IMR/PINRO J O S I E N I 4 R T 2007 E R E S P O R T SURVEY REPORT FROM THE JOINT NORWEGIAN/RUSSIAN ECOSYSTEM SURVEY IN THE BARENTS SEA AUGUST-OCTOBER 2007 Volume 1 Institute of Marine Research - IMR Polar Research Institute of Marine Fisheries and Oceanography - PINRO This report should be cited as: Anon. 2007. Survey report from the joint Norwegian/Russian ecosystem Survey in the Barents Sea August-October 2007 (vol.1). IMR/PINRO Joint Report Series, No. 4/2007. ISSN 1502-8828. 97 pp. REPORT FROM THE JOINT ECOSYSTEM SURVEY OF THE BARENTS SEA IN 2007, VOL. 1 SURVEY REPORT FROM THE JOINT NORWEGIAN/RUSSIAN ECOSYSTEM SURVEY IN THE BARENTS SEA AUGUST – SEPTEMBER 2007 Volume 1 Preface The fifth joint ecosystem survey was carried out during the period 1st of August to 30th of September 2007. This survey encompasses various surveys that previously have been carried out jointly or at national basis. Joint investigations include the 0-group survey, the acoustic survey for pelagic fish (previously known as the capelin survey), and the investigations on young Greenland Halibut north and east of Spitzbergen. Oceanographic investigations have always formed a part of these surveys, and studies on plankton have been included for many years. In recent years, observations of sea mammals, seabirds, bottom fishes and benthos have been included. Consequently, from 2003, these surveys were called “ecosystem surveys”. The present volume of the survey report covers many but not all of aspects of the survey. The main focus is on the hydrographical conditions of the Barents Sea, the results from the 0- group investigations and from the acoustic investigation on pelagic fish (capelin, young herring, blue whiting and polar cod). Preliminary materials on sea mammals and seabird observations are also presented in volume 1 of the report. Results from the investigations on plankton, bottom fishes and benthos will not be covered entirely in this volume of the report since the data has not been fully analysed yet. The remaining results from these investigations will be presented in volume 2 of the survey report. The 1st volume of the report was made during a meeting between scientists participating in the survey, in Murmansk 1 -10 October. A list of the participating vessels with their respective scientific crews is given in Appendix I. Besides the participants on the vessels, the following specialists took part in preparing the survey report: from PINRO - K. Drevetnyak, Yu. Kovalev, E. Orlova, A. Dolgov; from IMR - J. E. Stiansen, B. Bogstad, S. Tjelmeland, K. Michalsen. - 1 - REPORT FROM THE JOINT ECOSYSTEM SURVEY OF THE BARENTS SEA IN 2007, VOL. 1 Synopsis The main aim of the ecosystem survey was to map the distribution and abundance of the young and adult stages of several demersal and pelagic fish species, and in addition to gather information about hydrographical features, zooplankton, benthos, seabirds and sea mammals. The water temperature in all observed areas was still higher (+0.7-+1.2 0C) than the long term mean but somewhat lower than in the same period 2006. The 2007 year-class of capelin and redfish are rich. 0-group of haddock, herring, eastern component of polar cod and sandeel are below average. 0-group of cod, Greenland halibut, saithe, long rough dab, wolffish and western component of polar cod were estimated to be poor. The total capelin stock was estimated to be 1.9 million tonnes, which is 2.4 times higher than last year. About 0.84 million tonnes were assumed to be maturing. However, the stock is still at a low level compared to the long term mean. The polar cod stock was estimated to be 1.2 million tonnes, which is less than last year but still higher than the long term mean. The abundance of juvenile Norwegian spring spawning herring was estimated to 1.22 million tonnes. Large parts of the numberous 2004 year-class migrated to the southeastern part of the Barents Sea, usually dominated by younger year-classes. Blue whiting of age groups 1 to 9, but mostly age 3 and 4, were observed in the western and southwestern parts of the surveyed area, and the biomass of this stock component was estimated to be 0.66 million tones, which is the third following year of decline since 2004, where the stock reached 1.4 mill. tonnes. - 2 - REPORT FROM THE JOINT ECOSYSTEM SURVEY OF THE BARENTS SEA IN 2007, VOL. 1 1 METHODS ....................................................................................................................... 5 1.1 HYDROGRAPHY ............................................................................................................ 5 1.2 0-GROUP FISH INVESTIGATIONS .................................................................................... 5 1.3 ACOUSTIC SURVEY FOR PELAGIC FISH........................................................................... 6 1.3.1 Area coverage ...................................................................................................... 6 1.3.2 Computations of the stock sizes ............................................................................ 6 1.4 BOTTOM TRAWL SURVEY .............................................................................................. 7 1.4.1 Strata system used ................................................................................................ 7 1.5 PLANKTON INVESTIGATIONS ......................................................................................... 7 1.6 STOMACH INVESTIGATIONS .......................................................................................... 8 1.7 MARINE MAMMALS AND SEABIRDS INVESTIGATIONS .................................................... 9 1.8 BENTHOS OBSERVATIONS ............................................................................................. 9 1.8.1 Purpose ................................................................................................................. 9 1.8.2 Criteria for selection of sampling locations ......................................................... 9 1.8.3 Gear and methods .............................................................................................. 10 1.8.4 Bottom trawl ....................................................................................................... 10 1.8.5 van Veen grab ..................................................................................................... 10 1.8.6 Epibenthos trawls ............................................................................................... 10 1.8.7 Video survey ....................................................................................................... 11 2 RESULTS AND DISCUSSION ..................................................................................... 12 2.1 HYDROGRAPHICAL CONDITIONS ................................................................................. 12 2.2 DISTRIBUTION AND ABUNDANCE OF 0-GROUP FISH ..................................................... 14 2.2.1 Capelin ............................................................................................................... 14 2.2.2 Cod ..................................................................................................................... 15 2.2.3 Haddock ............................................................................................................. 15 2.2.4 Herring ............................................................................................................... 15 2.2.5 Polar cod ............................................................................................................ 15 2.2.6 Saithe .................................................................................................................. 15 2.2.7 Redfish ................................................................................................................ 16 2.2.8 Greenland halibut .............................................................................................. 16 2.2.9 Long rough dab .................................................................................................. 16 2.2.10 Wolffish ............................................................................................................... 16 2.2.11 Sandeel ............................................................................................................... 16 2.3 DISTRIBUTION AND ABUNDANCE OF PELAGIC FISH ..................................................... 17 2.3.1 Capelin ............................................................................................................... 17 2.3.2 Polar cod ............................................................................................................ 18 2.3.3 Herring ............................................................................................................... 19 2.3.4 Blue whiting ........................................................................................................ 20 2.4 DEMERSAL FISH .......................................................................................................... 21 2.4.1 Cod ..................................................................................................................... 21 2.4.2 Haddock ............................................................................................................. 21 2.4.3 Saithe .................................................................................................................. 21 2.4.4 Greenland halibut .............................................................................................