Intern Spotlight: Adam Mercer
Updated: Apr 7
Over the past few years, almost a dozen undergraduates and postgraduates from UC Santa Cruz have worked with me on plankton sorting and larval fish identification. Larval fish identification involves long hours of staring at specimens through microscopes, counting tiny pigment spots and muscle bands. Over the past three quarters, Adam has become a larval fish master and one of my star identifiers! He graduated from UCSC in 2020 with a degree in marine biology. He recently finished identifying all the larvae from an especially large sample (several thousand individuals) so I decided it was a good moment to sit down and ask him about his work.
What is your favorite fish that you have found?
"I have to say that the Syngnathidae larvae [the family of seahorses and pipefishes] were the most exotic and cool to look at. But the varying pigmentation patterns of different stage Atherinidae [the family of silversides] are the most eye-catching."
"My favorite larval fish is one of the most common I found though. Tridentiger trigonocephalus had us stumped for the longest time because our larval identification guide didn't have great descriptions or illustrations of some of the intermediate ages. So uncovering their identity is a source of pride and feels really cool to find something that was less documented."
What's one thing you've learned since starting working on this project?
"Since working in the Mehta lab, some species that once seemed so alien have become familiar enough that I can see differences even between individuals."
What has been the most difficult part of identifying larvae?
"The most difficult part of identifying larvae is not assuming what a specimen is just from seeing similar ones [or finding many of the same species in a sample]. Also, I have to remind myself that I can't spend all my time uncovering one cool mystery fish when there are hundreds of common ones that also need to be identified."
How has your experience working on the larval fish project influenced your career goals?
"I have really enjoyed the experience I have gotten in the Mehta lab, and the research we have accomplished has encouraged my desire to pursue a career in marine research. Sorting fish isn’t glamorous, but getting to input all my identifications at the end of each day makes me appreciate the sheer variety of various larval stages and species we're seeing. It's really interesting and satisfying to look over and think, “huh, there must be a reason why we are seeing older fish in one season/year but younger individuals at a different season/year.” I can talk ad nauseam about how I enjoy working in the lab, but one of my big motivators is that I’m curious about what the data will show us. It’s like a puzzle, and it’s shaping into a picture that no one has really seen or looked into before."