Cape Town - Sea Search Research and Conservation have said there is a massive Cape fur seal mortality event unfolding along the West Coast after a large number of dead seals were reported last month – which seems to be continuing.
Overfishing and fishing line entanglements appear to be the most likely cause of the deaths at present.
A few key players working on the investigation into the cause of these deaths include Sea Search, the Department of Environment, Forestry and Fisheries (Deff), CapeNature, SANParks, the SPCA, TwoOceans, SharkSpotters and various municipalities.
Stellenbosch University senior lecturer and Sea Search co-director Tess Gridley said it was difficult to give the exact number of mortalities but it was in the thousands.
They are collating data collected from Shelly Beach, Elands Bay and Lamberts Bay (where the deaths were occurring) on the Cape fur seal mortality event and Avian flu, but so far no direct links between this occurrence and the Avian flu outbreaks had been made.
Deff director of communications Zolile Nqayi said two of their technicians and scientists were sent out on an inspection visit at the onset of these mortalities last month. However, numbers were low at the time and only four of the encountered carcasses were sampled for veterinary tests, of which preliminary observations revealed the carcasses had signs of undernourishment and malnutrition.
“The number of mortalities have since increased and coincided with the outbreak of Avian flu in the same hot spots. Although seal mortalities are not uncommon at this time of the year, the rapid increase in numbers has alarmed the department and her stakeholders,” said Nqayi.
Gridley said that their researchers’ scientific instincts argued that something else was going on, as they were seeing above-normal levels of mortality across age ranges. The high nutritional demand observed, together with the time of the life cycle the seals were in, coincided with low fish stocks and seal entanglement by fishing lines.
“We think this may be indicative of the overfishing that’s been taking place for many years in the environment and in addition to the entanglements we’re seeing in Cape fur seals – perhaps a larger issue here is the competition for food resources,” said Gridley.
Nqayi said the department had since approached the State Vet at the Western Cape’s Department of Agriculture for assistance with post-mortems.
AfriOceans Conservation Alliance founder Lesley Rochat said the recent deaths of many Cape fur seals was no surprise as these seals fed predominantly on small, migrating schooling fish – but there had been documented changes in the availability of prey species in the Benguela (current), which was having a detrimental effect on marine life, and this was largely because of overfishing and climate.