Bottlenose dolphin module

The study area

The Gulf of California is a hotspot for cetacean species: 8 baleen whales and 23 odontocete species occur there, representing 40 % of the global diversity of this taxon.

Approximately 200 km north of the tip of the Baja California, at the southern edge of the Gulf, is positioned La Paz. La Paz is a fast-growing state capital and it is located at the entrance of the Ensenada de La Paz, a natural lagoon that accommodates the biggest mangrove areas along the east coast of Baja California. This area is highly important for the foraging and nursery of fish, birds, marine turtles, and marine mammals.

In particular, bottlenose dolphins (Tursiops truncatus) enter and use the area to forage and nurse their calves constantly.

The species:

Bottlenose dolphin is a cosmopolite species and it is one of the best studied marine mammals in the world.

The knowledge of their ecology in the Ensenada is based primarily on visual methods. This means that the acquisition of data is light dependent and there is not information about the use of the area by night.

Within the channel that connects the Ensenada with Bahía de La Paz lies the fisheries harbor, from where fishery and touristic boats leave every day in great number. Due to this anthropogenic impact, it is highly possible that dolphins enter the area as well during night time, when the disturbance is lower.

Thanks to the present project, a net of passive acoustic stations will be deployed to study the distribution and habitat use of the bottlenose dolphins.

For the first time in Mexican waters, the presence of this species will be quantified and the diel pattern evaluated.

Moreover, biological samples will be taken continuously to estimate the food web composition and bottlenose’s prey distribution and growth.

Stable isotopes and fatty acid will be analyzed from each sample.

Additionally, satellite data will give an indication of how physical variables work in the Ensenada and Bahía de La Paz.

Finally, model will be computed to show which variables (biological and physical) affect the predators’ distribution the most.