The Biological Setting of the BIOS Site at Cape Hatt, N.W.T., Including the Sampling Design, Methodology and Baseline Results for Macrobenthos

Abstract

The Baffin Island Oil Spill (BIOS) Project was carried out in nearshore shallow waters at Cape Hatt, northern Baffin Island. Observations and limited data on phytoplankton, Zooplankton, fishes, birds and mammals at Cape Hatt and more detailed information on microheterotrophs indicate that the BIOS site is typical of the majority of eastern and central High Arctic coastal areas. Detailed baseline information on nearshore macrobenthos (infauna, epibenthos and macroalgae) is, in general, similar to that previously reported for other eastern and central arctic locations; comparisons were hindered by a scarcity of detailed studies elsewhere, differences in sampling methods and complexity in infaunal community structure. Infaunal density (means from 1 1 19 to 3981 individuals· m 2 in different study bays and sampling periods) was dominated by polychaetes, especially Pholoe minuta, whereas infaunal biomass (59-2267 gm"2) was dominated by bivalves, primarily Mya truncata. Epibenthic crustaceans (207-2527 individuals m'2) were dominated by ostracods, amphipods (notably Guernea sp.) and cumaceans (Lampropsfuscata). The sea urchin Strongylocentrotus droebachiensis (up to 10 individuals · m 2) and the seastar Leptasterias polaris (up to 2 individuals m"2) were the large and conspicuous echinoderms on study transects. Macroalgal biomass was from 178 to 1112 gm"2 (not including a Laminaria zone); communities at 3 m depth were dominated by loose-lying understory algae, particularly Stictyosiphon tortilis, Pilayella littoralis and Dictyosiphonfoeniculaceus. The deeper transects (7 m) supported a considerably higher infaunal biomass and density of epibenthos than did 3 m transects in both sampling periods, whereas depth differences in macroalgal biomass varied from September 1980 to August 1981. An evaluation of the sampling design and procedures used in this study (including efficiency of the diver-operated airlift sampler; the area, location and number of replicate samples collected; and bias, efficiency and consistency in laboratory analysis) indicated that representative samples of the nearshore macrobenthic communities were obtained. The study design and analysis of variance procedures used to analyze the data provided a rigorous framework within which oil effects were evaluated.