Verena Gill

Verena Gill
National Marine Fisheries Service | NMFS · Protected Resources Division

Master of Science
Supervisor of a Marine Mammal Conservation Branch in the Alaska Region of NOAA Fisheries

About

63
Publications
14,702
Reads
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Citations
Introduction
Verena Gill currently works at the Alaska Region of NOAA Fisheries' Protected Resources Division as the supervisor of the Marine Mammals Conservation Branch 3.
Additional affiliations
July 2016 - October 2020
NOAA Fisheries
Position
  • Researcher
September 2014 - July 2016
Bureau of Ocean Energy Management
Position
  • Wildlife Biologist
November 2002 - September 2014
U.S. Fish and Wildlife Service
Position
  • Wildlife Biologist

Publications

Publications (63)
Article
For the sea otter (Enhydra lutris), genetic population structure is an area of research that has not received significant attention, especially in Southwest Alaska where that distinct population segment has been listed as threatened since 2005 pursuant to the U.S. Endangered Species Act. In this study, 501 samples from 14 locations from Prince Will...
Article
Full-text available
Most of the world’s sea otters reside in Alaska, but there has never been an assessment of long-term mortality patterns for this keystone predator. We examined data collected from 780 northern sea otter ( Enhydra lutris kenyoni) carcasses recovered in Alaska from 2002 to 2012 to evaluate the causes of mortality and risk factors associated with deat...
Article
Full-text available
Climate change-driven alterations in Arctic environments can influence habitat availability, species distributions and interactions, and the breeding, foraging, and health of marine mammals. Phocine distemper virus (PDV), which has caused extensive mortality in Atlantic seals, was confirmed in sea otters in the North Pacific Ocean in 2004, raising...
Article
Full-text available
To better understand the spatial context of population dynamics of sea otters (Enhydra lutris) in Southeast Alaska (SEAK), we investigated the spatial and temporal patterns of subsistence sea otter harvest and assessed the effect of harvest on population growth. U.S. federal law permits subsistence harvest of sea otters and sale of clothing and han...
Article
Full-text available
Sea otter populations in Southeast Alaska, USA, have increased dramatically from just over 400 translocated animals in the late 1960s to >8,000 by 2003. The recovery of sea otters to ecosystems from which they had been absent has affected coastal food webs, including commercially important fisheries, and thus information on expected growth and equi...
Article
Full-text available
Background In the North Pacific, northern fulmar (Fulmarus glacialis) forms extensive colonies in few locales, which may lead to limited gene flow and locale-specific population threats. In the Atlantic, there are thousands of colonies of varying sizes and in Europe the species is considered threatened. Prior screens and classical microsatellite de...
Article
Infection with Brucella spp., long known as a cause of abortion, infertility, and reproductive loss in domestic livestock, has increasingly been documented in marine mammals over the past two decades. We report molecular evidence of Brucella infection in Asian sea otters (Enhydra lutris lutris). Brucella DNA was detected in 3 of 78 (4%) rectal swab...
Technical Report
Full-text available
Alaska Department of Fish and Game (ADF&G) conducted a pot survey for Dungeness crab Metacarcinus magister in the Kodiak Area during August–September 2014 and collaborated with U.S. Fish and Wildlife Service (USFWS) to evaluate sea otter Enthydra lutris kenyoni bycatch in the Kodiak Area Dungeness crab fishery by concurrently performing transect...
Article
Full-text available
Like other top predators that compete with human beings for prey species, sea otters inspire extremes of emotion. Debates about sea otter management in California and Alaska over the past several decades have revealed widely divergent perspectives. Proponents of the fisheries affected by sea otters advocate a balance of uses, whereby sea otters are...
Article
Valvular endocarditis has been well described in northern sea otters Enhydra lutris kenyoni of Alaska and in many cases no cause has been identified. It is also one of the most common conditions observed in people with chronic Coxiella burnetii infection. Given the high levels of C. burnetii exposure in marine mammals distributed throughout the sam...
Article
Full-text available
The quantification of individuality is a common research theme in the fields of population, community, and evolutionary ecology. The potential for individuality to arise is likely context-dependent, and the influence of habitat characteristics on its prevalence has received less attention than intraspecific competition. We examined individual diet...
Article
Abstract Since 2002, an increased number of northern sea otters (Enhydra lutris kenyoni) from southcentral Alaska have been reported to be dying due to endocarditis and/or septicemia with infection by Streptococcus infantarius subsp. coli. Bartonella spp. DNA was also detected in northern sea otters as part of mortality investigations during this u...
Article
Sea cucumbers (Parastichopus californicus), which are an important commercial, subsistence, and ecological resource, are negatively affected by an expanding sea otter (Enhydra lutris) population in southeast Alaska. A few hundred sea otters were reintroduced into southeast Alaska in the late 1960s after their extirpation during the 18th and 19th ce...
Article
Full-text available
Sea otters (Enhydra lutris) are the most recent group of mammals to return to the sea, and may exemplify divergent somatosensory tactile systems among mammals. Therefore, we quantified the mystacial vibrissal array of sea otters and histologically processed follicle-sinus complexes (F - SCs) to test the hypotheses that the number of myelinated axon...
Article
Abstract Histoplasmosis of local origin has not been reported in humans or wildlife in Alaska, and the disease has never been reported in a free-ranging marine mammal. In 2005 a northern sea otter (Enhydra lutris kenyoni) was found on Kodiak Island, Alaska, at 57° latitude north, far outside the known distribution of Histoplasma capsulatum. The ani...
Conference Paper
Background/Question/Methods The recognition and quantification of individuality is now a common research theme in the fields of behavioral, evolutionary, community, and population ecology. Individual level differences in behavior, prey choice, and movement have been documented over a wide variety of taxa and ecosystems. The potential for individu...
Conference Paper
Full-text available
Since 1999, the Alaska SeaLife Center has routinely screened live marine animals found in distress, and those found dead, for fecal pathogens (e.g., Salmonella, E. coli 0157, Campylobacter, Vibrio spp.) and exposure to a variety of diseases known to affect marine mammals and/ or humans (e.g., Brucella, Morbillivirus, Leptospirosis, Herpesvirus). Ad...
Article
Full-text available
Pulsed-field gel electrophoresis (PFGE) was used to type 128 Streptococcus infantarius subsp. coli isolates from sea otters and mussels. Six SmaI PFGE groups were detected, with one predominant group representing 57% of the isolates collected over a wide geographic region. Several sea otter and mussel isolates were highly related, suggesting that a...
Article
Oral ulcerations and plaques with epithelial eosinophilic intranuclear inclusions were observed in northern sea otters (Enhydra lutris kenyoni) that died or were admitted for rehabilitation after the 1989 Exxon Valdez oil spill (EVOS) in Alaska, USA. Transmission electron microscopy demonstrated the presence of herpesviral virions. Additionally, a...
Article
Factors affecting winter survival may be key determinants of status and population trends of seabirds, but connections between breeding sites and wintering areas of most populations are poorly known. Pelagic Cormorants (Phalacrocorax pelagicus; N = 6) surgically implanted with satellite transmitters migrated from a breeding colony on Middleton Isla...
Article
Full-text available
Northern sea otter (Enhydra lutris kenyoni) abundance has decreased dramatically over portions of southwest Alaska, USA, since the mid-1980s, and this stock is currently listed as threatened under the Endangered Species Act. In contrast, adjacent populations in south central Alaska, USA, and Russia have been stable to increasing during the same per...
Article
We used satellite telemetry to investigate the migration patterns and wintering areas of Glaucouswinged Gulls (Larus glaucescens) from Middleton Island, Alaska, where this species' population increased tenfold from the 1970s to the 1990s. Fall migration spanned 11 weeks, including numerous stopovers en route, apparently for feeding. Spring migratio...
Article
Bacterial infections are an important cause of sea otter (Enhydra lutris) mortality, and some of these infections may originate from terrestrial and anthropogenic sources. Antimicrobials are an important therapeutic tool for management of bacterial infections in stranded sea otters and for prevention of infection following invasive procedures in fr...
Article
Seabird mortality associated with longline fishing in the eastern Bering Sea occurs mainly from September to May, with northern fulmars (Fulmarus glacialis) comprising the majority (60%) of the bycatch. Along the west coast of North America, winter dieoffs of fulmars may be increasing in frequency and magnitude, the most severe on record being a wr...
Article
Full-text available
Life-history theory predicts that within a species, reproduction and survival rates will differ among populations that differ in resource availability or predation rates through phenotypic plasticity. When populations are near carrying capacity (K) or when they are declining due to reduced prey resources, the average age at 1st reproduction (averag...
Article
Phocine distemper virus (PDV) has caused 2 epidemics in harbor seals in the Atlantic Ocean but had never been identified in any Pacific Ocean species. We found that northern sea otters in Alaska are infected with PDV, which has created a disease threat to several sympatric and decreasing Pacific marine mammals.
Data
Full-text available
Phocine Distemper Virus in Northern Sea Otters in the Pacific Ocean, Alaska, USA
Article
We present data on the colonization of Middleton Island, Alaska, by Black Oystercatchers (Haematopus bachmani) following the creation of an extensive rocky intertidal zone after the Alaskan earthquake of 1964. The first pair of oystercatchers was detected in 1976, and it was another 5 years before the population increased to three pairs. Oystercatc...
Article
Perfluorinated chemicals (PFCs) have been detected in abiotic and biotic matrices worldwide, including the Arctic Ocean. Considering these chemicals' persistent and bioaccumulative potentials, it was expected that levels of PFCs, like those of many legacy organic pollutants, would respond slowly to the restrictions in production and usage. Temporal...
Article
Sexing oystercatchers in the field is difficult because males and females have identical plumage and are similar in size. Although Black Oystercatchers (Haematopus bachmani) are sexually dimorphic, using morphology to determine sex requires either capturing both pair members for comparison or using discriminant analyses to assign sex probabilistica...
Article
Age at first reproduction (AFR) has been difficult to quantify in mammals, as the most commonly used methods require reproductive tracts or direct observations. However, work in several large mammal species suggests that the width of cementum light bands in teeth decline once females begin to reproduce, suggesting that teeth structures might provid...
Article
Mothers can improve the quality of their offspring by increasing the level of certain components in their eggs. To examine whether or not mothers increase deposition of such components in eggs as a function of food availability, we food-supplemented black-legged kittiwake females (Rissa tridactyla) before and during egg laying and compared depositi...
Conference Paper
Due to a small population, restricted range, threats to preferred habitat, and susceptibility to human-related disturbances, the Black Oystercatcher (Haematopus bachmani) is listed as a species of high concern within the U.S., Canadian, Alaskan, and Northern and Southern Pacific shorebird conservation plans and is a featured species in the Comprehe...
Article
Females of many species copulate more frequently than necessary to fertilize their eggs despite the potential costs. Several studies, particularly on socially monogamous birds, have suggested that females obtain immediate material benefits by trading copulations for nutrients or other resources. We experimentally tested this hypothesis by manipulat...
Article
Many life-history traits are expressed interactively in life, but to a varying extent on different occasions. Changes in trait expression can be accounted for by differences in the quality of the environment ('environmental constraint' hypothesis) or by strategic adjustments, if the relative contribution of the trait to fitness varies with time ('s...
Article
1. The immune system plays an important role in fitness, and interindividual variation in immunocompetence is due to several factors including food supply. 2. Seasonal variation in food resources may therefore explain why immunocompetence in bird nestlings usually declines throughout the breeding season, with chicks born early in the season receivi...
Conference Paper
This project aligns and expands several previously unrelated studies of the black oystercatcher (Haematopus bachmani) at multiple sites in the heart of the species’ range. Coordinated efforts to assess breeding ecology, productivity, local threats, survival, mate and site fidelity, and population structuring began in 2003 and will continue through...
Article
Full-text available
We conducted pelagic seabird surveys in the Gambier and Tuamotu Archipelagos in the southeastern Pacific Ocean totaling 40 hours during 7–27 March 2003 and 22.5 hours during 22–27 July 2001. We used a 300-m-wide strip transect to estimate seabird density, and we estimated relative abundance of birds at all distances. In 2001, we observed a total of...
Technical Report
Full-text available
The purpose of this guide is to provide a collection of photographs of normal anatomy and lesions previously seen during necropsies of Northern sea otters (Enhydra lutris kenyoni). Organ systems that are minimally represented indicate areas where additional focus and photos are needed in future necropsies. This guide will take you through the syste...
Article
We present data on the colonization of Middleton Island, Alaska, by Black Oystercatchers (Haematopus bachmani) following the creation of an extensive rocky intertidal zone after the Alaskan earthquake of 1964. The first pair of oystercatchers was detected in 1976, and it was another 5 years before the population increased to three pairs. Oystercatc...
Article
We evaluated the use of corticosterone to gauge forage availability and predict reproductive performance in black-legged kittiwakes (Rissa tridactyla) breeding in Alaska during 1999 and 2000. We modeled the relationship between baseline levels of corticosterone and a suite of individual and temporal characteristics of the sampled birds. We also pro...
Article
In contrast to the high productivity of black-legged kittiwakes in Britain, kittiwakes at many colonies in Alaska have failed chronically to reproduce since the mid 1970s. To determine if food is limiting productivity and, if so, at what stages of nesting food shortages are most severe, in 1996 and 1997 we supplementally fed kittiwakes nesting on a...
Article
Full-text available
We fed Herring Clupea pallasi to pairs of Black-legged Kittiwakes Rissa tridactyla throughout the breeding season in two years at a colony in the northern Gulf of Alaska. We measured responses to supplemental feeding in a wide array of breeding parameters to gauge their relative sensitivity to food supply, and thus their potential as indicators of...
Article
Full-text available
We present historic and contemporary information on the distribution and abundance of Buff- breasted Sandpipers (Tryngites subruficollis ) in South America. Historic information was collated from the literature, area ornithologists, and museums, whereas contemporary data were derived from surveys conducted throughout the main wintering range in Arg...
Article
Full-text available
We used a supplemental feeding experiment, the doubly labeled water technique, and a model selection approach based upon the Akaike information criteria to examine effects of food availability on energy expenditure rates of Black-legged Kittiwakes (Rissa tridactyla) raising young. Energy expenditure rates of supplementally fed females (n = 14) and...
Article
Full-text available
We used a supplemental-feeding experiment, the doubly labeled water technique, and a model-selection ap- proach based upon the Akaike Information Criterion to examine effects of food availability on energy expenditure rates of Black-legged Kittiwakes (Rissa tridactyla) raising young. Energy expenditure rates of supplementally fed females (n = 14) a...
Article
Full-text available
We sexed adult Black-legged Kittiwakes (Rissa tridactyla) using DNA-based genetic techniques, behavior and morphology and compared results from these techniques. Genetic and morphology data were collected on 605 breeding kittiwakes and sex-specific behaviors were recorded for a sub-sample of 285 of these individuals. We compared sex classification...
Article
Thesis (M.S.)--University of Alaska Anchorage, 1999. "December 1999." Includes bibliographical references.

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Cited By

Projects

Projects (11)
Project
The Alaska Beluga Monitoring Partnership (AKBMP) is a collaboration between several organizations that offer opportunities for volunteer citizen scientists to contribute to endangered beluga monitoring efforts in Alaska’s Cook Inlet. Together we design standardized scientific monitoring protocols, train volunteers to support monitoring efforts, and coordinate shore-based beluga monitoring activities at various sites throughout Cook Inlet. See akbmp.org
Project
To understand the population biology, ecology and behavioral biology of northern sea otters in mixed and soft-sediment habitats in Alaska.
Project
The USGS, Alaska Science Center's Nearshore Marine Ecosystem Research program (https://www.usgs.gov/centers/asc/science/nearshore-marine-ecosystem-research?qt-science_center_objects=0#qt-science_center_objects) includes a long-running research project focused on sea otters. With the exception of 13 small remnant populations, sea otters were extirpated from their historic range in the north Pacific Ocean during the 18th and 19th centuries as a result of the commercial harvest for their fur. During most of the 20th century, through protection and reintroduction, sea otter populations generally increased in abundance and distribution such that most of their range in Alaska, with the exception of southeast Alaska, was occupied by 2000. Although population abundance data are incomplete, there is evidence of increasing, stable and declining sea otter populations in different areas within their range. The factors that ultimately regulate sea otter population abundance are not completely understood, but can include predation, human harvest, food limitation, disease and catastrophic events such as oil spill. There is good evidence that the recent declines in sea otters in SW Alaska are related to killer whale predation and the Exxon Valdez oil spill reduced the size of the western Prince William Sound population in 1989. Human harvest of sea otters can adversely affect sea otter abundance, evidenced by the commercial fur trade leading to near extirpation. Because sea otters occupy relatively small home ranges and do not migrate, sustainable harvest requires management at appropriate spatial scales. Sea otters also provide one of the best documented examples of top-down forcing effects on the structure and function of nearshore marine ecosystems in the North Pacific Ocean. Much of our knowledge of the role of sea otters as a source of community variation resulted from the spatial and temporal pattern of sea otter population recovery since their near extirpation about 100 years ago. During most of the early 20th century sea otters were absent from large portions of their habitat in the north Pacific. During the absence of sea otters, many of their prey populations responded to reduced predation through increased densities and sizes. Since the middle of the 20th century sea otter populations have been recovering previous habitats, due to natural dispersal and translocations. Following the recovery of sea otters, scientists have continued to provide descriptions of nearshore marine communities and have been able to contrast those communities before and after the sea otters return. Objectives of our sea otter population assessment studies include: 1) develop and test methods to identify the degree of population structuring among north Pacific sea otter populations, 2) develop and test techniques to accurately and precisely estimate the status of sea otter populations, 3) develop and test methods to identify cause(s) of change in the status and numeric trends of sea otter populations, 4) develop and test methods to determine the role of density dependent processes in affecting change in sea otter populations, and 5) evaluate the effects of population reductions and translocations on sea otter genetic variability. We also continue to study the role of sea otters in structuring nearshore communities using a time-series of data we have collected in Glacier Bay in Southeast Alaska where the sea otters first appeared in the early 1990's and since have reoccupied the entire Bay with an estimated population of over 5000 animals. We are using this situation in Glacier Bay as a laboratory to experimentally evaluate the role of sea otter in structuring coastal marine communities in a predominately soft sediment habitat.