Dolphin Family Tree

Ben photographing dolphins for later ID

GVI Kenya started with the Marine Mammal Conservation Program in 2006. Since then we have been studying the Indo-Pacific Bottlenose dolphin population dynamics of the area comprised by the Mpunguti Marine Reserve, Kisite Marine Park and the surrounding areas. We have identified 144 individuals of them 100 resident Bottlenose dolphins, which mean these individuals stay in the area year round.

On our research boat at sunrise 

We have constructed a Mother and Calf family tree based on the information we have collected from 2006 to 2009. We have recorded 27 mothers with 35 calves, meaning there are mothers that have had more than one calf in this time interval. With the pictures we have taken during the sightings we reconstructed the life history of the calves and we constructed a family tree. With all the information we have gathered we have been exploring further the population dynamics in the area; specifically the reproductive parameters. The birth rate tells us the number of calves born to known mothers of the population per number of dolphins in the population per year. This gives us an idea of the rate of population growth. It also lets us know the inter-birth interval, which means the time between the first and second calf of the same mother; this gives us a idea of how often they produce new calves and what is the average time of weaning. If their calf dies, the inter-birth intervals can be shorter. We  have also been exploring the calf mortality rate or the number of calves that die every year.

Dolphin ID 

 This gives us an indication of the health of the population in the area. Finally the birth seasonality that is the period of the year when most of the births take place. In some populations the birth seasonality can be related to water temperature and food availability.

Dolphin  family tree

Mónica Mariño- Marine staff

Dolphin Family Tree