Arctic Fishes in the Barents Sea 2004-2015: Changes in Abundance and Distribution
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IMR/PINRO J O S I 1 E N I T 2017 R E R E S P O R T Arctic fishes in the Barents Sea 2004-2015: Changes in abundance and distribution By E.Johannesen, H. L. Mørk, K. Korsbrekke, R. Wienerroither, E. Eriksen, M. Fossheim and T. de Lange Wenneck IMR and A. Dolgov, T. Prokhorova, and D. Prozorkevich PINRO Institute of Marine Research - IMR Polar Research Institute of Marine Fisheries and Oceanography - PINRO Arctic fishes in the Barents Sea 2004-2015: Changes in abundance and distribution AUTHORS: IMR: Edda Johannesen, Herdis Langøy Mørk, Knut Korsbrekke, Rupert Wienerroither, Elena Eriksen, Maria Fossheim, Thomas de Lange Wenneck PINRO: Andrey Dolgov, Tatiana Prokhorova, Dmitry Prozorkevich We thank everybody that participated on the IMR PINRO ecosystem survey 2004-2015. Sigbjørn Mehl, Åsmund Skålevik and Arne Johannes Holmin for help with StoX and Karen Gjertsen and Kjell Bakkeplass for making the maps. This report was partly funded by the Norwegian Environmental Agency as part of the work under the CAFF (Conservation of Arctic Flora and Fauna www.caff.is) program under Arctic Council. Contents 1. Synopsis ............................................................................................................................. 3 2. Zoogeographical classification of Barents Sea fishes ........................................................ 4 3. Sampling ................................................................................................................................. 7 3.1 Survey coverage and strata system ................................................................................... 7 3.2 Catchability and sub-sampling ......................................................................................... 7 4. Species identification ............................................................................................................. 9 4.1 Procedures for species identification of fishes at IMR and PINRO ................................. 9 4.2 Description of the families with Arctic fishes, and issues related to identification ......... 9 4.2.1 Rajidae ....................................................................................................................... 9 4.2.2 Gadidae ...................................................................................................................... 9 4.2.3. Cottidae .................................................................................................................. 10 4.2.4 Agonidae ................................................................................................................. 10 4.2.5 Cyclopteridae .......................................................................................................... 10 4.2.6 Liparidae .................................................................................................................. 10 4.2.7 Zoarcidae ................................................................................................................. 11 4.2.8 Pleuronectidae ......................................................................................................... 11 5. Results .................................................................................................................................. 12 5. 1 Overall trend .................................................................................................................. 12 5.2 Trends by species ........................................................................................................... 18 5.2.1. Amblyraja hyperborea ............................................................................................ 19 5.2.2 Gymnocanthus tricuspis .......................................................................................... 20 5.2.3 Icelus spp. ................................................................................................................ 22 5.2.4 Triglops nybelini ..................................................................................................... 23 5.2.5 Aspidophoroides olrikii ........................................................................................... 25 5.2.6 Eumicrotremus derjugini ......................................................................................... 27 5.2.7 Eumicrotremus spinosus ......................................................................................... 28 5.2.8 Careproctus spp. ...................................................................................................... 29 5.2.9 Liparis bathyarcticus ............................................................................................... 30 5.2.10 Liparis fabricii ....................................................................................................... 31 5.2.11 Gymnelus spp. ....................................................................................................... 33 5.2.12 Lycodes eudipleurostictus ..................................................................................... 34 5.2.13 Lycodes polaris ..................................................................................................... 36 5.2.14 Lycodes reticulatus ................................................................................................ 37 5.2.15 Lycodes rossi ......................................................................................................... 39 5.2.16 Lycodes seminudus ............................................................................................... 41 5.3 Conclusions .................................................................................................................... 44 6. Recommendations ................................................................................................................ 44 7. References ............................................................................................................................ 45 Synopsis The Barents Sea is one of nine shelf ecosystem survey bordering the Arctic Basin. The Arctic region is warming faster than the rest of the world. In the Barents Sea the years since 2000 were the warmest since the onset of regular measurements (1900, Bochkov 1982, ICES 2016) and paleo-records based on foraminifera even suggest that the Atlantic Water flowing into to the Barents Sea area was at its warmest for the last 2000 years (Spielhagen et al. 2011). As a result the extent of Arctic Water with sub-zero temperatures and sea ice is shrinking in the Barents Sea (e.g. ICES 2016). The changes in hydrographic conditions change the conditions for the poorly known Arctic fish fauna in the region. Here we present for the first time results on trends in abundance and distribution of demersal Arctic fishes in the northern Barents Sea. Here we define an “Arctic shelf ecosystem” as a system with Arctic water masses and Arctic biota. The North-northeastern Barents Sea is such an Arctic shelf ecosystem. The Joint IMR/PINRO ecosystem survey covers the whole Barents Sea shelf including the northern Arctic part. The survey started in 2004, and in October 2016 the 13th survey was completed. Due to its broad area coverage and now 13 years of data this survey is the most extensive survey of an Arctic shelf ecosystem in existence. With ever more years of monitoring amended understanding of the dynamic of the poorly known northern Barents Sea and the fishes found here can be gained. Therefore, abundance and distribution of Arctic fishes from this survey should be reported regularly. When analyzing trends in occupancy and abundance of Arctic fishes in the northern Barents Sea using data from the ecosystem survey we found that: • Overall there was a negative trend in occupancy and the number of Arctic fish species caught at each station from 2004-2015 in the Barents Sea • The decline was most pronounced in the eastern and central part of the area studied here • Some species declined all over, some decline only in the southern part over the area studied, some decline in the southern part of the study area and increased in the north indicating a displacement, while some did not show any significant change. We provide an inventory of all fishes caught at the ecosystem survey and discuss problems with species identity and identification as well as limitation due to survey coverage and sampling, and provide recommendations for future work. 3 2 Zoogeographical classification of Barents Sea fishes Biogeographical patterns are created by large-scaled historical, phylogenetic processes (Box 1). The range limits maintaining the zoogeographical patterns are due to spatial variation in the environment (including geographical barriers), the ecological traits of the species (their niche), and to what extent these traits are maintained over time (niche conservatisms). There is no approved methodology for marine biogeography and categories can be defined by distribution in relation to temperature regimes or by taxonomic/phylogenetic discreteness defined by the degree of endemism (Dipner 2001). The classification used here (below) is based on with water mass affiliation and include four different categories (CAFF 2013): Arctic (A) species are distributed in Arctic waters, spawn solely at sub-zero temperatures and are only infrequently found in temperate waters, Arctic-boreal (AB) species are distributed in Arctic and cold temperate waters and may spawn in both sub-zero temperatures and positive temperatures, Boreal (B) species are distributed