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Scwds Briefs: Volume 24, Number 4 (January 2009), Gary L. Doster , Editor, Scwds Briefs, Michael J. Yabsley

Southeastern Cooperative Wildlife Disease Study: Publications

Table of Contents:

HD in 2007: A Year to Remember

Ecology of AIV in Shorebirds

New USDA Brucellosis Proposal

TWS Seeks Comments on Draft Lead Policy

Unusual Eagle Death

New SCWDS Grad Students

Tennessee Director Retiring

3rd International CWD Symposium

Another SCWDS Student Award

Biofuels, Land, And Water: A Systems Approach To Sustainability, Gayathri Gopalakrishnan, M. Cristina Negri, Michael Wang, May Wu, Seth W. Snyder, Lorraine Lafreniere

United States Department of Energy: Publications

There is a strong societal need to evaluate and understand the sustainability of biofuels, especially because of the significant increases in production mandated by many countries, including the United States. Sustainability will be a strong factor in the regulatory environment and investments in biofuels. Biomass feedstock production is an important contributor to environmental, social, and economic impacts from biofuels. This study presents a systems approach where the agricultural, energy, and environmental sectors are considered as components of a single system, and environmental liabilities are used as recoverable resources for biomass feedstock production. We focus on efficient use of land and …

Artificial Insemination In South American Camelids And Wild Equids, G. P. Adams, M. H. Ratto, C. W. Collins, D. R. Bergfelt

United States Environmental Protection Agency: Publications

An overview of the present status of the use of artificial insemination (AI) in South American camelids and wild equids is offered. Technical aspects of semen collection, dilution and cryopreservation have limited the development and use of AI in camelid and equid species. To-date, efficiency is low but progress has been made and viable offspring have been produced through the use of AI in domestic South American camelids using both fresh and frozen semen. The origin, composition, and function of the viscous component of camelid seminal plasma remain a mystery and an obvious area for future research. A better understanding …

Foodweb Modeling For Polychlorinated Biphenyls (Pcbs) In The Twelvemile Creek Arm Of Lake Hartwell, South Carolina, Usa, Brenda Rashleigh, M. Craig Barber, David M. Walters

United States Environmental Protection Agency: Publications

PCBs from the Sangamo-Weston Superfund Site near Clemson, South Carolina, USA, were released into the Twelvemile Creek Arm of Lake Hartwell until the early 1990s. Monitoring data have shown that while PCB concentration in sediments declined since 1995, PCB concentrations in fish have remained elevated, e.g., largemouth bass (Micropterus salmoides) concentrations have ranged from 5 to 10 ppm. The EPA aquatic ecosystem model AQUATOX was applied to this system to better characterize foodweb dynamics that lead to biomagnification of PCBs. The model was calibrated with observed fish biomass data. Simulated PCB loading over a 12-year period provided a …

Comparing The Mutagenicity Of Toxaphene After Aging In Anoxic Soils And Accumulating In Fish, James C. Young, Anne D. Freeman, Robert M. Bruce, Douglas Williams, Keith Maruya

United States Environmental Protection Agency: Publications

A test program was conducted to evaluate the mutagenicity of toxaphene residuals extracted from aged soils and from fish collected in creeks near a toxaphene-contaminated site. The ultimate objective was to determine if the residual toxaphene congeners were more or less mutagenic than those in technical- grade toxaphene.The study showed that the mutagenicity of the bioaccumulated toxaphenecongeners in fish, expressed as colony revertants per mg of residual toxaphene, was no greater than that of technical-grade toxaphene.Themutagenicimpactofthetoxapheneresidualsinagedsoilstatistically was less than that for technical-grade toxaphene. Two specific congeners, a hexachlorobornane(labeled Hx-Sd) and a heptachlorobornane (labeled Hp-Sd), were found to accumulate over time …

Finfish And Aquatic Invertebrate Pathology Resources For Now And The Future, Jan M. Spitsbergen, Vicki S. Blazer, Paul R. Bowser, Keith C. Cheng, Keith R. Cooper, Timothy K. Cooper, Salvatore Frasca Jr., David B. Groman, Claudia M. Harper, Jerry M. (Mac) Law, Gary D. Marty, Roxanna M. Smolowitz, Judy St. Leger, Douglas C. Wolf, Jeffrey C. Wolf

United States Environmental Protection Agency: Publications

Utilization of finfish and aquatic invertebrates in biomedical research and as environmental sentinels has grown dramatically in recent decades. Likewise the aquaculture of finfish and invertebrates has expanded rapidly worldwide as populations of some aquatic food species and threatened or endangered aquatic species have plummeted due to overharvesting or habitat degradation. This increasing intensive culture and use of aquatic species has heightened the importance of maintaining a sophisticated understanding of pathology of various organ systems of these diverse species. Yet, except for selected species long cultivated in aquaculture, pathology databases and the workforce of highly trained pathologists lag behind those …

Combining Risks From Several Tumors Using Markov Chain Monte Carlo, Leonid Kopylev, John Fox, Chao Chen

United States Environmental Protection Agency: Publications

In animal bioassays, tumors are often observed at multiple sites. Unit risk estimates calculated on the basis of tumor incidence at only one of these sites may underestimate the carcinogenic potential of a chemical (NRC 1994 ). Furthermore the National Research Council (NRC, 1994 ) and Bogen (1990) concluded that an approach based on counts of animals with one or more tumors (counts of “ tumor - bearing animals ” ) would tend to underestimate overall risk when tumors occur independently across sites. On independence of tumors, NRC (1994) stated: “ … a general assumption of statistical independence of tumor …

Inter-Laboratory Control Data For Reproductive Endpoints Required In The Oppts 870.3800/Oecd 416 Reproduction And Fertility Test, M. S. Marty, B. Allen, R. E. Chapin, R. Cooper, G. P. Daston, J. A. Flaws, P. M. D. Foster, S. L. Makris, E. Mylchreest, D. Sandler, R. W. Tyl

United States Environmental Protection Agency: Publications

BACKGROUND: The U.S. EPA revised the Reproduction and Fertility Effects Test Guideline (OPPTS 870.3800/OECD 416) in 1998, adding numerous endpoints in an effort to incorporate new methodologies, improve the sensitivity for detecting reproductive toxicants, and more efficiently utilize study animals. Many of these new endpoints have not been used in regulatory reproductive toxicology studies prior to their inclusion in the test guidelines; thus, the Health and Environmental Sciences Institute (HESI) of the International Life Sciences Institute (ILSI) initiated the Reproductive Endpoints Project to examine the utility of these new endpoints. METHODS: This report provides a retrospective analysis of 43 multi-generation …

Arsenate And Dimethylarsinic Acid In Drinking Water Did Not Affect Dna Damage Repair In Urinary Bladder Transitional Cells Or Micronuclei In Bone Marrow, Amy Wang, Andrew D. Kligerman, Steven D. Holladay, Douglas C. Wolf, John L. Robertson

United States Environmental Protection Agency: Publications

Arsenic is a human skin, lung, and urinary bladder carcinogen, and may act as a cocarcinogen in the skin and urinary bladder. Possible modes of action of arsenic carcinogenesis/cocarcinogenesis include oxidative stress induction and inhibition of DNA damage repair. We investigated the effects of arsenic in drinking water on DNA damage repair in urinary bladder transitional cells and on micronucleus formation in bone marrow. F344 rats were given 100 ppm arsenate [As(V)] or dimethylarsinic acid [DMA(V)] in drinking water for 1 week. The in vivo repair of cyclophosphamide (CP)-induced DNA damage resulting from a single oral gavage of CP, and …

Safety Assessment Of Biotechnology Products For Potential Risk Of Food Allergy: Implications Of New Research, Maryjane K. Selgrade, Christal C. Bowman, Gregory S. Ladics, Laura Privalle, Susan A. Laessig

United States Environmental Protection Agency: Publications

Food allergy is a potential risk associated with use of transgenic proteins in crops. Currently, safety assessment involves consideration of the source of the introduced protein, in silico amino acid sequence homology comparisons to known allergens, physicochemical properties, protein abundance in the crop, and, when appropriate, specific immunoglobulin E binding studies. Recently conducted research presented at an International Life Sciences Institute/Health and Environmental Sciences Institute–hosted workshop adds to the scientific foundation for safety assessment of transgenic proteins in five areas: structure/activity, serum screening, animal models, quantitative proteomics, and basic mechanisms. A web-based tool is now available that integrates a database …

Mitigation Under Section 404 Of The Clean Water Act: Where It Comes From, What It Means, Palmer Hough, Morgan Robertson

United States Environmental Protection Agency: Publications

The requirement to mitigate impacts to wetlands and streams is a frequently misunderstood policy with a long and complicated history. We narrate the history of mitigation since the inception of the Clean Water Act Section 404 permit program in 1972, through struggles between the US Environmental Protection Agency and the US Army Corps of Engineers, through the emerging importance of wetland conservation on the American political landscape, and through the rise of market-based approaches to environmental policy. Mitigation, as it is understood today, was not initially foreseen as a component of the Section 404 permitting program, but was adapted from …

Anthropogenic Scarring Of Western Gray Whales (Eschrichtius Robustus), Amanda Bradford, David Weller, Yulia Ivaschenko, Alexander Burdin, Robert L. Brownell Jr.

United States Department of Commerce: Staff Publications

Western gray whales (Eschrichtius robustus) are critically endangered and anthropogenic threats, such as entanglement in fishing gear and collisions with vessels, may be acting to limit recovery of the population. Thus, examining the magnitude of such anthropogenic interactions using a scar-based approach is warranted. A multi-year (1995–2005) photo-identification study of western gray whales on their feeding ground off northeastern Sakhalin Island, Russia, has resulted in a large data set of digital and film images of 150 individuals. These images were reviewed and scored for anthropogenic scarring by recording the presence of visible scars resulting from fishing gear entanglement …

Do Monk Seals Exert Top-Down Pressure In Subphotic Ecosystems?, Frank Parrish

United States Department of Commerce: Staff Publications

Patterns of subphotic fish assemblages on seamounts in the Northwestern Hawaiian Islands were identified and compared for potential structuring influences, including the bottom-up effects of regional oceanic productivity and top-down predation pressure exerted by visiting monk seals (Monachus schauinslandi). Patterns in fish size, density, and biomass were evaluated at the deep extreme (350–500 m) of the seals feeding range to avoid confounding effects of diverse shallow habitats (e.g., coral reefs). Fish number and size were used to calculate biomass density of the seamount fish assemblages that were then compared to the independent variables of summit depth, substrate type, …

Investigation Of Growth Phases For Bottlenose Dolphins Using A Bayesian Modeling Approach, Wayne Mcfee, John Schwacke, Megan Stolen, Keith Mullin, Lori Schwacke

United States Department of Commerce: Staff Publications

The Gompertz function is the most commonly used growth function for cetacean studies. However, this function cannot represent multiple phases of growth. In this study, we present a Bayesian framework fitting parameters of a triple-logistic growth function to describe multiple phases of growth for bottlenose dolphins (Tursiops truncatus), simultaneously fitting and comparing all growth parameters between South Carolina (SC), Mississippi Sound (MSS), and Indian River Lagoon (IRL) cohorts. The fitted functions indicated a preliminary early, rapid growth phase, followed by a second phase of slower growth, and then a moderate growth spurt later in life. Growth parameters between …

Blubber Testosterone: A Potential Marker Of Male Reproductive Status In Short-Beaked Common Dolphins, Nicholas Kellar, Marisa Trego, Corina Marks, Susan Chivers, Kerri Danil, Frederick Archer

United States Department of Commerce: Staff Publications

A novel molecular technique was used to measure blubber testosterone (BT) in 114 male short-beaked common dolphins, Delphinus delphis, collected from incidental fishery bycatch and strandings. When these concentrations were compared across maturity states, the mean (± SEM) BT levels of mature D. delphis (14.3 ± 3.0 ng/g) were significantly higher than those of pubertal (2.5 ± 0.5 ng/g, P = 0.006) and immature animals (2.2 ± 0.3 ng/g, P < 0.0001). BT concentrations in mature males were significantly higher in summer months (53.9 ± 2.0 ng/g) than during the rest of the year (7.9 ± 0.69 ng/g, P < 0.0001), indicating reproductive seasonality. An analysis of BT in different anatomical locations showed that hormone concentrations were not homogenous throughout the body; the levels in the dorsal fin were significantly lower than in most other areas (F = 5.39, P = 0.043). Conversely, we found no significant differences in BT concentration with respect to subepidermal depth (F = 2.09, P = 0.146). Finally, testosterone levels in biopsies from 138 free-swimming male D. delphis, of unknown maturity state, sampled off California were found to be of concentrations similar to those from the fishery bycatch and stranding samples and revealed an …

Population Structure Of Island-Associated Dolphins: Evidence From Photo-Identification Of Common Bottlenose Dolphins (Tursiops Truncates) In The Main Hawaiian Islands, Robin Baird, Antoinette Gorgone, Daniel Mcsweeney, Allan Ligon, Mark Deakos, Daniel Webster, Gregory Schorr, Karen Martien, Dan Salden, Sabre Mahaffy

United States Department of Commerce: Staff Publications

Management agencies often use geopolitical boundaries as proxies for biological boundaries. In Hawaiian waters a single stock is recognized of common bottlenose dolphins, Tursiops truncatus, a species that is found both in open water and nearshore among the main Hawaiian Islands. To assess population structure, we photo-identified 336 distinctive individuals from the main Hawaiian Islands, from 2000 to 2006. Their generally shallow-water distribution, and numerous within-year and between-year resightings within island areas suggest that individuals are resident to the islands, rather than part of an offshore population moving through the area. Comparisons of identifications obtained from Kaua‘i/Ni‘ihau, O‘ahu, the …

Movements And Diving Behavior Of Pelagic Spotted Dolphins, Michael Scott, Susan Chivers

United States Department of Commerce: Staff Publications

We radio tracked 20 pantropical spotted dolphins (Stenella attenuate) in the pelagic waters of the eastern tropical Pacific Ocean during three research cruises in 1992, 1993, and 2001. Dolphins were tracked for up to 6 d from 20 to 1,000 km offshore. Seventeen of these dolphins also carried time–depth recorders, nine of which were recovered with a combined total of 477 h of dive data. The movement data suggested that the dolphins associate with areas of relatively high biological productivity. Dolphins close to shore moved along the continental slope, while some dolphins traveled farther offshore along thermocline “ridges.” …

Behavior Of Melon-Headed Whales, Peponocephala Electra, Near Oceanic Islands, Robert L. Brownell Jr., Katherine Ralls, Simone Baumann-Pickering, M. Michael Poole

United States Department of Commerce: Staff Publications

Southall et al. (2006) concluded that a near mass stranding (MS) of melon-headed whales (MHWs), Peponocephala electra, in Hanalei Bay, Kauai, Hawaii, on 3–4 July 2004, was likely related to the operation of mid-frequency sonars (MFS). However, subsequent authors argued that the nearly simultaneous entry of MHWs into Sasanhaya Bay, Rota (∼5,740 km away) made this conclusion untenable. They suggested that both sightings, and other MSs of MHWs, could be related to lunar cycles. To resolve this question, we reviewed information on the biology and behavior of MHWs and compared the two sightings to observations of MHWs around Palmyra …

Catches Of Humpback Whales, Megaptera Novaeangliae, By The Soviet Union And Other Nations In The Southern Ocean, 1947–1973, Phil Clapham, Yuri Mikhalev, Wally Franklin, David Paton, C. Scott Baker, Yulia V. Ivashchenko, Robert L. Brownell Jr.

United States Department of Commerce: Staff Publications

The great whales of the Southern Ocean were extensively exploited by modern whaling methods, with the first catches made in the Falkland Islands Dependencies region of IWC Management Area II in 1904 (Tønnesson and Johnsen, 1982; Hart, 2006). Exploitation went through several phases. Populations of humpback whales, Megaptera novaeangliae, and blue whales, Balaenoptera musculus, around South Georgia crashed around the time of World War I, and further exploitation occurred in other regions into the 1930’s. There was a hiatus in whaling during World War II, but large-scale catches resumed in Antarctic waters after 1945.

Indo-Pacific Bottlenose Dolphin Assessment Workshop Report, R.R. Reeves, R. L. Brownell Jr.

United States Department of Commerce: Staff Publications

A workshop on the assessment of Indo-Pacific bottlenose dolphins (Tursiops aduncus), with the Solomon Islands as a case study, took place from 21-23 August 2008 in Apia, Samoa. It was planned and organized under the auspices of the Cetacean Specialist Group and attended by 19 invited participants from eight countries. Financial support was provided by WWF (International), The Ocean Conservancy, Animal Welfare Institute, Humane Society of the United States, Whale and Dolphin Conservation Society, U.S. Marine Mammal Commission and U.S. National Oceanic and Atmospheric Administration. The workshop was hosted by the Secretariat of the Pacific Regional Environment Program …

Demography And Population Viability Of Polar Bears In The Gulf Of Boothia, Nunavut, Mitchell Taylor, Jeff Laake, Philip Mcloughlin, H. Dean Cluff, Francois Messier

United States Department of Commerce: Staff Publications

We estimated demographic parameters and harvest risks for polar bears (Ursus maritimus) inhabiting the Gulf of Boothia, Nunavut, from 1976 to 2000. We computed survival and abundance from capture–recapture and recovery data (630 marks) using a Burnham joint live–dead model implemented in program MARK. Annual mean total survival (including harvest) was 0.889 ± 0.179 ( x ± 1 SE) for cubs, 0.883 ± 0.087 for subadults (ages 1–4), 0.919 ± 0.044 for adult females, and 0.917 ± 0.041 for adult males. Abundance in the last 3 yr of study was 1,592 ± 361 bears. Mean size of newborn …

Contrasting Patterns Of Genetic Diversity At Three Different Genetic Markers In A Marine Mammal Metapopulation, J. I. Hoffman, K. K. Dasmahapatra, W. Amos, C. D. Phillips, T. S. Gelatt, J . W. Bickham

United States Department of Commerce: Staff Publications

Many studies use genetic markers to explore population structure and variability within species. However, only a minority use more than one type of marker and, despite increasing evidence of a link between heterozygosity and individual fitness, few ask whether diversity correlates with population trajectory. To address these issues, we analyzed data from the Steller’s sea lion, Eumetiopias jubatus, where three stocks are distributed over a vast geographical range and where both genetic samples and detailed demographic data have been collected from many diverse breeding colonies. To previously published mitochondrial DNA(mtDNA) and microsatellite data sets,we have added new data for …

Health Assessment Of Weddell Seals, Leptonychotes Weddellii, In Mcmurdo Sound, Antarctica, P.K. Yochem, B.S. Stewart, T.S. Gelatt, D.B. Siniff

United States Department of Commerce: Staff Publications

The demography of Weddell seals in eastern McMurdo Sound, Antarctica, has been well studied during the past three decades (e.g. Stirling 1971; Siniff et al. 1977; Testa and Siniff 1987; Hastings and Testa 1998; Gelatt et al. 2001). Detailed life-history data are available on thousands of seals tagged as pups in McMurdo Sound, making this population a rich resource for wildlife health studies because health parameters can be evaluated in the light of reproductive histories and genetic relationships of several generations of tagged seals.

Recently, evidence of exposure to diseases generally associated with domestic animals and feral wildlife has been …

A Fish Of Many Scales: Extrapolating Sublethal Pesticide Exposures To The Productivity Of Wild Salmon Populations, David H. Baldwin, Julann A. Spromberg, Tracy K. Collier, Nathaniel L. Scholz

United States Department of Commerce: Staff Publications

For more than a decade, numerous pesticides have been detected in river systems of the western United States that support anadromous species of Pacific salmon and steelhead. Over the same interval, several declining wild salmon populations have been listed as either threatened or endangered under the U.S. Endangered Species Act (ESA). Because pesticides occur in surface waters that provide critical habitat for ESA-listed stocks, they are an ongoing concern for salmon conservation and recovery throughout California and the Pacific Northwest. Because pesticide exposures are typically sublethal, a key question is whether toxicological effects at (or below) the scale of the …

Movements Of Satellite-Tagged Cuvier’S And Blainville’S Beaked Whales In Hawai‘I: Evidence For An Offshore Population Of Blainville’S Beaked Whales, Robin W. Baird, Gregory S. Schorr, Daniel L. Webster, Sabre D. Mahaffy, Daniel J. Mcsweeney, M. Bradley Hanson, Russel D. Andrews

United States Department of Commerce: Staff Publications

The impacts of mid-frequency active sonar on the behavior of individual cetaceans may vary depending on their history of prior exposure. Evidence from habitat use, repeated sightings of identified individuals, and satellite tagging all indicate the existence of resident populations of Cuvier’s and Blainville’s beaked whales off the island of Hawai‘i, within the Navy’s Hawai‘i Range Complex. The number of individuals that have been satellite tagged is small however, and we are combining additional satellite tagging with individual photo-identification studies to assess movements and residency of both species. Field efforts were undertaken off the island of Hawai‘i in December 2008 …

Insights Into The Population Structure Of Blue Whales In The Eastern North Pacific From Recent Sightings And Photographic Identification, John Calambokidis, Jay Barlow, John K. B. Ford, Todd E. Chandler, Annie B. Douglas

United States Department of Commerce: Staff Publications

Blue whales were widely distributed in the North Pacific prior to the primary period of modern commercial whaling in the early 1900s. Despite concentrations of blue whale catches off British Columbia and in the Gulf of Alaska, there had been few documented sightings in these areas since whaling for blue whales ended in 1965. In contrast, large concentrations of blue whales have been documented off California and Baja California and in the eastern tropical Pacific since the 1970s, but it was not known if these animals were part of the same population that previously ranged into Alaskan waters. We document …

Feedback Between Zebra Mussel Selective Feeding And Algal Composition Affects Mussel Condition: Did The Regime Changer Pay A Price For Its Success?, Henry A. Vanderploeg, Thomas H. Johengen, James R. Liebig

United States Department of Commerce: Staff Publications

1. We investigated the role of algal composition on pumping, clearance, assimilation, pseudofaeces and faeces production, feeding time budgets, and condition of zebra mussels from spring to autumn at two sites in Saginaw Bay (Lake Huron) and one site in western Lake Erie. Size-fractioned chlorophyll was used to distinguish between feeding on small (<53 >µm) and large (>53 µm) size fractions, and mussel feeding behaviour was quantified by video observations.

2. Mussel pumping, clearance and assimilation rates varied among sites, particularly during summer, when phytoplankton composition varied considerably among sites. Lowest values were seen at the inner-bay site of …

Birding In The United States: A Demographic And Economic Analysis Addendum To The 2006 National Survey Of Fishing, Hunting, And Wildlife-Associated Recreation

United States Fish and Wildlife Service: Publications

The following report provides up-todate information so birders and policy
makers can make informed decisions regarding the management of birds and
their habitats. This report identifies who birders are, where they live, how
avid they are, and what kinds of birds they watch. In addition to demographic
information, this report also provides an economic measure of birding. It
estimates how much birders spend on their hobby and the economic impact of these expenditures.

By understanding who birders are, they can be more easily reached and informed about pressures facing birds and bird habitats. Conversely, by knowing who is likely not …

Neglect Of Genetic Diversity In Implementation Of The Convention On Biological Diversity, Linda Laikre, Fred W. Allendorf, Laurel C. Aroner, C. Scott Baker, David P. Gregovich, Michael M. Hansen, Jennifer A. Jackson, Katherine C. Kendall, Kevin Mckelvey, Maile C. Neel, Isabelle Olivieri, Nils Ryman, Michael K. Schwartz, Ruth Short Bull, Jeffrey B. Stetz, David A. Tallmon, Barbara L. Taylor, Christina D. Vojta, Donald M. Waller, Robin S. Waples

United States Department of Commerce: Staff Publications

Genetic diversity is the foundation for all biological diversity; the persistence and evolutionary potential of species depend on it. World leaders have agreed on the conservation of genetic diversity as an explicit goal of the Convention on Biological Diversity (CBD). Nevertheless, actions to protect genetic diversity are largely lacking. With only months left to the 2010-biodiversity target, when the 191 parties to the CBD have agreed on achieving a significant reduction of the rate of biodiversity loss, gene-level diversity is still not being monitored, and indicators and thresholds that can be used to devise strategies to conserve this important component …

Effects Of Age, Sex And Reproductive Status On Persistent Organic Pollutant Concentrations In ‘‘Southern Resident” Killer Whales, Margaret M. Krahn, M. Bradley Hanson, Gregory Schorr, Candice K. Emmons, Douglas G. Burrows, Jennie L. Bolton, Robin W. Baird, Gina M. Ylitalo

United States Department of Commerce: Staff Publications

‘‘Southern Resident” killer whales (Orcinus orca) that comprise three fish-eating ‘‘pods” (J, K and L) were listed as ‘‘endangered” in the US and Canada following a 20% population decline between 1996 and 2001. Blubber biopsy samples from Southern Resident juveniles had statistically higher concentrations of certain persistent organic pollutants than were found for adults. Most Southern Resident killer whales, including the four juveniles, exceeded the health-effects threshold for total PCBs in marine mammal blubber. Maternal transfer of contaminants to the juveniles during rapid development of their biological systems may put these young whales at greater risk than adults …