a a b c d e a) b) c) d) e) Lynghammar University of Tromsø, Norway, A., Christiansen University of Washington,, J. USAS., Gallucci Murmansk Marine, V. BiologicalF., Karamushko Institute, Russia California, O. V., AcademyMecklenburg of Sciences, USA, C. Natural W. History& Møller Museum ,of P. Denmark R. Contact: [email protected]

introduction

The sea ice cover decreases and human activity increases in Arctic waters. Fisheries (by-catch issues), shipping and petroleum exploita- tion (pollution issues) make it imperative to establish biological base- OCCURRENCE OF lines for the marine fishes inhabiting the Arctic Ocean and adjacent seas (AOAS).

As a first step towards credible conservation actions for the Arctic marine fish faunae, we examine the species-richness of chondrich- thyan fishes (class Chondrichthyes) pertaining to 16 regions within the AOAS: chimaeras, sharks and skates. CHONDRICHTHYAN materials and methods

• Voucher specimens from Natural History Collections IN THE ARCTIC OCEAN • Annotated checklists (see selected references) • The CAFF Database on Arctic marine fishes (Christiansen et al., in AND ADJACENT SEAS progress) FISHES Only presence and absence data are considered, as reliable abundance data lack for most species. Occurrences known only from floating or beach-cast carcasses, such as Pacific sleeper shark (no. 17) and Alaska skate (no. 29) in the Chukchi Sea, are not considered conclusive evidence of presence and are not included.

CHIMAERIFORMES HEXANCHIFORMES RAJIFORMES Chimaeridae - ratfishes Chlamydoselachidae - frill sharks Rajidae - skates 31 Bathyraja spinicauda 1 10 Chimaera monstrosa Chlamydoselachus anguineus 19 Amblyraja badia 32 Bathyraja taranetzi (Jensen 1914) - Spinetail ray LAMNIFORMES Hexanchidae - cow sharks Linnaeus 1758 - Rabbit fish Garman 1884 - Frilled shark 20 Amblyraja hyperborea (Garman 1899) - Broad skate 33 Bathyraja trachura (Dolganov 1983) - Mud skate 11 Hexanchus griseus Alopiidae - thresher sharks 21 Amblyraja radiata (Collett 1879) - Arctic skate 34 Bathyraja violacea (Gilbert 1892) - Roughtail skate 2 Alopias vulpinus SQUALIFORMES (Bonnaterre 1788) - Bluntnose sixgill shark 22 Bathyraja abyssicola (Donovan 1808) - Starry ray 35 Dipturus batis (Suvorov 1935) - Okhotsk skate Cetorhinidae - basking (Bonnaterre sharks 1788) - Thresher shark Squalidae - dogfish sharks 3 Cetorhinus maximus 12 Squalus acanthias 23 Bathyraja aleutica (Gilbert 1896) - Deepsea skate 36 Dipturus linteuscomplex (Linnaeus 1758) - Blue skate

Lamnidae - mackerel (Gunnerus sharks 1765) - Basking shark 13 Squalus suckleyi Linnaeus 1758 - Spiny dogfish 24 Bathyraja interrupta (Gilbert 1896) - Aleutian skate 37 Dipturus nidarosiensis (Fries 1838) - Sailray 4 Lamna ditropis Centrophoridae(Girard - gulper 1855) sharks - Spotted spiny dogfish 25 Bathyraja lindbergi (Gill & Townsend 1897) - Sandpaper skate 38 Dipturus oxyrinchus (Storm 1881) - Norwegian skate 5 Lamna nasus Hubbs & Follett 1947 - Salmon shark 14 Deania calceus Ishiyama & Ishihara 1977 39 Leucoraja circularis (Linnaeus 1758) - Longnosed skate CARCHARHINIFORMES Somniosidae - sleeper sharks 26 -Bathyraja Commander maculata skate (Bonnaterre 1788) - Porbeagle (Lowe 1839) - Birdbeak dogfish 40 Leucoraja fullonica 15 Centroscymnus coelolepis (Couch 1838) - Sandy ray Scyliorhinidae - cat sharks Ishiyama & Ishihara 1977 41 Raja binoculata (Linnaeus 1758) - Shagreen ray 6 Galeus melastomus Barbosa du Bocage & de Brito 27 -Bathyraja Whiteblotched mariposa skate 16 CapelloSomniosus 1864 microcephalus - Portuguese dogfish 42 Raja clavata Girard 1855 - Big skate 7 Scyliorhinus canicula Rafinesque 1810 - Blackmouth catshark Stevenson, Orr, Hoff & McEachran 2004 28 -Bathyraja Butterfly minispinosaskate 43 Raja rhina Triakidae - hound sharks (Bloch & Schneider 1801) Linnaeus 1758 - Thornback ray (Linnaeus 1758) - Small-spotted catshark 17 -Somniosus Greenland pacificus shark 8 Galeorhinus galeus Ishiyama & Ishihara 1977 44 Rajella bathyphila Jordan & Gilbert 1880 - Longnose skate Bigelow & Schroeder 1944 29 -Bathyraja Smallthorn parmifera skate Carcharhinidae - requiem sharks 45 Rajella fyllae (Linnaeus 1758) - Tope shark -Dalatiidae Pacific sleeper - kitefin shark sharks (Holt & Byrne 1908) - Abyssal ray 9 Prionace glauca 30 Bathyraja panthera 18 Etmopterus spinax (Bean 1881) - Alaska skate (Lütken 1887) - Round ray Orr, Stevenson, Hoff, Spies & McEachran (Linnaeus 1758) - Blue shark (Linnaeus 1758) - Velvet belly - Leopard skate

AN E Fig. 1. Occurrence of chondrichthyan C BER species in the 16 AOAS regions. Note O BERING SEA the dominance of skates (green dots) compared to sharks (red dots) in the C Bering Sea. The Arctic skate (no. 20) I 4 13 17 19 22 23 24 25 26 IF is present in most regions and it is dissimilarity scale 27 28 29 30 32 33 34 41 43 the only species in the Arctic zoogeo- C graphic category (Fig. 3). A P BERING STRAIT sib cge lap grs acb baf bea can ber chu bar kar nor whi hud cgw

Fig. 2. Cluster analysis (UPGMA) of the 16 AOAS regions. Three distinct clusters appear: the Bering Sea with a high endemicity, the species-rich Norwegian and Barents Seas, and the remaining species-poor high Arctic regions. All regions except for the Bering Arc and Chukchi Seas are inhabited by Atlantic species. tic C ircle CHU 1 4 5 6 CHUKCHI SEA 7 13 15 17 19 21 13 SIB 22 23 24 25 26 27 EAST SIBERIAN SEA 28 29 30 31 32 33 2 3 8 20 34 35 36 37 38 39 9 10 11 40 41 42 43 44 45 12 14 18 20 16 BEA BEAUFORT SEA Boreal widely distributed arctic arctic-boreal 20 Fig. 3. Zoogeographic categories. ‘Boreal’ and ‘Widely Distributed’ species spawn at positive temperatures. ‘Boreal’ species comprise mostly skates but only sharks are ‘Widely Distributed’. ‘Arctic-Boreal’ species spawn at sub-zero or positive temperatures CAN and ‘Arctic’ species solely at sub-zero temperatures. CANADIAN ARCTIC ARCHIPELAGO LAP LAPTEV SEA 20 20 4 ACB 6 7 14 ARCTIC CENTRAL BASIN 18 19 20 20 21 23 24 25 1 9 10

26 28 29 11 15 16 2

32 33 36 31 37 38 3 5 8 17 22 16 43 44 45 40 41 42 12 21 39 35 27 34 13 30 KAR HUD 20 least near vulnerable critically data not KARA SEA concern threatened endangered deficient evaluated HUDSON BAY & LABRADOR COAST Fig. 4. Number of AOAS chondrichthyan species in IUCN Red List categories. The ‘Least 16 20 21 31 36 45 Concern’ category is assigned to species thought to have a depth refuge. However, quantitative data lack for most of these species. BAF BAFFIN BAY

15 16 20 21 44 45 BAR BARENTS SEA main conclusions GRS 1 3 5 6 8 9 10 12 16 18 20 21 31 35 36 38 40 42 45 GREENLAND SEA

5 16 20 21 45

• A total of 45 chondrichthyan species occur within the AOAS: 1 chimaera, 17 shark and 27 skate species. CGW • The Norwegian, Barents and the Bering Seas are particularly WEST GREENLAND species-rich and skates comprise roughly 50–80% of the COAST WHI chondrichthyan species. NOR 3 5 12 16 21 WHITE SEA NORWEGIAN SEA • The high Arctic regions are depauperate with merely 1 or 2 3 12 16 21 species each. CGE 1 2 3 5 6 7 8 9 11 12 14 16 18 EAST GREENLAND 20 21 31 35 36 37 38 39 40 42 45 • The Chukchi Sea is practically devoid of chondrichthyans except for COAST a single specimen of spotted spiny dogfish (no. 13). The shallow 3 12 16 21 and narrow Bering Strait appears to form an effective barrier against the exchange of chondrichthyans between the Bering and A Chukchi Seas. T LA (http://maps.grida.no/go/graphic/arctic-map-political). UNEP/GRID-Arendal Ahlenius, Hugo The map is modified from SELECTED REFERENCES Canadian Manuscript Report of Fisheries and Aquatic Sciences Fishes of Alaska Aschehougs store fiskebok Voprosy Ikhtiologii 34 2674 Marine Biodiversity 41 Journal of Ichthyology 35 Coad, B. W. & Reist, J. D. (2004). Annotated list of the arctic marine fishes of Canada. Journal of Ichthyology 48 N Mecklenburg, C. W., Mecklenburg, T. A. & Thorsteinson, L. K. (2002). . American Fisheries Society. Zootaxa 2378 Pethon, P. (2005). Marine Biodiversity. Oslo: H.41: Aschehoug & Co. [in Norwegian] Andriashev, A. P. & Chernova, N. V. (1994). Annotated list of fishlike vertebrates and fish of the ArcticPolar seas Research and adjacent26 waters. (4): 435 :iv:+112 p. Nature of the Maritime Arctic: Modern Mecklenburg, C. W., Møller, P. R. & Steinke, D. (2011). Biodiversity of arctic marine fishes: taxonomy and zoogeography. (1): 109-140. Wienerroither, R. M., Nedreaas, K. H., Uiblein, F., Christiansen, J. S., Byrkjedal, I. & Karamushko, O. V. (2011). The marine fishes of Jan Mayen Island, - 456 [In Russian; English translation 1995, : 81 - 123]. ChallengesKaramushko, and O. the V. (2008). Role of ScienceSpecies composition and structure of the ichthyofauna of the Barents Sea. (4): 277-291. Møller, P. R., Nielsen, J. G., Knudsen, S. W., Poulsen, J. Y., Sünksen, K. & Jørgensen, O. A. (2010). A checklist of the fish fauna of Greenland waters. : NE Atlantic – past and present. 395-411. Byrkjedal, I. & Høines, Å. (2007). Distribution of demersal fish in the south-western Barents Sea. (2): 135-151. Karamushko, O. V. (2010). Biological diversity and the structure of fish communities in the Russian arctic seas. In: T 1 - 84. (Matishov, G. G., ed.). Murmansk Marine Biological Institute KSC RAS. IC O C EA N