Eider Research Articles

A morphometric study of the salt gland in freshwater‐ and saltwater‐adapted eider ducks (Somateria mollissima)

A morphometric study of the salt gland in freshwater‐ and saltwater‐adapted eider ducks (Somateria mollissima)

A morphometric study of the salt gland in freshwater- and saltwater-adapted eider ducks (Somateria mollissima)

A morphometric study of the salt gland in freshwater- and saltwater-adapted eider ducks (Somateria mollissima)

The calux (chemical‐activated luciferase expression) assay adapted and validated for measuring TCDD equivalents in blood plasma

AbstractA method was developed to isolate lipophilic compounds efficiently from small aliquots of blood plasma and test these for total dioxin‐like toxic potency using recombinant rat (H4IIE) and mouse (Hepa1c1c7) hepatoma cell lines, containing the firefly (Photinus pyralis) luciferase gene under trans‐activational control of the aryl hydrocarbon receptor (AhR). For this experiment, blood plasma was used originating from eider ducks (Somateria mollissima) that had been dosed with 3,3′,4,4′‐tetrachlorobiphenyl (PCB‐77) or with the technical PCB‐mixture Clophen A50. For each sample the CALUX (chemical‐activated luciferase expression) response of both the fat‐containing organic extract and the fat‐free, cleaned extract were compared with data from chemical analyses of these samples. The CALUX responses for the extracts were converted into so‐called CALUX TEQs (TCDD equivalents), using a 2,3,7,8‐tetrachlorodibenzo‐p‐dioxin (TCDD) standard curve. The CALUX TEQs in both fatty and cleaned extracts correlated significantly with PCB‐77 or PCB‐153 levels (depending on the dosage group) determined in blood plasma using gas chromatography–mass spectrometry (GC‐MS). For PCB‐77 a toxic equivalency factor (TEF) of 1.5 × 10−3 was calculated based on these correlations. In addition, PCB‐118 and PCB‐156 levels in abdominal fat (assessed with GC with electron capture detection) and hepatic ethoxyresorufin O‐deethylase activities correlated well with the CALUX TEQs in both fatty and cleaned blood plasma extracts, suggesting the TEQ levels in blood offer a good measure for internal dose. Plasma cholesterol and triglyceride levels were determined as a measure of lipid content, in 10‐μl aliquots of blood plasma using enzymatic spectrophotometric determination. In conclusion, we have demonstrated that the CALUX assay is a rapid, sensitive assay for assessing the toxic potency of (mixtures of) AhR‐active compounds in small aliquots of blood plasma. The limit of detection for the CALUX assay is currently less than 0.1 fmol (32 fg) TEQ, which corresponds with the amount of TEQs present in 0.1 to 1 ml of blood plasma in environmentally exposed species or man.

DNA Fingerprinting Reveals Monogamy in the Bushtit, a Cooperatively Breeding Species

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Salt gland function in the common eider duck (Somateria mollissima)

The function of the supra-orbital salt gland was studied in the common eider duck (Somateria mollissima). The maximum salt-secreting capacity was determined in (1) wild ducks which had been living in a marine environment, (2) ducks reared in captivity on fresh water, and (3) ducks from group 2 adapted to salt water. The maximum secreting capacity was found by infusing a solution of NaCl (1000 mosmol·kg-1) at increasing rates, from 0.691 to 1.671 mosmol·min-1. Freshwater-adapted ducks secreted at a maximum rate of 0.785 mosmol·min-1 (1500 mosmol·kg-1). Adapted to salt water they increased their capacity, and the best duck secreted at a rate of 1215 mosmol·min-1 (1600 mosmol·kg-1). The best wild duck secreted at a rate of 1516 mosmol·min-1. Ducks in group 3 were used to examine the response to a hyperosmotic or an isoosmotic infusion. The amount of salt (NaCl) given per unit time was the same. Given a hyperosmotic solution their salt glands secreted at a high rate: 30 min after the infusion had stopped the ducks had excreted 94% of the sodium infused, 92.9% via the salt gland. Given an isoosmotic solution they secreted at a rate about half the infusion rate: 30 min after cessation of infusion they had excreted 73% of the sodium, 42.9% via the salt gland and the rest by the kidneys.

The Role of the Mussel (Mytilus edulis L.) and Mussel Culture in the Dutch Wadden Sea

Mussel populations (Mytilus edulis) in the Dutch Wadden Sea (intertidal mussel beds, subtidal beds and culture plots), the culture methods, the extent of mussel culture, and the ecology of the mussel are described. Mussels filter suspended matter from the water column and deposit it as feces and pseudofeces. Mussel beds consume large amounts of phytoplankton and speed up the cycle of production and breakdown of organic matter. There are indications that the consumption of phytoplankton can lead to food shortage for several animal groups. Mussels serve as an important food source for a wide range of organisms (e.g., starfish, eider ducks, and oystercatchers). Because mussel culture increased the mussel biomass in the Dutch Wadden Sea, the impact also increased. The most obvious impact of the culture is the dredging of seed mussels. Overexploitation of intertidal mussel and cockle beds and bad spatfall of both mussels and cockles since 1988 had a negative impact on bird populations. The extent of positive and negative aspects of mussel culture depends on natural and human influences. The negative aspects may (partly) be overcome by appropriate measures. *** DIRECT SUPPORT *** A01BY069 00007

The monitoring of breeding seabirds and eiders

Twenty-one species of seabirds breed regularly in Shetland, some of them in huge, spectacular, multi-species colonies on cliffs. The Sullom Voe Environmental Advisory Group Environmental Impact Statement (SVEAG 1976) provides a table showing the relative importance of seabird species in terms of Scotland and the British Isles. We have updated these data in the light of the Seabird Colony Register (Lloyd et al. 1991) and present data for seven species, vulnerable to oil pollution, in Table 1. It is clear that these populations are of national importance and indeed several are internationally important. Separately, an estimate was provided by SVEAG of the numbers of sea ducks and divers wintering in Shetland waters and updated estimates are given by Suddaby (1992) (Table 2). Chief among these is the eider duck (Somateria mollissima) which is apparently resident in Shetland throughout the year (Heubeck 1993a). In its Eighth Report, on Oil Pollution at Sea, the Royal Commission on Environmental Pollution (1981) recognised the vulnerability of seabirds to oil pollution and this was clearly a matter of concern in Shetland and elsewhere when the flow of enormous quantities of crude oil into Sullom Voe via undersea pipelines and out of Sullom Voe by large tankers became a reality. The risk to seabirds of oil pollution is well documented (Bourne 1968; RSPB 1979). Dunnet (1974, 1980, 1982, 1987) has reviewed the situation in relation to the North Sea oil industry.

In vitro metabolism of 3,3′,4,4′-tetrachlorobiphenyl in relation to ethoxyresorufin- O-deethylase activity in liver microsomes of some wildlife species and rat

A qualitative study was performed of the capacity of hepatic microsomes of several wildlife species to metabolize 3,3′,4,4′-tetrachlorobiphenyl (TCB). Hepatic microsomes of species environmentally exposed to a polychlorinated biphenyls (PCBs): harbour porpoise ( Phocoena phocoena), harbour seal ( Phoca vitulina), common tern ( Sterna hirundo), and hepatic microsomes from species experimentally exposed to PCBs: eider duck ( Somateria mollissima), rainbow trout ( Salmo gairdneri), flounder ( Platichthys flesus), and Wistar rat, were incubated with 14C-labelled TCB ([ 14C]TCB). The mammals and birds were able to metabolize TCB at a rate that correlated with their ethoxyresorufin- O-deethylase (EROD) activity. No [ 14C]TCB metabolism was observed in the fish, despite elevated EROD activity in the trout. HPLC analysis of diisopropylether extracts of the microsomal incubations indicated the presence of 4-OH-, 5-OH-, and 6-OH-tetrachlorobiphenyl metabolites and a yet unidentified metabolite. The ratio of the different hydroxy metabolites formed varied for the various species.

Ethoxyresorufin O-deethylase (EROD) and aryl hydrocarbon hydroxylase (AHH)-inducing potency and lethality of chlorinated naphthalenes in chicken (Gallus domesticus) and eider duck (Somateria mollissima) embryos.

The 7-ethoxyresorufin O-deethylase (EROD)- and aryl hydrocarbon hydroxylase (AHH)-inducing potencies and lethalities of a technical preparation of polychlorinated naphthalenes (PCNs) (Halowax 1014, approximate congener ratio: 20% tetrachloronaphthalenes, 40% pentachloronaphthalenes, 40% hexachloronaphthalenes), a mixture of 50% 1,2,3,5,6,7-hexachloronaphthalene and 50% 1,2,3,4,6,7-hexachloronaphthalene (HxCN-mix), and 1,2,3,4,5,6,7-heptachloronaphthalene (HpCN) were studied in chicken (Gallus domesticus) and eider duck (Somateria mollissima) embryos. Mortality and hepatic EROD activity were determined on day 10 of incubation in chicken embryos exposed to various doses of the PCNs via the air-sacs of the eggs on day 7. The HxCN-mix and Halowax 1014 proved to have both embryolethal and EROD-inducing properties, while the HpCN had low EROD-inducing potency and embryolethality. ED50 values for EROD induction by the HxCN-mix and Halowax 1014 were estimated to be 0.06 mg/kg egg and 0.2 mg/kg egg, respectively. Fifty percent of the chicken embryos died (6/12) when given 3.0 mg/kg of the HxCN-mix while a similar dose of Halowax 1014 caused mortality in 4 out of 12 chicken embryos. The dose-response curve for EROD induction by Halowax 1014 exhibited a decline after the maximal level was reached. When Halowax 1014 (1.0 mg/kg egg) was coinjected with 3,3',4,4',5-pentachlorobiphenyl (PCB IUPAC #126) (0.1 microgram/kg egg) no additive effects on EROD activity were found, but when the same dose of Halowax 1014 was coinjected with a dose of PCB #126, known to cause maximal induction (1.0 microgram/kg egg), the resulting EROD activity was lower than that caused solely by 1.0 micrograms PCB #126/kg egg.(ABSTRACT TRUNCATED AT 250 WORDS)

Toxic and biochemical effects of 3,3′,4,4′-tetrachlorobiphenyl (CB-77) and clophen A50 on eider duckling ( Somateria mollissima) in a semi-field experiment

In this study the possible toxic and biochemical effects of one intraperitoneal dose of 5 or 50 mg kg −1 of 3,3′,4,4′-tetrachlorobiphenyl (CB-77) or 50 or 200 mg kg −1 of Clophen A50 (CloA50) on 28-day-old eider ducklings ( Somateria mollissima) were investigated. After ten days, no significant differences could be observed in any of the toxic and biochemical parameters studied, apart from ethoxyresorufin (EROD) activity, when comparing group average values of the dosed and control animals. However, significant correlations were observed at day 10 after exposure between the individual internal PCB concentration and body weight gain and beak length growth (negative correlations in the CloA50 groups); relative liver weight and cytochrome P4501A activity (positive correlations in CB-77 and CloA50 groups); plasma thyroid-hormone and hepatic retinoid levels (negative correlations in CB-77 groups); and plasma retinol levels and the ratio plasma retin/hepatic retinyl palmitate (positive correlations in CB-77 groups only). Animal activity was significantly reduced in the group that received 50 mg CB-77 kg −1. These observations indicate that eider ducks are a sensitive species to PCB toxicity and may be at risk for development of adverse health effects in relatively highly contaminated areas such as the Waddenzee.

Variation in the morphology of adult Apatemon gracilis Rudolphi, 1819 (Digenea: Strigeidae) reared in different avian hosts

Adult Apatemon gracilis (Rudolphi, 1819) were reared experimentally in three different avian hosts: herring gulls Larus argentatus Gmelin, domestic chicks Gallus gallus (L.) and eider ducklings Somateria mollissima (L.). Comparisons of size, body proportions and fecundity were made between these and specimens obtained from a naturally infected goosander Mergus merganser L. The eider duck proved to be a suitable experimental host, rearing adults of comparable size and fecundity to those from the natural host. The growth and development of the parasite in domestic chicks and herring gulls were significantly reduced. Similar conditions are likely to exist in the natural environment and this should be taken into consideration when choosing experimental hosts for use in the laboratory or when identifying species.

The shivering response during cross-circulation in the common eider duck (Somateria mollissima).

The possible role of humoral factors in the control of shivering in the common eider duck (Somateria mollissima) was investigated using a cross-circulation technique. Pairs of animals were coupled so that the arterial system of one animal was connected to the venous system of the other. The rate of blood transferral was 12.8 ml min-1. By adequate heparinization of the extracorporeal blood supply, cross-circulation could be maintained for periods of up to 12 h. The temperature of blood entering each animal Tinlet) was controlled by heat exchangers. During control experiments Tinlet was maintained at a temperature close to normal body temperature. During cooling experiments Tinlet was maintained at c. 20 degrees C. Changes in metabolic heat production and oesophageal temperature in response to blood cooling were measured in cross-circulated pairs of animals cooled simultaneously or individually. Based on analysis of the metabolic responses under the different experimental situations, no evidence was found to indicate that blood-borne substances are involved in the shivering response in these animals.

Chromatographic separation of the enantiomers of marine pollutants. Part 6: Comparison of the enantioselective degradation of α-hexachlorocyclohexane in marine biota and water

The enantiomeric ratios of the chiral marine pollutant α-hexachlorocyclohexane [α-HCH] was determined in blue mussels (Mytilus edulis L.), flounders (Platychthys flesus (L.)), Common eider ducks (Somateria mollissima (L.)), and in North Sea water of experimental sites in the German Bight by means of capillary gas chromatography using β-cyclodextrin derivatives as chiral stationary phases. Different enzymatic degradation pathways are revealed by opposite enantioselective enrichments of the α-HCH enantiomers: while in the liver of Common eider ducks the preferable degradation of (−)-α-HCH leads to an enrichment of (+)-α-HCH [i.e., (+)-α- HCH (t)-α- HCH ≈ 1.4 − ∞ ], the enantiomeric ratios measured in the liver samples of flounders [ (+)-α- HCH (t)-α- HCH ≈ 0.80 − 0.94 ], in blue mussels [ (+)-α- HCH (t)-α- HCH ≈ 0.84 − 0.93 ] and in the North Sea water samples [ (+)-α- HCH (t)-α- HCH ≈ 0.84 ] imply enzymatic processes in the course of which common structural elements are preferred represented by (+)-α-HCH.

Using ratios of stable nitrogen isotopes to estimate bioaccumulation and flux of polychlorinated dibenzo‐p‐dioxins (PCDDs) and dibenzofurans (PCDFs) in two food chains from the Northern Baltic

AbstractPresented in this study is a new method to quantitatively estimate in situ biomagnification of organic contaminants that uses ratios of naturally occurring stable isotopes of nitrogen to classify trophic levels of organisms from one littoral and one pelagic food chain in the northern Baltic proper. Results indicated a biomagnification of the three most toxic 2378‐substituted polychlorinated dibenzo‐p‐dioxins and ‐dibenzofurans (PCDD/Fs), whereas the total concentration of 2378‐ substituted PCDD/Fs, and particularly octachlorodibenzo‐p‐dioxin and ‐dibenzofuran (OCDD/F), decreased with increasing trophic level in the food chains. A calculated flux estimate of PCDD/Fs in juvenile eider ducks was supported by results from the biomagnification study; that is, the most toxic 2378‐substituted isomers tended to accumulate in the tissue of the eider duck. Out of the total PCDD/Fs consumed by the eider ducks, only 10% were recovered in the body and approximately 10% were recovered in feces, whereas 80% were not recovered, that is, were excreted or remained as unidentified metabolites. Of the most toxic 2378‐substituted isomers, 57% were recovered in the tissue, 30% were recovered in the feces, and only 13% were not recovered (i.e., metabolized and/or excreted).

Enantioselective Metabolism of (±)‐α‐l,2,3,4,5,6‐Hexachlorocyclohexane in Organs of the Eider Duck

Enantioselective Metabolism of (±)‐α‐l,2,3,4,5,6‐Hexachlorocyclohexane in Organs of the Eider Duck

An in situ study on the distribution, biotransformation and flux of polycyclic aromatic hydrocarbons (pahs) in an aquatic food chain (seston‐Mytilus edulis L.‐Somateria mollissima L.) from the baltic: An ecotoxicological perspective

AbstractThis in situ study is focusing on the distribution, biotransformation and flux of 19 polycyclic aromatic hydrocarbons (PAH19) in the food chain seston‐blue mussel (Mytilus edulis L.)‐common eider duck (Somateria mollissiima L.) as well as the distribution in the gallbladder, liver, adipose tissue and egg of the duck. All samples were collected within the open northern Baltic proper coastal areas. Analyses were carried out by gas chromatography/mass spectrometry with electron impact (GC‐MSEI) and negative ion chemical ionization (GC‐MSNICI). With a multivariate statistical method (SIMCA) a significant change in the PAH composition through the food chain was found. This change probably depends on an increasing metabolic activity with increasing trophic level, due to a selective biotransformation capacity for different PAHs. Decreasing PAH concentrations with increasing trophic level were found. The PAH concentrations in the different eider duck organs were: gallbladder > adipose tissue ≥ liver. The theoretical inhalation of air‐dispersed PAHs was of no significance compared to the exposure from food. The relatively high theoretical PAH flux through the food chain did not result in increasing concentrations with increasing trophic level, which indicates that PAHs are biotransformed quite fast. However, many intermediate metabolites of PAHs have a mutagenic and carcinogenic potential, which makes it important to observe these compounds when assessing ecotoxicological risks.

Feeding traces and bioturbation by birds on a tidal flat, Dutch Wadden Sea

Gulls (mainly Larus ridibundus) and Shelducks (Tadorna tadorna) make characteristic feeding traces on the Dutch tidal flat studied. Troughs up to 3 m long, ca. 15 cm wide, and ca. 3 cm deep made by L. ridibundus were most frequent from July to October. Craters made by Shelducks, ca. 10 cm deep and up to 60 cm in diameter, were most common in summer. The larger craters compare well with feeding traces reported for Eider ducks (Somateria mollissima) and rays (Hypotremata); the smaller craters compare with those of Flounder (Platichtys flesus) and Bream (Abramis brama). All illustrate uniformity in origin: benthic feeding by predators. Annually ca. 30% of the area studied was reworked by gulls and ca. 15% was reworked by Shelducks. The annual sediment reworking rate by these birds equals a sediment layer 2.5 cm thick. This volume is about one order of magnitude less than the ∼35 cm reworked annually by the most important deposit feeders of this tidal flat, collectively: the polychaetes Arenicola marina and Heteromastus filiformis and the bivalve Macoma balthica.

Embryotoxicity of polycyclic aromatic hydrocarbons (PAHs) in three domestic avian species, and of PAHs and coplanar polychlorinated biphenyls (PCBs) in the common eider

The embryotoxicity of an artificial mixture of 18 polycyclic aromatic hydrocarbons (PAHs) was tested by injection into the yolk sacs of eggs of four avian species: chicken Gallus domesticus, turkey Meleagris gallopavo, domestic duck Anas platyrhynchos and common eider Somateria mollissima. A dose of 2·0 mg kg egg −1 of the PAH mixture increased the mortality among the embryos of all four species. In the domestic duck, but not in the three other species, there was a significantly increased embryonic mortality at a dose of 0·2 mg kg −1 of this mixture. All 18 individual compounds in the mixture were tested for embryotoxicity in the chicken. The compound most toxic to chick embryos was benzo[k]fluoranthene. This substance also proved to be highly embryotoxic in the three other species. Previous studies have shown coplanar polychlorinated biphenyls (PCBs) to be much more embryotoxic in the chicken than in other avian species studied. In accordance with this, eider duck embryos proved to be considerably less sensitive to 3,3′,4,4′-tetrachlorobiphenyl and 3,3′,4,4′,5-pentachlorobiphenyl than was previously found for chick embryos. For PAHs, however, chick embryos did not have a higher sensitivity than the other species tested.

Profilicollis botulus (Van Cleave, 1916) from Diving Ducks and Shore Crabs of British Columbia

Adults of Profilicollis botulus were found in 6 species of diving ducks in British Columbia including 3 new hosts: common goldeneye, Bucephala clangula (L.); Barrow's goldeneye, B. islandica (Gmelin); and greater scaup, Aythya marila (L.). The identification of the species was verified by the examination of co-types and specimens from eider ducks, Somateria mollissima (L.), from Scotland and oldsquaw, Clangula hyemalis (L.), from New Brunswick. Cystacanths from the hairy shore crab, Hemigrapsus oregonensis (Dana), were similar in morphology to those from Carcinus maenas (L.) from Scotland.

Eider Ducks in Canada, ed. Austin Reed [Review

Eider Ducks in Canada, ed. Austin Reed [Review