Attu Island Research Articles

Two New Variegated Snailfishes of the Genus Careproctus (Teleostei: Scorpaeniformes: Liparidae) from the Aleutian Islands, Alaska

Two new species of snailfishes are described on the basis of 99 individuals collected from the Aleutian Islands during resource assessment surveys conducted by the National Marine Fisheries Service. Both are distinguished from all known species of Careproctus by a variegated red, white, and gray body coloration, an unlobed dorsal fin, protruding snout, the absence of distal pectoral radials at the base of 8–12 ventral rays, and counts of median-fin rays and vertebrae. Careproctus comus, new species, is distinguished from Careproctus faunus, new species, by having a greater number of caudal vertebrae and median-fin rays, as well as a narrower interorbital width, shorter maxilla, shorter snout, shorter connection of anal-fin membrane to caudal fin, and more slender caudal-fin base. Careproctus comus ranges from west of Attu Island, on Stalemate Bank, to the eastern Aleutian Islands, near Unalaska Island. Careproctus faunus ranges from Adak Island in the central Aleutians to just east of Unalaska Island. Both species are found at depths of approximately 150–400 m. Among other liparids of the North Pacific, the new species are superficially similar to Temnocora candida, from which both can be readily distinguished on the basis of their unlobed dorsal fin and higher counts of median-fin rays and vertebrae.

Tub toys orbit the Pacific subarctic gyre

In 1992, a cargo container of children's bath toys fell overboard in the middle North Pacific Ocean. Subsequently, 29,000 toys were tracked 4,000 kilometers to southeastern Alaska [Ebbesmeyer and Ingraham, 1994]. The spill's upcoming fifteenth anniversary has prompted an examination of the reports of toys stranded on shorelines around the Subarctic Gyre, a planetary vortex the size of the United States.Previous articles have reported the drift of sneakers and toys for a year or so only along the southern edge of the Pacific Subarctic Gyre [Ebbesmeyer and Ingraham, 1992, 1994]. However, continuing reports of stranded toys have stimulated curiosity about how long it would take the currents that link the Gyre's perimeter between Asia and America to transfer flotsam around the Gyre, that is, its orbital period. These currents (Figure 1) are the North Pacific Drift Current, Alaska Current/ Alaska Coastal Current, Alaskan Stream, Bering Slope Current and East Kamchatka Current, Oyashio Current, and Kuroshio. In the Bering Sea, the North Aleutian Current recurves north from Attu Island eastward along the north side of the Aleutians to merge with the Bering Slope Current.

A bumblebee new to the New World: Bombus distinguendus (Hymenoptera: Apidae)

AbstractBombus (Subterraneobombus) distinguendus Morawitz, 1869 is recorded from Attu Island, in the western Aleutian archipelago, and is recognised as a species new to both the Alaskan and the New World faunal lists. Colour variation and food plants are described and a key to females of Nearctic Subterraneobombus species is provided.

Northwestern song sparrow populations show genetic effects of sequential colonization

Two genetic consequences are often considered evidence of a founder effect: substantial loss in genetic diversity and rapid divergence between source and founder populations. Single-step founder events have been studied for these effects, but with mixed results, causing continued controversy over the role of founder events in divergence. Experiments of serial bottlenecks have shown losses of diversity, increased divergence, and rapid behavioural changes possibly leading to reproductive isolation between source and final populations. The few studies conducted on natural, sequentially founded systems show some evidence of these effects. We examined a natural vertebrate system of sequential colonization among northwestern song sparrows (Melospiza melodia). This system has an effectively linear distribution, it was probably colonized within the last 10,000 years, there are morphological and behavioural differences among populations, and the westernmost populations occur in atypical habitats for the species. Eight microsatellite loci from eight populations in Alaska and British Columbia (n = 205) showed stepwise loss of genetic diversity, genetic evidence for strong population bottlenecks, and increased population divergence. The endpoint population on Attu Island has extremely low diversity (H(E) = 0.18). Our study shows that sequential bottlenecks or founder events can have powerful genetic effects in reducing diversity, possibly leading to rapid evolutionary divergence.

Active displacement partitioning and arc-parallel extension of the Aleutian volcanic arc based on Global Positioning System geodesy and kinematic analysis

Research Article| August 01, 2000 Active displacement partitioning and arc-parallel extension of the Aleutian volcanic arc based on Global Positioning System geodesy and kinematic analysis Hans G. Avé Lallemant; Hans G. Avé Lallemant 1Department of Geology and Geophysics, Rice University, Houston, Texas 77251-1892, USA Search for other works by this author on: GSW Google Scholar John S. Oldow John S. Oldow 2Department of Geological Sciences, University of Idaho, Moscow, Idaho 83844-3022, USA Search for other works by this author on: GSW Google Scholar Geology (2000) 28 (8): 739–742. https://doi.org/10.1130/0091-7613(2000)28<739:ADPAAE>2.0.CO;2 Article history received: 10 Jan 2000 rev-recd: 18 May 2000 accepted: 26 May 2000 first online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Tools Icon Tools Get Permissions Search Site Citation Hans G. Avé Lallemant, John S. Oldow; Active displacement partitioning and arc-parallel extension of the Aleutian volcanic arc based on Global Positioning System geodesy and kinematic analysis. Geology 2000;; 28 (8): 739–742. doi: https://doi.org/10.1130/0091-7613(2000)28<739:ADPAAE>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu nav search search input Search input auto suggest search filter All ContentBy SocietyGeology Search Advanced Search Abstract Global Positioning System geodesy and structural analysis of parts of the Aleutian island chain support the interpretation of forearc migration westward along right-lateral transcurrent faults. Measured displacements are essentially arc parallel in the eastern (Unalaska Island) and western (Attu Island) parts of the arc and vary from 3.1 mm/yr to 31.4 mm/yr, respectively. At the center of the arc (Adak) subduction of the Amlia fracture zone disrupts the pattern of arc-parallel displacement and records an upper plate velocity of 9.6 mm/yr parallel to plate motion. Where active, displacement partitioning accommodates 30%–50% of the strike-slip component of plate convergence. In the area of impeded subduction partitioning ceases, suggesting that the process is sensitive to the degree of coupling across the plate-boundary megathrust. The differential arc-parallel displacements observed at the ends of the arc together with structural relations indicate substantial arc-parallel extension, which may play an important role in exhumation of high-pressure–low-temperature metamorphic rocks in ancient arc systems. You do not currently have access to this article.

First Breeding Records of Whooper Swan and Brambling in North America at Attu Island, Alaska

We document the first breeding records of Whooper Swan (Cygnus cygnus) and Brambling (Fringilla montifringilla) in Alaska and North America on Attu Island in the Western Aleutians in the spring of 1996. Five cygnets were seen with adults and the nest located, and a territorial pair of Bramblings was observed and a nest with eggs found.

Lichens of Adak Island, Central Aleutian Islands, Alaska

Two hundred nineteen taxa of lichens including one lichen parasite are reported from Adak Island in the central Aleutian Islands, Alaska. Stereocaulon leprocephalum is new to North America; Caloplaca ferrugineofusca and Verrucaria ditmarsica are new to Alaska. The lichen flora is dominated by wide-ranging arctic-alpine and boreal species; a coastal element is moderately represented, while amphi-Beringian species form a minor element. This phytogeographic pattern is very similar to that of Attu Island, the westernmost Aleutian Island. The Aleutian Islands are a chain of mountainous volcanic islands extending in an arc 1,900 km west from the tip of the Alaska Peninsula approaching the Commander Islands of northeast Asia. Adak Island is in the Andreanof Islands group within the central Aleutian Islands. Adak, the largest (748 km2) of this island group, is dominated by rugged mountainous terrain and broad rolling lowland areas; modified volcanic cones, Mt. Moffett and Adagdak, occur in the northern part and narrow beaches are usually found adjacent to sea cliffs. As one of the central islands in the Aleutian chain, Adak Island is of considerable phytogeographic interest. Hitherto the lichen flora of Adak Island has received little attention. The only existing literature records are found in three reports that collectively report 32 species. Degelius (1937) reported lichen specimens collected by the Swedish botanist Eric Hult6n in 1932 that included 14 lichens from Adak Island. Later, Stair (1948) added five species to the flora based on a collection of W. J. Christian. Hein (1980) increased the list by 13 species. Of the species reported on Adak Island by previous authors only five, Alectoria sarmentosa (Ach.) Ach., Cetraria ciliaris Ach. (= Tuckermannopsis ciliaris), Cladonia pseudoevansii Asah. (= Cladina pseudoevansii), Pertusaria glomerata (Ach.) Schaerer, and Umbilicaria proboscidea (L.) Schrader, were not collected by the present authors. Comparative data from the nearest Aleutian Islands for which the lichen flora is relatively well known are Amchitka Island, 250 km to the west of Adak Island, and Attu Island, 650 km to the west. Thomson and Sowl (1989) reported the known total of Amchitka Island as 149 species and Talbot et al. (1991) reported 160 taxa for Attu Island. In the Tuxedni Wilderness Area of western lower Cook Inlet, Alaska, 1,800 km to the east of Adak Island, Talbot et al. (1992) reported 218 taxa. Caribou were introduced to Adak Island during the 1940's and lichens are known to be important in their diet (Sjenneberg & Slagsvold 1979; Sveinbjornsson 1990). Our qualitative observations of Adak Island lichens suggest that lichen cover may have been reduced due to grazing pressure from caribou. As a pioneering effort, the present study provides a checklist and voucher collection if future range assessment becomes necessary.

Displacement partitioning and arc-parallel extension in the Aleutian volcanic island arc

Convergence between the Pacific and North American plates along the Aleutian volcanic island arc is generally right-oblique; the obliquity increases from 0° in the east to nearly 90° in the west where the plate boundary becomes a transform fault zone. Preliminary results of a structural geology study of Attu Island (the most westerly U.S. island in the Aleutian chain and part of the Near Islands group) shows that the deformational structures are not directly related to the relative plate-convergence-rate vector, but to the plate-boundary-normal and -parallel components of this vector. The plate-boundary-(sub)normal component is responsible for conjugate sets of arc-(sub)parallel thrust faults and the plate-boundary-parallel component resulted in arc-parallel dextral strike-slip faults and their conjugates. However, the most penetrative structures measured in outcrop are conjugate sets of strike-slip faults and arc-perpendicular normal faults and fractures (veins and dikes) which have formed by arc-parallel extension. This extension is most likely the result of the increase of obliquity from east to west and thus the increase of the arc-parallel component of the convergence-rate vector along the Aleutian arc. These structures require that Attu Island migrated westward, possibly for as many as 1150 km.

Contribution toward an Understanding of Polystichum aleuticum C. Chr. on Adak Island, Alaska

Polystichum aleuticum has been described as one of the most restricted and rare ferns in North America (Smith 1985). The species was first collected in 1932 on Atka Island, Aleutian Islands, Alaska, by W. J. Eyerdam (an assistant to E. Hulten), and described by Christensen (1938). Recent attempts to relocate the original collection site on Atka Island have been unsuccessful (Smith & Davison, 1988). It was not rediscovered until a new population was found in 1975 on the northeast arm of Mt. Reed, Adak Island (Smith, 1985). Several subsequent searches in the Aleutian Islands led by R. Lipkin (Adak, Kagalaska Island), D. K. Smith (Adak, Atka Island), S. S. Talbot (Adak, Attu Island), and G. Tande (Adak Island) failed to locate new populations (Anderson, 1992). Finally, in 1988, S. L. Talbot and S. S. Talbot identified a second Adak Island locality on Mt. Reed, several hundred meters north of the first. These two populations formed the basis of a detailed study designed to characterize the habitat and establish permanent monitoring plots (Tande, 1989). Because Polystichum aleuticum is an endangered species (U.S. Department of Interior, 1988), field surveys were initiated in September 1993 to locate new populations. Thirteen major areas were selected for searches on Adak Island in September 1993 (S.L.T., S.S.T.) and twelve in August 1994 (W.B.S, S.L.T, S.S.T.). These extended from Mt. Adagdak in the north to the Lake Joan area in the south, a distance of 28 km, and from Three Arm Bay in the west to Kagalaska Strait in the east, a distance of 30 km. Sites include a wide range of geographic variation with habitats strongly matching those of known locations. While exploring a rock outcrop on the northwest arm of Mt. Reed in 1993, Sandra Talbot discovered a third locality of Polystichum aleuticum located at 51?49.960'N, 176?44.141'W at an elevation of 360.4 m asl. Like previous localities, the site was at the base of a steep rock outcrop on a northeast-facing upper slope below the summit. Notably, the third site was 2.8 km from previously known sites and approximately 120 m lower in elevation, thus expanding the geographical and elevational range of P aleuticum. The other two sites were on the northeast arm of Mt. Reed and separated from each other by only 370 m. A total of five clumps constituted the new population, four associated with rock grottos and one clump located close to the grotto in a herb meadow. One clump in the grotto contained four fronds about 10 cm in height, and lacked sori; a second clump contained five fronds 10 cm in height, also

Numerical classification of the coastal vegetation of Attu Island, Aleutian Islands, Alaska

Abstract. This phytosociological study of the beaches, dunes, and associated lower mountain slopes of Attu Island is the first effort to identify the major coastal vegetation types of the Aleutian Islands using numerical methods. It is the first attempt to use the relevé method in southern coastal Alaska and provides a basis for future comparison with other areas. 76 relevés represent the range of structural and compositional variation in the matrix of vegetation and landform zonation at 16 locations. Data are analyzed by multivariate methods using the MULVA‐4 computer package and ordered with Wildi's numerical procedure to produce results similar to traditional phytosociological tabular classification. Nine major community types are distinguished in four physiognomic groups: 1. Dwarf‐shrub mire: Vaccinium uliginosum‐Empetrum nigrum; 2. Meadow: Athyrium filix‐femina‐Streptopus amplexifolius, Artemisia tilesii‐Veratrum album, Elymus mollis‐Montia (Claytonia) sibirica, Ligusticum scoticum‐Elymus mollis; 3. Beach meadow: Elymus mollis‐Senecio pseudo‐arnica, Lathyrus maritimus‐Elymus mollis; and 4. Beach: Mertensia maritima and Arenaria (Honckenya) peploides. These community types are described and interpreted in response to a complex, topographic gradient. Phytogeographic comparison of Attu Island with neighboring areas suggests close relationship to the beach and beach‐meadow types of eastern Kamchatka and to the mesic meadows of the Alaskan Semidi Islands; there is a slightly lower relationship to the mesic meadows of nearby Buldir Island.

Magmatic and tectonic development of the western Aleutians: An oceanic arc in a strike‐slip setting

The Paleogene Basement Series on Attu Island in the Western Aleutians is dominated by tholeiitic basalts chemically similar to mid‐ocean ridge basalts (MORB; La/Yb ∼ 2, ϵNd &gt; +10.0, 206Pb/204Pb &lt; 18.4). These basalts evolved in “open” magma systems. Contemporaneous rhyolites and albite granites are chemically analogous to silicic volcanic rocks of modern ocean ridges (e.g., Iceland, Galapagos Spreading Center). The occurrence of chemically arc‐type tholeiitic basalts, with high Th/La and La/Ta relative to MORB, suggests that a depleted MORB‐like mantle source was variably modified by a subduction component. The Attu Basement Series is not allochthonous. Geological and tectonic constraints imply formation in arc‐adjacent, transtensional rifts that developed in a strike‐slip regime that was established ∼43 m.y. ago. Rifting of this kind may have produced much of the Western Aleutian crust between ∼43 and 15 Ma. Subsequently, small volumes of crystal‐rich andesite and dacite were erupted on Attu Island as well as throughout the Western Aleutians. These strongly calcalkaline rocks (FeO*/MgO∼1.1, CaO/Al2O3 ∼0.35 at 65% SiO2) are chemically akin to magnesian andesites of Piip Volcano, a hydrothermally active seamount that overlies small dilational structures within the broadly transpressional regime of the modern western arc. This transpressional setting is inferred to have been established throughout the Western Aleutians approximately 15 m.y. ago. The switch from tholeiitic magmatism in a transtensional regime to strongly calcalkaline magmatism in a transpressional regime may have resulted from clogging of the Aleutian‐Kamchatka junction with buoyant, subduction‐related terranes. These terranes probably originated to the east and were transported by strike‐slip motion along the western arc.

A New Combination for the Single American Element of Parasenecio (Asteraceae: Senecioneae)

In accordance with the acceptance of the generic name Parasenecio for the Asiatic-centered species historically referred to Cacalia, new combination is made for the single species that ranges to North America: Parasenecio auriculata (A. P. de Candolle) J. R. Grant. Cacalia auriculata was described by A. P. de Candolle (1837) from specimen collected in 1835 by Turczaninow between Yakutsk and Okhotsk, Yakutia, Russia. It ranges from Kamtchatka to the Commander and Kurile Islands (Russia), to Hokkaido and northern Honshu (Japan), and from the Russian Far East to Manchuria (China) and Korea (Hulten, 1930). In Alaska, it has been collected on five islands at the westernmost end of the Aleutian chain roughly adjacent to the Commander Islands, Attu, Agattu, and Alaid of the Near Islands, and Kiska and Buldir of the Rat Islands. Cacalia auriculata is one of number of species of primarily Asiatic distribution that ranges to the westernmost islands of the Aleutian chain. Hulten (1937) documented the American range for several species with this of distribution pattern including Senecio palmatus Pallas and Cirsium kamtchaticum Ledebour. The of the islands where these species are found is a distinctly Kamtchatkan type (Hulten, 1937: 37). The presence of these species in the Aleutians is due to their association with high-grown vegetation typical of Kamchatka that also extends to the Near and Rat Island groups, but is unknown to the remainder and majority of the Aleutian chain (Hulten, 1937). Robinson & Brettell (1973) described the genus Koyamacalia for the Asian species referred to Cacalia. Cacalia auriculata was transferred into Koyamacalia along with 46 other species (Robinson & Brettell, 1973). Jeffrey & Yi-Ling (1984) pointed out that Koyamacalia H. E. Robinson & R. D. Brettell was later synonym of Parasenecio W. W. Smith & Small. Jeffrey (1992) again commented on Parasenecio, but as in the earlier work, no new combinations were made. In order to update noNOVON 3: 154-155. 1993. menclature in the North American flora, the following new combination is made: Parasenecio auriculata (A. P. de Candolle) J. R. Grant, comb. nov. Basionym: Cacalia auriculata A. P. de Candolle, Prod. 6: 329. 1837 [1838]. TYPE: Inter Ochotiam [Okhotsk] et Jacutiam [Yakutsk], N. Turczaninow s.n. (holotype, G-DC, photo on microfiche seen). Ligularia auriculata Turczaninow ex A. P. de Candolle, Prod. 6: 329. 1837, pro syn. Koyamacalia auriculata (A. P. de Candolle) H. E. Robinson & R. D. Brettell, Phytologia 27: 271. 1973. Specimens examined. UNITED STATES. Alaska: Near Islands, Attu Island, 13?52'56N, 173015'E, 25 July 1943, Beals A (ALA); Attu Island, 13?52'56N, 173?15'E, Beals, 1943 (ALA); Attu Island, Massacre Bay area, 10 July 1973, Williams 3212 (US); Agattu Island, 13052'26N, 17033'06E, 13 Aug. 1974, Trapp 104 (ALA); Attu Island, Peaceful Valley, near Navy Town, 13052'50N, 173011'E, 18 Aug. 1983, Friedman & Michaelson 83-64 (ALA); Rat Islands, Buldir Island, 14052'21N, 175056'E, 14 July 1974, Dick 164 (ALA); Buldir Island, 14?52'21N, 175056'E, 25 Aug. 1974, Dick 403 (ALA). Acknowledgments. I thank Harold E. Robinson (Smithsonian Institution) for bringing my attention to this species, and for review of the manuscript. I also thank Alan R. Batten of the Northern Plant Documentation Center, Herbarium, University of Alaska Museum, Fairbanks, for sending data on the specimens at ALA.

Lichens of Attu Island, Alaska

One hundred fifty-three taxa of lichens and one lichenicolous fungus are reportedfrom Attu Island, the westernmost island of the Aleutian chain. Amygdalaria consentiens, Lecanora confusa, and Rhizocarpon obscuratum, are new to Alaska. The lichen flora ofAttu Island is primarily comprised of wide-ranging arctic-alpine and boreal species; a coastal element is moderately rep- resented, while amphi-Beringian species form a minor element. As the westernmost island in the Aleutian chain, Attu Island is of considerable phytogeographic in- terest; yet it is one of the poorly known islands. Cummings (1910), in the report of the Harriman Expedition, listed only four lichens collected by C. H. Townsend, in connection with the work of the U.S. Fish Commission Steamer Albatross at Attu

Late Quaternary vegetation of the Aleutian Islands, southwestern Alaska

Late Quaternary vegetational history of the Aleutian Islands is interpreted from fossil pollen and spore stratigraphy and radiocarbon chronology of sections of mires on the islands of Attu, Adak, Atka, and Umnak. Mires postdate the withdrawal of ice-age glaciers between approximately 12 000 and 10 000 years ago with the exception of the mire on Attu Island, where deglaciation apparently began as late as 7000 years ago. No uniform pattern of change in Pacific coastal tundra communities is evident in the fossil assemblages. Pollen assemblages, consisting variably of Gramineae, Cyperaceae, Empetrum, Umbelliferae, Salix, Ranunculaceae, Compositae, Polypodiaceae, and Lycopodium, reflect conditions in effect in different sectors of the Aleutian chain. Climate, soil, topography, volcanism, and seismic activity are noteworthy parameters influencing vegetation composition and distribution. Volcanism has been of major importance, as shown by thickness, distribution, and frequency of tephra layers that number 5 on Attu, 24 on Adak, 17 on Atka, and 5 on Umnak. A repeated condition of patch dynamics, created in the main by recurrent volcanic eruptions with widespread accompanying ashfalls, has apparently overprinted the effects of climatic change. Key words: Aleutian Islands, Quaternary, vegetation, fossil pollen, volcanism.

First North American Nesting and Occurrence of Haliaeetus albicilla on Attu Island, Alaska

The nearctic range of White-tailed Eagles (Haliaeetus albicilla) is listed as casual in the Aleutian Islands, Alaska (Attu, where probably breeds, Unalaska), in eastern Greenland and off Massachusetts, near Nantucket Lightship (AOU 1983). The species breeds only in western Greenland in the nearctic; a breeding report from Baffin Island has not been confirmed (AOU 1983). Reference in the AOU Check-list to H. albicilla breeding at Attu is based on data presented herein. We discovered an active aerie of this species on Attu Island (52049'N, 173010'E) in 1982. We have numerous observations of four individual H. albicilla there in May to September, 1977 to 1986 (summary follows). These observations and the nest site are all from the river valleys and coastline at the east end of Attu Island. We located the active nest in Temnac Valley on 25 May 1982 after watching both adult eagles take turns sitting in a rocky depression on a cliff ledge. On subsequent trips to this site in 1982 (31 May, 4 June) both adults were seen attending to a single downy chick. Photographs of the nest site are on file at the University of Alaska Museum (UAM). The same nest was active in 1983 with a single chick present. This chick was fledged and feeding on pink salmon (Oncorhynchus gorbuscha) with the adults along the Temnac River in September 1983. This nest has not been active since 1983; only one adult eagle has been recorded at Attu since 1983. The nest site was located on the north side of Temnac Valley, 2.7 km from the Temnac River mouth (and salt water) at approximately 80 m above sea level. The nest cup sat on a fractured rock ledge 20 m up the southeast face of a rock pinnacle. This pinnacle stood immediately in front of a south-facing 40-m high cliff face. A heavily vegetated 350 talus slope stretched from the pinnacle base to a point close to the river, roughly 30 m away. With a rim about 10 to 15 cm high on the outside, the nest was approximately 1 m in diameter. The wellpacked cup consisted of kelp (probably Laminaria), fronds and rachis of Athyriumfilix-femina, and Elymus arenarius. Stalks and a few umbel heads of Heracleum lanatum were included in the rim. This is a similar to contents from Aleutian nests of Bald Eagle H. leucocephalus (Murie 1959).

Observation on the Emaciated and Dead Short-tailed Shearwaters, Puffinus tenuirostris, in the North-Western Sea Area of the North Pacific in 1983

A study on migratory activities of the short-tailed shearwaters, Puffinus tenuirostris, was conducted during a voyage of trans-North Pacific from Japan to the United States. Its mass mortality was found occurring off Kashima-nada, Honshu, early June 1983. No weakened nor dead birds were observed on the navigation routes from Toyohashi to Portland, via the Hawaii, and from Portland to the Kuril Islands, via the Unimak Pass and Attu Island. A first floating emaciated bird occurred on June 5, when we came to off Hokkaido; in the waters south of it, along Tohoku to Kashima-nada, most of the 294 birds we encountered on June 6 were apparently emaciated, with 3 floating birds already dead. This sea area well coincided with the northern limit of the mass mortality recorded in that year, and was within the Kuroshio warm current. This suggests that birds which were strong enough to pass into the northern cold current, richer in marine productivity, would survive and that those exhausted not reaching there would die within the Kuroshio Current, owing to the food shortage.

Activity and Prey Election in the Sea Otter: Influence of Population Status on Community Structure

The population of sea otters (Enhydra lutris) at Amchitka Island has been at or near equilibrium density for at least 3 decades. At Amchitka, sea otters spent 55% of daylight hours foraging; there were distinct early morning and late afternoon peaks in foraging activity; and fish made up over 60% of their overall diet by volume. In contrast, the more recently established populations at Attu Island and off the coast of Oregon are far below equilibrium density. At both Attu and in Oregon, sea otters spent 17% of daylight hours foraging; there was no peak in foraging activity; and herbivorous macroinvertebrates made up their entire diet. We interpret these observations in the following way. Subsequent to the over-exploitation of sea otters, uncontrolled populations of herbivorous sea urchins greatly reduced or eliminated sublittoral kelp assemblages. In areas only recently reoccupied by otters, sea urchins are abundant and easily accessible as prey. Otters in these areas invest relatively little effort in foraging, and distribute that effort uniformly throughout the day. Where otters are abundant sea urchins are scarce, in turn promoting the growth of kelp beds and an associated fish fauna. Consequently otters at Amchitka invest more time in pursuit of more elusive prey (fish), and distribute that effort disproportionally toward morning and evening to correspond with availability of kelp bed fishes. These observations demonstrate that foraging tactics of a consumer are closely linked to its influence on the structure of the community.

UMBILICAL BROOD PROTECTION AND SEXUAL DIMORPHISM IN THE BOREAL PACIFIC TROCHID GASTROPOD,MARGARITES VORTICIFERUSDALL

Specimens of Margarites vorticiferus Dall collected at Attu Island, Alaska, during July 1979, were found brooding eggs and young in the umbilicus. The number of developing young in each brood ranged between 471 and 3264. Each brood contained several developmental stages including uncleaved eggs, unhatched embryos, hatched pro-toconch-bearing juveniles and two distinct juvenile size classes. The umbilicus of M. vorticiferus is significantly (t-test; P < 0.001) larger in female specimens than in male specimens. Margarites vorticiferus is the largest member of the genus found at Attu and the only member known to brood its young.

REVISION OF THE WOLF SPIDER GENUSALOPECOSASIMON IN NORTH AMERICA (ARANEAE: LYCOSIDAE)

AbstractThe genusAlopecosaSimon is revised for North America. A general description for the group is given, and a key to species is presented. Seven species are represented in North America:A.aculeata(Clerck, 1757) from Alaska to Newfoundland and southward to Arizona;A.kochi(Keyserling, 1877) (=Tarentula gertschiSchenkel, 1951 syn. n., =Lycosa jollensisSchenkel, 1951 syn. n.) from southern B.C., southern Ontario, and western and northern U.S.A.;A.pulverulenta(Clerck, 1757) (=Tarentula aquilonarisFox, 1940 syn. n.), recorded from the Nearctic on the basis of a female from Attu Island, Alaska;A.exasperans(O. Pickard-Cambridge, 1877) from the Canadian Arctic islands;A.mutabilis(Kulczynski, 1908) from northern Alaska;A.pictilis(Emerton, 1885) from Alaska to Labrador and New Hampshire; andA.hirtipes(Kulczynski, 1907) (=Tarentula hirtaKulczynski, 1908, syn. n., =Lycosa asivakEmerton, 1919, syn. n., =Tarentula hamiltoniChamberlin &amp; Ivie, 1947, syn. n.) from Alaska to northern Quebec.

Microtextures and microintergrowths of irontitanium-aluminium oxide minerals in a magmatic tinaniferous iron ore from Attu island, southwestern Finland

Microtextures and microintergrowths of irontitanium-aluminium oxide minerals in a magmatic tinaniferous iron ore from Attu island, southwestern Finland