Protecting marine mammals

Tuesday, September 15th, 2020 00:00 |
Sea mammals.

Keeping an eye on dolphins and whales is important to make sure perils such as human activities and natural threats impact their existence.

Jasmine Atieno @sparkleMine

Among the attractions to the Kenyan coast, especially Watamu is the humpback whales, a species of animals that travel from as far as Antarctica, covering over 4,000km to mate and calve in the warm Indian Ocean waters.

Other species that enjoy these waters are the minke whale, Bryde’s whale, the toothed sperm whales, the killer whale, the false killer whale, the melon headed whales and most recently the blue whale.

Besides whales, the Kenyan coast is also the abode of dolphins. More details on the dolphins indicate that five species of dolphins have been sighted within Kenya’s marine waters: the common dolphine, Indo-Pacific bottlenose, Indo-Pacific humpback, spinner, and the spotted dolphins.

Three other species, the striped dolphin, Fraser’s dolphin, and Risso’s dolphin are also reported to visit. 

These two animals work well together, according to Marine Scientist at Kenya Marine and Fisheries Research Institute (KMFRI), Dr Jacqueline Uku.

“Studies into social behaviours of whales and dolphins revealed they have developed sophisticated social behaviour amongst themselves including complex alliance relationships, social transfer of hunting techniques (teaching how to hunt and using tools), cooperative hunting; “talking” to each other and using “name” recognition.

They also exhibit interspecific cooperation with humans and other species and alloparenting— looking after youngsters that aren’t their own, and social play,” she explains. 

However they both face natural and human induced threats such predation by large sharks and killer whales. 

“Human-induced threats include entanglement in fishing gear, ship strikes, habitat degradation, oil and gas development, and climate change.

Whales are also affected greatly by ocean noise from ships,” adds Dr Uku. 

KMFRI, through the platform of opportunity for marine mammal sightings provided by RV Mtafiti, a research boat, has facilitated information on occurrence and distribution patterns.

It is also part of the Kenya Marine Mammal Network, a collaborative group that identifies marine mammal hotspots to increase protection. 

Michael Mwangombe, project coordinator, Kenya Marine Mammal Research and Conservation, says these mammals also experience acoustic pollution, habitat loss and by-catch (unintentional catch).

“Whale and dolphins rely on sound for communication, mating, foraging, and migration. Addition of loud noises from ships, sonar, drilling rigs, and other human sources can distort messages sent by marine mammals.

Acoustic noise pollution prevents these mammals from detecting approaching ships or fishing nets, adding to the risk of being killed.

By and large, loss of habitat is the biggest threat to their livelihoods. Habitat loss can occur as the result of pollution, changes in ecosystems, ship traffic, and a number of other human-related problems. By-catch leads to their deaths,” he shares. 

Critical numbers

Humpback whales were first seen in Kenya by fishermen 30 years ago, in single numbers during the migration season usually between July and September.

Numbers have steadily increased over the decades due to the ban on whale hunting in 1986. 

According to Animal Welfare Institute, commercial whaling nearly wiped out the populations of these sea mammals in the world.

The approximate number of humpback whales in the Southern Hemisphere is at least 80,000.  

From 2011, Kenya and the International Whaling commission have recognised the importance of humpback whales not only from their ecological importance, but also economic value, with the rise in the whale watching industry globally.

They are, however, on the lookout for the Indian Ocean humpback dolphins, which are listed in the International Union for Conservation of Nature Red List as Endangered because of their close interactions with humans.

Research indicates their preference to reef areas and to specific fish found in these areas make them more susceptible to interference from humans and their activities.

As at 2016, the population was at 10,000 individuals, with scientists concerned that the number of mature dolphins is continously decreasing.

Sightings and surveys

Since the establishment of the Kenya Marine Mammal Network in May 2011 until December 2019, a total of 1,511 sightings were reported from 105 collaborators.

The top three reported species until 2019 are the Indo-Pacific bottlenose dolphin at 657, the humpback whale at 644 and Indo-Pacific humpback dolphins at 58.

However, there was a heavy decrease with unknown causes of humpback whales between 2018 and 2019 from 197 to 35.

Since 2019, Kenya Wildlife Service in Malindi-Watamu Marine Protected Area led by Senior Warden Jane Gitau and Warden Dadley Tsinganyiu have been conducting  boat surveys, studying species, populations and distribution, including photo identification of individuals.

There have also been collaborations between various stakeholders in conservation throug research, monitoring and education.

More on Lifestyle