IFAW Canada: Dead seals found in Newfoundland -- 3/27/10
We’d heard reports of thousands of dead seal pups being found on the beaches of western Newfoundland, so our team went to investigate. We didn’t have to look far.
We were very close to the road, and attracted some attention with our cameras and brightly coloured flotation suits. The helicopter didn’t help much either. An extremely nice woman stopped to chat. She told us that the previous week, this very beach had been covered with mothers giving birth to their pups and that it was quite the attraction, with local folks coming down to take photos and hold the pups. She was sad and angry to see many of them now dead.
Although seeing the dead pups was heartbreaking, the news that the pups had been born here was interesting. Unlike some other species, harp seals rarely give birth on land - even in poor ice years – and the general view is that when they can’t find ice, most mothers will give birth in the water rather than haul out on land.
Gulf harp seals generally return to the same area year after year to give birth, either in the Northern Gulf of St. Lawrence or near the Magdalen Islands in the southern Gulf. But with no ice in the Gulf this year, no one knew what they would do upon discovering that “their” traditional birthing places did not exist. Would they give birth in the water where the pups would die? Would they be able to hold off giving birth, and swim northward in search of ice? Would they try to give birth on land?
It is expected that many of the Gulf pups died by being born underwater this year. Others will have been born on ice that was not sufficiently solid and those pups would also perish or - like the pups we found on PEI - be washed ashore. Those pups, and any pups that were born on land, are much more vulnerable to disturbance and predation. Scienfitic studies of ice-based harp seal ecotourism show that occasional disturbance of harp seal pups will not cause a mother to abandon it, but repeated disturbances may disrupt the nursing period enough that pups will not gain the thick layer of blubber they need to survive. Once weaned, pups undergo a fasting period of up to 6 weeks. If nursing is repeatedly disrupted the pups won’t gain enough fat to meet their energy needs during this time.
Given the lack of ice this year, it is likely that many mothers simply abandoned their pups at birth. The energy cost to a seal mother of giving birth is very low. But the cost of nursing a pup to weaning is very high – mothers lose some 36 kg as they transfer energy (fat-rich milk) to their pup during the nursing period.
Given the lack of ice, and in the presence of human disturbance and predation, many mothers would have given birth, “cut their losses” so to speak, then gone off to find a mate in hopes of better conditions next year. This does not make harp seals bad mothers; it’s what mammals to do survive and maximize their number of healthy pups produced over a lifetime.
Even if they manage to survive long enough to build up blubber reserves, pups face a long and arduous swim northward with no ice platform on which they can rest, and many more will die from exhaustion.
Whatever the reason, we have now seen for ourselves that the lack of Gulf ice has resulted in high pup mortality again this year. We will never know exactly how many pups died, although we may begin to see the impact in harp seal population surveys in 5 or 6 years time, when this year’s pups come back to give birth as sexually mature adults.
Government scientists say the loss of this year’s pups won’t have much of an impact on the harp seal population overall. If this were a single event, that might be true. But the fact is that we are not talking about a single year or a rare occurrence; these years of “bad ice” and high pup mortality are increasing, and many scientists - as well as the IUCN Red List of Endangered Species - are warning that climate change is going to have negative impacts for harp seal populations in the future.
And of course, there is no question that the effect of climate change on individual animals is absolutely devastating: abandoned seal pups starving on beaches, crying for food and trying to suckle off of each other, pups swimming desperately in search of ice on which to rest, until they die from exhaustion. These are terrible things even to think about, much less to actually observe.
And what about any pups that do manage to survive, through sheer luck, determination, or by the good fortune that they (or their mothers) exhibit some trait that is pre-adaptive to climate change?
Well, the government of Canada is doing their best to ensure that those spunky survivors are killed too, by increasing the allowable catch to 330,000 and escalating their efforts to create commercial markets for dead seals.For the survival of the seals, we must do everything we can to ensure they do not succeed.