Cabo San Lucas is a city at the far southern end of the Baja California Sur, Mexico. The area was remote and rural until the latter 20th century, when the Mexican government began to develop this area for main stream tourism due to the appealing climate and spectacular geography of the area. In recent years, sightings of pelagic species of sharks have been reported such as blue, smooth hammerhead, mako, silky and whale sharks, providing a fruitful platform for the study of these species.

Project overview:

Sharks are an essential part of the pelagic system as they act as top predators. Due to the deep canyons in the bay of Cabo San Lucas, it is possible to encounter pelagic species of sharks near the coast, which has given way to ecotourism activities seeking to observe these animals in their natural habitat using bait. Shark baiting is a technique used to attract sharks to the study area.

Overarching goals:

- Determine the relative abundance and species richness of pelagic shark species in Cabo San Lucas

- Understand the effect of the sea surface temperature, chlorophyll and currents on sharks

- Examine movement patterns and residency of sharks using acoustic and satellite telemetry

Activities:

1. Direct observation. Direct observations underwater by snorkeling or free diving, it is possible to determine the shark species, as well their sex and visual estimation of their size. Individual sharks can be identified using scars, markings and other coloration patterns.

2. Ultrasonic tagging. We affix ultrasonic transmitters on different species of sharks. We use ultrasonic tags, which emit a specific code that is recorded by acoustic receivers (listening stations). The transmitters are placed externally in the base of the dorsal fin with a Hawaiian sling used for spearfishing by SCUBA or free divers. Transmitters are also put internally in the intraperitoneal cavity through capture and a small surgery.

3. Listening stations. The stations consist of an underwater receiver VR2W (Vemco Ltd) that records acoustic pulses from the ultrasonic tags in a maximum range of 500 m. The stations are placed at depths between 20 and 40 meters at aggregation areas of sharks and pelagics. We have 1 listening station in Los Cabos region.

4. Satellite tagging. Satellite transmitters are designed to track the large-scale movements and behavior of fish and sharks. These transmitters are equipped with light, temperature, depth and accelerometer sensors, that either archives data in an on-board memory or transmits during deployment. We are deploying satellite transmitters in mako and smooth hammerhead sharks.

Other institutions participating in this Project:

- Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE-La Paz)

- México Azul, A.C.

Species under investigation: