Questions adressed in this presentation:

1. Demersal fish assemblages and spatial diversity patterns in the Arctic-Atlantic transition zone in the Barents Sea Johannesen E, Høines ÅS, Dolgov AV, Fossheim M (2012) Demersal Fish Assemblages and Spatial Diversity Patterns in the Arctic-Atlantic Transition Zone in the Barents Sea. PLoS ONE 7(4): e34924. doi:10.1371/journal.pone.0034924

2. Questions adressed in this presentation: 1) How many fish species are there in the BS? 2) How are the fish species structured in space into fish communities? 3) How does the fish species richness/diversity vary in space (”hot spots”)? 4) What characterize the different fish communities?

3. 1) How many species are there? • BS is a transition zone between Arctic and Boreal faunas (Michael Sars 1851) • - Species rich to be at such a high latitude • Numberoffishspeciesrecorded has increasedwithresearcheffort: • Knipovich (1926): 114 • Andriyashev (1954): 149 • Dolgov (2004)/Dolgov et al (2011): 200 • Outofthe 200: • 36 lacksconfirmation, • uncleartaxonomic status ofsome • sculpins, eelpouts and liparids

4. late 1990-early 2000: • Increased focus on non-commercial species on IMR and PINRO surveys • Cooperation with Bergen Museum, genetics, identification keys • 2007 annual workshops for technical staff at IMR in fish taxonomy, • including work on identification keys • 2008 new routines for freezing difficult/rare species for • later identification in the laboratory, • 2009 work on species names for data conversion between Norway and Russia • 2011 Fish Atlas sum up the ”state of the art” species identity for species caught • on the ecosystem survey (Norwegian and Russian literature, genetics • 2012 work on unifying and translating species identification keys Norw./Russ. vessels

5. On the ecosystem survey (started in 2003/2004):: => 90-100 fish species every year 2) How are the fish species structured in space into fish communities? Demersal fish => pelagic fish poorly sampled by bottom trawl => pelagic fish different community (but the borders are fuzzy) Gridded data (averages 2004-2009) Pooling of species, eelpouts values only 2007-2009 etc. Exlusion of stations >500m and <50m => 75 demersal fish species

6. 2) How are the fish species structured in space into fish communities? Høy Arktisk/Kara Arktisk Novaya Zemlya Atlantisk Sørvest Sørøst Artsammensetning i Barentshavet Grid celler with similar colour has similar species compositon

7. 1) Hvordan er er bunnfiskartene fordelt romlig i i fiskesamfunn? Deep <= => Shallow Cold <= => Warm Depth and og temperature important factors Determining the species composition

8. 2) How does diversity vary geographically? • diverisity • Speciesrichness • Evenness • Shannon index both evenness and richeness • Species density: species caught per unit effort, depends on overall density and richness

9. 3) How does diversity vary in space? Is it determined by temperature og depth? Species richness: Evenness ? Temperature Temperature ? Depth Depth Shannon index =?

10. 2) How does the diversty vary in space? Shannon index: Rishness & evenness Species density: Rishness & overall density Species richness highest in varmer areas at intermediate depths Evenness highest in cold areas at intermediate depths ?

11. 3) What is the characteristing the different communities? Novaya Zemlya: Coastal Cold water species Arctic staghorn sculpin

12. 3) Hva karakteriserer fiskesamfunnene? South-west: coastal Warmwater species, Northern distribution limit Norway redfish

13. 3) What is the characteristing the different communities?

14. Species rank log abundance Species richness

15. 3) Hva karakteriserer fiskesamfunnene? • North of the polar front: • Low biomass, • Small-bodied • arctic species dominates • Relatively high evenness • South of the polar front : • High biomass • More large-bodied • species • Low evenness • (a little) more species • Boreal species dominates Høy Arktisk/Kara Arktisk Novaya Zemlya Atlantisk Sørvest South East og High Arctic are the most distance geographically, Regarding species composition, species richness, abundance, biomass, species density the difference between ”Atlantisk” og”Arktisk” in the study years is slight - boreale species widely distributed in northern areas (seasonal migrations in warm years) Sørøst

17. 3) Hotspots? Cold spots!! Diversity variation when large scale temperature and depth relationship is removed: Høy Arktisk/Kara Arktisk Novaya Zemlya Atlantisk Sørvest Sørøst

18. Summary: • Sixcummunitiesseparatedalongtemperature- and depth gradients • Three coastal/shallow water communities: • NovayaZemlyaSouth-eastSouth west • Three oceanic/deepwatercommunity • High Arctic/Kara ArcticAtlantic temperature Temperature

19. Summary: • hotspots: • Two coastalcommunity: • ”South west”, northern border for somespecies, highspeciesdensity, • highbiomass and abundance • (warm, relativelyshallow, but variable depth, high habitat complexity) • ”NovayaZemlya” – uniqe fauna ofcoastal, smallbodied, arcticcoldwaterspecies • (shallow, verycold (<0 someplaceseven in summer) • ”coldspots”: • ”South east”og ”Higharctic” • Relativelysmalldiffeencebetweenthe large oceaniccommunities • ”Atlantisk” and”Arktisk” • =>survey yearswarm, southernmigratingspecies (cod) northofthe polar front

21. Dolgov et al 2011

22. 2007

23. Blue whiting 1. Quarter 2. quarter 3. quarter Dolgov et al 2010

24. Takk for oppmerksomheten!

25. 2.4. WP1: Fish and benthos communities, past changes and regime shifts WP1 will investigate the past and present spatial and temporal variability in fish and benthos communities in the Barents Sea in relation to environmental variability in space and time. The general approach will be to evaluate 1) the baseline present community structure and diversity of demersal fish and benthos in the Barents Sea, 2) the changes in community structure through descriptors such as e.g. species composition, trophic position, habitat use, water mass affinity etc., and 3) the community response to changes in environmental factors, in particular climate change and fishery.