Harbor seal population decline in the Aleutian Archipelago

Populations of Steller sea lions, northern fur seals, and northern sea otters declined substantially during recent decades in the Bering Sea and Aleutian Islands region, yet the population status of harbor seals has not been assessed adequately. We determined that counts obtained during skiff‐based surveys conducted in 1977–1982 represent the earliest estimate of harbor seal abundance throughout the Aleutian Islands. By comparing counts from 106 islands surveyed in 1977–1982 (8,601 seals) with counts from the same islands during a 1999 aerial survey (2,859 seals), we observed a 67% decline over the ～20‐yr period. Regionally, the largest decline of 86% was in the western Aleutians (n= 7 islands), followed by 66% in the central Aleutians (n= 64 islands), and 45% in the eastern Aleutians (n= 35 islands). Harbor seal counts decreased at the majority of islands in each region, the number of islands with >100 seals decreased ～70%, and the number of islands with no seals counted increased ～80%, indicating that harbor seal abundance throughout the Aleutian Islands was substantially lower in the late 1990s than in the 1970s and 1980s.     

Mercury in polar bears from Alaska

Alaskan polar bear (Ursus maritimus) muscle and liver samples collected in 1972 were analyzed for total mercury. Bears north of Alaska had more mercury than bears west of Alaska. The only difference between young and adult animals was in the northern area where adults had more mercury in liver tissue than young animals. Levels were probably not high enough to be a serious threat to bears.     

Levels of Polychlorinated Biphenyls (PCBs) and Three Organochlorine Pesticides in Fish from the Aleutian Islands of Alaska

Background

Persistent organic pollutants (POPs), including polychlorinated biphenyls (PCBs) and chlorinated pesticides, have been shown to have many adverse human health effects. These contaminants therefore may pose a risk to Alaska Natives that follow a traditional diet high in marine mammals and fish, in which POPs bioaccumulate.

Methods and Findings

This study examined the levels of PCBs and three pesticides [p, p′-DDE, mirex, and hexachlorobenzene (HCB)] in muscle tissue from nine fish species from several locations around the Aleutian Islands of Alaska. The highest median PCB level was found in rock sole (Lepidopsetta bilineata, 285 ppb, wet weight), while the lowest level was found in rock greenling (Hexagrammos lagocephalus, 104 ppb, wet weight). Lipid adjusted PCB values were also calculated and significant interspecies differences were found. Again, rock sole had the highest level (68,536 ppb, lipid weight). Concerning the PCB congener patterns, the more highly chlorinated congeners were most common as would be expected due to their greater persistence. Among the pesticides, p, p′-DDE generally dominated, and the highest level was found in sockeye salmon (Oncorhynchus nerka, 6.9 ppb, wet weight). The methodology developed by U.S. Environmental Protection Agency (USEPA) was used to calculate risk-based consumption limits for the analyzed fish species. For cancer health endpoints for PCBs, all species would trigger strict advisories of between two and six meals per year, depending upon species. For noncancer effects by PCBs, advisories of between seven and twenty-two meals per year were triggered. None of the pesticides triggered consumption limits.

Conclusion

The fish analyzed, mainly from Adak, contain significant concentrations of POPs, in particular PCBs, which raises the question whether these fish are safe to eat, particularly for sensitive populations. However when assessing any risk of the traditional diet, one must also consider the many health and cultural benefits from eating fish.     

A burial cave in the western Aleutian Islands, Alaska

During the 1998 field season, the Western Aleutians Archaeological and Paleobiological Project (WAAPP) team located a cave in the Near Islands, Alaska. Near the entrance of the cave, the team identified work areas and sleeping/sitting areas surrounded by cultural debris and animal bones. Human burials were found in the cave interior. In 2000, with permission from The Aleut Corporation, archaeologists revisited the site. Current research suggests three distinct occupations or uses for this cave. Aleuts buried their dead in shallow graves at the rear of the cave circa 1,200 to 800 years ago. Aleuts used the front of the cave as a temporary hunting camp as early as 390 years ago. Finally, Japanese and American military debris and graffiti reveal that the cave was visited during and after World War II. Russian trappers may have also taken shelter there 150 to 200 years ago. This is the first report of Aleut cave burials west of the Delarof Islands in the central Aleutians.     

Experimental and Natural Warming Elevates Mercury Concentrations in Estuarine Fish

Marine food webs are the most important link between the global contaminant, methylmercury (MeHg), and human exposure through consumption of seafood. Warming temperatures may increase human exposure to MeHg, a potent neurotoxin, by increasing MeHg production as well as bioaccumulation and trophic transfer through marine food webs. Studies of the effects of temperature on MeHg bioaccumulation are rare and no study has specifically related temperature to MeHg fate by linking laboratory experiments with natural field manipulations in coastal ecosystems. We performed laboratory and field experiments on MeHg accumulation under varying temperature regimes using the killifish, Fundulus heteroclitus. Temperature treatments were established in salt pools on a coastal salt marsh using a natural temperature gradient where killifish fed on natural food sources. Temperatures were manipulated across a wider range in laboratory experiments with killifish exposed to MeHg enriched food. In both laboratory microcosms and field mesocosms, MeHg concentrations in killifish significantly increased at elevated temperatures. Moreover, in field experiments, other ancillary variables (salinity, MeHg in sediment, etc.) did not relate to MeHg bioaccumulation. Modeling of laboratory experimental results suggested increases in metabolic rate as a driving factor. The elevated temperatures we tested are consistent with predicted trends in climate warming, and indicate that in the absence of confounding factors, warmer sea surface temperatures could result in greater in bioaccumulation of MeHg in fish, and consequently, increased human exposure.     

Selenium and Mercury in Native and Introduced Fish Species of Patagonian Lakes,Argentina

A survey of mercury (Hg) and selenium (Se) contents was performed in fish collected from lakes located in two National Parks of the northern patagonian Andean range. Two native species, catfish (Diplomystes viedmensis) and creole perch (Percichthys trucha), and three introduced species, brown trout (Salmo trutta), rainbow trout (Oncorhynchus mykiss), and brook trout (Salvelinus fontinalis), were caught from lakes Nahuel Huapi, Moreno, Traful, Espejo Chico, and Guillelmo belonging to Nahuel Huapi National Park and from lakes Futalaufquen and Rivadavia, Los Alerces National Park. In lake Moreno, fish diet items were analyzed and rainbow trout grown in a farm. Hg and Se were measured in muscle and liver tissues by instrumental neutron activation analysis. The average concentrations in muscle of Hg for all species, ages, and lakes are between 0.4 to 1.0 μg g⁻¹ dry weight (DW) with a few fish, mainly native, exceeding the United States Environmental Protection Agency health advisory for freshwater fish limited consumption, and from 0.8 to 1.5 μg g⁻¹ DW for Se. Average concentrations in liver of Hg in all species range from 0.4 to 0.9 μg g⁻¹ DW. Brown trout, the top predator in these lakes, showed the lowest average Hg burden in both tissues. Se concentrations in the liver of brown and rainbow trout, up to 279 μg g⁻¹ DW, are higher than those expected for nearly pristine lakes, exceeding 20 μg g⁻¹ DW, the threshold concentration associated with Se toxicity. These species show lower Hg contents in muscle, suggesting a possible detoxification of Hg by a Se-rich diet. Creole perch and velvet catfish livers have lower Se concentrations, with a narrower span of values (2.3 to 8.5 μg g⁻¹ and 3.3 to 5.5 μg g⁻¹ DW respectively).     

Seasonal Variation of Cadmium, Copper, and Lead Concentrations in Fish from a Freshwater Lake

This paper aims to compare the Cd, Cu, and Pb concentration in the bone, gills, and muscle of the seven fish species sampled during normal and dry seasons. Cadmium, Cu, and Pb concentrations varied significantly depending on the type of the tissue and season. Bone samples of the Osteochilus hasseltii showed the highest concentrations of Pb (6.08 μg/g dw) during September (the dry season), whereas bone samples of the Puntioplites bulu showed the lowest concentrations of Cd (0.08 μg/g dw) during September. Muscle samples of the P. bulu indicated the highest concentrations of Cu (2.58 μg/g dw) during March (the normal season). On the other hand, muscle samples of Channa straitus sowed the lowest concentrations of Cd (0.04 μg/g dw) during July (the dry season). Gills samples of the O. hasseltii showed the highest concentration of Pb (6.56 μg/g dw) during March (the normal season), while gills samples of C. straitus indicated the lowest concentration of Cd (0.06 μg/g dw) during July (the dry season).     

Hair Mercury Concentrations of Lactating Mothers and Breastfed Infants in Iran (Fish Consumption and Mercury Exposure)

Coastal populations with high seafood consumption in the South Caspian Sea (Iran) have a significant exposure to dietary mercury. This study assesses the biomonitoring of mercury in mothers and breastfed infants in the South Caspian Sea. The mean of mercury concentration in the hair of 93 pairs of mothers and infants was obtained and was 3.55 and 1.89???g?g^?1, respectively. A statistically significant correlation (R?=?0.850, P?=?0.000) was seen between mercury concentration in the hair of mothers and infants. The results of this study indicate that hair mercury concentrations exceeded the USEPA reference dose of 1???g?g^?1 in 82.7?% of mothers and 61.2?% of infants. Also, 31?% of the mothers and 10.7?% of the infants had mercury concentrations more than the WHO ??threshold?? level (5???g?g^?1). The age and fish consumption of mothers were the factors that significantly affected the hair mercury concentration of mothers and infants. Number of dental amalgam fillings of mothers was the factor that only affected mercury in the hair of mothers. According to the results, we can conclude that the main determinant of mercury exposure was the intake of mercury through fish consumption of mothers.     

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.     

A new species of Polymastia (Porifera, Hadromerida, Polymastiidae) from the Aleutian Islands, Alaska, USA

Polymastia fluegeli n. sp. is described from deep water off the Aleutian Islands (Alaska, USA). P. fluegeli is disc-shaped and lives partly buried in the sediment, with only the papillae protruding above the surface. This new species has a basal layer of agglutinated sediment particles occurring between the choanosome and the ectosomal lower layer. This conspicuous sediment layer is not described for other species of Polymastia. Occurring spicule types and sizes are different from known species of the area.     

Marine paleoclimatology and paleoecology of a Pleistocene invertebrate fauna from Amchitka Island,Aleutian Islands,Alaska

Sea cliff exposures at the head of South Bight on Amchitka Island contain an invertebrate fauna consisting of 24 bivale, 14 gastropod, 4 barnacle, 2 brachiopod, 1 amphineuran, 1 echinoid, 1 annelid and 2 planktonic foraminifer species and various unstudied bryozoans, benthonic foraminifers and ostracodes, as well as bone fragments of marine mammals. With the exception of 4 species of Chlamys, all taxa appear to be living along the Alaskan coastline today.Paleotemperature analyses based on the average size of adult Hiatella arctica, the median of midpoints technique, the extralimital species technique, a biogeographic method, species distribution and coiling ratios of planktonic foraminifers, and oxygen stable isotope ratios give varied values. The extralimital species, biogeographic and oxygen isotope techniques are judged to give the most reliable evidence of paleotemperature at South Bight. These data suggest that mean February sea surface temperature was about 3.9° C and that mean August temperatures were somewhere between 10.0° C and 11.7° C. Present-day mean February temperature at South Bight is 3.9° C and mean August temperature is 10.0° C.The fauna lived in shallow (0–23 m?) water in a sublittoral environment on the open coast. Remains of a few rocky-shore littoral organisms were displaced downslope a short distance where they accumulated with remains of epifaunal, infaunal and neritopelagic elements of the inner sublittoral zone and open ocean planktonic foraminifers. The fauna is most closely comparable to that of the present-day Aleutian Province, and to a lesser degree comparable to that of the Arctic.Astarte bennettii, A. borealis, Diplodonta aleutica, and Liomesus nux are unreported in North Pacific strata older than those of the Einahnuhtan transgression, and Chlamys hanaishiensis amchitkana, C. islandica powersi and C. coatsi middletonensis are unknown from strata younger than those of the Einahnuhtan. However, the almost entirely modern aspect of the fauna, coupled with the absence of Astarte mortonensis-like variants of the Astarte borealis lineage, and radiometric dates on bone and shell material of $\text{130,000 ± 15,000}$ years, appear to indicate a Kotzebuan age.     

Identification of parasitoses in a child burial from Adak Island (Central Aleutian Islands, Alaska)

Bothriocephalid (Diphyllobothrium pacificum) and Ascarid (Ascaris lumbricoides) eggs have been identified in a sample taken in the abdominal cavity of a child skeleton found in Zeto Point (ADK-011), an archaeological site on Adak Island in the Central Aleutian Islands (Alaska).     

Fish communities in the African Great Lakes

Synopsis Ecological conditions in tropical lacustrine systems are considered by focusing on the evolution, maintenance, exploitation and vulnerability of fish communities in the African Great Lakes. The exceptionally high biodiversities in the littoral/sublittoral zones of the very ancient, deep, clear, permanently stratified rift lakes Tanganyika and Malawi, are contrasted with the simpler systems in their pelagic zones, also with biodiversity in the much younger, shallower Victoria, the world's largest tropical lake.Paper from the Canadian Society of Zoologists symposium Great Lakes of the World, organized by David L.G. Noakes     

Mercury Exposure: Protein Biomarkers of Mercury Exposure in Jaraqui Fish from the Amazon Region

Poly-trans-[(2-carboxyethyl)germasesquioxane] (Ge-132) is a water-soluble organogermanium compound that exerts various physiological effects, including anti-inflammatory activity and pain relief. In water, Ge-132 is hydrolyzed to 3-(trihydroxygermyl)propanoic acid (THGP), which in turn is capable of interacting with cis-diol compounds through its trihydroxy group, indicating that this compound could also interact with diol-containing nucleic acid constituents. In this study, we evaluated the ability of THGP to interact with nucleosides or nucleotides via nuclear magnetic resonance (NMR) analysis. In addition, we evaluated the effect of added THGP on the enzymatic activity of adenosine deaminase (ADA) when using adenosine or 2′-deoxyadenosine as a substrate. In solution, THGP indeed formed complexes with nucleotides or nucleosides through their cis-diol group. Moreover, the ability of THGP to form complexes with nucleotides was influenced by the number of phosphate groups present on the ribose moiety. Notably, THGP also inhibited the catalysis of adenosine by ADA in a concentration-dependent manner. Thus, interactions between THGP and important biological nucleic acid constituents might be implicated in the physiological effects of Ge-132.     

Temporal Hyperacuity in the Gymnotiform Electric Fish, Eigenmannia

SYNOPSIS. The gymnotiform electric fish, Eigenmannia, exhibitsextraordinary sensitivity to small timing differences betweensensory signals. The jamming avoidance response, gradual frequencyshifts of the electric organ discharges, requires the detectionof temporal disparities between sensory signals impinging upondifferent electroreceptors. This behavior occurs reliably evenwith temporal disparities being smaller than one microsecond.Since individual sensory receptors are not capable of encodingsuch minute timing with certainty, the high behavioral sensitivitymust, therefore, emerge from signal processing within the centralnervous system. Individual neurons, at the top of a well definedneuronal hierarchy have been found to be sensitive to temporaldisparities in the range of 1 microsecond. The response propertiesof these neurons as well as behavioral results suggest thatspatial convergence of sensory information plays a major rolein the emergence of this temporal hyperacuity.     

Egg production rates of the neritic marine copepod Acartia tumida Willey in the Aleutian Archipelago

Acartia tumida, a neritic copepod of the northern North Pacific Ocean and Bering Sea, is an unusually large member of its genus, adult females measuring 2.0–2.4 mm in total length. In the summers of 1986 and 1987 we investigated egg production of A. tumida in nearshore habitats of several islands in the Aleutian Island chain. A. tumida was found within protected embayments, where it could reach adult densities as high as 1000m^–3. Highest egg production rates were measured at Amchitka Island (up to 86 eggs copepod^–1 d^–1 at 6°C), where the phytoplankton was dominated by chain-forming Thalassiosira spp. In situ egg production rates at Amchitka were more than twice as high as maximum rates measured with cultured T. weissflogii, a single cell diatom, or during blooms of chain-forming Chaetoceros spp. at Adak and Kiska Islands. Approximately 12–24 h was necessary for recent feeding to be reflected in egg production. At high food concentrations 75% of spawning occurred at night and in discrete clutches, a pattern not observed at a lower food concentration.     

Biological interactions maintain the boundaries between kelp forests and urchin barrens in the Aleutian Archipelago

This study used benthic surveys and manipulative experiments to examine (1) if boundaries between kelp forests and urchin barrens exist at multiple locations spanning the Aleutian Archipelago, (2) if these boundaries are spatially stable, and (3) how changes in algal density within the kelp forests influence the ability of urchins to invade them. Our results demonstrate that sharply punctuated kelp forest-urchin barren boundaries occur throughout the Archipelago, and they are spatially stable for at least 2 years. Further, when all macroalgae were experimentally removed from the kelp forest side of the boundaries, urchins rapidly moved into these clearings and excluded macroalgae for up to 2 years. However, these movements were not observed where 75% or less of the macroalgae was removed (leaving 25% or more in place), suggesting that even low macroalgal abundances can prevent urchins from invading the kelp forests. Further, urchin densities were negatively related to kelp density, again indicating that kelp can reduce urchin densities. While the ability of urchins to overgraze kelp forests is widely known, our results indicate that kelp can inhibit urchins, that these inhibitory influences are a widely recurrent phenomenon, and that this interaction is important to maintaining kelp forests across the Aleutians.     

Factors Affecting Elevated Arsenic and Methyl Mercury Concentrations in Small Shield Lakes Surrounding Gold Mines near the Yellowknife,NT, (Canada) Region

Gold mines in the Yellowknife, NT, region—in particular, the Giant Mine—operated from 1949–99, releasing 237,000 tonnes of waste arsenic trioxide (As₂O₃) dust, among other compounds, from gold ore extraction and roasting processes. For the first time, we show the geospatial distribution of roaster-derived emissions of several chemical species beyond the mine property on otherwise undisturbed taiga shield lakes within a 25 km radius of the mine, 11 years after its closing. Additionally, we demonstrate that underlying bedrock is not a significant source for the elevated concentrations in overlying surface waters. Aquatic arsenic (As) concentrations are well above guidelines for drinking water (10 μg/L) and protection for aquatic life (5 μg/L), ranging up to 136 μg/L in lakes within 4 km from the mine, to 2.0 μg/L in lakes 24 km away. High conversion ratios of methyl mercury were shown in lakes near the roaster stack as well, with MeHg concentrations reaching 44% of total mercury. The risk of elevated exposures by these metals is significant, as many lakes used for recreation and fishing near the City of Yellowknife are within this radius of elevated As and methyl Hg concentrations.     

Mercury Concentrations in Tissues of Osprey From the Carolinas,USA

Abstract: Mercury (Hg) contamination is believed to be one of the most significant pollution hazards to wildlife in the southeastern United States, yet comprehensive studies of Hg contamination of piscivorous raptors are rare in this region. We analyzed total Hg (THg) concentration in tissues of 39 osprey (Pandion haliaetus) primarily from coastal counties of South Carolina, USA, to describe tissue distribution of Hg and to determine whether age or sex influenced Hg accumulation. To determine whether Hg poses health risks to osprey breeding in this region, we also measured selenium in all tissues and the percentage of THg that was methylated in a subset of individuals. Osprey with adult plumage tended to have higher and more variable Hg concentrations in their tissues than younger birds. Whereas highest concentrations of Hg were found in liver and kidney of older birds, chicks had highest concentrations in keratinized tissues. Mercury concentrations were correlated between feathers and soft tissues, but talon concentrations of Hg were better correlated with organs than to feathers in most cases. Contrary to previous studies on birds, we found no relationship between Hg concentration in primary feathers and the sequence in which the feather was molted. We attribute this observation to the irregular and protracted molting pattern of osprey. Also contrary to other studies, feather concentrations of Hg were considerably lower than concentrations in liver and kidney. Osprey with high concentrations of Hg in their livers and kidneys accumulated as much as 99% of it as Hg(II), suggesting that demethylation and sequestration of Hg(II) may be even more critical to mitigating adverse effects than it is for other birds that eliminate most of their Hg burden in feathers. In addition, selenium was co-sequestered with Hg in the liver and kidneys and may further mitigate any adverse effects. Based on these findings, we suggest that most osprey in this region are not currently at risk of Hg toxicosis, but recommend that additional ecotoxicological studies be performed to monitor risk to osprey in this coastal region facing heavy development. We also suggest that concentrations of Hg in talon and claw may serve as important indicators of previous exposure and provide useful information for natural resource managers seeking to assess health risks to birds.