ADVANCES IN BULL SHARK TAGGING IN QUINTANA ROO, MEXICO.
Text written by Laura Torres
Revised by Biol. Mauricio Hoyos
Dr. Mauricio Hoyos
Well-known shark researcher Dr. Mauricio Hoyos is back in Playa del Carmen to continue his work with our local bull shark population. In the 2011/2012 shark season we have entered into the second phase of the Playa del Carmen bull shark study - in addition to our initial goal of collecting 30 individual biopsies to carry out genetic and stable isotope analysis, we are also marking sharks with GPS and ultrasonic transmitters to determine their range and movement.
Through the genetic studies we will determine if the Playa del Carmen bull shark population is related to other nearby bull shark populations. Stable isotopes analysis will provide us with a more complete picture of the individual species that make our local bull shark's diet.
Since November 2010 we have obtained 14 biopsies.
Dr. Mauricio Hoyos performs a biopsy
The ultrasonic tags we are using can be attached to the animal internally or externally and emit a pulse of sound outside of the sharks' hearing range so as not to interfere with their natural behavior. Once activated, the ultrasonic signal is picked up by a portable receiver (VR100) aboard one of our research boats. The research or chase boat uses these signals to follow the shark from a distance. Once the tagged shark has become relatively stationary a submersible receiver is lowered into the water and anchored. This receiver gives a more precise picture of the sharks home range, movement habits and habitat.
Internal and external ultrasonic tags, VR2W receiver and satellite tag
VR100 portable receiver
Dr. Mauricio Hoyos attaches an internal ultrasonic tag
LOCATION OF SUBMERSIBLE RECEIVERS
With the generous help of CONANP and RAZONATURA we have installed three submersible receivers in the following areas: Playa del Carmen, Canún and Punta Allen. Five additional submersible receivers will be installed in the following areas in the near future: Laguna de Yalahau, Chinchorro, Punta Herero, Xcalac and Bahia de Chetumal.
Divers who find these receivers should not touch them. If you observe something that may affect the functionality of the receiver please contact us immediately.
Submersible receiver label with S.O.S. contact number
The data generated by our network of stationary receivers and the tagged sharks will contribute to a better understanding of the life cycle and habitat of the bull sharks that visit Playa del Carmen each winter. Through collection and analysis of this data we hope to establish the location of shark nurseries - where female bull sharks go to give birth - and the time of year in which they give birth. The shark location data will also be used to help Protección Civil (Mexico's federal civil safety organization) determine if recent reports of sharks near popular tourist beaches are based in fact. This same data can be used to analyze potential risk and avert possible accidents and calls for a reactionary shark cull should a shark-human incident occur.
We are using SPOT satellite tags. These tags are equipped with a sensor that activates the onboard antenna and transmits collected data each time the shark's dorsal fin breaks the surface of the water. The tag records location data around the clock and will help us follow the sharks' movements over extended periods of time and larger geographical areas. This expanded data will help us follow migration patterns of the Playa del Carmen bull shark population.
Our first satellite tag was attached to a female bull shark on February 1, of this year. The tag is transmitting well; our first transmission came from the waters just off Playa del Carmen.
Jorge Loría attaching a satellite tag
Alex Antoniou and Jorge Loría double check the tag before releasing this bull shark
We hope that the accurate, scientific data collected in this study will help national and international decision makers form solid management and conservation policy to ensure the continued survival and abundance of this invaluable species.
Special thanks to Alex Antoniou, director of the nonprofit "Fins Attached" , based out of Colorado Springs, Colorado. Alex and a student group with Fins Attached brought us our first Satellite tag and dived with the bull sharks in Playa del Carmen, getting to know these magnificent creatures up close and personal.
Be part of the solution with Phantom Divers / Saving Our Sharks a.c. and support the conservation of one of our planet's most important species.
The Fins Attached group on their recent visit to Phantom Divers, Riviera Maya, Mexico. January 2012.
Want to do something to help the bull shark population in Playa del Carmen and sharks worldwide? Check out www.savingoursharks.com and www.phantomdivers.com to donate and learn more about what you can do to help out at home. Your much needed donation will fund shark research and conservation that makes a difference!
DONATIONS: SAVING OUR SHARKS AC (SOS)
This video shows how we attach the satellite and ultrasonic tags. Special thanks to Dr. Mauricio Hoyos and Roberto Navarro (fishing industry) for their invaluable help in this project.