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Humpback whale tagging in Tanzania

During September 2023, WCS and partners implemented a tagging project in Tanzania. The team was based at Fish Eagle Point, an eco-lodge north of Tanga and just south of the Kenyan border. Previous efforts to tag whales in Kenya in 2018 and 2019 were unsuccessful given either rough seas or an almost complete absence of whales (see previous #wherearethewhales articles). The team were anxious about renewing the effort, but a combination of working later in the season and moving the effort within the Pemba Channel offered more protection from the weather.

The 2023 season was good in terms of whale numbers but their availability for tagging from the Tanzanian site was limited. Three tags were deployed on mothers with calves. The mothers were named for Tanzanian peaks (Kilulu, Amani and Lengai). All the whales swam north initially, staying close to shore and crossing Kenya within a few days before continuing into Somali waters. The most northerly transmissions were recorded ~1000 km north of the Kenya-Somali border. Two of the tags stopped transmitting while the whales were still in Somali waters, though both have subsequently re-transmitted. Southbound routes appear to be very different, with one whale swimming to southern Madagascar (Fort Dauphin) and another swimming along the South African shelf to a point southwest of Cape Town before crossing to waters south of Bouvet Island, suggesting a minimum linear distance travelled of over 6500 km within 3 months. The hope is to continue the work in 2024, though is funding dependent.

Contributor: Tim Collins