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Organic halogenated contaminants in mother-fetus pairs of harbor seals (Phoca vitulina richardii) from Alaska, 2000-2002.

ABSTRACT: This study measured organochlorine pesticides (OCPs) including hexachlorocyclohexanes (HCHs), hexachlorobenzene (HCB), heptachlor and dichlorodiphenyltrichloroethanes (DDTs), polychlorinated biphenyls (PCBs), polychlorinated naphthalenes (PCNs) and polybrominated diphenyl ethers (PBDEs) in tissues of six mother-fetus pairs of harbor seals that were hunted for subsistence in Alaska waters of the Northern Pacific Ocean. These data suggest that significant amounts of these contaminants were transferred from mother harbor seals to fetuses during pregnancy and distributed among fetal organs. The tissue distribution depended on the chemical groups, the specific compounds in the groups and the target organs. Concentration profiles of ?OCPs, ?PCBs, ?PCNs and ?PBDEs were remarkably similar among maternal blubber, liver, and placenta, fetal blubber, and liver (except for HCHs), possibly indicating that the placenta did not serve as a barrier for all of the compounds analyzed. DDTs, HCB, HCHs, PCBs and PBDEs could penetrate the placenta and accumulate in the blubber of the fetus in utero, while HCHs, PCBs and PBDEs penetrated the placenta and accumulated more preferentially in the fetal liver than in the fetal brain in comparison with DDTs and HCB. Heptachlor and PCNs penetrated the placenta and accumulated in the fetal liver and brain instead of fetal blubber. Similar maternal transfer trends for OCPs, PCBs, PCNs and PBDEs were shown by fetal to maternal (FM) blubber ratios and FM liver ratios. Prenatal transfer of these toxic contaminants from mothers to fetus presumably through the placenta may pose health risks to the fetus during early development.

SUBMITTER: Wang D

PROVIDER: S-EPMC3361608 | biostudies-literature | 2012 Jul

REPOSITORIES: biostudies-literature

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Project description:BackgroundThere are approximately 10,000-12,000 Pacific harbor seals (Phoca vitulina richardii) inhabiting the Oregon coast, and unlike other species of pinnipeds in this region, are reliably present year-round. Despite this, and drastic rebounds in population since the enactment of the Marine Mammal Protection Act, limited data is available for the present period regarding their space use at sea, and within estuarine, riverine, or bay areas within the state.ObjectiveTo examine site-based differences in space use for 24 adult Pacific harbor seals captured and outfitted with satellite transmitters at two predominant haulout sites on the Oregon Coast, USA.DesignWe captured 24 adult harbor seals from two haulout sites on the Central Oregon coast between September 2014-16 and fitted them with external Wildlife Computers SPOT5 satellite transmitters to track movement. Using state-space modeled locations derived from satellite telemetry data, we evaluated spatial behavior of these animals using a correlated random walk model via R package crawl. Kernel density estimation was subsequently used to calculate home range and core area for each animal. Percent use of open ocean habitat versus use of estuaries, rivers and bays was quantified, as was an initial examination of presence within five newly-established marine reserves in Oregon. Examination of haulout site-related differences in spatial behavior were examined for seals captured in Netarts and Alsea Bays, Oregon and haul out behavior related to time of day, season, and tidal level was also investigated.ResultsThe average individual home range for seals was 364.47 ± 382.87 km2 with seals captured in Alsea bay demonstrating a significantly higher home range area than those captured in Netarts Bay. Alsea bay seals also tended to range farther from shore than Netarts Bay animals. The average calculated core area for seals encompassed on average 29.41 ± 29.23 km2 per animal, however the home range of one animal was so small, core area could not be calculated. Use of marine reserves was limited for animals in this study, representing less than 2% of locations with a majority occurring in Cape Perpetua Marine Reserve and North Marine Protected Area. Seals were more likely to haul out during low tides and periods of low light (dusk, night and dawn), and hauling out behavior increased in winter months.SignificanceThese findings demonstrate the first major documentation of space use of harbor seals in the state for nearly three decades, and lends itself to future comparison and formation of mechanistically-based hypotheses for behavior of a common marine mammal in the highly productive northern California Current System.

Project description:Large numbers of harbor seals (Phoca vitulina) use habitat in tidewater glaciers in Alaska for pupping, breeding, and molting. Glacial fjords are also popular tourist destinations; however, visitation by numerous vessels can result in disturbance of seals during critical life-history phases. We explored factors affecting haul-out behavior of harbor seals at a glacial site frequented by tourism vessels. In 2008-10, we deployed VHF transmitters on 107 seals in Endicott Arm, Alaska. We remotely monitored presence and haul-out behavior of tagged seals and documented vessel presence with time-lapse cameras. We evaluated the influence of environmental and physical factors on the probability of being hauled out, duration of haul-out bouts, and as factors associated with the start and end of a haulout. Location, season, hour, and interactions of location by year, season, hour, and sex significantly influenced haul-out probability, as did ice, weather, and vessels. Seals were more likely to be hauled out with greater ice availability during the middle of the day, and less likely to be hauled out if vessels were present. Cruise ships had the strongest negative effect; however, most vessel types negatively affected haul-out probability. Haul-out duration was longest in association with starting on incoming tides, clear skies, no precipitation, occurring in the middle of the day, and ending in the late afternoon or evening. End of haulouts was associated with increasing cloud cover, low ice availability, and vessel presence; large-sized tourism vessels or all-vessel-types combined were significant predictors of ending a haul-out bout. Probability of being hauled out was highest in June, during pupping season. Potential disturbances of harbor seals could be reduced, enabling longer resting times for seals and fewer interruptions for nursing pups, if vessels focused the majority of visits to glacial habitat to before or after the hours of 08:00-17:00 or, less optimally, 09:00-16:00.

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Organic halogenated contaminants in mother-fetus pairs of harbor seals (Phoca vitulina richardii) from Alaska, 2000-2002.

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