Understanding patterns of fish movement is essential for researchers and park managers to weigh conservation and protection strategies by providing information on habitat use, seasonal migrations, and residency within protected areas. Cabo Pulmo National Park is perhaps the most successful marine protected area in terms of restoring populations of large endemic species to a region. The park through proper management and support has fostered the return of a growing population of Gulf Grouper (Mycteroperca jordani), which once was widespread throughout the Gulf of California. Given that this endemic species has experienced vast reductions in population size throughout the last century, Cabo Pulmo National Park presents an ideal and important setting to study patterns of movement and residency within the park. 
In October, researchers from El Centro para la Biodiversidad Marina y la Conservación, A.C. (CBMC), Scripps Institution of Oceanography of the University of California San Diego, California State University Northridge, and Texas A&M University teamed up to deploy an array of 12 acoustic telemetry receivers within Cabo Pulmo National Park and just outside its boundaries. These receivers are 100% passive and thus, do not interfere with the parks mission or operations nor harm the wellbeing of wild life. Over the course of a week, the researchers also externally tagged 19 Gulf Grouper with acoustic tags that transmit an inaudible acoustic signal for detection by the receiver array strategically placed throughout the park. The team utilized modified dart applicators and spear guns in a manner that prevented the need to capture individuals and thereby minimize stress and harm to the animals. This non-invasive methodology has been widely used to study movements of large groupers throughout the world, providing groundbreaking information with minimal implications on the wellbeing of the fish. 
The objective of the study is to document patterns of movement, site usage, and residency of Gulf Grouper inside and outside of Cabo Pulmo National Park through acoustic telemetry techniques. In the upcoming months and years, the 19 tagged Gulf Grouper will be detected by the acoustic receivers, revealing movement patterns indicative of the population in the Cabo Pulmo region. 
We are hopeful that we will observe seasonal migrations to specific locations during the spawning season and a high level of residency within the park. An outstanding question is whether Gulf Grouper remain within the park year-round or are solely seasonal visitors. We suspect that they reside within the park for a large portion of the year, and this study will allow for this important question to be answered. With such information, we will be able to bolster the already exceptional reputation of Cabo Pulmo National Park by stating its role in helping to restore a charismatic and culturally important endemic species to the waters within it once flourished.
The team of researchers:
Mark A. Steele, California State University
Thomas Tinhan, Texas A&M
Timothy J. Rowell, Scripps Institution of Oceanography
David Castro, Cabo Pulmo Divers
Juan José Cota Nieto, CBMC
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Authors: Timothy Rowell PhD student, SIO Timothy holds a master’s degree in Marine Sciences from the Universidad de Puerto Rico Mayagüez and is currently pursuing a PhD in Marine Biology at SIO under Dr. Octavio Aburto. His research involves using a suite of acoustic technologies to characterize fish spawning aggregations in the Gulf of California with an end goal of enhancing information available to stakeholders and resource managers. He is currently studying spawning aggregations of the Gulf Corvina (Golfo de Santa Clara) and Gulf Grouper (Cabo Pulmo) in partnership with the Gulf of California Marine Program. trowell@ucsd.edu
Juan José Cota Project Coordinator, CBMC José received his bachelor’s degree in marine biology from the Universidad Autónoma de Baja California Sur (UABCS) and has experience in the compilation of databases, ecosystem monitoring fieldwork, and fisheries monitoring surveys. He is the primary liaison between scientists and fishers in the fisheries programs in wetland areas like Bahia Magdalena and Punta Abreojos (B.C.S.), on the Pacific Ocean and on the Gulf of California including Golfo de Santa Clara (Sonora), San Felipe (B.C.), Espiritu Santo and La Partida Island (B.C.S.) juan.jose@gocmarineprogram.org
