Beaufort Sea Marine Fish Monitoring 2008: ... REPORT AVAILABILITY ...... survey provided recommendations for future monitoring methods in addition to ...
BOEMRE 2010-048
Beaufort Sea Marine Fish Monitoring 2008: Pilot Survey and Test of Hypotheses Final Report 1
Alaska Fisheries Science Center NOAA National Marine Fisheries Service 7600 Sand Point Way, NE Seattle, WA 98115-6349
Report Authors: Elizabeth Logerwell1 and Kimberly Rand1 Sandra Parker-Stetter and John Horne School of Aquatic and Fishery Science University of Washington Box 355020, Seattle, WA 98115-0070
Tom Weingartner and Bodil Bluhm Institute of Marine Science School of Fisheries and Ocean Sciences University of Alaska Fairbanks Box 757220, Fairbanks, AK 99775-7220
Prepared for Minerals Management Service U.S. Department of the Interior 3801 Centerpoint Drive, Suite 500 Anchorage, AK 99503-5823
This study was funded by the U.S. Department of the Interior, Minerals Management Service now called the Bureau of Ocean Energy Management, Regualtion and Enforcement (BOEMRE) Alaska Outer Continental Shelf Region, Anchorage Alaska, through an Inter-agency Agreement between BOEMRE and the Alaska Fisheries Science Center, Agreement No. AKC-058, MMS Agreement No. M07PG13152, as part of the
BOEMRE Alaska Environmental Studies Program.
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DISCLAIMER This report has been reviewed by the Bureau of Ocean Energy Management, Regulation and Enforcement (BOEMRE) and approved for publication. Approval does not signify that the contents necessarily reflect the views and policies of the Service, nor does mention of trade names or commercial products constitute endorsement or recommendation for use. Further analysis and interpretation of the ecological data collected in this study will be published in a future BOEMRE report.
REPORT AVAILABILITY This document is available to the public through: National Technical Information Service 5285 Port Royal Road Springfield, Virginia 22161 FAX: (703) 605-6900
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Table of Contents Abstract.......................................................................................................................................... 5 Introduction................................................................................................................................... 6 Methods.......................................................................................................................................... 7 Survey area.................................................................................................................................. 7 Fish, invertebrate, and habitat data collection .......................................................................... 11 Demersal fish and invertebrate data collection.................................................................... 11 Demersal fish and invertebrate sampling ............................................................................. 13 Pelagic fish sampling............................................................................................................ 15 Demersal and pelagic trawl data entry ................................................................................ 15 Zooplankton data collection ................................................................................................. 15 Habitat characteristic data collection (physical oceanography) ......................................... 16 Fish lengths and biological collections ................................................................................ 16 Special projects..................................................................................................................... 18 Auxiliary studies ....................................................................................................................... 18 Marine mammals .................................................................................................................. 18 Seabirds................................................................................................................................. 18 Demersal fish data analysis....................................................................................................... 19 Abundance............................................................................................................................. 19 Cluster analysis..................................................................................................................... 19 Coefficient of variation ......................................................................................................... 19 Demersal fish-habitat associations....................................................................................... 20 Pelagic fish data analysis .......................................................................................................... 22 Acoustic data processing ...................................................................................................... 22 Backscatter estimates............................................................................................................ 22 Target strength...................................................................................................................... 23 Density distribution, mean density, and abundance ............................................................. 24 Comparing acoustic and bottom trawl surveys .................................................................... 25 Pelagic fish-habitat associations .......................................................................................... 27 Results .......................................................................................................................................... 31 Demersal fish ............................................................................................................................ 31 Demersal fish abundance...................................................................................................... 31 Demersal fish cluster analysis .............................................................................................. 41 Demersal fish distribution maps ............................................................................................... 45 Demersal fish biological collections..................................................................................... 55 Demersal fish geographic comparisons................................................................................ 60 Demersal fish historical comparisons .................................................................................. 63 Benthic invertebrates ................................................................................................................ 65 Benthic invertebrate abundance ........................................................................................... 65 Pelagic fish data analysis .......................................................................................................... 76 Pelagic fish midwater trawls ................................................................................................ 76 Backscatter............................................................................................................................ 80 Target strength...................................................................................................................... 82 Density distribution, mean density, and abundance ............................................................. 84 Comparing acoustic and bottom trawl surveys .................................................................... 89 3
Fish habitat (physical oceanography) ....................................................................................... 99 Winds and sea ice.................................................................................................................. 99 Temperature and salinity .................................................................................................... 103 The spatial distribution of temperature and salinity........................................................... 104 Results of the demersal fish habitat associations ............................................................... 114 Pelagic fish habitat associations ........................................................................................ 158 Discussion................................................................................................................................... 162 Demersal fish and benthic invertebrates ................................................................................. 162 Pelagic fish.............................................................................................................................. 166 Comparison of demersal trawl and pelagic acoustic methods ........................................... 168 Fish habitat (physical oceanography) ..................................................................................... 169 Literature Cited ........................................................................................................................ 178 Appendix I – Database table documentation.......................................................................... 186 Appendix II – Review of Beaufort Sea Fish Studies .............................................................. 199 Appendix III – CTD cast data.................................................................................................. 214 Appendix IV – Net mensuration data and trawl design and rigging ................................... 216 Appendix V – Sample size and final destination of biological samples................................ 219 Appendix VI – Auxiliary studies ............................................................................................. 221 Bitter crab syndrome in Beaufort Sea snow (Chionoecetes opilio) and Arctic lyre (Hyas coarctacus) crabs................................................................................................................ 221 Platforms of Opportunity Program – Marine Mammals .................................................... 223 Marine bird and mammal surveys conducted during AFSC marine fish surveys in the Beaufort Sea and transit routes, August 2008 .................................................................... 225 Appendix VII – Under-ice sampling workshop ..................................................................... 241 Appendix VIII – Recommendations for future monitoring methods .................................. 244 Vessel...................................................................................................................................... 244 Survey design and methods .................................................................................................... 246 Station and transect spacing............................................................................................... 246 Bottom trawl field methods and data analyses (demersal fish sampling) .......................... 247 Acoustic field methods and data analysis (pelagic fish survey) ......................................... 249 Fish habitat (phycial oceanography).................................................................................. 252 Quality control and disposition of samples and/or data..................................................... 252 Survey Planning ...................................................................................................................... 253 Scientific staffing................................................................................................................. 253 Logistics .............................................................................................................................. 253 Safety................................................................................................................................... 254 Contigency planning ........................................................................................................... 255 Necessary permits-Federal ................................................................................................. 257 Necessary permits-Local..................................................................................................... 260 Subsistence activities .......................................................................................................... 261 Coordination with related projects..................................................................................... 261 Funding ............................................................................................................................... 261
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Abstract The Minerals Management Service (MMS), Alaska OCS Region funded a pilot survey in 2008 of the offshore marine fishes of the Beaufort Sea. This was the first offshore marine fish survey to have taken place since an opportunistic survey in 1977 (Frost and Lowry 1983). This pilot survey provided recommendations for future monitoring methods in addition to baseline data against which to compare future anthropogenic and climate impacts. Because it was a pilot survey, different techniques were employed to assess fish abundance. It is important to note that density, abundance, and biomass estimates from the bottom trawl and acoustic/midwater trawl surveys targeted different sections of the water column, used different sampling gears, and followed disparate sampling strategies and analytic paths. Demersal fish and benthic invertebrates were assessed using standardized bottom trawl gear and methods. Pelagic fish abundance was assessed using hydroacoustics and midwater net tows. The distribution of zooplankton was sampled with small-meshed bongo nets and physical oceanographic data were collected with conductivity-temperature-depth instruments. Demersal fish made up 6% of the bottom trawl catch by weight, and invertebrates made up the remaining 94% of the catch. A total of 32 fish were identified to species, two were identified to genus and 1 to family, and 174 species of invertebrates were identified. The four most abundant benthic fish taxa were Arctic cod (Boreogadus saida), eelpouts (Lycodes spp.), Bering flounder (Hippoglossoides robustus), and walleye pollock (Theragra chalcogramma). The most abundant invertebrates were notched brittle stars (Ophiura sarsi), opilio crab (Chionoecetes opilio), mollusks (Musculus spp.) and a seastar (Ctenodiscus crispatus). Comparison of our results with historic data suggests that climate change may have resulted in northward expansion of some species’ ranges, including commercially valuable species such as pollock and Pacific cod (Gadus macrocephalus). This survey was also the first to document commercial-sized opilio crab (Chionoecetes opilio) in the North American Arctic. Acoustics and midwater trawling were used to quantify density distributions of pelagic and semi-demersal fish in the survey area (20-500 m bottom depths) and to evaluate relationships between fish distribution and habitat descriptors. Year-plus Arctic cod were the dominant pelagic/semi-demersal fish species, with peak densities of 150,000 fish/ha at bottom depths of 100-350 m. Oceanographically, year-plus Arctic cod were associated with cold, saline waters. The density distribution of year-plus Arctic cod closely mirrored published foraging distributions for beluga whales (Delphinapterus leucas). Young of the year fish (Arctic cod, unidentified sculpin (Cottidae), and undentified eelblenny (Lumpenus sp.)), dominated the pelagic biomass at bottom depths of 20-75 m, with peak densities up to 160,000 fish/ha, but were also found in surface waters at bottom depths greater than 75 m. The age-0 fish were associated with warm, fresher water throughout the study area. Physical oceanographic data indicated the presence of Pacific Ocean-derived waters (modified on the Bering and Chukchi shelves) that likely exited the Chukchi shelf through Barrow Canyon and into the Beaufort Sea. In addition, evidence of recent ice melt was found in cold, low salinity waters in the upper few meters of the water column in the western portion of the study area. River outflow water influenced water column properties in the eastern portion of our study area, as evidenced by a lens of very low salinity, warm water near the surface.
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Introduction In August 2008 researchers from NOAA-NMFS Alaska Fisheries Science Center (AFSC), University of Washington (UW) and University of Alaska Fairbanks (UAF) conducted a survey of offshore marine fish, invertebrates, and physical and biological oceanography of the western Beaufort Sea in the vicinity of Cape Simpson to Cape Halkett. The most recent previous survey of Beaufort Sea offshore marine fish was conducted opportunistically from a US Coast Guard cutter during 1976-1977 (Frost and Lowry 1983). The majority of previous fish studies have focused on anadromous fish in estuaries, inlets, river deltas, or lagoons (Bond and Erickson 1997, Gallaway et al. 1997, Jarvela and Thorsteinson 1997, Moulton et al. 1997, Underwood et al. 1997). A few studies have examined the occurrence of marine fish in nearshore waters (
