DISTRIBUTION, ABUNDANCE, COMMUNITY STRUCTURE. AND TROPHIC RELATIONSHIPS OF THE BENTHOS OF THE NORTHEASTERN GULF OF ALASKA FROM YAKUTAT BAY TO CROSS SOUND by H. M. Feder, S. C. Jewett, S. G. McGee, and G. E. M. Matheke Final Report Outer Continental Shelf Environmental Assessment Program Research Unit 5 March 1981 1 TABLE OF CONTENTS List of Figures . 5 List of Tables . 7 I. SUMMARY OF OBJECTIVES AND CONCLUSIONS . 9 II. INTRODUCTION . 10 General Nature and Scope of Study . 10 Relevance to Problems of Petroleum Development . 12 III . CURRENT STATE OF KNOWLEDGE . 14 IV. STUDY AREA . ● . ● . ● . .* ● * 15 v. SOURCES, METHODS AND RATIONALE OF DATA COLLECTION . 19 Numerical Analysis of van Veen Grabs . 20 Diversity of van Veen Grabs . 22 VI. RESULTS. ..*. .**.. ● ✎ ✎ ✎ ✎ ● ✎ ✎ 24 Benthic Epifaunal Program .**.. ...* . ..*. 24 Offshore Stations. ...* ● ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ 24 Yakutat Bay Stations . ✎ ✎ ✎ ✎ ✎ ✎ ✎✎✎☛ ✎ ✎ ✎ ✎ ✎ ✎✎☛ 32 Benthic Infaunal Program. ...* . 35 Van Veen Grab . ● ☛✎✎✎✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ ✎ 35 Pipe Dredge . 55 Fishes. 63 Offshore Stations . 63 Yakutat Bay Stations . ...* . 65 Feeding Studies. ● ✎✎☛✎✎ ✎✎☛☛✎✎ 65 Offshore Stations . ..**. 65 Yakutat Bay Stations . .*..* ● . .*. 87 Pollutants on the Bottom . 90 VII . DISCUSSION . ..** . ● ✎ ✎ 90 Benthic Epifaunal Program. ...* . 90 Offshore Stations . ● . ...* . 90 Yakutat Bay Stations . ..*. ..* 92 Benthic Infaunal Program . 93 Van Veen Grab . ● . ...* . 93 Pipe Dredge . ● . ● ..*.. ..*.. 94 Fishes. 94 Offshore Stations . ..*. ..* 94 3 TABLE OF CONTENTS (Continued) Feeding Studies. 96 Arrowtooth flounder (Atheresthes stomias) . 96 Rex sole (Glyptocephalus zachirus). 96 Flathead sole (Hippoglossoides elassodon) . 96 Butter sole (Isopsetta isolepis). 97 English sole (Parophrys vetulus). 97 Dover sole (Microstomus pacificus). 97 Pacific halibut (Hippoglossus stenolepsis). 98 Starry flounder (Platichthys stellatus) . 98 Rock sole (Lepidopsetta bilineata). 99 Sand sole (Psettichtys melanostictus) . 99 Sablefish (Anaplopoma fimbria). 99 Walleye pollock (Theragra chalcogramma) . 99 Pacific cod (Gadus macrocephalus) . 100 Rockfishes (Sebastes spp.). 100 Spiny dogfish (Squalus acanthias) . 101 Sculpins (Cottidae) . .101 Sunflower sea star (Pycnopodia helianthoides) . 102 Dungeness crab (Cancer magister). 102 Snow crab (Chionoecetes bairdi) . 103 Pollutants on the Bottom . ...104 VIII. CONCLUSIONS. 104 IX. NEEDS FOR FURTHER STUDY. ..105 x* PROBLEMS ENCOUNTERED. 105 REFERENCES. 106 APPENDIX A - Trawl Data Northeast Gulf of Alaska. 113 APPENDIX B - Polychaetes and Amphipods as Commensals with Hermit Crabs from the Northeastern Gulf of Alaska. , . 185 APPENDIX C - Pipe Dredge Data Northeast Gulf of Alaska. 197 4 LIST OF FIGURES Figure 1. Northeastern Gulf of Alaska station grid occupied by the NOAA ship Miller Freeman, November 1979 Figure 2. Priority sampling areas established in the north- eastern Gulf of Alaska Figure 3. Yakutat station grid occupied by the NOAA ship Miller Freeman, November 1979 Figure 4. Dendrogram produced by a cluster analysis of l!n transformed abundance data from benthic grab samples Figure 5. Distribution of stations in station groups formed by a cluster analysis of natural logarithm trans- formed abundance data from benthic van Veen grab samples Figure 6. Dendrogram of species groups formed by an inverse cluster analysis of Zn transformed abundance data Figure 7. Dendrogram produced by a cluster analysis of un- transformed abundance data from benthic grab samples Figure 8. Plots of the first three coordinate axes of a prin- cipal coordinate analysis using Czekanowski similarity and Zn transformed abundance data Figure 9. Plots of the first three coordinate axes of a prin- cipal coordinate analysis using Canberra metric similarity coefficient and Zn transformed abundance data Figure 10. Plots of the first three coordinate axes of a prin- cipal coordinate analysis using Czekanowski similarity coefficient and untransformed abundance data Figure 11. Plots of the first three coordinate axes of a prin- cipal coordinate analysis using Canberra metric similarity coefficient and untransformed abundance data 5’ LIST OF TABLES Table I. Species of invertebrates taken by trawl from the northeastern Gulf of Alaska excluding Yakutat Bay, November 1979 Table II. Numbers, weights and biomass (g/m2) of the major epifaunal taxa of Cnidaria, Mollusca, Arthropods, and Echinodermata from the northeastern Gulf of Alaska, excluding Yakutat Bay, November 1979 Table 111. Stations at which the dominant epifaunal invertebrate species occurred in the northeastern Gulf of Alaska, excluding Yakutat Bay, November 1979 Table IV. Species of invertebrates taken by trawl from Yakutat Bay, November 1979 Table V. Numbers, weights and biomass (g/m2) of the major epifaunal taxa of Mollusca, Arthropoda, and Echi- nodermata from Yakutat Bay, November 1979 Table VI. Station locations and sediment descriptions for samples of the benthic infauna collected by van Veen grab, November 1979 Table VII. The abundance, biomass and diversity of benthic grab samples arranged by station groups Table VIII. Species groups formed by cluster analysis of natural logarithm transformed abundance data from benthic grab samples Table IX. Two way coincidence table of average cell density comparing the major species groups and the station groups formed by a cluster analysis of Zn trans- formed abundance data Table X. Comparison of station groups formed by cluster analysis using Zn transformed and untransformed abundance data Table XI. Numbers, weights and biomass (g/m2) of the major fishes from the offshore region of the northeastern Gulf of Alaska and Yakutat Bay, November 1979 Table XII. Major food groups found in stomachs of selected fishes and invertebrates from the northeastern Gulf of Alaska, excluding Yakutat Bay, November 1979 7 LIST OF TABLES (Continued) Table XIII. Individual taxa found in stomachs of selected fishes and invertebrates from the northeastern Gulf of Alaska, excluding Yakutat Bay, November 1979 Table XIV. Individual taxa found in stomachs of selected fishes and invertebrates from Yakutat Bay, November 1979 Table XV. Frequency of occurrence of man-made debris on the northeastern Gulf of Alaska sea floor I. SUMMARY OF OBJECTIVES AND CONCLUSIONS The specific objectives of this investigation were to present: (1) a quantitative inventory of dominant epifaunal invertebrates; (2) a descrip- tion of spatial distribution patterns of selected epifaunal invertebrates; (3) assess spatial distribution and relative abundance of selected infaunal invertebrate species; and (4) observations of biological interrelationships, emphasizing trophic interactions, between selected segments of the benthic biota. During 6-25 November, 1979, trawls were made at 42 offshore stations, 33 of which were within an identified high priority area (designated Area 1). Twenty-seven additional offshore stations were surveyed and considered to be untrawlable. A total of 34 van Veen grab stations were sampled; 27 sta- tions in Priority Area 1. Pipe dredge samples were taken from 34 stations, most of which were in Priority Area 1. Dredge samples were mainly used as an aid in identification of stomach contents from various species. Trawls were made at three stations in Yakutat Bay; eleven additional stations were surveyed and considered to be untrawlable. Grab samples were analyzed from seven stations. Analysis of the trawl material from offshore stations resulted in a delineation of benthic invertebrates belonging to 10 phyla, 19 classes, 72 families, 100 genera, and 134 species. Yakutat Bay trawl material de- lineated 4 phyla, 6 classes, 16 families, 19 genera, and 23 species. It is probable that all species with numerical and biomass importance have been collected in the area of investigation and only rare species will be added in future sampling. Information derived from the grab sampling program indicates that the infauna at most stations was similar to that found in other areas of the northeastern Gulf of Alaska (NEGOA) where there is a soft substrate (Feder and Matheke, 1980). The infauna was dominated by motile deposit- feeding organisms, and the diversity of the fauna was relatively low com- pared to areas with a more heterogeneous substrate (Feder and Matheke, 1980) . Information on the feeding biology of 20 species from NEGOA (Cross Sound to Yakutat Bay), in conjunction with data collected on other Outer Continental Shelf Environmental Assessment Program (OCSEAP) cruises, should enhance the understanding of benthic trophic relationships for the Gulf of Alaska. II. INTRODUCTION GENERAL NATURE AND SCOPE OF STUDY Operations associated with oil exploration, production, and transporta- tion in the northeast Gulf of Alaska (NEGOA) present a broad spectrum of potential dangers to the marine environment (see Olson and Burgess, 1967; Malins, 1977 for general discussions of marine pollution problems). Adverse effects on the marine environment of this area cannot be assessed nor pre- dicted, unless background data are recorded prior to industrial development. Insufficient long-term information about an environment, and the basic biology and recruitment of species in that environment, can lead to erroneous interpretations of changes in species which might occur if the area becomes altered (see Nelson-Smith, 1973; Pearson, 1971, 1972, 1975, 1980; Rosenberg, 1973 for general discussions on benthic biological investigations in indus- trialized marine areas). Populations of marine species may fluctuate over a time span of