Mysterious mass deaths of African cape fur seals alarm conservationists

Nerea Gonzalez

Johannesburg, Oct 27 (efe-epa).- At the end of each year, Cape fur seals welcome their new pups during their mating season in the southern hemisphere’s spring, regenerating their colonies in southeastern Africa. This year, however, the beaches of Namibia have been filled with thousands of seal fetuses, triggering alarm among conservationists and scientists.

The situation is especially concerning with a colony of around 50,000 seals near Pelican Point, a peninsula near the town of Walvis Bay.

In that area alone, members of the conservation organizations Ocean Conservation Namibia (OCN) and the Namibian Dolphin Project estimate that there have already been “thousands” of aborted fetuses and premature deaths of pups found on the beach at Pelican Point.

Fur seals usually give birth in November and December, but have been known to abandon their young when there are food shortages or other environmental factors.

Scientists fear that the phenomenon that is killing the babies of Pelican Point will spread to other places – or is already present – at a time when travel and scientific research have been complicated or impeded because of restrictions associated with the Covid-19 pandemic.

Given these dynamics, it is “very difficult to tell for sure” how many have died, Tess Gridley, co-director of the Namibian Dolphin Project, tells Efe.

Current estimates indicate about 5,000 bodies in Pelican Point alone, although the precise reasons are still unknown.

“We are very cautious right now assigning a particular causative factor. There are many many reasons why you can have an abortion event,” says Gridley, pointing to the presence of bacteria, contamination, malnutrition or a combination of different factors as potential causes.

CAPE SEALS, PART OF THE LANDSCAPE

South African sea lions or Cape fur seals (Arctocephalus pusillus pusillus) are very similar to seals, differing only in minor features such as their smaller ears.

Known for lazily lounging on the sand when they are not feeding, they are capable of diving up to 200 meters in search of food. It is estimated that southern Africa’s Atlantic coasts, from South Africa to Angola, are home to about 1.7 million sea lions.

Their large numbers mean that they are not viewed by conservationists as particularly at risk, beyond the threat of industrial fishing affecting their food supplies.

In Namibia, they are a major tourist attraction, with visitors flocking to view the seal colony on beaches where the wet sand turns into arid desert in a matter of meters.

Much like with human mothers, if these marine mammals have any health problems or, for example, if a lack of food lowers their levels of body fat needed to survive, problems can arise during pregnancies.

Since the species adopts a seasonal “simultaneous birth strategy” of young at the end of each year, Gridley highlights that it is possible that all of the pregnant females in a colony could be affected by “the same conditions” or the same “agent” that causes mass abortions.

A similar phenomenon was recorded in 1994, when 10,000 specimens died and 15,000 fetuses were aborted due to food shortages caused by a lack of fish and indirect bacterial infections.

SEARCHING FOR THE CAUSE

“What we are trying to get a hold of is samples of the pups, particularly those freshly dead pups, which sounds very bad, but they are needed for really detailed analysis,” Gridley says.

Those samples must be sent to laboratories in Pretoria, the capital of neighboring South Africa, which involves high costs that are difficult to finance. OCN and the Namibian Dolphin Project are collecting donations.