To the top

Page Manager: Webmaster
Last update: 9/11/2012 3:13 PM

Tell a friend about this page
Print version

Collapse of a Marine Mamm… - University of Gothenburg, Sweden Till startsida
To content Read more about how we use cookies on

Collapse of a Marine Mammal Species Driven by Human Impacts

Journal article
Authors T. Harkonen
Karin C. Harding
S. Wilson
M. Baimukanov
L. Dmitrieva
Carl Johan Svensson
S. J. Goodman
Published in Plos One
Volume 7
Issue 9
ISSN 1932-6203
Publication year 2012
Published at Department of Biological and Environmental Sciences
Language en
Keywords canine-distemper virus, southern caspian sea, phoca-caspica, ringed, seal, monk seal, mnemiopsis-leidyi, baltic sea, population, consequences, hispida
Subject categories Biological Sciences


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 may have long-term data accessible from hunting records. Here we make use of annual hunting records for Caspian seals (Pusa caspica) dating back to the mid-19th century, and current census data from aerial surveys, to reconstruct historical abundance using a hind-casting model. We estimate the minimum numbers of seals in 1867 to have been 1-1.6 million, but the population declined by at least 90% to around 100,000 individuals by 2005, primarily due to unsustainable hunting throughout the 20th century. This collapse is part of a broader picture of catastrophic ecological change in the Caspian over the 20th Century. Our results combined with fisheries data show that the current biomass of top predators in the Caspian is much reduced compared to historical conditions. The potential for the Caspian and other similar perturbed ecosystems to sustain natural resources of much greater biological and economic value than at present depends on the extent to which a number of anthropogenic impacts can be harnessed.

Page Manager: Webmaster|Last update: 9/11/2012

The University of Gothenburg uses cookies to provide you with the best possible user experience. By continuing on this website, you approve of our use of cookies.  What are cookies?