Ecosystem Modeling in Cobscook Bay, Maine: A Boreal, Macrotidal Estuary 2004 Northeastern Naturalist 11(Special Issue 2):243–260 A Preliminary Survey of the Subtidal Macrobenthic Invertebrates of Cobscook Bay, Maine PETER FOSTER LARSEN1,* AND EDWARD S. GILFILLAN2 Abstract - Cobscook Bay, a boreal, macrotidal estuary in the northeastern Gulf of Maine is noted for its species richness and has been the site of extensive natural history investigations. In spite of this level of investigative activity, no quantitative survey of the subtidal, macroinvertebrate communities exist. Here we present the results of a 1975 benthic grab survey of outer Cobscook Bay prior to recent salmon aquaculture and port development. The limited 11-station survey resulted in the identification of 172 taxa. Densities ranged from 870 to 12,970 m-2. Multivariate and qualitative analyses clearly dissected the station set into sandy cove stations and coarse sediment channel stations. Cove stations were characterized by burrowing and tube-dwelling infauna, while channel station fauna was epifaunal. Community distribution is controlled by strong tidal currents and resulting sharp geological discontinuities. Because 70% of the Bay bottom is floored by gravel, the epifaunal community characterizing the channel stations may be the most representative of the Bay. The grab sampler certainly underestimated large filter feeders that may be important in the nutrient budget of the Bay. Future surveys need to be more extensive and use a combination of sampling methods to quantitatively measure all components of the community. Introduction The Gulf of Maine ranks among the world’s most productive and rich marine ecosystems. Many of the Gulf’s most remarkable examples of dynamic physical processes, species richness, and natural abundance are concentrated in the northern Gulf of Maine around the mouth of the Bay of Fundy (Larsen 2004a). The region contains North America’s only boreal, macrotidal estuaries, which include some of the least impacted estuaries in the United States. Cobscook Bay is a preeminent example of such an estuary. The biodiversity of Cobscook Bay was recognized early and much of the Northwest Atlantic invertebrate fauna was described from here (e.g., Verrill 1871, Webster and Benedict 1887). In subsequent decades, Cobscook Bay became a collecting destination for professionals and student groups, which has produced a solid qualitative database of the macroinvertebrates (Trott 2004). Additional information 1Bigelow Laboratory for Ocean Sciences, PO Box 475, West Boothbay Harbor, Maine 04575. 2Bowdoin College, Brunswick, ME 04011.*Corresponding author - plarsen@bigelow.org. 244 Northeastern Naturalist Vol. 11, Special Issue 2 on invertebrates was generated during investigations related to fisheries, tidal power development, oil refinery proposals, and salmon aquaculture monitoring (Larsen 2004a, Larsen and Webb 1997). Nevertheless, no quantitative investigations of the subtidal macrobenthos of Cobscook Bay are available in the published literature. In this communication, we present the results of a 1975 preliminary macrobenthic sampling survey in outer Cobscook Bay. The stations occupied are in the precise location of subsequent salmon aquaculture operations and port development (Sowles and Churchill 2004). Physical Environment Cobscook Bay is located in extreme eastern Maine on the USCanadian border near the mouth of the Bay of Fundy (Fig. 1). Together Figure 1. Map of Cobscook Bay, ME. Shaded box indicates the study area. 2004 P.F. Larsen and E. Gilfillan 245 with Passamaquoddy Bay and the enveloping islands, the area is known as the Quoddy region. Cobscook Bay is a rock-framed, glaciated, tidally dominated estuary (Kelley and Kelley 2004). The large tidal range, with a mean value of 5.7 m, is a dominating ecological forcing function (Campbell 2004). Freshwater input is small, < 1% of the intertidal volume, whereas the tidal flow over the narrow outer portion of the Bay, where our study area is located, is equivalent to the mean outflow of the Mississippi River over the duration of both the ebb and flood tides (Brooks et al. 1999). Peak current speeds are on the order of 2 m/sec. Mean depth of the Outer Bay is about 30 m with pockets to about 45 m. The well-mixed nature of the tidal waters results in moderated seasonal ranges of temperature and salinity. Mean temperature variation is less than 10 oC, while salinity variation is only about 1 ppt (Shenton and Horton 1973). More information on the Cobscook Bay region can be found in the comprehensive bibliography of Larsen and Webb (1997). Methods Eleven stations located in the vicinity of Broad Cove, Shackford Head, and Deep Cove in the eastern portion of outer Cobscook Bay Figure 2. Locations of the 11 subtidal stations sampled in 1975 in outer Cobscook Bay. 246 Northeastern Naturalist Vol. 11, Special Issue 2 were sampled with a 0.1-m2 Smith-McIntyre grab (Figs. 1 and 2). Multiple casts of the grab were often required to obtain the planned two replicates per station because of the coarseness of the sediments and/or bedrock outcroppings. In spite of this effort, only one sample was recovered successfully from Stations 23 and 31. A small subsample was removed from the first grab at each station for use in sediment analyses. The contents of the grab samples were sieved on a 1.0 mm screen. The residue was fixed in a 5% buffered formaldehyde solution and later transferred to 70% ethanol. Surface water samples were taken for temperature and salinity determinations at Stations 29 and 32 at slack low water. In the laboratory, the sediment grain size distributions were determined using nested series sieves based on the Wentworth scale. Particles in the silt and clay size range were negligible. All organisms were removed from the sample residue, identified to the lowest practical taxonomic level using a low-powered dissecting microscope, and counted. Oligochaetes and colonial species were not treated quantitatively. Statistical analyses was completed with the aid of PRIMER software (Clarke and Warwick 1994) and standard diversity formulas (Margalef 1958, Pielou 1970). Results Abiotic factors Sediments ranged from very fine sand to granule, with a marked gradient from the inner cove stations to the main tidal channel (Table 1). Sediments at the four stations in the interior of Broad and Deep Coves (i.e., stations 22, 29, 32, and 33) consisted of 79% or higher fine and very fine sands (Table 1, Fig. 2). The outer stations along the tidal channel (23, 25, 26, 27, 28, and 31) all were dominated by granule-sized particles, i.e., gravel and cobble. Station 24, with the sediment grain size Table 1. Grain size distributions at 11 stations in Cobscook Bay. % dry weight Coarse/ Fine/ Station # granule very coarse sand Medium sand very fine sand 22 4 4 3 89 23 100 0 0 0 24 4 19 46 31 25 59 20 12 9 26 62 26 9 5 27 41 24 23 10 28 48 13 26 13 29 0 0 0 100 31 72 12 4 12 32 1 2 2 95 33 5 9 7 79 2004 P.F. Larsen and E. Gilfillan 247 mode in the medium sand class, was the only station not dominated by sediments on the ends of the observed grain size spectrum. Low water surface temperature and salinity measured at station 29 in Broad Cove were 12.5 oC and 31.98 ppt, respectively. Corresponding values at station 32 in Deep Cove were 11.0 oC and 31.95 ppt. Species composition One hundred and seventy-two taxa from 12 phyla were identified from the 20 grab samples; 142 of them were identified to the genus or species level (Appendix 1). Annelids were the most diverse group with 59 putative species followed by arthropods and molluscs with 47 and 44 taxa, respectively. Complete faunal data can be found in Larsen (2004b). Cluster analysis The dendrogram based on a group-average sorting classification using the Bray-Curtis similarity measure on square root transformed species data resulted in branching revealing a clear-cut spatial pattern (Fig. 3). The primary dichotomy (A) separated stations into those in the tidal channel (stations 23, 24, 25, 26, 27, 28 and 31) and those in the coves (stations 22, 29, 32, and 33). Dichotomy B segregated station 26A, the only channel replicate containing no Spirorbis borealis (Larsen 2004b), from the other channel stations. All other channel Figure 3. Dendrogram based on a group-average sorting classification using the Bray-Curtis similarity measure on non-transformed species data. 248 Northeastern Naturalist Vol. 11, Special Issue 2 samples exhibited similarities in the 40–60% range. Dichotomy C separated station 29, containing the finest sediments, from the three mixed sand cove stations. Finally, both Deep Cove stations were separated from the outer, homogenous Broad Cove station 22 by dichotomy D. The sensitivity of the analysis was further reflected by the pair-grouping of replicates of five of the nine multiple replicate stations, i.e., stations 22, 24, 29, 32, and 33. The biological relationships amongst the 20 samples were investigated further using a non-metric multidimensional scaling (MDS) ordination with the Bray-Curtis similarity measure calculated on square root transformed abundance data. The two-dimensional MDS ordination produced distinct separation of channel stations (23, 24, 25, 26, 27, 28, and 31) and cove stations (22, 29, 32, and 33) (Fig. 4), thus matching the cluster analysis results. The agreement of the classification and ordination was further reflected by the outlying positions of samples 26a, 29a, and 29b. The goodness-of-fit of the two-dimensional ordination was measured by calculating a stress value. The observed stress value of 0.09 “corresponds to a good ordination with no real prospect of misleading interpretation” (Clarke and Warwick 1994). ANOSIM confirmed the strength of the analysis and yielded a Global R value of 0.577 at a significance level of p < 0.002. One hundred and four putative species were found at the four cove stations and 135 were identified from the seven channel stations (Appendix 1). Thirty-eight and 68 species were limited to the cove and Figure 4. MDS ordination of the 20 replicate samples based on square root transformed species abundances and Bray-Curtis similarities (stress = 0.09). 2004 P.F. Larsen and E. Gilfillan 249 channel stations, respectively, and 66 species were common to both areas. Fifty-three taxa were limited to a single station. Cnidarians, bryozoans and echinoderms, with the exception of the brittle star Ophiura robusta, were found only at channel stations. Other species which were found exclusively or more abundantly at the channel stations include: the chitons Lepidopleurus cancellotus and Puncturella noachina; the limpet Acmaea tectura; the jingle shells Anomia sqamula and A. simplex; the cockle Cerastoderma pinnulatum; the gastropod Margarites costalis; the scaleworms Harmothoe imbricata, Lagisca extenuata, and Lepidonotus squamatas; the serpulids Hydroides dianthus, Spirorbis borealis, and S. spirillum; the pycnogonids Achelia spinosa, Nymphon hirtipes, and Phoxochilidium sp.?; and the epifaunal pericarids Aeginina longicornis and Megamaera dentata. Few numerically important species were limited to or had their centers of abundance at the cove stations. These few included the isopod Edotia triloba, the amphipods Haploops spinosa, Leptocheirus pinguis, and Unciola irrorata, and the deposit feeding polychaete Nephtys bucera. Community structure The numbers of species, density, informational diversity, and numerical dominance were measured at each station (Table 2). Numbers of Table 2. Community parameters and numerical dominance. # of # of Stations replicates species Density (m2) Diversity (H1) Numerical dominance Channel 23 1 39 3380 1.62 Spirorbis borealis 68% 24 2 54 2195 2.32 Spirorbis borealis 52% 25 2 59 2470 2.11 Spirorbis borealis 60% 26 2 50 2460 1.57 Spirorbis borealis 70% 27 2 48 870 3.03 Spirorbis borealis 28% 28 2 52 3345 1.55 Spirorbis borealis 72% 31 1 29 2900 1.89 Spirorbis borealis 46%, S. spirillum 23% Cove 22 2 54 12,970 1.15 Unciola irrorata 80% 29 2 28 1330 2.34 Diastylis sp. 26%, Edotia triloba 17%, Scoloplos sp. 15%, Nephtys bucera 12% 32 2 70 2235 3.40 Casco bigelowi 15%, Haploops spinosa 15% 33 2 62 6880 2.59 Haploops sp. 28%, Leptocheirus pinguis 18%, Unciola irrorata 14% All Mean 50 3730 2.14 Min 28 870 1.15 Max 70 12,970 3.40 250 Northeastern Naturalist Vol. 11, Special Issue 2 species per station ranged from 28 to 70 with a mean of 50. Lowest number of species occurred at station 29, the most inshore station in Broad Cove that also exhibited the finest sediments (Table 1). The two single sample channel stations also exhibited below average numbers of species. The most species rich stations were located in Deep Cove. Abundance ranged between 870 and 12,970 individuals/m2 with an overall mean of 3730 (Table 2). Lowest density was found at station 27. The other six channel stations exhibited similar densities with a mean and standard deviation of 2792 ± 497. The highest densities occurred at the outer cove stations, 22 and 33, which exhibited densities of 12,970 and 6880 individuals/m2, respectively. Unpaired t-tests indicated that there were no statistically significant differences for any of the community parameters between the cove and channel stations. Discussion This first published quantitative account of the subtidal benthos of the macrotidal Cobscook Bay is remarkable for the sharp faunal contrasts revealed over relatively short distances. Two distinct communities, one occupying the cove stations and the other located at the channel stations, are clearly defined by both multivariate and qualitative analyses. The four nearshore stations located in Broad Cove and Deep Cove are characterized by various grades of sand and are dominated by burrowing or tube-dwelling infauna. The highest densities encountered occur at the outer of the cove stations (stations 22 and 32) that have slightly coarser sediments than the more landward inner stations (Tables 1 and 3). The outer, coarse-bottomed stations in the tidal channel have high species richness with 135 taxa identified from only 12 grab samples. All channel stations are numerically dominated by epifaunal, filter feeding tube-worms of the genus Spirorbis. A study of the feeding habits of three coexisting chiton species in Deep Cove also emphasizes the epifaunal nature of the community (Langer 1983). Cobscook Bay is a rock-framed, tidally dominated estuary and the community distribution mirrors the geological parameters of the sites and the underlying physical forcing functions. Cobscook Bay is subject to a semi-diurnal M-2 tide with a mean range of 5.7 m (Brooks et al. 1999). The relatively large tidal range combined with the shallow nature of the Bay results in the exchange of 38% of the high tide volume on each mean tide which produces currents of up to 2 m/sec (Brooks 2004). These high tidal flows winnow out fine landward-derived sediments and result in gravel being the most abundant seafloor material in each arm of the Bay (Kelley and Kelley 2004). Overall, gravel and rock account for 70% of the subtidal Bay bottom, with 90% of the Outer Bay, 54% of the Middle Bay, and 83% of the Inner Bay being floored by gravel (Kelley 2004 P.F. Larsen and E. Gilfillan 251 and Kelley 2004). Kelley and Kelley (2004) also note the abrupt changes between the fine landward sediments and the dominant gravel. The origin of the sandy sediments is the eroding bluffs at the interior of the coves and the grain size increases toward the main tidal channel (Kelley and Kelley 2004). The linkages between the physical and biological attributes are unusually clear in this energetic estuary. Overlying the modeled currents on the station map demonstrates the relationships between currents, sediments, and fauna (Figs. 5 and 6). The inner cove stations (29, 32) have the lowest current levels and the finest sediments most recently eroded from the bluffs. The outer cove stations have higher currents, slightly coarser sediments, and highest faunal densities. All cove stations are dominated by infaunal species. The channel stations (23, 24, 25, 26, 27, 28, and 31) experience high currents, are characterized by granule-sized sediments (Table 1, Fig. 6), and are dominated by filterfeeding epifauna. Given that 70% of the Bay is floored by this sediment Figure 5. Stations overlain on surface currents from hydrographic model simulation. Longer arrows indicate currents of 2 m/sec. Modified from Brooks et al. (1999). 252 Northeastern Naturalist Vol. 11, Special Issue 2 type (Kelley and Kelley 2004) and that the very minor amount of freshwater input results in only very narrow ranges of temperature and salinity throughout the Bay (Brooks et al. 1999), the epifaunal community described in the vicinity of Shackford Head may be the most extensive subtidal community in the Bay. Further exploratory sampling is indicated. The Smith-McIntyre grab is not ideal for sampling the coarse sediments occurring in the Bay; no sampler is entirely adequate (Holme and McIntyre 1984). Larger and motile macrofauna may be missed or underestimated by the grab, and thus the exploratory results presented here are incomplete. This may be significant because, as Garside and Garside (2004) demonstrate, a remarkable feature of the Cobscook Bay ecosystem is the degree that ammonium plays in the nutrient budget. These authors conclude that the tidal exchange of ammonium is up to 14.9 metric tons per day. Furthermore, the seasonal pattern of ammonium in the Bay’s waters, high in the spring and fall when primary production is low, indicates that the principal source of the ammonium must be regeneration by long-lived filter feeders and grazers. Since the gravel community described here covers 70% of the Bay bottom (Kelley and Kelley 2004), it seems likely that some component of the community would be involved in the regeneration process. The numerically dominant filter feeders identified in the present study are the serpulid worms Spirorbis borealis and S. spirillum. It has been reported that small epifaunal suspension feeders, including spirorbid polychaetes, occur- Figure 6. Stations with overlain bottom types. Modified from Kelley and Kelley (2004). 2004 P.F. Larsen and E. Gilfillan 253 ring in high densities may constitute filtering capacities on the same order of magnitude as macro suspension feeders (Lemmens 1996, Lemmens et al. 1996). Using filtering rates given by Dales (1957) and areas and volumes provided by Kelley and Kelley (2004) and Brooks et al. (1999), it can be estimated that these small spirobids filter 1.55 x 105 m3/tide, i.e., well less than 1% of the tidal prism. More likely candidates, suggested by Garside and Garside (2004), are the sea scallop, Placopecten magellanicus (Gmelin), and blue mussel, Mytilus edulis (L.), which filter 2.1 L g-1h-1 (Bacon et al. 1998) and 2.0 L g-1h-1 (Newell et al 1989), respectively. Dredge sampling reveals that the highest densities of P. magellanicus in the State of Maine occur in Cobscook Bay (Schick et al. 2004). Although density figures for M. edulis in Cobscook Bay are not available, a commercial dragging fishery does exist indicating high abundance. These species, however, would not be adequately sampled by a Smith-McIntyre grab. Future work needs to be focussed on the larger filter-feeders and grazers to get fuller understanding of the functional components of the ecosystem. Cobscook Bay stands apart from other Maine estuaries and embayments because of the coarse nature of the bottom sediments. Although deposits of sand and gravel do occur along the Maine coast as a result of the reworking of glacial sediments, glaciomarine muds are probably predominant in most areas (Belknap et al. 1987). It is our experience that the interior of Maine estuaries are characterized by mud and sand, and even sawdust bottoms (Larsen 1979; Larsen, unpubl. data; Larsen and Johnson 1985; Larsen et al. 1983, Shorey 1973). For this reason, as well as the small number of sand samples involved, comparisons of the present results with previous studies are of little value. Likewise, investigations of rock and cobble substrates in the region have used different methodologies making comparisons inappropriate (Logan et al. 1983, Scheibling and Raymond 1990). In conclusion, the distribution of the macroinvertebrate communities of Cobscook Bay are closely linked to hydrographic and geological attributes. The subtidal areas of the outer Cobscook Bay are characterized by infaunal and tube-dwelling species in the protected sandy coves and a rich epifaunal community in the extensive current-swept channel areas. The latter areas comprise 70% of the subtidal areas of the Bay, which is unusual for a Maine estuary. It also suggests that filter-feeding components of this community may play an important role in the nutrient budget of the Bay that is characterized by high levels of ammonium (Garside and Garside 2004). While these implications are intriguing, this study is preliminary and limited in spatial coverage and in the adequacy of the sampling gear. Future surveys need to be more extensive and use a combination of sampling methods to quantitatively assess all components of the community. The cove stations, however, provide 254 Northeastern Naturalist Vol. 11, Special Issue 2 a good benchmark with which to evaluate the affects of subsequent aquaculture and port development. Acknowledgments These data were originally collected to evaluate the potential impacts of an oil refinery proposed for Eastport, ME, by the Pittston Company of New York. Lee Doggett ably assisted sampling and sample processing. Data analysis was undertaken as part of a research program entitled “Developing an Ecological Model of a Boreal, Macrotidal Estuary: Cobscook Bay, Maine,” funded by a grant from the A.W. Mellon Foundation to The Nature Conservancy, with matching funds from Funders and Organizations involved, and services provided by Bigelow Laboratory for Ocean Sciences, University of Maine at Orono and Machias, Texas A&M University, US Fish and Wildlife Service Gulf of Maine Program, Suffolk University (Friedman Field Station), Maine Department of Marine Resources, and The Nature Conservancy. Tom Trott and Jill Fegley were invaluable in data processing. Stacy Edgar and David Phinney prepared most of the figures. The manuscript was improved through reviews by Thomas Trott, Gerhard Pohle, and an anonymous reviewer. Literature Cited Bacon, G.S., B.A. MacDonald, and J.E. Ward. 1998. 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The effects of natural seston particle size and type on feeding rates, feeding selectivity, and food resource availability for the mussel Mytilus edulis Linnaeus, 1758 at bottom culture sites in Maine. Journal of Shellfish Research 8:187–196. Pielou, E.C. 1970. An Introduction to Mathematical Ecology. Wiley- Interscience, New York, NY. 286 pp. Scheibling, R.E., and B.G. Raymond. 1990. Community dynamics on a subtidal cobble bed following mass mortalities of sea urchins. Marine Ecology Progress Series 63:127–145. Schick, D., S. Feindel, and G. Nutting. 2004. Completion report: Interjurisdictional fisheries resource monitoring and assessment. State of Maine, Grant No. NA03NMF4070101. Maine Department of Maine Resources, Hallowell, ME. 256 Northeastern Naturalist Vol. 11, Special Issue 2 Shenton, E.H., and D.B. Horton. 1973. Literature review of the marine environmental data for Eastport, Maine. TRIGOM Report No. 2A.The Research Institute of the Gulf of Maine, Portland, ME. Shorey, W.K. 1973. Macrobenthic ecology of a sawdust-bearing substrate in the Penobscot River estuary (Maine). Journal of the Fisheries Research Board of Canada 30:493–497. Sowles, J.W., and L. Churchill.2004. Predicted nutrient enrichment by salmon aquaculture and potential effects in Cobscook Bay, Maine. Northeastern Naturalist 11(Special Issue 2):87–100. Trott, T.J. 2004. Cobscook Bay inventory: A historical checklist of marine invertebrates spanning 162 years. Northeastern Naturalist 11(Special Issue 2):261–324. Verrill, A.E. 1871. Marine fauna of Eastport, ME. Bulletin of the Essex Institute, Salem, MA. 3:2–6. Webster, H.E., and J.E. Benedict. 1887. Annelida Chaetopoda from Eastport, Maine. Report of the US Fishery Commission 1885:707–755. 2004 P.F. Larsen and E. Gilfillan 257 Appendix 1. List of subtidal macrobenthic invertebrates collected at 11 stations in outer Cobscook Bay. Species listed in alphabetical order within higher taxa. # of occurrences at Cove Channel Phylum Species stations stations Porifera Polymastia robusta (Bowerbank, 1816) 1 Porifera sp. 1 Cnidaria Actiniaria sp. 1 Drifa glomerata (Verrill, 1869) 1 Hydrozoa 5 Metridium senile (Linnaeus, 1767) 1 Nemertea Nemertea 4 3 Priapula Priapulus caudatus Lamarck, 1816 2 Bryozoa Bryozoa 6 Brachiopoda Terebratulina septentrionalis (Couthoy, 1838) 1 Mollusca Anomia simplex D’Orbigny, 1842 2 Anomia squamula Linnaeus, 1758 3 Astarte borealis (Schumacher, 1817) 2 Astarte castanea (Say, 1822) 1 Astarte undata Gould, 1841 2 2 Astyris lunata (Say,1826) 2 2 Bivalve sp. juv. 1 Buccinum ciliatum (Fabricius, 1780) 2 Buccinum polaris Gray, 1839 1 2 Calliostoma occidentale (Mighels and Adams, 1842) 1 Cerastoderma pinnulatum (Conrad, 1831) 3 7 Clinocardium ciliatum (Fabricius, 1780) 1 Colus pubescens (Verrill, 1882) 2 Crenella decussata (Montagu, 1808) 2 4 Crepidula fornicata (Linnaeus, 1758) 2 Cyclocardita borealis (Conrad, 1831) 3 2 Cylichna alba (T. Brown, 1827) 3 1 Euspira immaculata (Verrill, 1880) 2 2 Hiatella arctica (Linnaeus, 1767) 1 1 Lepeta caeca (Müller, 1776) 2 Lepidopleurus cancellotus (Sowerby, 1839) 7 Lyonsia arenosa (Müller, 1842) 4 Macoma balthica (Linnaeus, 1758) 1 Margarites costalis costalis (Gould, 1841) 5 Margarites sp. 1 2 Musculus discors (Linnaeus, 1767) 1 Musculus niger (Gray, 1824) 1 2 Mya arenaria Linnaeus, 1758 1 2 Mytilidae sp. juv. 2 Neptunea lyrata decemcostata (Say, 1826) 1 Nucula delphinodonta Mighels and Adams, 1842 2 1 258 Northeastern Naturalist Vol. 11, Special Issue 2 # of occurrences at Cove Channel Phylum Species stations stations Mollusca Nucula proxima Say, 1822 3 1 Onoba mighelsi (Stimpson, 1851) 1 1 Pandora gouldiana Dall, 1886 1 Puncturella noachina (Linnaeus, 1771) 4 Scabrotrophon fabricii (Möller, 1842) 1 Solariella sp. 1 2 Tectura testudinalis (Müller, 1776) 4 Tellina agilis Stimpson, 1857 1 1 Thyasira flexuosa (Montagu, 1803) 3 2 Tonicella marmorea (Fabricius, 1780) 1 Tonicella rubra (Linnaeus, 1767) 3 Unidentified gastropod 1 1 Yoldia sapotilla (Gould, 1841) 3 3 Annelida Ampharetidae sp. 1 1 Aphrodita hastata Moore, 1905 2 Aricidae sp. 1 Aricidea catherinae Laubier, 1967 2 2 Brada granosa Stimpson, 1854 1 Brada villosa (Rathke, 1843) 1 Cirratulidae sp. 1 2 Drilonereis magna Webster and Benedict, 1887 1 Eteone longa (Fabricius, 1780) 1 2 Eteone sp. 1 Eteone trilineata Webster and Benedict, 1887 1 Exogone dispar (Webster, 1879) 2 Exogone verugera (Claparéde, 1868) 2 1 Flabelligera affinis Sars, 1829 2 1 Glycera capitata Örsted, 1843 1 Harmothoe imbricata (Linnaeus, 1767) 3 7 Harmothoe sp. 1 2 Hydroides dianthus (Verrill, 1873) 1 Lagisca extenuata (Grube, 1840) 1 5 Lepidonotus squamatus (Linnaeus, 1767) 6 Levinsenia gracilis (Tauber, 1879) 3 5 Lumbrineris fragilis (Müller, 1776) 3 3 Lumbrineris sp. 2 Lumbrineris tenuis (Verrill, 1873) 1 Maldanidae sp. 2 5 Neanthes diversicolor (Müller, 1776) 1 1 Nephtyidae sp. 1 Nephtys bucera Ehlers, 1868 4 2 Nepthys sp. 2 1 Nereis sp. 1 Nereis zonata Malmgren, 1867 1 2 Ninoe nigripes Verrill, 1873 3 1 Oligochaeta 3 5 Ophelina acuminata Örsted, 1843 2 5 Owenia fusiformis Delle Chiaje, 1844 3 4 Paraonis sp. 2 1 2004 P.F. Larsen and E. Gilfillan 259 # of occurrences at Cove Channel Phylum Species stations stations Annelida Pectinaria gouldii (Verrill, 1873) 2 1 Pectinaria sp. 2 Pholoe minuta (Fabricius, 1780) 4 7 Phyllodoce groenlandica (Örsted, 1842) 2 Phyllodoce maculata (Linnaeus, 1767) 2 1 Phyllodoce sp. 1 Polychaete A 1 2 Polychaete B 2 Polychaete C 3 Polycirrus sp. 2 Polynoidae sp. 2 Scoloplos acutus (Verrill, 1873)? 1 Scoloplos sp. 4 Spionidae sp. 4 5 Spirorbis borealis Daudin, 1800 7 Spirorbis spirillum (Linnaeus, 1758) 6 Sternaspis scutata (Renier, 1807) 2 Syllidae sp. 3 Syllis gracilis Grube, 1840 3 6 Terebellidae sp. 4 7 Travisia carnea Verrill, 1873 1 Unidentified polychaete 2 4 Sipuncula Phascolion strombus strombus (Montagu, 1804) 2 1 Arthropoda Achelia spinosa (Stimpson, 1853) 6 Aeginina longicornis (Kröyer, 1842–43) 5 Ampelisca macrocephala (Liljeborg, 1852) 3 Ampelisca vadorum (Mills, 1963) 1 Anonyx lilljeborgi (Boeck, 1871) 4 1 Caprella linearis (Linnaeus, 1767) 1 Casco bigelowi (Blake, 1929) 3 1 Chiridotea tuftsi (Stimpson, 1853) 1 Corophium bonelli (Milne-Edwards, 1830) 1 4 Corophium crassicorne (Bruzelius, 1859) 2 Corophium sp. 1 Cyathura polita (Stimpson, 1856) 1 Deflexilodes intermedius (Shoemaker, 1930) 1 Dexamine thea (Sars, 1893) 1 Diastylis quadrispinosa Sars, 1871 3 2 Diastylis sp. 4 2 Edotia triloba (Say, 1818) 4 Erichthonius rubricornis Smith, 1873 1 Eualus pusiolus (Kröyer, 1841) 1 Eudorella sp. 1 Eusiridae sp. A 2 Eusiridae sp. B 1 2 Gnathia sp. 1 Haploops tubicola Lilljeborg, 1855 3 Harpinia propinqua (Sars, 1895) 2 260 Northeastern Naturalist Vol. 11, Special Issue 2 # of occurrences at: Cove Channel Phylum Species stations stations Arthropoda Harpinia sp. 1 Hippomedon serratus (Holmes, 1905) 1 Ischyrocerus anguipes Kröyer, 1838 1 Jaera albifrons Leach, 1814 1 Lafystiidae? Sp. 1 Lebbeus groenlandicus (Fabricius, 1775) 1 Leptocheirus pinguis (Stimpson, 1853) 3 5 Megamaera dentata (Kröyer, 1842) 5 Nymphon hirtipes Bell, 1853 2 Orchomenella minuta (Kröyer, 1842) 4 1 Orchomenella pinguis (Boeck, 1861) 2 Pagurus pubescens Kröyer, 1842 1 Pandalus montagui Leach 1814 1 1 Photis sp. 1 Phoxocephalus holbolli (Kröyer, 1842) 2 4 Phoxochilidium? sp. 2 Pycnogonum littorale (Storm, 1762) 1 2 Spirontocaris phippsii (Kroyer, 1841) 1 Stenopleustes inermis Shoemaker, 1949 1 Tanaidacea sp. 2 Unciola irrorata Say, 1818 3 3 Unidentified amphipod 1 Echinodermata Asterias sp. 1 Crossaster papposus (Linnaeus, 1766) 2 Ctenodiscus crispatus (Retzius, 1806) 1 Echinarachnius parma (Lamarck, 1816) 2 Edwardsia sp. 2 Henricia sp. 3 Ophuira robusta (Ayres, 1861) 2 7 Strongylocentrotus droebachiensis (Müller, 1776) 7 Chordata Molgula complanata Alder and Hancock, 1870 1 3 Unidentified stalked Ascidiacea 1 3 Phylum unknown 1 1 Totals 104 135