Karin C Harding

University of Gothenburg | GU · Department of Biological & Environmental Sciences

Many biologically important processes, such as genetic differentiation, the spread of disease, and population stability, are affected by the (natural or enforced) subdivision of populations into networks of smaller, partly isolated, subunits. Such "metapopulations" can have extremely complex dynamics. We present a new general model that uses only t...

1. Modelling of the population dynamics of seals require data on an array of vital parameters (fecundity, mortality, age structure, migrations, population growth rate). The most common way to obtain these data is to estimate the parameters from samples taken from the population. However, the influence from skewed samples can be substantial in popul...

Wildlife population dynamics are shaped by multiple natural and anthropogenic factors, including predation, competition, stressful life history events, and external environmental stressors such as diseases and pollution. Marine mammals such as gray seals rely on extensive blubber layers for insulation and energy storage, making this tissue critical...

Many endangered marine mammal populations are difficult to study, spread out over large areas, and capturing them for branding and research purposes would be unethical. Yet, they are in urgent need for assessment and conservation actions. We suggest collecting data from other more abundant populations of the same species, with careful consideration...

Body mass is a fundamental indicator of animal health closely linked to survival and reproductive success. Systematic assessment of body mass for a large proportion of a population can allow early detection of changes likely to impact population growth, facilitating responsive management and a mechanistic understanding of ecological trends. One cha...

The Baltic Sea is home to a genetically isolated and morphologically distinct grey seal population. This population has been the subject of 120‐years of careful documentation, from detailed records of bounty statistics to annual monitoring of health and abundance. It has also been exposed to a range of well‐documented stressors, including hunting,...

Changes in species abundance and distribution are driven by short-term interactions between individuals and their environment, as well as by long-term shifts in climate, prey abundance, disease outbreaks and predators, acting across generations. Unfortunately, management of wildlife populations by humans has often overlooked these long-term effects...

Aerial line transect surveys of the density of humpback whales (Megaptera novaeangliae) conducted off West Greenland eight times between 1984 and 2007 were used to estimate the rate of increase on the summer feeding ground. Only surveys in 1993, 2005 and 2007 had enough sightings to construct independent density estimates, whereas the surveys in 19...

The Centre for Marine Evolutionary Biology (CeMEB) at the University of Gothenburg, Sweden, was established in 2008 through a 10‐year research grant of 8.7 m€ to a team of senior researchers. Today, CeMEB members have contributed >500 scientific publications, 30 PhD theses and have organised 75 meetings and courses, including 18 three‐day meetings...

Supplementary Information

Empirical evidence has shown that historical exposure of polychlorinated biphenyls (PCBs) to Baltic grey seals not only severely affected individual fitness, but also population growth rates and most likely caused the retarded recovery rate of the depleted population for decades. We constructed a new model which we term a toxicokinetic–toxicodynami...

Detecting changes in population trends depends on the accuracy of estimated mean population growth rates and thus the quality of input data. However, monitoring wildlife populations poses economic and logistic challenges especially in complex and remote habitats. Declines in wildlife populations can remain undetected for years unless effective moni...

Generation time is a measure of the pace of life and is used to describe processes in population dynamics and evolution. We show that three commonly used mathematical definitions of generation time in age-structured populations can produce different estimates of up to several years for the same set of life history data. We present and prove a mathe...

Empirical evidence has shown that historical exposure of polychlorinated biphenyls (PCBs) to Baltic grey seals not only severely affected individual fitness, but also population growth rates and most likely caused the retarded recovery rate of the depleted population for decades. We construct a new model which we term a toxicokinetic-toxicodynamic...

Empirical evidence has shown that historical exposure of polychlorinated biphenyls (PCBs) to Baltic grey seals not only severely affected individual fitness, but also population growth rates and most likely caused the retarded recovery rate of the depleted population for decades. We construct a new model which we term a toxicokinetic-toxicodynamic...

The harbour seal (Phoca vitulina) is the most widely distributed pinniped, occupying a wide variety of habitats and climatic zones across the Northern Hemisphere. Intriguingly, the harbour seal is also one of the most philopatric seals, raising questions as to how it colonised virtually the whole of the Northern Hemisphere. To shed light on the ori...

To understand the bioaccumulation and food web dynamics of persistent organic pollutants (POPs) as a function of species, age and sex in Antarctic mammals, blubber samples of 3 killer whales (Type C) and 77 pinnipeds (Weddell, Ross and crabeater seals) were collected from the Southern Ocean, Antarctica. They were analyzed for polychlorinated biphen...

This introductory chapter to our Environment International VSI does not need an abstract and therefore we just include our recommendations below in order to proceed with the resubmission. Future work should examine waterbirds as food web sentinels of multiple stressors as well as Baltic Sea food web dynamics of hazardous substances and how climate...

Conservation efforts have mainly been focused on depleted species or populations, but many formerly reduced marine mammal populations have recovered to historical abundances. This calls for new management strategies and new models for ecological risk assessment that incorporate local density dependence and multiple environmental stressors. The harb...

Here we review contaminant exposure and related health effects in six selected Baltic key species. Sentinel species included are common eider, white-tailed eagle, harbour porpoise, harbour seal, ringed seal and grey seal. The review represents the first attempt of summarizing available information and baseline data for these biomonitoring key speci...

Many aspects of sexual and asexual reproduction have been studied empirically and theoretically. The differences between sexual and asexual reproduction within a species often lead to a biased geographical distribution of individuals with different reproductive strategies. While sexuals are more abundant in the core habitat, asexuals are often foun...

Evolutionary genomics has recently entered a new era in the study of host-pathogen interactions. A variety of novel genomic techniques has transformed to the identification, detection and classification of both hosts and pathogens, allowing a greater resolution that helps decipher their underlying dynamics and provides novel insights into their env...

Ross seals Ommatophoca rossii are one of the least studied marine mammals, with little known about their foraging ecology. Research to date using bulk stable isotope analysis suggests that Ross seals have a trophic position intermediate between that of Weddell Leptonychotes weddellii and crabeater Lobodon carcinophaga seals. However, consumer bulk...

Radionuclides from the Chernobyl accident in 1986 still circulate in the Baltic marine ecosystem and activity levels in water, sediments and fish species such as herring and perch are monitored annually. However, the activity levels of radionuclides in marine mammals have only been sporadically reported. Tissue samples from a museum collection were...

The harbor seal populations of Danish and Swedish waters have had turbulent population dynamics during the last century. They were severely depleted by hunting in the beginning of the twentieth century, followed by rapid recovery due to protective measures. They were victims to two mass mortalities caused by Phocine Distemper Virus (PDV) epidemics....

The 1988 and 2002 phocine distemper virus (PDV) outbreaks in European harbour seals Phoca vitulina are among the largest mass mortality events recorded in marine mammals. Despite its large impact on harbour seal population numbers, and 3 decades of studies, many questions regarding the spread and temporal origin of PDV remain unanswered. Here, we s...

Harbor seals (Phoca vitulina) inhabit the seas surrounding Denmark and are an important top predator in the marine food chain. This trophic position exposes them to environmental contaminants with disease epidemics and hunting being additional threats to this population. It is therefore important to study how environmental pollution at the current...

We analyzed a long-term data set of the body condition of Baltic gray seals (Halichoerus grypus) over time and investigated how average subcutaneous blubber thickness of different age groups of seals corresponds to environmental factors. Blubber thickness of pups declined until 2010. The decreasing weight of 5–6-year-old herring (Clupea harengus),...

Weddell (Leptonychotes weddellii), Ross (Ommatophoca rossii) and crabeater seals (Lobodon carcinophaga) are phocid seals with a circumpolar distribution around Antarctica. As long-lived and large top predators, they bioaccumulate contaminants and are considered as sentinels of ecosystem health. Antarctic seals are increasingly exposed to climate ch...

Life history parameters for narwhals ( Monodon monoceros ) were estimated based on age estimates from aspartic acid racemization of eye lens nuclei. Eyes, reproductive organs, and measures of body lengths were collected from 282 narwhals in East and West Greenland in the years 1993, 2004, and 2007–2010. Age estimates were based on the racemization...

Dinoflagellate blooms of the genus Dinophysis occur regularly in the coastal Arabian Sea. By producing toxins, which may accumulate in marine bivalves, they impose threat to human health. Using time-series data on environmental variables (e.g., nutrients, sea surface temperature and salinity) and concurrent Dinophysis abundances for the surface wat...

An aspect of life history that has seen increasing attention in recent years is that of strategies for financing the costs of offspring production. These strategies are often described by a continuum ranging from capital breeding, in which costs are met purely from endogenous reserves, to income breeding, in which costs are met purely from concurre...

To understand the use and importance of the Antarctic sea ice to the Ross seal (Ommatophoca rossii), four adult females were tagged with Argos satellite transmitters in the Amundsen Sea, Antarctica. The Ross seal is the least studied of the Antarctic seal species and nothing was previously known about their behaviour in the Amundsen Sea. During alm...

The length of intervals between epidemic outbreaks of infectious diseases is critical in epidemiology. In several species of marine mammals and birds, it is pivotal to also consider the life history of the species of concern, as the contact rate between individuals can have a seasonal flux, for example, due to aggregations during the breeding seaso...

Understanding historical roles of species in ecosystems can be crucial for assessing long term human impacts on environments, providing context for management or restoration objectives, and making conservation evaluations of species status. In most cases limited historical abundance data impedes quantitative investigations, but harvested species ma...

Caspian seal hunting data 1867–2005. (DOC)

A global trend of a warming climate may seriously affect species dependent on sea ice. We investigated the impact of climate on the Baltic ringed seals (Phoca hispida botnica), using historical and future climatological time series. Availability of suitable breeding ice is known to affect pup survival. We used detailed information on how winter tem...

Marine isopods of the genus Idotea [I. balthica (Pallas, 1772), I. chelipes (Pallas, 1766), and I. granulosa Rathke, 1843] are common meso-grazers that enter deep into the Baltic Sea and here appear to live at their physiological limit, determined by salinity and temperature tolerance. We review available data on distribution and community ecology...

Aerial line transect surveys of the density of humpback whales (Megaptera novaeangliae) conducted off West Greenland eight times between 1984 and 2007 were used to estimate the rate of increase on the summer feeding ground. Only surveys in 1993,2005 and 2007 had enough sightings to construct independent density estimates, whereas the surveys in 198...

Mean age at sexual maturity (ASM) in crabeater seals (Lobodon carcinophagus) was estimated according to two different methods. Samples were from 1964, 1977, and 1989. Using the first method, the estimated ASM in 1989 was 6.57 ± 0.82 years, which was considerably older than reported earlier. This estimate is the only one existing for crabeater seals...

Time series of abundance estimates are commonly used for analyses of population trends and possible shifts in growth rate. We investigate if trends in age composition can be used as an alternative to abundance estimates for detection of decelerated population growth. Both methods were tested under two forms of density dependence and different level...

Phocine Distemper Virus (PDV) caused mass mortality in European harbour seals (Phoca vitulina) in 1988 and in 2002. Both epizootics likely originated from refugia in Arctic seals, where data indicate PDV hops among populations and species. The metapopulation structure of host populations is suggested to be the reason why PDV is preserved among Arct...

Some small populations are characterized by periods of exponential growth interrupted by sudden drops. These drops can be linked to the population size itself, for example, through overexploitation of local resources. The long-term population extinction risk and the time to extinction for such a repeatedly collapsing population are estimated from g...

A recent study [Harding and McNamara, 2002. A unifying framework for metapopulation dynamics. Am. Nat. 160, 173-185] presented a unifying framework for the classic Levins metapopulation model by incorporating several realistic biological processes, such as the Allee effect, the Rescue effect and the Anti-rescue effect, via appropriate modifications...

EPIDEMICS caused by phocine distemper virus (pdv) resulted in mass mortalities of European harbour seals ( Phoca vitulina ) in 1988 and 2002 ([Harkonen and others 2006][1]). A third epidemic started in June 2007; the gross pathological changes observed in seals that died in the 2007 outbreak were

Simple scaling arguments suggest that, among air-breathing divers, dive duration should scale approximately with mass to the one-third power. Recent phylogenetic analyses appear to confirm this. The same analyses showed that duration of time spent at the surface between dives has scaling very similar to that of dive duration, with the result that t...

Although ringed seals are important components in oceanic and fresh water ecosystems at high latitudes, little is known about how they exploit these harsh environments. Seasonal activity and diving behaviour of 19 adult Baltic ringed seals were studied by satellite telemetry. We elaborated an activity budget for ten months of the year, extending ov...

Adaptation of pinnipeds to the marine habitat imposed parallel evolutions in their parasites. Ancestral pinnipeds must have harboured sucking lice, which were ancestors of the seal louse Echinophthirius horridus. The seal louse is one of the few insects that successfully adjusted to the marine environment. Adaptations such as keeping an air reservo...

Analyses of the dynamics of diseases in wild populations typically assume all individuals to be identical. However, profound effects on the long-term impact on the host population can be expected if the disease has age and sex dependent dynamics. The Phocine Distemper Virus (PDV) caused two mass mortalities in European harbour seals in 1988 and in...

The grey seal (Halichoerus grypus) population in the Baltic Sea is recovering after a century of bounty hunting and 3 decades of low fertility rates caused by environmental pollution. A con- servative estimate of the population size in 2003 was 19,400 animals, and available data suggest an annual rate of increase of 7.5% since 1990. The growing pop...

Energy storage is an important component of life-history variation. A distinction is recognized between species that provision offspring using energy gained concurrently (income breeders) and those that provision offspring using energy stores accumulated at an earlier time (capital breeders). Although this distinction has been recognized for some t...

Increasing Scandinavian harbour seal populations during the last decades coincide in time with the collapse of the cod fishery. Assumptions of a causal relationship have led to claims favouring re-introduction of seal hunting. Proposals for 'adaptive management' often assume that decimating seal populations will automatically favour the fishery. Th...

Detailed knowledge about the history of colonization, population dynamics and behavior greatly enhance evaluation of genetic models of population units and migration rates in spatially structured populations. Here, the genetic uniqueness of harbor seals (Phoca vitulinia) in the eastern Baltic is evaluated in the light of new information on the dist...

We present new and revised data for the phocine distemper virus (PDV) epidemics that resulted in the deaths of more than 23 000 harbour seals Phoca vitulina in 1988 and 30,000 in 2002. On both occasions the epidemics started at the Danish island of Anholt in central Kattegat, and subsequently spread to adjacent colonies in a stepwise fashion. Howev...

Many invasive species experience a world that is heterogeneous and patchy, and experience it at multiple scales. In this chapter we will show how metapopulation theory can be used to explore general mechanisms which determine the initial spread and long term establishment of invasive species in novel environments. Metapopulation ecology is a branch...

Disease can generate intense selection pressure on host populations, but here we show that acquired immunity in a population subject to repeated disease outbreaks can impede the evolution of genetic disease resistance by maintaining susceptible genotypes in the population. Interference between the life-history schedule of a species and periodicity...

Winter survival rate in Harbour Seal pups is significantly correlated with the autumn body mass of pups. Multi‐type mark–recapture statistics were applied to individual re‐sighting histories of branded seals, and survival probability was estimated with weight as a covariate. The probability of surviving to an age of 1 year is only 0·63 for the smal...

It is common to estimate the extinction probability for a vulnerable population using methods that are based on the mean and variance of the long-term population growth rate. The numerical values of these two parameters are estimated from time series of population censuses. However, the proportion of a population that is registered at each census i...

We present the first epidemiological data on the 2002 outbreak of phocine distemper virus (PDV) in European harbour seals (Phoca vitulina). The epizootic curve to date supports a mortality rate and probability of infection identical to that of the 1988 outbreak, which killed 58% of the population. Thus immunity is playing no significant role in the...

Behavioural differences among population segments coupled with the transient dynamics of perturbed population structures lead to severely biased estimates of the intrinsic rates of increase in natural populations. This phenomenon is expected to occur in most populations that are structured by age, sex, state, or rank. The 1988 epizootic in European...

Many biologically important processes, such as genetic differentiation, the spread of disease, and population stability, are affected by the (natural or enforced) subdivision of populations into networks of smaller, partly isolated, subunits. Such “metapopulations” can have extremely complex dynamics. We present a new general model that uses only t...

A long-term study of freeze-branded harbour seals (Phoca vitulina) revealed explicit site fidelity. Individuals were followed up to 14 years of age and none of the 163 branded animals were observed to haul out beyond a 32-km distance from the site where they were branded as pups. Within this range, striking spatial segregation by age and sex prevai...

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Development in the Baltic ringed (Phoca hispida) and grey seal (Halichoerus grypus) populations during the past century is reconstructed using uniquely detailed hunting records from the Nordic countries and published data on demographic parameters. A projection model was elaborated where annual variations in the composition of catches by sex and ag...