Rare dolphin behaviour amazes scientists
MARINE biologists were stunned when they observed a tiny common dolphin calf swimming with a group of humpback dolphins in Mossel Bay last week.
Dr Tess Gridley, director of Sea Search and a research associate in the department of botany and zoology at Stellenbosch University, said this was highly unusual behaviour, and they had no idea whether the baby dolphin was lost, orphaned or even stolen.
They have been conducting field work in the area for the past week, looking for humpback dolphins for PhD student Sasha Dines’ research.
Sea Search uses a passive listening system to record the individually unique whistles of the dolphins. As these devices work 24 hours a day, they allow researchers to study the behaviour and abundance of endangered species such as the elusive humpback dolphin. In collaboration with Ocean Research they have deployed 24 recorders in Mossel Bay, forming a network of acoustic listening devices, and are collecting sightings and photographic records to determine which species are present in the bay during this study period.
“Humpback dolphins are South Africa’s most endangered marine mammal yet most people have never even heard of the species. While humpback dolphins live close to the shore in waters up to about 20 metres deep, they are very shy and only swim in small groups, making them hard to spot,” Dines explained.
Gridley said over the coming week they would be keeping an eye out for the baby common dolphin and would update their social media platforms with new sightings.
“Humpback dolphins can be identified through high-quality images of their dorsal fins. Some of the individuals identified this (last) week match the South African catalogue and were first seen in 2011.
“Photo-identification of humpback dolphins is a core part of the SouSA Consortium research – a collaborative project between multiple research groups to help generate scientific information to conserve the species,” she said.