Guadalupe Island is a volcanic island located 241 km off the west coast of the northern Baja California Peninsula, in the Pacific Ocean. The island has a rugged landscape with a total surface area of 244 km2. To the south of the main island three islets lie: Black Islet, El Toro and El Zapato, each with a surface area of approximately 1 km2. Since 2015 it has held national protection as a Biosphere Reserve. There is a great variety of fauna around Guadalupe Island such as the great white shark and populations of three pinnipeds that reproduce on the island (the elephant Northern seal, the California sea lion, and the Guadalupe's fur seal).

Project overview:

Isla Guadalupe has recently been recognized as one of the most important aggregation sites of great white sharks in the Eastern Pacific, where this species can be studied easily due to the clarity of water and seasonal predictability. The presence of white sharks in these aggregation sites make them vulnerable to their capture that could lead to a regional population decline. These sites are important for the monitoring of this species because individuals sharks can be easily recognized.

The overarching goals are:

- Understand movement patterns and residency of white sharks using acoustic and satellite telemetry

- Examine abundance of white sharks using underwater surveys and photo ID

- Understand fine-scale movements and habitat preferences of white sharks using acoustic tracking

- Understand population size and structure, and connectivity of white sharks using genetics

Activities:

1. Ultrasonic tagging. We place ultrasonic transmitters on the white shark. We use ultrasonic tags, which emit a specific code that is recorded by acoustic receivers (listening stations). The transmitters are placed externally into the base of the dorsal fin with a Hawaiian sling used for spearfishing by SCUBA and free divers or from a boat bringing the shark near the surface with a lure. 

2. Listening stations. The stations consist of an underwater receiver VR2W (Vemco Ltd) that record acoustic pulses from the ultrasonic tags in a maximum range of 500 m. The stations are placed at depths between 20 and 40 meters around the island.

3. Ultrasonic tracking. We follow several individual white sharks with an acoustic receiver and hydrophone.

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.

5. Underwater surveys and photo-ID. Surveys are performed from cages to observe the behavior of white sharks and to take photos of the markings and scars for the photoID catalog.

6. Genetics. We collect skin biopsies for genetic analysis by SCUBA and free diving or from a boat bringing the shark near the surface with a lure, to compare and identify differences between populations of white sharks of Guadalupe, California and Gulf of California.

Other institutions participating in this Project:

- ECOCIMATI, A.C.

- California State University, Long Beach

- Centro Interdisciplinario de Ciencias Marinas-IPN

- Florida International University

- Stanford University

Species under investigation: