A new study from Duke has found that as sea ice cover declines off the coast of eastern Canada, harp seal pups are suffering from a higher rate of strandings than their parents. It’s the first study of seal stranding rates that takes into account genetics, as well as environmental and demographic factors like age and gender. Duke research scientist David Johnston says that genetic fitness does not affect the rate of stranding.
"It's not just the weakest pups -- those with low genetic diversity and presumably lower ability to adapt to environmental changes -- that are stranding," Johnston said in a statement from Duke. "It appears genetic fitness has little effect on this."
The scientists were following up a Duke-led study done last year that revealed sea ice is declining in all regions where harp seals breed in the North Atlantic. Johnston said that sea ice is vital for the survival of baby seals.
“Harp seals rely on stable winter sea ice as safe platforms to give birth and nurse their young until the pups can swim, hunt and fend off predators for themselves, “ he said. “In years of extremely light ice cover, entire year-classes may be disappearing from the population.”
A range of species that inhabit the high latitudes are being affected by the decline in sea ice. The reason that harp seals are important is because they are what scientists consider an indicator species, a species whose well-being is indicative of the health of the region as a whole.
The International Fund for Animal Welfare created a video that shows seals struggling on thin ice in the region where the study was conducted:
The study was published in the scientific journal PLoS One.