan & Starks, 1904), Scalicus amiscus (Jordan & Starks, 1904), Atrobucca nibe (Jordan & Thompson, 1911), and an unidentified species of the eelpout family Zoarcidae. The taxonomic identity of the eelpout and the biogeography of the Uraga Suido Channel are considered. Further research is required to resolve outstanding faunistic issues, but live collections will likely end when the aging fishers who provide the specimens retire. At that point, existing museum collections will become increasingly important for future research. Examination of a collection that may have been previously deposited in the Chiba Prefectural Museum will be essential.
deep sea, distributional boundary, Sagami Sea, western Pacific
The deep ocean is a frontier for ichthyological exploration. The fish fauna of the deep sea is much less well known than that of shallow coastal zones. Efforts to conserve deep-water fish faunas are essential in the face of threats from anthropogenic disturbance, such as seabed mining (
The Tokyo Submarine Canyon has an unusual hydrography. The shoreward end is located at the mouth of Tokyo Bay (in the narrow sense, defined below). About 31 million people live around the shores of the bay’s basin (
Knowledge of the fish fauna in the submarine canyon is fragmentary.
Data for the ichthyological surveys in the deep waters of the channel have been obtained by examining the bycatch in commercial bottom gill nets. These nets are used to catch the Japanese spider crab, Macrocheira kaempferi Temminck, 1836, and the Japanese lobster, Metanephrops japonicus (Tapparone-Canefri, 1873). The nets have been deployed by a single fishing boat, the Chougorou-maru, since the 1980s. The first author of this report was able to sail on this boat with a TV crew, and was provided with bycatch specimens as the nets were hauled onboard. The specimens captured included some of the first records from the Uraga Suido Channel. Here, we provide a checklist of the fishes of the Tokyo Submarine Canyon with voucher specimens and photographs. We discuss ichthyofaunal issues in the region.
Biogeographical studies of the Uraga Suido Channel have been confused by conflicting definitions of the regions through which it passes, i.e., Tokyo Bay and the Sagami Sea. Some publications have included the channel within Tokyo Bay, while others consider it a component of the Sagami Sea. The broad definition of Tokyo Bay encompasses the Uraga Suido Channel, which includes almost the entire length of the Tokyo Submarine Canyon (Kanou et al. 2010).
Map showing the study site in the eastern Uraga Suido Channel (extending from Cape Tsurugisaki [south-east of the Miura Peninsula] to Cape Sunosaki [south-west of the Boso Peninsula] and from Cape Kan-nonzaki [east of the Miura Peninsula] to Cape Futtsu [west of the Boso Peninsula]). The channel is included within the broad definition of Tokyo Bay (northward from the Uraga-suido Channel) and Sagami Bay (from Cape Irozaki on the southern Izu Peninsula to Cape Nojimazaki, on the southern Boso Peninsula, including Izu-oshima Island). The channel is not included in the narrow definition of Tokyo Bay.
The fishing depth was 100–500 m (averaging 200–300 m) below the water surface within the east Tokyo Submarine Canyon, Chiba Prefecture, Japan (Fig.
Collected specimens were immediately transferred to a mixture of ambient seawater and ice held in insulated boxes. The fishes were later fixed in 10% formalin, and subsequently preserved in 70% ethanol, except for larger specimens more than approximately 1.0 m total length (TL). Color images were captured after about 1–3 hours fixation. The specimens were deposited in the Kanagawa Prefectural Museum of Natural History, Odawara, Japan (
We were not provided with specimens of fishes with commercial value; these we photographed with an Olympus camera on board the vessel or on the dock. In addition to still shots, we also cut frames from video sequences. These images were also registered to the Image Database of Fishes, and some are available online as “FishPix” (see also
The systematic arrangement of families, scientific names, and standard Japanese names generally follow
Based on examinations of our voucher specimens (56 individuals) and the photographic images, we identified 36 species in 25 families and 13 orders (Table
An ichthyofaunal list with their vouchers collected by our surveys from the seep-sea area (ranges 100–500 m, average 300 m) of the Uraga Suido Channel, the Sea of Sagami, central Japan. The species with an asterisk indicate the first records with voucher(s) from this area.
Order/Family/Species | Standard Japanese name | Voucher number |
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Myxiniformes | ||
Myxinidae | ||
Eptatretus atami (Dean, 1904) | Kuro-nuta-unagi | MTUF-P 30681 |
Chimaeriformes | ||
Chimaeridae | ||
Chimaera phantasma Jordan & Snyder, 1900 | Ginzame | KPN-NI 47883 |
Hydrolagus mitsukurii (Jordan & Snyder, 1904) | Aka-ginzame |
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Lamniformes | ||
Mitsukurinidae | ||
Mitsukurina owstoni Jordan, 1898 | Mitsukurizame |
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Carcharhiniformes | ||
Scyliorhinidae | ||
Cephaloscyllium umbratile Jordan & Fowler, 1903 | Nanukazame | MTUF-P 30716 |
Pentanchidae | ||
Apristurus platyrhynchus (Tanaka, 1909)* | Herazame |
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Chlamydoselachiformes | ||
Chlamydoselachidae | ||
Chlamydoselachus anguineus Garman, 1884 | Rabuka |
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Hexanchiformes | ||
Hexanchidae | ||
Heptranchias perlo (Bonnaterre, 1788) | Edo-aburazame | KPN-NI 47884; MTUF-P 30672 |
Squaliformes | ||
Dalatiidae | ||
Dalatias licha (Bonnaterre, 1788) | Yoroizame |
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Centrophoridae | ||
Deania calcea (Lowe, 1839) | Hera-tunozame |
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Deania hystricosa (Garman, 1906) | Sagamizame |
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Centrophorus atromarginatus Garman, 1913 | Aizame | MTUF-P 30717 |
Squalidae | ||
Cirrhigaleus barbifer Tanaka, 1912 | Hige-tsunozame |
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Squalus mitsukurii Jordan & Snyder, 1903 | Futo-tsunozame |
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Polymixiiformes | ||
Polymixiidae | ||
Polymixia japonica Günther, 1877 | Ginmedai | KPN-NI 47867–47869 |
Gadiformes | ||
Macrouridae | ||
Coryphaenoides marginatus Steindachner & Döderlein, 1887 | Heri-dara |
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Coelorinchus kishinouyei Jordan & Snyder, 1900 | Mugura-hige | KPN-NI 47876 |
Coelorinchus japonicus (Temminck & Schlegel, 1846) | Tōjin | MTUF-P 30678 |
Coelorinchus tokiensis (Steindachner & Döderlein, 1887) | Miyako-hige | MTUF-P 30680 |
Lophiiformes | ||
Lophiidae | ||
Lophiomus setigerus (Vahl, 1797) | Ankō |
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Beryciformes | ||
Berycidae | ||
Beryx decadactylus Cuvier, 1829* | Nan’yō-kinme | KPN-NI 47870 |
Trachichthyidae | ||
Gephyroberyx japonicus (Döderlein, 1883) | Hashikinme | KPN-NI 47871 |
Hoplostethus japonicus Hilgendorf, 1879* | Hiuchidai | KPN-NI 47872, 47873; MTUF-P 30682 |
Perciformes | ||
Sebastidae | ||
Helicolenus hilgendorfii (Döderlein, 1884) | Yume-kasago |
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Sebastes iracundus (Jordan & Starks, 1904)* | Ōsaga |
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Scorpaenidae | ||
Scorpaena neglecta Temminck & Schlegel, 1843 | Izu-kasago | KPN-NI 47877 |
Triglidae | ||
Lepidotrigla guentheri Hilgendorf, 1879 | Kanado | KPN-NI 47885 |
Peristediidae | ||
Scalicus amiscus (Jordan & Starks, 1904)* | Hige-kihōbō | KPN-NI 47887 |
Acropomatidae | ||
Doederleinia berycoides (Hilgendorf, 1879) | Akamutsu |
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Malakichthys griseus Döderlein, 1883 | Ōme-hata | KPN-NI 47879 |
Sciaenidae | ||
Atrobucca nibe (Jordan & Thompson, 1911)* | Kuroguchi |
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Pentacerotidae | ||
Pentaceros japonicus Steindachner, 1883 | Tsubodai | MTUF-P 30676 |
Zoarcidae | ||
Zoarcidae sp.* | Natsushimachojyagenge | KPN-NI 47888 |
Gempylidae | ||
Ruvettus pretiosus Cocco, 1833 | Baramutsu | MTUF-P 30674 |
Pleuronectiformes | ||
Pleuronectidae | ||
Tanakius kitaharae (Jordan & Starks, 1904) | Yanagi-mushigarei | KPN-NI 47878; MTUF-P 30675 |
Eopsetta grigorjewi (Herzenstein, 1890) | Mushi-garei |
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Photos of the voucher specimens of the agnathan and chondrichthyans species collected from the Uraga Suido Channel, the Sagami Sea, Japan. A MTUF-P 30681: Eptatretus atami, 503 mm TL B KPN-NI 47883: Chimaera phantasma, 481 mm TL (tail broken) C
Photos of the voucher specimens of the actinopterygian species (Polymixiiformes, Gadiformes, and Beryciformes) collected from the Uraga Suido Channel, the Sagami Sea, Japan. A KPN-NI 47868, Polymixia japonica, 171 mm SL B
Photos of the voucher specimens of the actinopterygian species (Perciformes, and Pleuronectiformes) collected from the Uraga Suido Channel, the Sagami Sea, Japan. A KPN-NI 47875, Helicolenus hilgendorfii, 146 mm SL B
Voucher images deposited to the Image Database of Fishes at the Kanagawa Prefectural Museum of Natural History without specimens collected from the Uraga Suido Channel, the Sagami Sea, Japan. A–D
We found seven species (Table
The fishers who provided our specimens are aging, and no successors are likely to take over their operations. Collections will likely cease when the fishing closes down and hence, museum holdings will become increasingly important for faunistic studies.
The specimen that we identified as Sebastes iracundus (Fig.
The unidentified eelpout (Fig.
We deeply appreciate H Tejima, A Tejima, and S Takei for kind cooperation to ride on their fishing boat together and to give us the bycatches for making specimens. We also thank J Matsuzawa, T Nagano, N Kawada, T Kanazawa, R Namiki, K Minomo, K Izumori, T. Moriyama, and other staff belonging to the TV Tokyo, and the Kyodo Television for their help our research and provisions of their movies to register to the image database, H Kohno and A Ishikawa for helping us to process specimens, and T Kudo for comments on ichthyofaunal issues of the Tokyo Bay including the Uraga Suido Channel.