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Characteristics of sex-biased dispersal and gene flow in coastal river otters: implications for natural recolonization of extirpated populations.

https://arctichealth.org/en/permalink/ahliterature5547
Source
Mol Ecol. 2002 Mar;11(3):289-303
Publication Type
Article
Date
Mar-2002
Author
G M Blundell
M. Ben-David
P. Groves
R T Bowers
E. Geffen
Author Affiliation
Alaska Cooperative Fish and Wildlife Research Unit and Institute of Arctic Biology, University of Alaska Fairbanks, USA.
Source
Mol Ecol. 2002 Mar;11(3):289-303
Date
Mar-2002
Language
English
Publication Type
Article
Keywords
Alaska
Animals
Ecosystem
Female
Gene Frequency
Genetics, Population
Male
Microsatellite Repeats
Otters - genetics - physiology
Population Dynamics
Research Support, Non-U.S. Gov't
Sex Characteristics
Abstract
River otters (Lontra canadensis) were extirpated from much of their historic distribution because of exposure to pollution and urbanization, resulting in expansive reintroduction programmes that continue today for this and other species of otters worldwide. Bioaccumulation of toxins negatively affects fecundity among mustelids, but high vagility and different dispersal distances between genders may permit otter populations to recover from extirpation caused by localized environmental pollution. Without understanding the influence of factors such as social structure and sex-biased dispersal on genetic variation and gene flow among populations, effects of local extirpation and the potential for natural recolonization (i.e. the need for translocations) cannot be assessed. We studied gene flow among seven study areas for river otters (n = 110 otters) inhabiting marine environments in Prince William Sound, Alaska, USA. Using nine DNA microsatellite markers and assignment tests, we calculated immigration rates and dispersal distances and tested for isolation by distance. In addition, we radiotracked 55 individuals in three areas to determine characteristics of dispersal. Gender differences in sociality and spatial relationships resulted in different dispersal distances. Male river otters had greater gene flow among close populations (within 16-30 km) mostly via breeding dispersal, but both genders exhibited an equal, low probability of natal dispersal; and some females dispersed 60-90 km. These data, obtained in a coastal environment without anthropogenic barriers to dispersal (e.g. habitat fragmentation or urbanization), may serve as baseline data for predicting dispersal under optimal conditions. Our data may indicate that natural recolonization of coastal river otters following local extirpation could be a slow process because of low dispersal among females, and recolonization may be substantially delayed unless viable populations occurred nearby. Because of significant isolation by distance for male otters and low gene flow for females, translocations should be undertaken with caution to help preserve genetic diversity in this species.
PubMed ID
11928704 View in PubMed
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Natural exposure of coastal river otters to mercury: relation to age, diet, and survival.

https://arctichealth.org/en/permalink/ahliterature4816
Source
Environ Toxicol Chem. 2001 Sep;20(9):1986-92
Publication Type
Article
Date
Sep-2001
Author
M. Ben-David
L K Duffy
G M Blundell
R T Bowyer
Author Affiliation
Institute of Arctic Biology, University of Alaska Fairbanks, 99775-7000, USA. bendavid@uwyo.edu
Source
Environ Toxicol Chem. 2001 Sep;20(9):1986-92
Date
Sep-2001
Language
English
Publication Type
Article
Keywords
Age Factors
Animals
Diet
Environmental Exposure
Female
Food chain
Male
Mercury - adverse effects - pharmacokinetics
Otters
Population Dynamics
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.
Survival Analysis
Tissue Distribution
Water Pollutants, Chemical - adverse effects
Abstract
We evaluated effects of location (i.e., Jackpot Bay, a naturally contaminated site, and Herring Bay, reference site), diet as determined by stable isotopes, and age on mercury concentrations in individual river otters (Lontra canadensis) from Prince William Sound, Alaska, USA. We also investigated the effects of mercury accumulation on survival of river otters from these two locations. Our results indicated that mercury concentrations in fishes from Jackpot Bay were significantly higher than those in fishes from Herring Bay and those in pelagic fishes. In addition, a predominant intertidal fish diet in both areas influenced the accumulation of mercury concentrations in otters. Concentrations of mercury in fur of river otters from Jackpot Bay were significantly higher than those of animals from Herring Bay. Nonetheless, we did not detect significant differences in survival between otters inhabiting the two areas, suggesting that this natural contamination was not high enough to impair survival. Our ability to investigate the effects of various factors such as location, diet composition, and age on mercury accumulation and subsequent survival of individuals offers an example for a link between individual-based captive studies and population-level field investigations.
PubMed ID
11521825 View in PubMed
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