Journal of Fish Biology (2014) 84, 243–246 doi:10.1111/jfb.12273, available online at wileyonlinelibrary.com
Northernmost record of a whale shark Rhincodon typus from the Sea of Okhotsk T. Tomita*†, T. Kawai*, H. Matsubara‡, M. Kobayashi‡ and S. Katakura§ *Hokkaido University Museum, 3-1-1, Minato-cho, Hakodate 041-8611, Hokkaido, Japan, ‡Department of Aquatic Biology, Faculty of Bioindustry, Tokyo University of Agriculture, 193, Yasaka, Abashiri 099-2493, Hokkaido, Japan and §City of Mombetsu, 1, Kaiyokoen, Mombetsu 094-0031, Hokkaido, Japan (Received 12 May 2013, Accepted 10 October 2013) The whale shark Rhincodon typus is the world’s largest fish and it occurs in tropical, subtropical and warm temperate waters. Here, the northernmost record of R. typus is reported, when it was found in the Sea of Okhotsk for the first time. This occurrence can be explained by the unusually high sea surface temperature during the summer of 2012. © 2014 The Fisheries Society of the British Isles
Key words: Chondrichthyes; distribution; Hokkaido; Orectolobiformes; sea surface temperature.
The whale shark Rhincodon typus Smith 1828 (Elasmobranchii, Orectolobiformes, Rhincodontidae) is the world’s largest fish, reaching at least 12 m in total length (LT ; Colman, 1997; Compagno, 2001). On 2 October 2012, a R. typus was found dead at 44◦ 22 50 N; 143◦ 21 44 E in a set net for chum salmon Oncorhynchus keta (Walbaum 1792) and pink salmon Oncorhynchus gorbuscha (Walbaum 1792) off Mombetsu (Hokkaido, Japan) (Fig. 1). The specimen was an immature male of 4·58 m LT and 880 kg body mass (see additional measurements in Table I). It was easily distinguished from other large shark species because of its slightly flattened head, terminal mouth, long straight gill openings, prominent lateral ridges on its flanks and the prominent pattern of white spots between vertical and horizontal stripes, reminiscent of a checkerboard pattern (Compagno, 2001). Following assessment of its external measurements, the pectoral, pelvic and caudal fins were removed from the specimen and preserved for further investigation at the Hokkaido University Museum (Hakodate, Japan; HUMZ 215293). The rest of the body was disposed of. This specimen was the first confirmed occurrence of R. typus in the Sea of Okhotsk. Rhincodon typus mainly occurs between 30◦ N and 35◦ S in the western Pacific Ocean (Compagno, 2001). The species rarely occurs at latitudes north of †Author to whom correspondence should be addressed. Tel.: +81 138 40 5553; email: t-tomita@ museum.hokudai.ac.jp
243 © 2014 The Fisheries Society of the British Isles
244
T. T O M I TA E T A L .
50° Sea of Okhotsk Hokkaido Yano et al. (2002)
HUMZ 215293 (44° 22′ 50′′ N, 143° 21′ 44′′ E)
40° Sea of Japan
North Pacific
30°
Mombetsu 44° Hokkaido
130°
140°
143°
Fig. 1. Location map of male Rhincodon typus, 4.85 m total length (museum catalogue number HUMZ 215293). Grey area in the left figure represents the limits to distribution suggested by Compagno (2001).
40◦ N. The northernmost record of R. typus in the western Pacific region is that of Uchida (1995), who noted rare occurrences of the species off southern Hokkaido (Japan), but detailed information (e.g. identification methods, dates and locations of sightings) was not provided. The most reliable northernmost report in the western Pacific Ocean is based on a specimen collected in Mutsu Bay (41◦ 13 N; 140◦ 46 E), Aomori, Japan (Yano et al., 2002) (Fig. 1). High-latitude occurrences have also been reported from the north-eastern Pacific Ocean, off Patrick’s Point, California (41◦ 10 N; 124◦ 15 W) and the north-western Atlantic Ocean, off Nantucket Island, Massachusetts, U.S.A. (42◦ 02 N; 62◦ 50 W and Bay of Fundy, Canada (44◦ 15 19 N; 67◦ 44 07 W) (Gudger, 1952; Ebert et al., 2004; Turnbull & Randell, 2006). The current record is the northernmost record worldwide, and extends the northern record of the species by over 3◦ latitude in the western Pacific Ocean. This occurrence was also the first reliable record of this species that was found in cold temperate waters in the western Pacific Ocean. As R. typus is unlikely to be able to survive the severe winter conditions in the Sea of Okhotsk, it is possible that the specimen in this study travelled north following the warm Tsushima Current, and entered the Sea of Okhotsk through the La P´erouse (Soya) Strait during summer 2012. All high-latitude sightings of R. typus north of 40◦ N have been made during summer or early autumn (Gudger, 1952; Yano et al., 2002; Ebert et al., 2004; Turnbull & Randell, 2006). This suggests that high-latitude occurrences of this species depend on a relatively high water temperature. Based on data from fishing vessels for skipjack tuna Katsuwonus pelamis (L., 1758) in the north-west Pacific Ocean from 1955 to 1967, sightings of R. typus were made in areas having a sea surface temperature (SST) of 18–30◦ C (mostly 21–25◦ C) (Iwasaki, 1970). This temperature preference of R. typus is supported by recent satellite tracking data for south-east Asia and Western Australia (Eckert & Stewart, 2001; Wilson et al., 2006). The Okhotsk Tower (44◦ 20·2 N; 143◦ 22·9 E, 9·5 m water depth, 1 km off Mombetsu) is a marine observatory station in the Sea of
© 2014 The Fisheries Society of the British Isles, Journal of Fish Biology 2014, 84, 243–246
R H I N C O D O N T Y P U S I N T H E S E A O F O K H OT S K
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Table I. Morphometric measurements of (male Rhincodon typus, 485 m total length (museum catalogue number HUMZ 21529)) from the Sea of Okhotsk
Total length (LT ) Fork length Precaudal length Pre-second dorsal length Pre-first dorsal length Head length Prebranchial length Prespiracular length Preorbital length Prepectoral length Snout-vent length Interdorsal space Dorsal-caudal space Pectoral-caudal space Vent-caudal length Interorbital space Mouth width Clasper outer length Clasper inner length Clasper base width
cm
%LT
458·0 393·0 359·5 284·0 196·5 102·5 71·8 28·0 15·7 111·0 246·0 52·2 40·5 103·0 212·0 85·0 64·0 12·4 20·8 4·2
100·0 85·8 78·5 62·0 42·9 22·4 15·7 6·1 3·4 24·2 53·7 11·4 8·8 22·5 46·3 18·6 14·0 2·7 4·5 0·9
Okhotsk. In the water around the tower, the monthly mean SST during September 2012 (20·8◦ C) was 1·8◦ C higher than the mean September SST from 1997 to 2011. Globally, 2012 was the ninth hottest year on record since 1880 according to the SST data from National Aeronautics and Space Administration (NASA). This suggests that the high SST during summer 2012 may explain the unusual occurrence of R. typus found in the Sea of Okhotsk. We are grateful to W.J. Richards (National Marine Fisheries Service, Southeast Fisheries Science Center, NOAA) for his valuable comments and English corrections. We also thank the director of set net section Hiroaki Iida, the crew members of F.V. 58 Shotoku Maru (Mombetsu Fisheries Cooperative Association) and K. Yoshiyama (Hokkai Minyu Newspaper Inc.) for providing data and specimens. Mombetsu Fisheries Cooperative Association staff, the Tokyo University of Agriculture, and HUMZ at Hokkaido University undertook preservation of the specimen. A part of this project was supported by the Tokyo University of Agriculture Strategic Research Program (TUA-SRP).
References Colman, J. G. (1997). A review of the biology and ecology of the whale shark. Journal of Fish Biology 51, 1219–1234. Compagno, L. J. V. (2001). Sharks of the World: An Annotated and Illustrated Catalogue of Shark Species Known to Date, Vol. 2. Bullhead, Mackerel and Carpet Sharks (Heterodontiformes, Lamniformes and Orectolobiformes). Rome: FAO. Ebert, D. A., Mollet, H. F., Baldridge, A., Thomas, T., Forney, K. A. & Ripley, W. E. (2004). Occurrence of the whale shark, Rhincodon typus Smith 1928, in California waters. Northwestern Naturalist 85, 26–28.
© 2014 The Fisheries Society of the British Isles, Journal of Fish Biology 2014, 84, 243–246
246
T. T O M I TA E T A L .
Eckert, S. A. & Stewart, B. S. (2001). Telemetry and satellite tracking of whale sharks, Rhincodon typus, in the Sea of Cortez, Mexico, and the north Pacific Ocean. Environmental Biology of Fishes 60, 299–308. Gudger, E. W. (1952). Northernmost record of the whale shark. Science 116, 432–433. Iwasaki, Y. (1970). On the distribution and environment of the whale shark, Rhincodon typus, in skipjack fishing grounds in the western Pacific Ocean. Journal of the College of Marine Science and Technology, Tokai University 4, 37–51. Turnbull, S. D. & Randell, J. E. (2006). Rare occurrence of a Rhincodon typus (whale shark) in the Bay of Fundy, Canada. Northeastern Naturalist 13, 57–58. Uchida, S. (1995). Whale shark. In Basic Data for the Japanese Rare Wild Animals II (Japan Fisheries Resource Conservation Association, ed), pp. 146–153. Tokyo: Fisheries Agency of Japan (in Japanese). Wilson, S. G., Polovina, J. J., Stewart, B. S. & Meekan, M. G. (2006). Movements of whale sharks (Rhincodon typus) tagged at Ningaloo Reef, Western Australia. Marine Biology 148, 1157–1166. Yano, K., Sugimoto, T. & Nomura, Y. (2002). Capture records of manta ray, Manta birostris, and whale shark, Rhincodon typus, at Mutsu Bay, Aomori, Japan. Report of Japanese Society for Elasmobranch Studies 39, 8–13.
© 2014 The Fisheries Society of the British Isles, Journal of Fish Biology 2014, 84, 243–246
Northernmost record of a whale shark Rhincodon typus from the Sea of Okhotsk T. Tomita*†, T. Kawai*, H. Matsubara‡, M. Kobayashi‡ and S. Katakura§ *Hokkaido University Museum, 3-1-1, Minato-cho, Hakodate 041-8611, Hokkaido, Japan, ‡Department of Aquatic Biology, Faculty of Bioindustry, Tokyo University of Agriculture, 193, Yasaka, Abashiri 099-2493, Hokkaido, Japan and §City of Mombetsu, 1, Kaiyokoen, Mombetsu 094-0031, Hokkaido, Japan (Received 12 May 2013, Accepted 10 October 2013) The whale shark Rhincodon typus is the world’s largest fish and it occurs in tropical, subtropical and warm temperate waters. Here, the northernmost record of R. typus is reported, when it was found in the Sea of Okhotsk for the first time. This occurrence can be explained by the unusually high sea surface temperature during the summer of 2012. © 2014 The Fisheries Society of the British Isles
Key words: Chondrichthyes; distribution; Hokkaido; Orectolobiformes; sea surface temperature.
The whale shark Rhincodon typus Smith 1828 (Elasmobranchii, Orectolobiformes, Rhincodontidae) is the world’s largest fish, reaching at least 12 m in total length (LT ; Colman, 1997; Compagno, 2001). On 2 October 2012, a R. typus was found dead at 44◦ 22 50 N; 143◦ 21 44 E in a set net for chum salmon Oncorhynchus keta (Walbaum 1792) and pink salmon Oncorhynchus gorbuscha (Walbaum 1792) off Mombetsu (Hokkaido, Japan) (Fig. 1). The specimen was an immature male of 4·58 m LT and 880 kg body mass (see additional measurements in Table I). It was easily distinguished from other large shark species because of its slightly flattened head, terminal mouth, long straight gill openings, prominent lateral ridges on its flanks and the prominent pattern of white spots between vertical and horizontal stripes, reminiscent of a checkerboard pattern (Compagno, 2001). Following assessment of its external measurements, the pectoral, pelvic and caudal fins were removed from the specimen and preserved for further investigation at the Hokkaido University Museum (Hakodate, Japan; HUMZ 215293). The rest of the body was disposed of. This specimen was the first confirmed occurrence of R. typus in the Sea of Okhotsk. Rhincodon typus mainly occurs between 30◦ N and 35◦ S in the western Pacific Ocean (Compagno, 2001). The species rarely occurs at latitudes north of †Author to whom correspondence should be addressed. Tel.: +81 138 40 5553; email: t-tomita@ museum.hokudai.ac.jp
243 © 2014 The Fisheries Society of the British Isles
244
T. T O M I TA E T A L .
50° Sea of Okhotsk Hokkaido Yano et al. (2002)
HUMZ 215293 (44° 22′ 50′′ N, 143° 21′ 44′′ E)
40° Sea of Japan
North Pacific
30°
Mombetsu 44° Hokkaido
130°
140°
143°
Fig. 1. Location map of male Rhincodon typus, 4.85 m total length (museum catalogue number HUMZ 215293). Grey area in the left figure represents the limits to distribution suggested by Compagno (2001).
40◦ N. The northernmost record of R. typus in the western Pacific region is that of Uchida (1995), who noted rare occurrences of the species off southern Hokkaido (Japan), but detailed information (e.g. identification methods, dates and locations of sightings) was not provided. The most reliable northernmost report in the western Pacific Ocean is based on a specimen collected in Mutsu Bay (41◦ 13 N; 140◦ 46 E), Aomori, Japan (Yano et al., 2002) (Fig. 1). High-latitude occurrences have also been reported from the north-eastern Pacific Ocean, off Patrick’s Point, California (41◦ 10 N; 124◦ 15 W) and the north-western Atlantic Ocean, off Nantucket Island, Massachusetts, U.S.A. (42◦ 02 N; 62◦ 50 W and Bay of Fundy, Canada (44◦ 15 19 N; 67◦ 44 07 W) (Gudger, 1952; Ebert et al., 2004; Turnbull & Randell, 2006). The current record is the northernmost record worldwide, and extends the northern record of the species by over 3◦ latitude in the western Pacific Ocean. This occurrence was also the first reliable record of this species that was found in cold temperate waters in the western Pacific Ocean. As R. typus is unlikely to be able to survive the severe winter conditions in the Sea of Okhotsk, it is possible that the specimen in this study travelled north following the warm Tsushima Current, and entered the Sea of Okhotsk through the La P´erouse (Soya) Strait during summer 2012. All high-latitude sightings of R. typus north of 40◦ N have been made during summer or early autumn (Gudger, 1952; Yano et al., 2002; Ebert et al., 2004; Turnbull & Randell, 2006). This suggests that high-latitude occurrences of this species depend on a relatively high water temperature. Based on data from fishing vessels for skipjack tuna Katsuwonus pelamis (L., 1758) in the north-west Pacific Ocean from 1955 to 1967, sightings of R. typus were made in areas having a sea surface temperature (SST) of 18–30◦ C (mostly 21–25◦ C) (Iwasaki, 1970). This temperature preference of R. typus is supported by recent satellite tracking data for south-east Asia and Western Australia (Eckert & Stewart, 2001; Wilson et al., 2006). The Okhotsk Tower (44◦ 20·2 N; 143◦ 22·9 E, 9·5 m water depth, 1 km off Mombetsu) is a marine observatory station in the Sea of
© 2014 The Fisheries Society of the British Isles, Journal of Fish Biology 2014, 84, 243–246
R H I N C O D O N T Y P U S I N T H E S E A O F O K H OT S K
245
Table I. Morphometric measurements of (male Rhincodon typus, 485 m total length (museum catalogue number HUMZ 21529)) from the Sea of Okhotsk
Total length (LT ) Fork length Precaudal length Pre-second dorsal length Pre-first dorsal length Head length Prebranchial length Prespiracular length Preorbital length Prepectoral length Snout-vent length Interdorsal space Dorsal-caudal space Pectoral-caudal space Vent-caudal length Interorbital space Mouth width Clasper outer length Clasper inner length Clasper base width
cm
%LT
458·0 393·0 359·5 284·0 196·5 102·5 71·8 28·0 15·7 111·0 246·0 52·2 40·5 103·0 212·0 85·0 64·0 12·4 20·8 4·2
100·0 85·8 78·5 62·0 42·9 22·4 15·7 6·1 3·4 24·2 53·7 11·4 8·8 22·5 46·3 18·6 14·0 2·7 4·5 0·9
Okhotsk. In the water around the tower, the monthly mean SST during September 2012 (20·8◦ C) was 1·8◦ C higher than the mean September SST from 1997 to 2011. Globally, 2012 was the ninth hottest year on record since 1880 according to the SST data from National Aeronautics and Space Administration (NASA). This suggests that the high SST during summer 2012 may explain the unusual occurrence of R. typus found in the Sea of Okhotsk. We are grateful to W.J. Richards (National Marine Fisheries Service, Southeast Fisheries Science Center, NOAA) for his valuable comments and English corrections. We also thank the director of set net section Hiroaki Iida, the crew members of F.V. 58 Shotoku Maru (Mombetsu Fisheries Cooperative Association) and K. Yoshiyama (Hokkai Minyu Newspaper Inc.) for providing data and specimens. Mombetsu Fisheries Cooperative Association staff, the Tokyo University of Agriculture, and HUMZ at Hokkaido University undertook preservation of the specimen. A part of this project was supported by the Tokyo University of Agriculture Strategic Research Program (TUA-SRP).
References Colman, J. G. (1997). A review of the biology and ecology of the whale shark. Journal of Fish Biology 51, 1219–1234. Compagno, L. J. V. (2001). Sharks of the World: An Annotated and Illustrated Catalogue of Shark Species Known to Date, Vol. 2. Bullhead, Mackerel and Carpet Sharks (Heterodontiformes, Lamniformes and Orectolobiformes). Rome: FAO. Ebert, D. A., Mollet, H. F., Baldridge, A., Thomas, T., Forney, K. A. & Ripley, W. E. (2004). Occurrence of the whale shark, Rhincodon typus Smith 1928, in California waters. Northwestern Naturalist 85, 26–28.
© 2014 The Fisheries Society of the British Isles, Journal of Fish Biology 2014, 84, 243–246
246
T. T O M I TA E T A L .
Eckert, S. A. & Stewart, B. S. (2001). Telemetry and satellite tracking of whale sharks, Rhincodon typus, in the Sea of Cortez, Mexico, and the north Pacific Ocean. Environmental Biology of Fishes 60, 299–308. Gudger, E. W. (1952). Northernmost record of the whale shark. Science 116, 432–433. Iwasaki, Y. (1970). On the distribution and environment of the whale shark, Rhincodon typus, in skipjack fishing grounds in the western Pacific Ocean. Journal of the College of Marine Science and Technology, Tokai University 4, 37–51. Turnbull, S. D. & Randell, J. E. (2006). Rare occurrence of a Rhincodon typus (whale shark) in the Bay of Fundy, Canada. Northeastern Naturalist 13, 57–58. Uchida, S. (1995). Whale shark. In Basic Data for the Japanese Rare Wild Animals II (Japan Fisheries Resource Conservation Association, ed), pp. 146–153. Tokyo: Fisheries Agency of Japan (in Japanese). Wilson, S. G., Polovina, J. J., Stewart, B. S. & Meekan, M. G. (2006). Movements of whale sharks (Rhincodon typus) tagged at Ningaloo Reef, Western Australia. Marine Biology 148, 1157–1166. Yano, K., Sugimoto, T. & Nomura, Y. (2002). Capture records of manta ray, Manta birostris, and whale shark, Rhincodon typus, at Mutsu Bay, Aomori, Japan. Report of Japanese Society for Elasmobranch Studies 39, 8–13.
© 2014 The Fisheries Society of the British Isles, Journal of Fish Biology 2014, 84, 243–246
