Scripps Student Spotlight: Fernando Melendez Vazquez

PhD candidate follows passion to understand evolutionary biology of fishes

Fernando Melendez Vazquez is a fifth-year PhD candidate studying marine biology with a focus on fish evolutionary biology at Scripps Institution of Oceanography at UC San Diego. Vazquez grew up in Toa Baja, Puerto Rico, and received his undergraduate degree in biological oceanography at University of Puerto Rico, Mayagüez. At Scripps, he is a member of the Fish Evolution Lab and is advised by marine biologist Dahiana Arcila. Vazquez is currently investigating the evolution of unique traits across the fish tree of life. He was awarded the second-place title for his talk on fishes at the 2024 UC San Diego Grad SLAM competition and he received University of Oklahoma's Provost’s Award for Outstanding Engaged Teaching.

Fernando Melendez Vazquez standing with oarfish
Melendez Vazquez participating in the necropsy of an oarfish (Regalecus russelii) that washed ashore at La Jolla Cove.

explorations now (en): Why did you choose to attend Scripps?

Fernando Melendez Vazquez (FMV): Attending Scripps Institution of Oceanography was never part of my original plan—it felt like a place far beyond my reach. Coming from a background where access to resources and opportunities was limited, being here is truly a dream come true. Scripps is not only a hub of cutting-edge science but also a community of kind, brilliant and humble scientists and staff. It is both inspiring and humbling to be part of such an extraordinary institution.

en: What are you researching at Scripps?

FMV: My research focuses on the evolution of unique traits across the fish tree of life, particularly why only about 40 out of the approximately 36,000 species of fishes are endothermic, or warm-blooded. We are investigating the ecological and physiological drivers of this rare trait, as well as the genetic mechanisms responsible for it. Our findings have uncovered exciting insights, and a manuscript detailing this work is currently under review—fingers crossed for a successful outcome!

Fernando Melendez Vazquez scuba diving
Melendez Vazquez working as a scientific diver, conducting Caribbean fish surveys in Puerto Rico.

en: How did you become interested in science and your field of study?

FMV: Growing up as an only child in Puerto Rico, the ocean was my backyard. I fell in love with fishes at an early age, partly because my parents didn’t want to get me a pet, so the fishes in the sea became my "pets." I became captivated by snorkeling in the same spot and discovering something new each time. That fascination has stayed with me, driving my curiosity about the natural world and leading to my pursuit of marine biology as a career.

en: What’s life like as a Scripps student? Describe a typical day.

FMV: Life at Scripps is both challenging and rewarding. While everyone is conducting high-impact research, the atmosphere is incredibly supportive and welcoming. My typical day involves coding, managing large genomic datasets, exploring new analytical methods, and assisting my lab mates. As the most senior member of the lab, “the old one,” I take pride in mentoring others. I teach my lab mates skills that took me months to master so they can build on that knowledge and achieve even greater discoveries. An amazing group of senior members in the lab helped me when I first joined, and now I am proud to be able to do the same for others. Teaching and collaboration are central to science, and it’s deeply fulfilling to see my colleagues thrive.

Fernando Melendez Vazquez holding a specimen
Melendez Vazquez holding a juvenile swordfish (Xiphias gladius), now preserved at the Scripps Marine Vertebrate Collection.

en: What’s the most exciting thing about your work (in the field or in the lab)?

FMV: While I no longer dive as much as I used to, working with computer codes, tissue samples, and genomes has become equally exciting. I’ve had the privilege of visiting fish collections and seeing some of the rarest specimens in the world, which continues to fuel my passion. More than anything, I’ve found that the best part of marine biology isn’t the traveling or diving—it’s the people you do the science with. Throughout my career, I’ve been incredibly fortunate to work with some of the most amazing individuals, and they remain the most exciting part of my job. Bonus points go to the outreach activities and collection tours I give to visiting scholars and groups, which provide a unique opportunity to share my love of fishes and marine biology. I also love working with the Scripps Communications Office doing outreach videos about fishes and marine biology; they are all very creative and supportive when it comes to my crazy fish-based projects. 

en: Are there any role models or mentors who have helped you along the way?

FMV: My advisor, Dahiana Arcila, and her husband, Scripps marine biologist Ricardo Betancur-R., have been incredible mentors. Their passion for marine biology and their unwavering support for their students have been transformative. They push us to reach our full potential while genuinely caring about our success. I also owe a great deal to the late Dave Johnson, the former curator of fishes at the Smithsonian National Museum of Natural History, and Juan Cruz Motta, a professor in the Department of Marine Sciences at the University of Puerto Rico, Mayagüez, who both provided me with my first opportunities in marine biology. Their guidance helped shape the scientist I am today. I strive to make my mentors proud through my work.

Fernando Melendez Vazquez sharing science with students
Melendez Vazquez introducing students to marine biology at the Elementary Institute of Science's (EIS) research summer camp.

en: What are some of the challenges you face as a student?

FMV: Time is the biggest challenge. There’s so much I want to do, both inside and outside the lab, that it often feels like there aren’t enough hours in the day or days in the week. Balancing research, outreach, and personal growth is a constant juggling act.

en: What are your plans post-Scripps?

FMV: It’s hard to have a fixed plan in marine biology because the field is full of unexpected opportunities. However, I hope to pursue a museum-related career where I can combine my passions for science communication, community work, education, and outreach. I want to continue contributing to conservation efforts, applying the skills I’ve gained during my PhD. I also see myself supporting my current lab as they move forward with exciting new projects after my departure as they have truly become part of my family, and I wish to continue helping as much as I can. 

You can find The Fish Evolution Lab on X (formerly Twitter) @FishEvoLabSIO.

About Scripps Oceanography

Scripps Institution of Oceanography at the University of California San Diego is one of the world’s most important centers for global earth science research and education. In its second century of discovery, Scripps scientists work to understand and protect the planet, and investigate our oceans, Earth, and atmosphere to find solutions to our greatest environmental challenges. Scripps offers unparalleled education and training for the next generation of scientific and environmental leaders through its undergraduate, master’s and doctoral programs. The institution also operates a fleet of four oceanographic research vessels, and is home to Birch Aquarium at Scripps, the public exploration center that welcomes 500,000 visitors each year.

About UC San Diego

At the University of California San Diego, we embrace a culture of exploration and experimentation. Established in 1960, UC San Diego has been shaped by exceptional scholars who aren’t afraid to look deeper, challenge expectations and redefine conventional wisdom. As one of the top 15 research universities in the world, we are driving innovation and change to advance society, propel economic growth and make our world a better place. Learn more at ucsd.edu.

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