00:00 The southern right whales are back from the Antarctic, and every sighting is a special
00:06 event. For more than 50 years now, researchers have carried out an annual survey of the whales
00:12 off the Cape of South Africa. From above, they photograph and count the whales and assess
00:18 their health. The current head of the study, Els Vermeulen, has been keeping a close eye
00:23 on the trends.
00:28 We see the right whales as the right sentinel to show us how climate change is affecting
00:33 the Southern Ocean and Antarctic regions. And these whales basically come to our coast
00:37 in South Africa with these messages of ecosystem changes. Therefore, we call them the right
00:42 whale.
00:46 The team covers hundreds of kilometers of coastline, hoping to capture photographs of
00:52 the whales, specifically the callosities on their heads. The rough patches of skin appear
00:58 white because they're covered with colonies of whale lice. The callosities produce a unique
01:05 pattern on each whale, which can be analyzed using computational modeling to identify individual
01:12 animals. But capturing the images can be a challenge.
01:18 We need to be directly overhead those whales. We need a shot straight down over the top
01:24 of their head to make sure we get a very good, clear callosity pattern. We can't have any
01:30 waves or breaking over the head. That is quite challenging, especially out of a helicopter
01:36 that is moving around a lot, especially getting buffeted around in the wind.
01:40 Less than 150 kilometers from Cape Town, the shallow waters of Walker Bay are teeming with
01:47 life. Along with the southern right whales, it's also a stopping point for humpback whales
01:53 who arrive here with their calves on their annual migration up South Africa's eastern
01:58 coast.
02:01 It's super important to have sanctuaries like that because these whales are spending a lot
02:05 of energy to get all the way up to South Africa from Antarctica, giving birth, producing milk
02:11 for their babies to get strong enough to head back down to Antarctica. And if this area
02:16 is protected, this place where they're resting, then they don't have to use additional energy
02:20 to move out of the way of ships or boats or other people around.
02:24 And outside the protected season, there are lots of people on the water here. South Africa
02:30 has the largest population of southern right whales in the world. More than 6,500 pass
02:37 through these waters every year. So it's not just the scientists who hope to spot them.
02:43 Thousands of tourists from all over the world visit the town of Hermanus, hoping to catch
02:47 a glimpse of the gentle giants. And that, of course, helps boost the local economy.
02:53 Tourism has been growing in the area for the last 20 or 30 years quite extensively, but
02:58 this has really put us in the front foot and even way ahead of some of the other smaller
03:03 towns around the area. And yeah, it's had a great, great impact. And financially, it
03:08 sustains a massive, massive amount of people around our direct area.
03:14 The number of whales has rebounded since the 1976 ban on commercial whaling in the southern
03:21 hemisphere. But researchers say the global population is still about 20% of pre-industrial
03:27 whaling levels. And while harpoons and whaling ships may be a thing of the past here, the
03:33 multi-decade study suggests that southern right whales are facing a new danger.
03:38 Feeding grounds of the South African right whale population is south of South Africa
03:42 in the Southern Ocean. And what we've seen there is a reduced sea ice conditions. And
03:48 that means a reduced ability for krill to reproduce, which is their main pre-source.
03:53 And this shows us how long-term monitoring is critical to see changes in whale populations,
03:59 but also then related to the environmental conditions these whales depend upon.
04:04 In this delicate ecosystem, changes that are taking place thousands of kilometers away
04:10 are of vital importance to the whales and the people who live here.
04:15 [water flowing]
04:17 (water splashing)
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