AMNWR 09/01 SEABIRD, FISH, MARINE MAMMAL AND OCEANOGRAPHY COORDINATED INVESTIGATIONS (SMMOCI) IN THE PRIBILOF ISLANDS, ALASKA, JULY 2005 By Donald E. Dragoo Key Words: Alaska, Bering Sea, CTD, fishes, hydroacoustics, marine mammals, oceanography, pelagic surveys, Pribilof Islands, St. George Island, St. Paul Island, salinity, seabirds, temperature U. S. Fish and Wildlife Service Alaska Maritime National Wildlife Refuge 95 Sterling Hwy., Suite 1 Homer, Alaska, USA 99603 August 2009 _____ Cite as: D. E. Dragoo. 2009. Seabird, fish, marine mammal and oceanography coordinated investigations (SMMOCI) in the Pribilof Islands, Alaska, July 2005. U. S. Fish and Wildl. Serv. Report AMNWR 09/01. Homer, Alaska. Executive Summary SMMOCI investigators conducted a survey of seabirds, fishes, marine mammals and oceanographic conditions in the Pribilof Islands, Alaska from the M/V Tigˆlaxˆ during 20-26 July 2005 as part of the Seabird, Fish, Marine Mammal and Oceanography Coordinated Investigations (SMMOCI) project. The objective was to characterize the marine environment in the vicinity of the Pribilof Islands, whose seabird colonies are monitored annually by the Alaska Maritime National Wildlife Refuge, and to repeat a 1997 SMMOCI survey of the area. In addition to surveying seabirds and marine mammals on transects, we characterized local oceanography by taking profiles of the water column at numerous stations on a series of CTD transects. We measured the relative abundance of zooplankton and fish biomass using a dual-frequency echosounder. We sampled with a mid-water trawl net to help associate species with observed acoustic sign. We set long-lines to catch large demersal fish species, used bottom trawls to describe the bottom fauna and sampled zooplankton. In 2005, we counted a total of 23,026 birds on 10 transects that covered approximately 791 linear km of surveys, resulting in an average density of approximately 101 birds/km2 over an area of some 228 km2. We also counted 10,268 birds during a circumnavigation of St. George Island. Bird density observed during circumnavigation was about 538 birds/km2. The study area for our 2005 Pribilof Island SMMOCI cruise was similar to that surveyed by us in 1997 except that in 2005, due to time constraints, we concentrated our efforts mainly on the transects south of St. George Island and added a circumnavigation survey of St. George Island. The overall density of seabirds encountered on linear transects in 2005 was nearly twice what we observed in 1997. Similar to 1997, northern fulmars, murres, fork-tailed storm-petrels and kittiwakes were the most numerous birds seen on surveys in 2005. We counted a few glaucous-winged gulls in 2005, whereas none were seen during the 1997 surveys. As in 1997, fin whales, Dall’s porpoises and northern fur seals were the most numerous marine mammals observed. Sculpins were the most numerous fishes caught in bottom trawls in both 1997 and 2005. Walleye pollock dominated the fish component of the mid-water trawl catch in both years. Similar numbers of Pacific cod, yellow Irish lord and Pacific halibut were caught on long-line gear in both surveys, even though we set the gear fewer times in 2005. New size records were set for great sculpin and northern sculpin. CTD profiles indicated a highly stratified water column in the survey area. i Table of Contents Executive Summary ......................................................................................................................... i Table of Contents ............................................................................................................................ ii List of Tables and Appendices ........................................................................................................ ii List of Figures ................................................................................................................................ iv Introduction ......................................................................................................................................1 Personnel ..............................................................................................................................1 Methods............................................................................................................................................1 Bird and Marine Mammal Observations..............................................................................1 Hydroacoustic Surveys ........................................................................................................2 Fishing..................................................................................................................................2 Oceanography ......................................................................................................................3 Results ..............................................................................................................................................3 Bird and Marine Mammal Observations..............................................................................3 Hydroacoustic Surveys ........................................................................................................4 Fishing..................................................................................................................................4 Oceanography ......................................................................................................................5 Discussion ........................................................................................................................................5 Acknowledgements ..........................................................................................................................5 Literature Cited ................................................................................................................................6 List of Tables and Appendices No. Title Page 1. Locations, dates and times of surveys used for bird and marine mammal observations, and hydroacoustics surve y s near the Pribilof Islands, Alaska, July 2005 ...........................8 2. Species composition and numbers of seabirds and marine mammals observed on 10 linear transects near the Pribilof Islands, Alaska, July 2005 ...............................................9 3. Species composition and numbers of seabirds and marine mammals observed during circumnavigation of St. George Island, Alaska, July 2005................................................10 ii List of Tables and Appendices (Continued) No. Title Page 4. Locations, times and depths of fishing efforts near the Pribilof Islands, Alaska, July 2005 ............................................................................................................................11 5. Count of fishes caught by bottom trawls near the Pribilof Islands, Alaska, July 2005 .....12 6. Total lengths of fishes caught by bottom trawls near the Pribilof Islands, Alaska, July 2005 ............................................................................................................................13 7. Counts of invertebrates caught by bottom trawls near the Pribilof Islands, Alaska, July 2005 ............................................................................................................................14 8. Count of fishes caught by mid-water trawls near the Pribilof Islands, July 2005 .............22 9. Total lengths of fishes caught by mid-water trawls near the Pribilof Islands, Alaska, July 2005 ............................................................................................................................23 10. Counts of invertebrates caught by mid-water trawls near the Pribilof Islands, July 2005 ............................................................................................................................24 11. Count of fishes caught by long-line near the Pribilof Islands, Alaska, July 2005 .............25 12. Total lengths and weights of fishes caught by long-line near the Pribilof Islands, Alaska, July 2005 ...............................................................................................................26 13. Prey composition of stomach samples taken from Pacific halibut caught by long-line near the Pribilof Islands, Alaska, July 2005 ......................................................................26 14. Prey composition of stomach samples taken from Pacific cod caught by long-line near the Pribilof Islands, Alaska, July 2005 ......................................................................27 15. Prey composition of stomach samples taken from yellow Irish lord caught by long-line near the Pribilof Islands, Alaska, July 2005 ......................................................................28 16. Count of individuals captured with plankton nets during SMMOCI near the Pribilof Islands, Alaska, July 2005 .......................................................................................................... 29 17. Locations, times and dates of CTD casts made near the Pribilof Islands, Alaska, July 2005 ............................................................................................................................31 18. Estimates of at-sea densities of seabirds near colonies at several Alaskan sites ...............32 A. Photographs of some species caught during the SMMOCI cruise near the Pribilof Islands, Alaska, July 2005 ................................................................................................54